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Broad-scale Impacts of Fire

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Green ash trees scarred by fire are vulnerable to postfire
fungal infection and decay. From 8 locations on
the Mississippi River floodplain of Louisiana and Mississippi, researchers
located 122 fire-scarred green ash trees. Fire scars were between 6 and 54 years old,
and 113 of the 122 trees surveyed had heart rot. The decay rate
calculated from 5 trees was 3.5 to 3.7
inches (8.9-9.4 cm)/year. Decay progressed up from the fire-damaged area [283].

Broad-scale Impacts of Plant Response to Fire

provided by Fire Effects Information System Plants
More info for the terms: basal area, density, forest, frequency, fuel, fuel moisture, grassland, hardwood, litter, natural, relative density, relative frequency, seed, severity, stand-replacing fire, tree, wildfire, woodland

The majority of literature regarding green ash and fire reports on just early
postfire responses. Based on these short-term studies, it is generally true that
the density of green ash trees, saplings, and/or seedlings is lower on burned
than unburned sites but that the number of green ash sprouts is greater on burned
than unburned sites. More information is needed on the long-term recovery of
green ash following fire.

Fires in bur oak woodlands:
Many have studied the recovery of green ash following fire in bur
oak-dominated woodland habitats.
In the following studies, green ash recovered from fire by
vegetative sprouting and perhaps seedling growth, but
typically green ash density was greater on unburned than burned plots. In
eastern Kansas, the pre-
and postfire densities of green ash saplings and seedlings*
were compared following 2 spring
prescription fires. Fires burned in late April 1984 and early April 1985. At the
time of the 1984 fire, air temperature was 61 °F
(16 °C), wind speed was 11 feet/s (3.3 m/s), and relative humidity was 21%.
During the 1985 fire,
the air temperature was 70 °F (21 °C), wind speed was 7.2 feet/s (2.2 m/s),
and relative humidity was 44%.
Both fires moved slowly, rarely exceeding 3 to 7 feet/min (1-2 m/min), and had low flame
heights, typically below 1.6 feet (0.5 m). The fires burned over
90% of the area but did
not reach into the canopy. Fires killed all green ash saplings, but seedlings
quickly emerged on burned sites. The 1984 fire encouraged
green ash seedling growth. The pre- and early postfire green ash
sapling and seedling densities (number/ha) are summarized below [2,3].

 
Prefire (1983)
Postfire (1984)
Postfire (1985)
saplings 100 0 0
seedlings* 250 900 150

*"Seedlings" represents a small stem size class.
Term does not imply or dispute origin from seed.

In mid-April of 1987, bur oak-dominated woodlands
were burned in the foothills of South Dakota's Black Hills.
Livestock grazing was excluded a year before burning. Bur oak density before the
fire was 1,097 trees/ha and
basal area was 39 m²/ha. The prefire density and basal area of other overstory species
including fireberry hawthorn (Crataegus
rotundifolia), green ash, and hophornbeam were 200 to 245 trees/ha and less than 1
m²/ha, respectively. The
fine fuel load was 589.6 kg/ha, fine fuel moisture was 14.6%, heavy (100-hour)
fuel moisture was 11.2%, and soil moisture was 37.8% before burning. Temperatures were
from 61 to 70 °F (16-21 °C), relative humidity ranged from 10% and 25%, and wind
speeds ranged from 6 to 10 miles/hour (9-16 km/h) at the time
of the fire. Fire spread was slow, between 0.01 and
0.09 m/s. Researchers noted that fewer than 5% of any tree species were top-killed. The number of green ash sprouts produced on burned sites was
significantly greater than that on unburned plots (p≤0.1), but green ash density
was greater on unburned than burned plots. The number of sprouts produced per green ash tree increased with
increasing scorch height, but sprout density decreased with increasing slope [256].

Fires in a red and white pine plantation:
Single and biennial fires in the
W. K. Kellogg Experimental Forest of Kalamazoo County, Michigan, killed all
large seedlings and saplings, but small seedlings* were present on
singly and biennially burned sites. Prescription
fires burned on 2 sites, one burned just once and the other burned biennially (2
fires in 2 years), in a mixed red and white pine plantation. The single fire
burned in May 1991, and the biennial fires burned in May 1991 and May 1993.
Postfire vegetation was measured in the 1994 and 1995 growing seasons. All fires
were strip fires that produced flame lengths less than 3 feet (1 m), and fewer
than 10 conifers lost over 80% of their needles to scorching. The understory was
almost completely top-killed, with only a few small unburned portions. In even
the most severely burned areas, nothing beyond the top 0.59 inch (1.5 cm) litter
layer was consumed. No downed woody fuels greater than 0.98 inch (2.5 cm) were
consumed either. The single fire and biennial fires killed all green ash
saplings and large seedlings. However, small green ash seedlings appeared on
both treatment sites. Researchers burned biennial plots again in 1995 and
reported that no green ash seedlings or sprouts survived the 3rd fire. The coverage of
small green ash seedlings, and density of large seedlings and saplings following
fire, are reported below [215]. See the
Effects of surface fires in a mixed red and eastern white pine stand in Michigan

Research Project Summary for a more detailed description of this study.

Size class Measurement Unburned Single fire Biennial fires
Large seedlings*
(>1 m tall,
≤1.9 cm dbh)¹ density (number/ha) 333 0 ----
Saplings
(2 to 5.9 cm dbh)¹ density (number/ha) 56 0 ----
Small ash (Fraxinus spp.) seedlings*
(<1 m)² cover
(%) 0.23 0.28 0.24

*"Seedlings" represents a small stem size class. Term does not imply or dispute
origin from seed.

¹Density counts made in 1995.

²Coverage assessed in 1994.

Fires in woody draws:
The following studies indicate that green ash recovers from fire chiefly through
vegetative sprouting, and that this regenerating strategy allows green ash to
survive even multiple fires. Green ash recovery following fire was
studied in 7 eastern Montana green ash woodland sites.
Sites had burned in August and
September from 1988 to 1998 and were assessed in 2001. Tree mortality was as high as
80%. There were more, larger sprouts but fewer
seedlings and a greater number of dead green ash trees on burned than unburned
sites. There was also a positive
relationship between burn severity and the number of sprouts produced;
however, burn severity was not
reported by site in this report. The low number of seedlings on
burned sites suggests that fire killed green ash seed on or near the soil surface,
making seedling recruitment dependent on seed producing trees, a lot of which
were killed by fire. The average number of sprouts, seedlings, and dead
trees on unburned and burned sites is presented below. Postburn data were
collected 3 to 13 years after fire [185].

Status Burned Unburned
Sprouts/0.25-ha plot 4.3 1.3
Diameter of sprouts (mm) 1.56 0.84
Seedlings/plot 1.8 8.1
Dead trees/plot 1.43 0.14

In southwestern Minnesota's Pipestone National Monument, spring prescription
fires burned each year from 1983 to 1987. Fires were ignited once grasses had
"initiated good growth." Most fires burned in early to late April, except the
1987 fire that burned in early May. Fires were considered low or moderate
severity. The 1983 fire burned when fuel loads were highest.
The burned area was dissected by a woody draw dominated by green
ash, Tatarian honeysuckle (Lonicera tatarica), and common buckthorn. Upslope
from the woody draw was a mixed short- and mid-grass prairie, and downslope was a
tallgrass prairie. The coverage of green ash increased as time since fire
increased, to a maximum of 4.9% [29].

Green ash density was greater on burned than unburned sites
after an October 1976 wildfire that burned approximately 6,000 acres (2,000 ha) of
southwestern North Dakota's Little Missouri
Badlands. Green ash occurred in lower portions of a drainage that was bordered by
a mixed-grass prairie of western wheatgrass, blue grama, and
little bluestem. Dry conditions were reported for 1976, but no other data
regarding fire behavior or severity were provided. Green ash tree
density was 0.05 stem/m² on
unburned sites. On burned sites the 1st postfire year, green ash averaged 0.1
stem/m² and
0.3 stem/m² the 2nd postfire year [318].

Fires in bottomland forests:
In bottomland forests, fire typically top-kills green ash trees. In Marshall County,
Oklahoma, a prescription fire burned a little bluestem-dominated grassland
invaded by woody vegetation from the bordering green ash-black willow-eastern cottonwood bottomland
forest community. The fire burned on 14 July 1979 when winds were 15 inches/s (37cm/s), air
temperature was 95 °F (35 °C), and relative humidity was
58%. The prefire density of green ash was 167 stems/ha. No green ash stems were
present in the 1st postfire year [5].

Managers in Cutoff Creek Wildlife Management Area in Drew County, Arkansas,
compared unburned, once burned, and multiple-burn sites in bottomland hardwood forest
openings. The objective of burning was to maintain open wildlife habitat.
Sites burned multiple times experienced fire up to 6 times in 14 years.
Fire conditions, severity, or behavior were not described. The authors report
that the last fire in all openings occurred in 1997, and the data provided below
were published in 1999 [276]. Likely, postfire measurements occurred in the 1st
postfire year. There were fewer green ash seedlings in burned
areas, but seedlings in burned areas produced more sprouts than those in
unburned areas. The single fire killed most green ash trees, and multiple fires
killed all green ash trees. Interestingly, the number of green ash seedlings 1
to 3 feet (0.3-0.9 m) tall was greater on sites burned in multiple fires than on sites
burned only once. However, some sites burned in multiple fires may have had
greater recovery time than sites burned just once. The study results are
summarized below [276].

  Unburned Burned once Burned multiple times
Seedlings (<1 foot tall)/acre 22 0 0
Seedlings (1-3 feet tall)/acre 134 25 120
Seedlings (>3 feet tall, ≤ 0.5 inch dbh)/acre 431 34 145
Trees (>0.5 inch dbh tall)/acre 231 3 0
Mean seedling height (cm) 109 100 106
Mean number of sprouts per seedling 1.4 5 6.6

Fires in deciduous forests:
Based on the following research, green ash may not recover following multiple
fires, and recovery from fires burned in drought conditions may be slow in
temperate deciduous forests. Researchers
indicate that green ash was eliminated from sites burned 3 times in a deciduous forest in east-central Minnesota's Cedar Creek Natural History Area.
Fires burned in 1992, 1997, and 2000. As of 2001, green ash was no longer
present on burned sites. No information regarding fire seasonality or
severity was provided [75].

In the Turtle Mountains of North Dakota, researchers compared burned and
adjacent unburned sites 72 years following a stand-replacing fire that burned during
drought conditions. Green ash density, basal area, and importance values were
greater on unburned than burned sites. The number and size of postfire green ash
trees differed by site. Burned site 1 had more green ash trees and
undulating topography and loam soils, but trees were larger on burned site 2,
which had level terrain
and clay soils. Data from the study are
provided below
[224].

Site Unburned Burn 1
silty-clay loam Burn 2
heavy silt, clay
Relative frequency (%) 16.4 17 12.3
Relative density (%) 13.5 9.8 5.1
Relative basal area (%) 8.2 2.6 3.5
Importance (%)* 12.7 9.8 7

*Average of the relative frequency, density, and basal area

Distribution

provided by Fire Effects Information System Plants
Green ash is widely distributed in the United States and Canada. Its native
range extends from Nova Scotia west to southeastern Alberta and south through
central Montana to southeastern Texas, Florida, and the east coast [167,269]. Green ash is nonnative
in Utah and Colorado, where it has escaped as an ornamental
and colonized [302,304]. Some suggest that green ash
trees along the Clark Fork River in western Montana are also escaped ornamentals [177]. The The US Geological Survey
provides a distributional map of green ash.

Fire Ecology

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More info for the terms: cover, cover type, fire frequency, fire regime, fire severity, fire suppression, forest, frequency, fuel, grassland, hardwood, litter, root crown, seed, severity, swamp, top-kill

Fire adaptations: Green ash trees
sprout from the root crown following top-kill [183,247,248]. However, green ash
may survive low-severity fires. Fire-scarred green ash trees have
been studied in the Mississippi River
delta by Hepting [140] and Toole [283]. Green ash may also produce epicormic
sprouts when fires scorch but do not kill the main trunk.

The high seed production potential [38,308], wind-dispersed seed [22,167],
and wide ecological tolerance of seedlings [63,162] make green ash
a likely candidate for off-site colonization of burned sites. It is noted, however, that
green ash seed on or near the soil surface does not survive fire [185].

FIRE REGIMES:
A wide range of FIRE REGIMES is described for green ash habitats. The savannah-like
prairie-forest ecotones are more likely to experience frequent fire than are wet
bottomland deciduous habitats. However, a variety of
anthropogenic, climatic, and environmental conditions have affected and continue
to affect the fire ecology of green ash habitats.

Prairie-forest ecotones:
Many have suggested that
fire may be important in woody draws and riparian areas of the Great Plains; however,
the preEuropean settlement fire frequency of these habitats is largely unknown.
Although riparian draws
of the northern Great Plains are typically moister, greener, and more humid than
surrounding grasslands, the narrow size of these draws, coupled with the
high frequency of grassland fires before active fire suppression in the area,
suggests that fires did burn these areas
especially during drought conditions [255]. Other researchers have
suggested that green ash/chokecherry habitats are fire adapted because most
associated species display some fire tolerance and/or postfire sprouting ability [133]. Based
on research that suggested low-severity
fires promoted regeneration by thinning stands and promoting sprouting, Lesica [183] reasoned
that some level of fire was important to the maintenance of upland green ash stands
in eastern Montana.
In a study designed to test his hypothesis, Lesica [185] found
more sprouts, fewer seedlings, and more dead trees on burned sites than on similar
nearby unburned
sites. All sites burned in wildland fires. The low number of seedlings on burned sites suggested that fire killed
green ash seed on or near the soil surface, making seedling recruitment dependent
on seed-producing trees, a lot of which were killed by fire. However, green ash
sprout production was greater on burned sites suggesting that asexual
reproduction may compensate for a temporary lack of sexual recruitment. For more
information on this and other green ash fire studies, see the Fire Effects
section.

In bur oak-dominated gallery forests of eastern Kansas, land surveys and
aerial photograph data indicate that these forests occupied less area in the
mid-1800s than they did in the 1900s. Increased woody vegetation in
tallgrass prairies was attributed to decreased fire frequency and/or fire
severity in postsettlement time [2]. Heinselman [138]
suggests that quaking aspen parklands of northwestern Minnesota and west-central Canada
that occur where southern boreal forests meet prairies experienced
low-severity fires every 2 to 15 years in presettlement
time. Fire severity likely varied with forest age
and time since fire in the savannah-like vegetation where quaking aspen, balsam poplar, bur oak, green ash,
and boxelder are typical. In the bottomlands of Lost
Creek in the Schultz Prairie of south-central Nebraska, green ash occupies
savannah-like riparian vegetation. Woody vegetation in this area is thought to
have increased with a decreased fire frequency in this prairie region [240].

Eastern deciduous forests:
Most researchers indicate that fire is rare in moist eastern deciduous forest habitats. In
hardwood forests of the Great Lakes States, Frelich [97] described fires as
uncommon in presettlement time and at present. The Big Woods of Minnesota are densely shaded
and dominated by elm, basswood, sugar maple, and
ash. It supports a sparse
understory, maintains an open canopy, and experiences high humidity
levels. This environment does not carry fire well and "limits the
destructive potential of fires that may occur"
in the Big Woods [125]. Extensive studies of the vegetation, environmental site
characteristics, and past disturbances in Riding Mountain National Park,
Manitoba, revealed that the green ash-American elm-boxelder eastern
deciduous forest type occurred almost exclusively in infrequently burned areas
[53]. The sugarberry-American elm-green ash forest cover type that occupies
floodplain habitats in the southeastern and south-central United
States reportedly experiences mixed or
stand-replacing fires at frequencies of less than 35 to 200 years. The low fuel loads and moist, humid
conditions associated with this forest type suggest that low-severity fires are most
typical [298].

Bottomland hardwood forests:
The following studies indicate that the fire ecology of bottomland
hardwood forests changed
with the level of anthropogenic influence. After studying landscape
and environmental factors together with historical
records and fire scar data, Frost [98] estimated that seasonally wet
southeastern bottomland forests where baldcypress, sweetgum, red maple, swamp
tupelo, swamp chestnut oak, and green ash occur
burned at 100- to 300-year intervals in presettlement time.
Fire severity was likely low, but fires may have damaged exposed roots
and scarred adult trees.
Green ash may also inhabit forests with relatively fire-proof characteristics
that include
saturated soils, standing water, and an absence of understory vegetation. In
these fire-protected forests,
any evidence of past fire
is completely lacking [98]. After settlement of the Mississippi River Delta,
however, Hepting [140]
claimed that hardwood forests often burned. In dry years in this area, fires
were recorded in 1899 to 1900; 1910 to 1911; 1916 to 1917; 1917 to 1918; and 1924
to 1925. From 1900
to 1930, at least some part of the Mississippi River Delta burned
each year. Fire fuel was leaf litter that, when present in a 1-year accumulation,
was sufficient
to produce "hot" fires in dry weather conditions.
However, the ignition source of
these fires was primarily anthropogenic. Ignition sources included hunters using
fire to flush game animals, farmers clearing land with fires that often escaped,
and woodsmen
leaving fires unattended.

The following table provides fire return intervals for plant communities and
ecosystems where green ash is important. Find further fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".

Community or Ecosystem Dominant Species Fire Return Interval Range (years)
maple-beech-birch Acer-Fagus-Betula spp. >1,000
silver maple-American elm A. saccharinum-Ulmus americana <5 to 200
sugar maple A. saccharum >1,000
sugar maple-basswood A. saccharum-Tilia americana >1,000
sugarberry-America elm-green ash Celtis laevigata-U. americana-Fraxinus pennsylvanica <35 to 200
Atlantic white-cedar Chamaecyparis thyoides 35 to >200
beech-sugar maple Fagus spp.-A. saccharum >1,000
black ash Fraxinus nigra 298]
green ash F. pennsylvanica <35 to >300 [98,298]
Rocky Mountain juniper Juniperus scopulorum <35 [220]
yellow-poplar Liriodendron tulipifera <35 [298]
shortleaf pine Pinus echinata 2-15
shortleaf pine-oak P. echinata-Quercus spp. <10
eastern white pine-northern red oak-red maple P. strobus-Q. rubra-A. rubrum 35-200
loblolly-shortleaf pine P. taeda-P. echinata 10 to <35
sycamore-sweetgum-American elm Platanus occidentalis-Liquidambar styraciflua-U. americana <35 to 200 [298]
eastern cottonwood Populus deltoides <35 to 200 [220]
aspen-birch P. tremuloides-Betula papyrifera 35-200 [83,298]
quaking aspen (west of the Great Plains) P. tremuloides 7-120 [16,127,200]
black cherry-sugar maple Prunus serotina-A. saccharum >1,000
oak-hickory Quercus-Carya spp. <35
northeastern oak-pine Quercus-Pinus spp. 10 to <35 [298]
oak-gum-cypress Quercus-Nyssa spp.-Taxodium distichum 35 to >200 [210]
southeastern oak-pine Quercus-Pinus spp. <10
white oak-black oak-northern red oak Q. alba-Q. velutina-Q. rubra <35
northern pin oak Q. ellipsoidalis <35
bur oak Q. macrocarpa <10 [298]
oak savanna Q. macrocarpa/Andropogon gerardii-Schizachyrium scoparium 2-14 [220,298]
chestnut oak Q. prinus 3-8
northern red oak Q. rubra 10 to <35
black oak Q. velutina <35 [298]
baldcypress T. distichum var. distichum 100 to >300
pondcypress T. distichum var. nutans <35 [210]
elm-ash-cottonwood Ulmus-Fraxinus-Populus spp. <35 to 200 [83,298]

Fire Management Considerations

provided by Fire Effects Information System Plants
More info for the terms: fire severity, prescribed fire, severity

The information on green ash and fire concentrates heavily on only early
postfire effects. Very few studies have
investigated both early and later postfire recovery of green ash. The above
information, however, does suggest that green ash is fire sensitive. An
evaluation of the utility or harm of prescribed fire in green ash
communities requires more
site and condition specific information than is currently available.
The wide range occupied by green ash is
not matched with a wide range of fire studies, and likely fire effects depend on
sites occupied, fire season, fire severity, and time since last fire.



Myers and Buchman [209] recommend against the use of prescribed fire as a tool in
elm-ash-cottonwood forests of the north-central United States if managing stands
for timber production. They suggest
that the genera are fire sensitive. Surface fires easily kill seedlings and
saplings and wound mature elm,
ash, and cottonwood trees.

Habitat: Cover Types

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More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the terms: cover, swamp

SAF COVER TYPES [90]:





14 Northern pin oak

15 Red pine

16 Aspen

20 White pine-northern red oak-red maple

21 Eastern white pine

26 Sugar maple-basswood

27 Sugar maple

39 Black ash-American elm-red maple

40 Post oak-blackjack oak

42 Bur oak

44 Chestnut oak

52 White oak-black oak-northern red oak

55 Northern red oak

57 Yellow-poplar

59 Yellow-poplar-white oak-northern red oak

60 Beech-sugar maple

61 River birch-sycamore

62 Silver maple-American elm

63 Cottonwood

64 Sassafras-persimmon

65 Pin oak-sweetgum

75 Shortleaf pine

81 Loblolly pine

82 Loblolly pine-hardwood

87 Sweetgum-yellow-poplar

88 Willow oak-water oak-diamondleaf (laurel) oak

89 Live oak

91 Swamp chestnut oak-cherrybark oak

92 Sweetgum-willow oak

93 Sugarberry-American elm-green ash

94 Sycamore-sweetgum-American elm

95 Black willow

96 Overcup oak-water hickory

97 Atlantic white-cedar

101 Baldcypress

102 Baldcypress-tupelo

103 Water tupelo-swamp tupelo

108 Red maple

110 Black oak

203 Balsam poplar

217 Aspen

220 Rocky Mountain juniper

222 Black cottonwood-willow

235 Cottonwood-willow

236 Bur oak

Habitat: Ecosystem

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More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

ECOSYSTEMS [99]:





FRES10 White-red-jack pine

FRES13 Loblolly-shortleaf pine

FRES14 Oak-pine

FRES15 Oak-hickory

FRES16 Oak-gum-cypress

FRES17 Elm-ash-cottonwood

FRES18 Maple-beech-birch

FRES19 Aspen-birch

Habitat: Plant Associations

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More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

KUCHLER [175] PLANT ASSOCIATIONS:





K017 Black Hills pine forest

K081 Oak savanna

K084 Cross Timbers

K089 Black Belt

K095 Great Lakes pine forest

K098 Northern floodplain forest

K099 Maple-basswood forest

K100 Oak-hickory forest

K101 Elm-ash forest

K103 Mixed mesophytic forest

K104 Appalachian oak forest

K106 Northern hardwoods

K109 Transition between K104 and K106

K111 Oak-hickory-pine

K112 Southern mixed forest

K113 Southern floodplain forest

Habitat: Rangeland Cover Types

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More info on this topic.

This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the terms: cover, hardwood, woodland

SRM (RANGELAND) COVER TYPES [252]:




411 Aspen woodland

412 Juniper-pinyon woodland

421 Chokecherry-serviceberry-rose

422 Riparian

732 Cross timbers-Texas (little bluestem-post oak)

733 Juniper-oak

805 Riparian

809 Mixed hardwood and pine

Immediate Effect of Fire

provided by Fire Effects Information System Plants
More info for the terms: fire severity, fire tolerant, severity, tree

The fate of burned green ash trees varies from main stem survival to complete
kill. Likely site conditions, season,
and fire severity play a role in green ash survival following
fire. Some green ash trees have survived fire. Fire-scarred
green ash trees were studied in
the Mississippi River Delta by Hepting [140] and Toole [283], and mangers
and biologists from Wind Cave National Park, South Dakota, suggested that
fire-scarred green ash trees there may be useful in reconstructing the
fire history of the area. In a review, Wasser [301] indicates that green
ash is fire tolerant when dormant.

However, in burned riparian areas of eastern Montana,
Lesica [185] reported green ash tree
(all size classes except seedling) mortality as high as 80%. In
oak-hardwood woodlands of the central and eastern United States, Kennedy and Nowacki [168] report that green ash is
"adversely affected" by fire.

Importance to Livestock and Wildlife

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More info for the terms: cover, density, forest, frequency, grassland, habitat type, hardwood, mesic, root crown, seed, shrub, species richness, tree, vines, woodland

Green ash trees and habitats provide food and/or cover for game and nongame
birds, American beavers, other small mammals, deer, bison, livestock, insects, and
aquatic species. The riparian habitat in Nebraska's Scotts Bluff National
Monument, dominated by eastern cottonwood, willow, boxelder, American elm, and
green ash, occupied just 4%
of the area but was habitat for 57% of the total vertebrate species
(amphibians, reptiles, mammals, and birds) surveyed [68].
However, the number of wildlife species supported by green ash habitats may
change with condition of the habitat. Bjugstad [34] found that the
green ash/chokecherry
habitat type in an early seral stage supported approximately half the number of birds, and fewer small
mammals, compared to a later seral stage.

Livestock:
Livestock browse green ash stems.
In studies along an 80-mile (100 km) stretch of North Dakota's Missouri river,
Johnson [162] considered green ash one of the most grazing-tolerant species.
In the Little Missouri National Grasslands, cattle exclusion grazing
experiments were monitored
for 7 years. The stocking rate on grazed sites was
1.07 AUM/ha
from 15 May to 30 October,
and forage utilization averaged 35% by late
August or early September. Green ash heights were significantly greater
(p= 0.04) on ungrazed sites in the
3rd, 4th, and 6th postexclusion years, suggesting that cattle fed on green ash
stems [291]. The effect of grazing on green ash seedlings was also assessed.
Survival of green ash seedlings averaged 72% on ungrazed and 38% on grazed
sites. Seedling height averaged 17 inches (42 cm) on ungrazed and 12 inches (30
cm) on grazed sites 5 years following planting. The density of green ash
seedlings was greater on grazed than ungrazed sites during the 4th, 5th, and 6th
posttreatment years. The majority of seedlings in a given year were 1st-year
seedlings [292].

Wooded draws dominated by green ash, western snowberry,
and chokecherry in the Little Missouri
Badlands were grazed at
light, moderate, or heavy levels. Grazing pressure was
evaluated by the number of animal
trails, extensiveness of lounge areas, and distance to water. Green ash
coverage, frequency, and density decreased with increased grazing. Results are
summarized below
[50,51].

Livestock use Light Moderate Heavy
Cover (%) 0.77 0.55 0.27
Frequency 6.5 4.8 2
Sapling density (stems/ha)
(1.8-7.5 cm dbh) 1,159 709 634
Tree density (stems/ha)
(>7.5 cm dbh) 429 411 354

Extensive livestock use of green ash habitats likely does more damage than
browsing. Many have highlighted the use or overuse of green ash/chokecherry
habitats by livestock in the northern Great Plains. Green ash habitats
provide shade, palatable forage, water sources, protection from severe
weather, and shelter during the calving season. Livestock also utilize green ash
habitats to avoid insects, especially horn flies in the northern Great Plains,
and trees are often used as rubbing posts to remove insect pests [35,133].
Not surprisingly, the same habitat
qualities attractive to livestock are attractive to wildlife in the area. The potential for livestock/wildlife
management conflicts is considerable [133]. Severson and Boldt [248] suggest
several management techniques and grazing systems that may reduce grazing
impacts on woody draw vegetation of the northern Great
Plains.

Bison:
In Oklahoma's Tallgrass Prairie Preserve, rubbing and
horning activities of 100 or more bison were monitored. Green ash was
used significantly (p<0.001) more than expected based on its availability.
Bison moderately damaged green ash bark, but overall damage to the area's woody
vegetation was not great. However, a number of
miscellaneous man-made or artificial objects in the area were used extensively
for horning and rubbing. Without these objects, woody vegetation
damage may have been greater. Researchers suggest that bison activity may have
acted to restrict woody
vegetation from the prairie [67].

Deer:
The literature suggests that deer utilize
green ash habitats extensively, but that browsing of green ash may be limited.
Vines [294] reports that white-tailed deer browse green ash twigs.
Rayburn and Barkalow [229]
monitored damage to trees in a logged tupelo-cypress forest in eastern
North Carolina and found that white-tailed deer fed on green ash
leaves only in May.

Monitoring white-tailed deer through aerial surveys, radio collars,
and markings revealed
selective use of eastern Montana's riparian habitats. On the north
side of the Yellowstone-Missouri River in Montana's Dawson and Richland
counties, riparian habitats dominated by green ash, eastern
cottonwood, western snowberry, and chokecherry occupied 7% of the
research area but received 86% of annual white-tailed deer use. Use levels significantly
(p<0.001) exceeded availability [86]. Aerial surveys in the winters from 1976
to 1979 in southeastern Montana showed heavy deer use of creek riparian habitats.
About 40% of 1,727 mule deer and 39% of 1,675 white-tailed deer
wintered in riparian habitats. Creek riparian habitats were either eastern
cottonwood or hardwood dominated. Important species included green ash, boxelder,
and/or American elm [274].

American beaver:
Reports of American beavers feeding on green ash
come from North Dakota, Wisconsin, and Mississippi. In a review, Allen [9]
indicated that green ash was a major winter food for North Dakota's American
beavers. On a river island in the Chippewa River near Eau Claire, Wisconsin,
American beavers preferentially fed on green ash stems and maintained
shrub-like green ash trees. The researcher was uncertain as to green ash's
survival and growth with heavy American beaver
browsing [22]. A later report on the same area indicated that decreased
green and black ash density was likely with continued American beaver feeding [23].

Hardwood seedlings planted on a batture (land between a river bank and the water's
edge when water level is below normal) of the Mississippi River in Issaquena
County, Mississippi, were preyed on heavily by American beavers.
American beavers uprooted
seedlings during flooded periods and consumed the root system
and part of the root crown, but
discarded the rest of the plant. Fifteen to eighteen percent of
green ash seedlings were
destroyed during the 2-year monitoring period. This type of
feeding is considered much more destructive than browsing
aboveground stems, since green ash
sprouts readily following aboveground damage [174].

Small mammals:
Green ash seeds, stems, and
foliage provide important cover and food for a diversity of rabbit and other
small mammal species. A study of habitat use by small mammals in Pipestone
National Monument, Minnesota, conducted in 1984 and 1985, found that
white-footed mouse abundance was significantly (p<0.05) greater in the bur
oak-green ash woodland habitat than in any other grassland, prairie, or riparian
area studied [261]. In southeastern Montana, researchers found that dwarf shrew
abundance was significantly (p<0.05) correlated with green ash cover [190]. In
old fields of north-central New Jersey, researchers studied microhabitat's
effect on rodent seed feeding behavior. White-footed mice, the predominant seed
predators in the area, consumed green ash seeds by gnawing the end of the seed
coat and splitting the seeds. A total of 1,920 feeding trials were monitored,
and an average 14.2% of green ash seed was removed by predators. More seed was
removed at night, 17.9%, than in the daytime, 10.5%. Coverage of
ground level vegetation explained most of the variation in green ash seed
predation [193].

Wildlife, chiefly cottontail rabbits and white-tailed jackrabbits,
browsed green ash in shelterbelts of eastern South Dakota. In 1-year-old
plantings, 4.8% of the overwinter mortality of 736 green ash trees was
attributable to wildlife browsing [21]. Researchers compared the use
of closed-canopy and open-canopy
green ash-dominated drainages in the Slim Buttes of Harding County, South Dakota.
Nineteen total mammal
species were observed during the 2-year study, and significantly more small
mammals (p≤0.05)
were found in closed-canopy than open-canopy forests. Only
white-tailed jackrabbits preferred open-canopy woodlands and for just 1 year
of the study [143].

Game birds:
Wood ducks, grouse, northern
bobwhites, and wild turkeys utilize green ash habitats. In Wyoming, green ash is considered important food and cover for
sharp-tailed grouse [214]. Twedt and Best [287]
also report that grouse commonly feed on ash seeds. In the Slim Buttes, researchers found that sharp-tailed grouse
preferred open-canopy green ash woodlands on gentle slopes [143].
Sharp-tailed grouse utilized hardwood draws of eastern Montana in
the fall and winter. Twelve percent of fall and winter observations were in hardwood draws where boxelder, silver
buffaloberry (Shepherdia argentea), American plum, green ash, and
American elm were common. Hardwood draws were likely used for berry foraging in the
fall and for bud feeding in the winter [275].

In the Duck Creek Wildlife Management Area of southeastern Missouri, the
esophageal contents of 20 male and 20 female wood ducks contained
green ash in the fall of 1975 and 1976. The occurrence of green ash was 30% in
males and 15% in females [81].

The movements of 88 male and 52 female northern bobwhites were monitored
by radio collars in an old-field habitat of Oktibbeha County, Mississippi.
Boxelder and green ash were the prominent woody species in low-lying,
poorly drained sites,
and brooding northern bobwhites selected woody vegetation in
a greater proportion than was available. The researchers suggest that forested
areas may have provided
display areas for males, cover for escape, and/or corridors for movement between
habitats [279].

Wild turkeys studied in Gregory County, South Dakota, selected woodland sites
over grassland sites for nesting. Woodlands in the study area were
bur oak-dominated, but green ash, American elm, and basswood were typical
on mesic sites [305].

Nongame birds:
Green ash provides food, nesting
sites, and roosts for numerous nongame bird species. Twedt and Best [287]
report that blackbirds, finches, grosbeaks, and cardinals feed on ash
fruits.

A large number of birds occupy green ash habitats in North
Dakota. In the Little Missouri National Grasslands, Hopkins [148]
found that green ash-dominated
woodlands supported 531 nesting bird pairs/40 ha. Green ash woodlands had the
highest density of bark foraging and ground nesting birds. Three, Cooper's hawk,
mountain bluebird, and a 3rd unidentified species, of the 50 species studied
nested only in ash woodlands. A total of 49 bird species, 23% of
North Dakota's known nesting avifauna, were encountered in wooded draws of
western North Dakota where green ash dominates. Common birds included rufous-sided towhees, brown-headed
cowbirds, house wrens, American goldfinches, and several species of sparrows,
warblers, blackbirds, and flycatchers [148].

In South Dakota, studies compared the canopy and seral condition of
communities as they relate to bird species richness. In the Slim
Buttes, researchers compared bird use of closed-canopy and
open-canopy drainages dominated by green ash. A total of 82 bird species
was observed in the woodlands, and significantly more (p=0.002) occurred in
closed-canopy sites. Mountain bluebird and western meadowlark were the only
nongame birds that preferred open-canopy woodlands
[143]. Researchers surveyed bird populations in 40 early to late seral
green ash/chokecherry vegetation stands of central South Dakota. Bird
censuses occurred in the summers of 1990, 1991, and 1992 near the
Missouri River. A total of 81 bird species was found in green ash
woodlands. Tree and shrub nesting birds preferred late-seral
and ground nesting species
preferred early seral communities [242].

Two studies report that green ash trees are typical in habitats used by
eastern screech-owls. The Souris River of southern Saskatchewan represents the
northwestern limit of the eastern screech-owl's range. Here eastern
screech-owls occur predominantly in river bottom
woodlands dominated by boxelder, green ash, and American elm. These woodlands
likely support no more than 50 eastern screech-owl pairs [4]. In and near the
Central Kentucky Wildlife Management Area, radio-tagged eastern
screech-owls were monitored from late May 1985 to early July 1986. Monitoring
revealed that woodlot and woodlot edge habitats were important to eastern screech-owls
during the breeding, predispersal, and nonbreeding periods. Woodlot habitats had
an overstory dominated by shagbark hickory, sweetgum, American elm, and green
ash. Trees likely provided important perching areas for
hunting [264].

Researchers observed 2,576 trees with fall blackbird roosts in Columbus, Ohio,
and indicated
that 13% of them were green ash. The study area included forested
tracts scattered within agricultural, residential, and industrial areas [203].

Insects:
Ash trees are hosts for tiger swallowtails, ash and waved sphinxes,
and polyphemus moths [287].

Aquatic species:
The green ash/chokecherry habitat
type in central and eastern Montana is important in maintaining streambank
stability and thermal cover for aquatic organisms [133].

Palatability/nutritional value:
Green ash is considered moderately palatable forage for cattle, domestic sheep,
and horses [133].

In a review, Blinn and Buckner [37] report the mean
foliar nutrient levels of green ash in Minnesota as:

Nutrient N P K Ca Mg
% oven-dry weight 2.13 0.37 1.64 1.46 0.36


  Al B Cu Fe Mn Mo Zn
ppm 49 48 17 105 71 8 22

The foliar nutrient content of green ash saplings based on a percentage
of dry weight was assessed from samples collected from 1978 to 1982 in different-aged
stands on the Atlantic Coast and east Gulf Coast plains. Findings are
summarized below [201]:

Stand age (years) N P K Ca Mg
20 1.47 0.09 0.32 0.73 0.21
40 2.35 0.25 0.98 0.9 0.26
40 1.56 0.3 0.68 0.9 0.21
60 1.5 0.13 0.41 0.64 0.39

The caloric content of green ash stump sprouts between 6 and 15 years of age
is provided below. Sprouts were collected mid-summer from
"fertile" bottomland sites along the Oconee River
in Greene County, Georgia. Calorie
measurements are based on oven-dry weights [212].

Sprout component Wood Bark Branches Twigs Leaves
Calories/g 4,768 4,618 4,857 4,818 5,119

Pardo and others [218] provide a searchable
database with information on above ground nutrient content of many
northeastern U.S. tree species including green ash. Information contained in the
database comes from numerous references.

Cover value:
Green ash provides
important cover for livestock and a diversity of wildlife species. Likely the
usage or reliance on green ash habitats depends on the relative environmental
conditions in neighboring
communities. Use may also change with season.
Hansen and others [133] categorized Montana's green ash/chokecherry habitat
type as providing fair cover for elk, mule deer, game birds, and waterfowl.
Fair cover value was defined as habitat that was moderately utilized when
available. The green ash/chokecherry habitat was considered good cover for
white-tailed deer, small nongame birds, and small mammals. Good cover was
habitat that was readily utilized when available [133].

Other cover value information has been integrated into Importance to livestock and wildlife
above. See the species of interest in that section for more information.

Key Plant Community Associations

provided by Fire Effects Information System Plants
More info for the terms: adventitious, association, basal area, climax, constancy, cotyledon, cover, cover type, density, dioecious, fire frequency, forest, frequency, fruit, habitat type, hardwood, litter, mesic, natural, phanerophyte, relative density, relative dominance, root crown, seed, sere, shrub, shrubs, stratification, succession, swamp, tree, woodland

Green ash is recognized as a dominant species in
the following vegetation classifications:


AR: [259]

GA: [306]

KS: [181]

NE: [7]

MA: [166]

MD: [49]

MN: Voyageurs National Park [176]

MO: [80]

MT: [128,129,133,134,183]

ND: [106,107,131,213]

NY: [234]

OK: [142]

SC: [306]

TX: Trinity River floodplain [217]

WY: [65]

Custer National Forest of ND, SD, and MT [130]

Great Plains: [35,132]

MB: [53]

PQ: [293]



Green ash is a component of many vegetation and cover types across its range.
The sugarberry-American elm (Celtis laevigata-Ulmus americana)-green ash cover type is found in southern
forests from eastern Texas east to the Gulf Coast region and north to the major
river floodplains of southern Illinois. This cover type occupies clay or silt loam soils and
is considered successionally "long-term." Pure stands of green ash are occasional
on moist flats or in shallow sloughs [159]. On low flats and sloughs of the
Mississippi River floodplain, this type is typical after heavy cutting or
fire. Other important associated species include dwarf hackberry (C.
tenuifolia), water hickory (Carya aquatica), and willow oak (Quercus phellos) [221].

Western U.S.:
Green ash is restricted to riparian areas in the westernmost portion of its range.

Montana: In central and eastern Montana, the green
ash/chokecherry (Prunus virginiana) habitat type is common. This type is typical
on older terraces of the Missouri River and commonly lines sections of the
Yellowstone, Powder, Tongue, Milk, and Little Missouri rivers [133]. Lesica [183]
recognizes a green ash-American elm/chokecherry vegetation association in which boxelder
(Acer negundo) and Rocky Mountain juniper
(Juniperus scopulorum) can occur. Quaking aspen (Populus tremuloides)
may occur in the early
successional stages. Associated shrubs include American plum (Prunus americana) and
Saskatoon serviceberry (Amelanchier alnifolia) [133,183].

Wyoming: Green ash occurs in riparian areas of
Wyoming in the boxelder-green ash-American elm/common snowberry (Symphoricarpos albus)
community type. Other species common in this vegetation type are bur oak (Q. macrocarpa),
hophornbeam (Ostrya virginiana), and cutleaf coneflower (Rudbeckia laciniata) [65].

Colorado: Green ash, American elm, and
boxelder are typically present as minor species and contribute less than 1%
coverage on the Arkansas and South Platte river drainages of eastern Colorado.
The dominant species are plains cottonwood (Populus
deltoides ssp. monilifera) and peachleaf willow (Salix
amygdaloides). Saltcedar (Tamarix chinensis) often forms a dense
subcanopy or shrub layer on the Arkansas River floodplain
[187].

North-central U.S. and south-central Canada:
In many forest cover types of the northern Great Plains and the Great Lakes regions, green ash
is important. Green ash is typical in the bur oak cover type in the Black Hills
of South Dakota and Wyoming where interior ponderosa pine (Pinus ponderosa
var. scopulorum), American elm, and plains cottonwood are common as well
[87]. In the northern Great Plains, green ash commonly invades the cottonwood (Populus
spp.) forest cover type as succession
advances beyond the pioneer stages [173]. In the sugar maple-basswood (Tilia
americana) cover type of western Wisconsin and central Minnesota,
green ash, hackberry, bitternut hickory (Carya cordiformis), and several
oak (Quercus spp.) species occur together [111]. Green ash is also a major associate
of the silver maple (Acer saccharinum)-American elm cover type that occurs
in central U.S. forests and Canada's Great Lakes-St. Lawrence forest region.
This type is considered "subclimax" along river bottoms and
floodplains [222]. Along the Red, Assiniboine, Souris, and other rivers of Manitoba and eastern
Saskatchewan, green ash is an important component of maple-elm-ash floodplain communities [33].

Manitoba: The eastern deciduous forest of
Manitoba has a canopy dominated by green ash, American elm, and boxelder and a shrub-dominated
understory of beaked hazelnut (Corylus cornuta), chokecherry, and
American cranberrybush (Viburnum opulus var. americanum).
This forest is predominant on nutrient-rich basic substrates [53].
Green ash is also typical of flooded and nonflooded woodlands surrounding Lake Manitoba. The
forest nearest to the lake is often flooded in the spring and supports a mixture of
green ash, shining willow (Salix lucida), peachleaf willow, and sandbar
willow (S. interior). Forests beyond these rarely flood and are dominated by
balsam poplar (Populus balsamifera),
quaking aspen, green ash, boxelder, black willow (S. nigra), and American
hazelnut (C. americana) [189].

North Dakota: Green ash is a dominant species in several upland
hardwood habitat types of southwestern North Dakota. The green ash-American
elm/chokecherry habitat type occupies mesic sites with gentle slopes and loam to
silt loam soils [107]. The green ash/chokecherry vegetation type occupies
intermittent drainages and narrow draws with slopes of up to 40% and
soils containing more than 35% clay. The green ash/common snowberry vegetation is restricted to floodplains
and tributaries of the Little Missouri River. The clay content of these soils is
often 30% to 59%. The eastern cottonwood (P. deltoides)-green ash community
type occurs on Missouri River floodplains. It is considered a
mid-seral type that develops into the green ash/common snowberry type [106].

In west-central North Dakota, green ash-box elder forests are typical in river valleys
of the Knife River Indian Villages National Historic Site [61].

Green ash is common in upland draws, valley bottoms, and
moderately steep north- and east-facing slopes of the Badlands. Green
ash-dominated vegetation abuts mixed-grass prairies in the uplands and cottonwood
and silver sagebrush (Artemisia cana) in the valleys.
American elm trees commonly occur with green ash in the northern
Badlands. Boxelder and Rocky Mountain juniper are occasional associates in the
bottomlands. Quaking aspen is present in disturbed stands that
have experienced fire or die-off in the past. Bur oak associates with green ash
north of the Killdeer Mountains [213].

Minnesota: Managers in Voyageurs National Park
recognize a rare ash-elm/trillium (Trillium spp.) vegetation type. Canopy
dominants in this type are black ash (Fraxinus nigra), green ash, and
American elm. Ash-elm/trillium habitats are moist with deep, nutrient-rich soils [176].

Wisconsin: Green ash, swamp white oak (Q. bicolor),
and common buckthorn (Rhamnus cathartica) are
important in floodplain forests of southeastern Wisconsin's eastern
ridges and lowland provinces. These species dominate soils with neutral pH
that are typically moist throughout the growing season and experience spring
flooding at intervals of every 2
to 3 years [85].

Along the lower 230 miles (370 km) of the Wisconsin River floodplain that includes
100-year-flood regions, river birch (Betula nigra), silver maple, black
ash, green ash, eastern cottonwood, swamp white oak, black willow, and American
elm are consistently found together [285].

Nebraska: Green ash is a subdominant
species of dry bur oak-bitternut hickory forests along the Missouri River
and northern red oak (Q. rubra var. rubra)-American basswood climax forests in eastern Nebraska.
The green ash-American elm forest type is also found on most of Nebraska's river floodplains.
However, it is most well developed on larger river floodplains [7].

In the bottomlands of Lost Creek in the Schultz
Prairie of south-central Nebraska, green ash occupies savannah-like riparian
vegetation. Associated canopy species may include bur oak, white mulberry
(Morus alba), and/or silver maple. Roughleaf dogwood (Cornus drummondii)
and American bittersweet (Celastrus scandens) are characteristic of the
understory. A decreased fire frequency in this prairie region is thought to have
facilitated an expansion of woody vegetation [240].

North-central Nebraska's Niobrara River valley
supports hardwood communities where green ash is dominant. Other typical
hardwood species include bur oak, basswood, boxelder, hophornbeam,
black walnut (Juglans nigra), and American elm [163].

Illinois: In Vermilion County's Horseshoe
Bottom Nature Preserve, silver maple, green ash, and black ash dominate all
diameter classes in swamp communities [180]. Along
the Oakwood Bottoms Greentree Reservoir of the Shawnee National Forest, green ash
occurs in pin oak-cherrybark oak (Q. palustris-Q.
pagoda) communities. This vegetation type is restricted to old fields [281].

Indiana: Green ash populates poorly drained sites in the
old-growth Ginn Woods of east-central Indiana. Other species of the Ginn Woods

include silver maple, red maple (A. rubrum), shellbark hickory (Carya laciniosa),
American sycamore (Platanus occidentalis), and eastern cottonwood [18].

South-central U.S.:
Abandoned agricultural fields and floodplains are typical green ash habitat in the
south-central plains and coasts. Hook [145] describes green ash in
association with the baldcypress (Taxodium distichum) cover type
of the coastal plains. In the lower Midwest states, green ash is considered
important in the sassafras-common persimmon (Sassafras albidum-Diospyros virginiana)
cover type. Green ash commonly invades this pioneer
type on old-field sites with deep soils [17].

Kansas: In the eastern portion of Kansas, the green ash-American
elm-hackberry vegetation type occurs in temporarily flooded
forests. Green ash is also a common component of the pecan (C. illinoensis)-hackberry
forests found in the Cherokee lowlands, Glaciated
Regions, and the Osage Cuestos area. The eastern cottonwood-black willow
floodplain forests and bur oak-Shumard oak (Q. shumardii)-bitternut
hickory/Indian woodoats (Chasmanthium
latifolium) communities also provide green ash habitat [181].

Missouri: Green ash is a component of Boone
County's old-growth Schnabel Woods, where some trees are as old as 205 years.
Since the last study of this area, 40 years ago, green ash
importance has declined, however. The dominant canopy species of the Schnabel
Woods is sugar maple (A. saccharum), and other canopy species include
northern red oak (Q. rubra), white oak (Q. alba), chinkapin oak
(Q. muehlenbergii), basswood, and slippery elm (Ulmus rubra) [235].

In floodplain forests of northern Missouri's Dissected Till Plains, green ash
dominates several forest types. In the black willow-green ash forest type, green
ash has an importance value of 77. Green ash importance is just over 20 in the
silver maple-American elm-green ash and oak-green ash-river birch forest types.
Researchers indicate that green ash is well represented in the sapling stage and
will likely remain in the area long term if there are no
major disturbances [80].

Oklahoma: The green ash-American
elm and American elm-slippery elm-sugarberry-hackberry-green ash vegetation
associations are widespread throughout Oklahoma. In the Red River drainage, the
green ash-cedar elm-(Ulmus crassifolia)-sugarberry vegetation type is
typical, and the loblolly pine (Pinus taeda)-green ash-American
elm/longleaf woodoats (C. sessiliflorum) community is common on floodplains
and Coastal Plain swamps [142].

Arkansas: Along the Cache River floodplain of
northeastern Arkansas, the Texas red oak (Q. texana)-green ash vegetation type
populates low-lying areas. Sites
occupied by this community may be flooded 90 to 100 days of the year [259].

Texas: Simpson [257] describes green ash in
piney woods, Gulf prairies, marshes, post oak (Q. stellata) savannahs, blackland prairies,
Cross Timbers, Rio Grande floodplains, and the Rolling Plains of eastern Texas.

In the Big Thicket National Preserve of southeastern Texas, green ash is common
in flatland hardwood forests between the
Trinity and Neches rivers where standing water is typical after heavy rains.
Other species associated with this habitat are swamp chestnut oak (Q. michauxii),
willow oak (Q. phellos), laurel oak (Q. laurifolia), and loblolly pine [194].
In low flood plains of the Roy E. Larsen Sandylands Sanctuary, green ash
associates with water tupelo (Nyssa
aquatica), sweetgum (Liquidambar styraciflua), baldcypress, and red
maple [195].

Louisiana: Green ash is widely distributed in the
Cat Island Swamp of Feliciana Parish. In the swamp, sugarberry and baldcypress are the most
conspicuous canopy species but water tupelo, overcup oak (Q. lyrata), and
pecan are also found [77].

Southeastern U.S.:
Along the Gulf and Atlantic coasts and in the interior southeastern states, green ash associates
with many vegetation types. The overcup oak-water hickory forest type is green
ash habitat on floodplains and back water basins of the Gulf
and Atlantic coast states and in Tennessee and southern Illinois. Sugarberry, American elm,
water locust (Gleditsia aquatica), red maple, and/or
Texas red oak are also typical of these forests [158]. In the coastal plains
states, green ash is occasional in the baldcypress forest cover type [145].
On islands and levees of southern Louisiana and southwestern Mississippi, green
ash associates with sugarberry and American elm in the live oak cover type [88].

Kentucky: In old-growth woodlands of Pennyroyal
Plain, green ash is important in the subcanopy and understory. The common upper
canopy vegetation of this area is dominated by a mix of shagbark hickory (Carya ovata),
red maple, slippery elm, sweetgum, pin oak, swamp chestnut oak,
and southern red oak (Q. falcata) [60].

Virginia: The hardwood forests of Virginia's lower Coastal Plain
characteristically include green ash, American elm, red maple, cherrybark oak,
swamp chestnut oak, willow oak, and/or
laurel oak [58].

Tennessee: Green ash is an occasional species
in wet and moist bottomland hardwood forests of the Natchez Trace State Forest,
State Resort Park, and Wildlife Management Area of western Tennessee.
Wet bottomland hardwood forests occupy poorly drained sites with moderate to
high soil fertility. Other wet bottomland forest species include red maple,
sweetgum, willow oak, and black willow. Moist bottomland hardwood forest
canopies are diverse and may include yellow-poplar (Liriodendron tulipifera),
sweetgum, white oak, loblolly pine, and/or red maple. Soils
in moist bottomland forests are well drained, and soil fertility remains moderate to high [258].

North Carolina: Along the expansive floodplain of Tyrrell
County's Scuppernong River, an assortment of bald cypress, loblolly pine, swamp tupelo
(N. biflora), sweetgum, red maple, and green ash
typically dominate the overstory. Occasionally water tupelo and Atlantic white-cedar
(Chamaecyparis thyoides) are found [208].

South Carolina: The laurel oak-green ash and swamp
chestnut oak-green ash floodplain forest types are common in Congaree Swamp
National Park of central South Carolina [306].

Mississippi: Sharkey County is home to the Green Ash Research
Natural Area. The vegetation of this area is dominated by Texas red oak, green ash,
and American elm. There are old-growth green ash trees between 200 and 250 years old in the area [78].

Alabama: Green ash is typical of bottomland communities
that line small streams in the lower Alabama Piedmont. Sweetgum and red maple
are often found with green ash in these narrow floodplains with
moderately well-drained soils [114].

Georgia: The swamp chestnut oak-green ash vegetation type
is common on high-elevation floodplains in Georgia's Piedmont province.
The red maple-green ash type is common in Georgia and occupies lower elevation
floodplains. The sweetgum-laurel oak-green ash vegetation type is rare and occupies moderately
wet to dry alluvial floodplains near Savannah [306].

Florida: Green ash is associated with several forest
communities on the Apalachicola River floodplain of northwestern Florida. Other species occurring
with green ash include sugarberry, water oak (Q. nigra), red maple, and planertree
(Planera aquatica). Researchers estimate that within this 175 mi²
(454 km²) floodplain 14,200 tons (12,900 tonnes) of ash leaf litter (predominantly Carolina ash
(Fraxinus caroliniana) and green ash) falls annually [89].

Northeastern U.S. and southeastern Canada:
Swamps and floodplains are typical green ash habitats in the northeastern United
States and southeastern Canada. Green ash is common in mature
sassafras-common persimmon forest types that occur in the
mid-Atlantic states. Green ash replaces this pioneer type on upland and
lowland old fields with deep soils [17].

Quebec: Green ash is a dominant canopy species in
silver maple-green ash forests in the Lac des Deux-Montagnes area. This
forest type occurs at elevations between 65.6 and 73.5 feet (20-22.5 m)
on imperfectly or poorly drained soils. Red-osier dogwood (Cornus sericea
ssp. sericea) and riverbank grape (Vitis riparia) dominate the shrub layer of silver
maple-green ash forests. Green ash is also typically present in northern red oak and eastern
white pine (Pinus strobus) forests that occupy well-drained soils at elevations of
79 to 98 feet (24-30 m) [293].

Massachusetts: The overstories of many small river
floodplain forests in eastern Massachusetts are green ash dominated. The silver
maple-green ash-pin oak vegetation type is typical of small tributaries of the Connecticut
and Nashua rivers where flooding occurs. This type also occurs on island edges
in the Merrimack River. Green ash is present but less common in the red maple-silver
maple-swamp white oak and silver maple-green dragon (Arisaema dracontium)
vegetation types [166].

New York: Green ash and black ash are
codominants in the silver maple-ash forest type that is common along
ravines and floodplains at the southern edge of Cayuga Lake in Tompkins
County. In this vegetation type, silver maple contributes up to 70% of the total
canopy coverage, and green and black ash together make up 5% to 15% cover [154].

Ohio: On poorly drained sites that are part of northwestern Ohio's Black
Swamp, green ash occurs with silver maple, black ash, American elm, bur oak,
and shellbark hickory [39].

Maryland: Green ash is a dominant species in the
American sycamore-green ash-box elder-silver maple vegetation type
characteristic of bottomlands in the Piedmont and Appalachian provinces. Along
the Pocomoke River, green ash occurs in the abundant baldcypress vegetation
association often together with red maple and sweetgum. Green ash also occurs in
river birch-American sycamore vegetation in bottomlands and along shorelines of the
Potomac River [49].


BOTANICAL AND ECOLOGICAL CHARACTERISTICS


SPECIES: Fraxinus pennsylvanica


 

 

©Kitty Kohout,
Wisconsin State Herbarium





GENERAL BOTANICAL CHARACTERISTICS:



This description provides characteristics that may be relevant to fire ecology,
and is not meant for identification. Keys for identification are available
[44,47,62,84,108,109,110,124,155,177,206,227,249,257,269,272,294,297,304,312,317].

Green ash is a deciduous tree with high branches and a slender growth form. It grows to 100 feet (40 m) in the
southern part of its range but is typically half that
height in the northern portion of its range [84,110,124,167,269]. Some research
indicates height differences across the east to west range of this species as well.
Trees found in New York are typically greater than 100 feet (30 m) tall, while
those in South Dakota rarely exceed 49 feet (15 m) [1]. South Carolina's state
champion green ash tree grows in the bottomland hardwood floodplain forest of Congaree National Park and was last measured in 2002. This tree was 143 feet
(43.6 m) tall, and had a crown spread of 96 feet (29 m) and a
circumference of 181 inches (460 cm) [263]. The 2004-2005 National Tree Register
reports that the national champion green ash
tree grows in Cass County, Michigan, and is 95 feet (29 m) tall, 259 inches (658
cm) in circumference, and has a 95-foot (29 m) canopy spread. This tree was
last measured in 1995 [11].



The trunk of green ash trees is large and straight [269]. When subjected to
prolonged periods of flooding, trunks may become enlarged
at the base [110]. Under dry conditions, the outer bark is
between 5 and 7 mm thick at breast height, while the inner bark
measures a thickness of 1.5 to 2.5 mm [211].

Green ash leaves are opposite, odd-pinnately compound, and measure between
4.3 and 12 inches (11-30 cm) long by 3 to 7.1 inches (8-18 cm) wide [110,124].
Commonly there are 5 to 9 leaflets that are typically 2 to 4 inches (6-10 cm)
long and 2 to 5 cm wide. Though thin, leaflets are "firm and leathery" [269].
Flowers appear before the leaves and are borne on old wood [110,304]. Female flowers are
short, dense panicles with 200 to 300 flowers per panicle [269]. Trees as small as
20 to 30 feet (6-8 m) tall with dbh of 3 to 4 inches (8-10 cm) have produced flowers
[167]. However, abundant flowers are not produced until trees are approximately 8 to 10 inches
(20-30 cm) in diameter (review by [93]). The fruit is a single-seeded, winged
samara measuring 10 to 15 mm long [108,269]. Seeds are small [308].

The rooting habit of young and adult green ash trees has been investigated by
several researchers. Lateral roots are long with few branches. Fine lateral
roots average 0.25 to 0.55 mm in diameter [48]. The rooting depth of green ash
on fine-textured soils is described as shallow, between 5 and 10 feet (2-3 m).
Although the root system is considered extensive,
green ash trees may topple with high winds (reviews by [226,301]). In East
Brunswick, New Jersey, 2- and 3-year-old green ash saplings were planted and
excavated 3 years later. Maximum root spread for the saplings was 1.68 times
their driplines, and crown and trunk diameter were significantly (p=0.01) correlated
with root spread [103]. In eastern Nebraska, researchers examined the
root depth and spread of several green ash trees representing a range of ages. A
3-year-old green ash tree in Lancaster County had roots that extended approximately
5 feet (2 m) deep and spread 8 feet (2 m) in diameter. A 24-year-old tree from
Pawnee County had a root spread of a
little over 30 feet (9 m) and a depth of more than 8 feet (2 m). In Merrick County, a
45-year-old green ash tree had roots that spread 44 feet (13 m) and extended 10 feet
(3 m) deep [266]. For information on green ash mycorrhizal associations and their
effect on green ash growth and/or resource acquisition, see [12,14,15,45].

Male and female trees: Green ash is dioecious.
Morphological differences between male and female green ash trees were studied
in Winnipeg, Manitoba. From a sample of 45 green ash trees between 15 and
45 years old, researchers found that the crown of male trees was generally
rounder, broader, and
fuller than female tree crowns [233]. However, from 6 male and 6 female
green ash trees in the same area between 254 and 373 inches (644-948 cm)
tall, researchers found that female trees had significantly greater shoot
length (p=0.04), greater lateral shoot length (p=0.0005), and a greater number of lateral shoots (p=0.007) than male
trees [74].

Adaptations to flooding:
Green ash trees tolerate flooding through a variety of physiological
and morphological adaptations.
Researchers have observed shoot lenticels, adventitious roots, increased lateral
root production coupled with decreased downward root growth, and succulent roots
with large air spaces [199]. Oxidation of the rhizosphere,
accelerated anaerobic respiration in secondary roots, and the growth of new
secondary roots
are important flood adaptations as well [146,278].

Phenotypic variation:
Green ash trees exhibit a
high level of phenotypic variation, and many researchers have
highlighted differences in the
growth rate, survival, drought tolerance, appearance, and cold tolerance of
green ash seedlings grown from seed collected in northern vs. southern and
eastern vs. western locations. Seed collected from similar latitudes in New
York, Ohio, Illinois, Nebraska, and South Dakota represented a gradient of
decreasing annual precipitation. Drought resistance of the
seedlings increased from east to west locations when grown in a common
location. South Dakota seedlings had small, thick leaves, while New York
seedlings' leaves were thin and large [1]. A similar study compared 6-month to
1-year-old seedlings grown in a common area from seed collected from 39
different locations in the Great Plains. Researchers observed an
increase in drought tolerance,
decrease in size of parent trees, and an increase in the percentage of trees
with dark green foliage as location of the seed varied from south to north and
east to west locations [202].

Growth rates decreased and winter hardiness
increased in green ash trees grown from seed collected in more northerly
latitudes. Green ash seed was collected from the Coastal Plain region of North
and South Carolina and from the Mississippi River valley from southern Illinois
to southern Louisiana and Mississippi. Five and ten years following
planting in a common location, green ash trees from northern seed grew
slower than those from southern seed [303].
Twenty seedlings collected from 9 eastern United States and Canada locations
grown in a common nursery were easily sorted into 2 distinct groups.
Northern seedlings collected from Maine, Michigan,
Wisconsin, Ontario, and Minnesota grew slowly, dropped leaves early in the fall,
and resisted winter kill. Southern seedlings collected from South Carolina,
North Carolina, and Virginia had rapid growth rates, retained their leaves until
late fall, and suffered more damage with cold winter temperatures. The length of
stem damage from winter cold was 0.1 inch (0.3cm) and 5.7 inches (14 cm)
in the northern and southern seedlings, respectively [314].


RAUNKIAER [
228] LIFE FORM:


Phanerophyte


REGENERATION PROCESSES:



Green ash reproduces both through seed production and
vegetative sprouting [250]. Two studies in Montana investigated sexual and asexual
regeneration of green ash. In east-central Montana, studies in 17 green ash
stands from 6 sites revealed that both vegetative regeneration and
seed production were important to regeneration. The stands were
uneven aged, suggesting an irregular recruitment pattern. On average 33% of green ash
trees had live basal sprouts, and the likelihood of finding sprouts was greater
for large-size trees than small trees.
The average density of seedlings was 10 plants/100 m² in all
stands, but 9 of 17 stands had 0 to 1 plants/100 m². Stands with
a greater number of seedlings typically had a more uneven age distribution than
those without seedlings. Likely vegetative regeneration, which is typically
coupled with periodic disturbances such as drought, fire, or logging, created the
more even-aged communities [184].

In a postfire study, Lesica [185] found heavy reliance on
vegetative regeneration and decreased production of seedlings by green ash trees
recovering from fire. Green ash woodland sites in eastern Montana that burned in
August or September between 1988 and 1998 were studied in 2001. There were more
sprouts, fewer seedlings, and more dead trees on burned sites
compared to unburned sites. Likely fire killed green ash seed on or
near the soil surface,
restricting seedling recruitment to seed producing trees, many of which
were killed in the fires. The average number of sprouts, seedlings, and dead
trees on unburned and 3- to 13-year-old burned sites is presented below. Data
were collected from 0.025-ha circular plots [185].

Population attribute (mean) Burned Unburned
Sprouts 4.3 1.3
Diameter of sprouts (mm) 1.56 0.84
Seedlings 1.8 8.1
Dead trees 1.43 0.14

Pollination:
Flowers are wind pollinated [22,167].
Male flowers mature earlier than female flowers, and female flowers are
receptive from the time of bud opening to the time the stigma withers. Female
receptiveness lasts 7 to 10 days for individual trees and 2 to 3 weeks for populations [277,315].
Some have observed green ash trees just 7 years old and 12 feet (3.7 m) tall flowering,
but typically flowering occurs after trees reach 3 to 4
inches (8-10 cm) in diameter and/or a height of 20 feet (6 m) [316].

The majority of pollen produced travels 25 to 50 feet (7.6-15 m)
from the source tree. Wright [313] counted the number of pollen grains
from open-grown green ash trees at increasing distances from the source tree. The
number of pollen grains from white and green ash trees was 2,502, 1,110, 110,
and 2 from stations 25, 50, 150, and 400 feet (7.6, 15, 45.7, and 122 m)
from the source tree, respectively. However, because of collection
technique limitations, the author suggests that
these numbers may incorporate an error factor of 2 or 3 [313].

Breeding system:
Green ash trees are dioecious [110,124,269]. With male and female flowers on separate,
wind-pollinated trees, outcrossing is mandatory and the potential for genetic
exchange is great.

Seed production:
Ash trees exhibit a masting behavior [38]. Sutherland and others [273] suggest that
ash trees produce good seed crops every 5 or more years, while others suggest that
good seed crops are produced every year by green ash [308]. Wright [316] reported a
high percentage of male and female flowers each year and a high percentage of
annual seed production by female trees.

In the Philadelphia area, green ash trees monitored from 1947 to 1951
revealed that a large number of flowers did not necessarily dictate a large number of
seeds, but greater than 33% of observed green ash trees produced large seed
crops for 2 or 3 sequential years [315]. Along the north shore forest margin
of Quebec's St. Lawrence estuary, green ash seed production was high even when
many trees showed signs of damage from ice and debris flows [179].
In forest fragments of southeastern Michigan, researchers monitored seed
rain from May through February for 2 years. The basal area of green ash averaged
3 m²/ha in the forests. Over the 2-year period, 73% of the
2.7 ft² (0.25 m²) seed traps received green ash seed rain, and an average of
60 green ash seeds were produced/m²/year. The number of seeds trapped was greater
in areas with a greater density of mature green ash trees [198].

Seed dispersal:
Green ash seeds are primarily dispersed by wind but movement by water is
also likely [10,167]. Animals cache ash seed [72], which may subsequently
germinate and establish.

Dispersal distance: The dispersal distance of green ash seeds is
dependent on season and time since seed shed. Seeds shed in the winter
potentially move great distances from the source on frozen surfaces; seeds
dropped in the fall typically rest near the parent tree [280]. Sutherland and others [273]
report that ash seeds may travel 300 feet (100 m) or more from the parent tree.

The natural invasion of a reforestation project in
the Tensas River National Wildlife Refuge was evaluated 6 years following Texas
red oak and water oak plantings. The frequency of green ash volunteers
was 61.9%, and green ash tree size averaged 13 inches (3.3 cm) dbh. The
distance of planted fields
ranged from 423 to 2,100 feet (129-640 m) from forested edges. Most green ash plants occurred on
plots within 850 feet (259 m) of the forested edge. The density of green ash in
nearby forested areas was not reported [197].

Green ash colonization of the Ouchita Wildlife Management Area of
northeastern Louisiana resembled an "advancing front." Agriculture
was abandoned in the area in 1984. In May of 2000, green ash, although
not planted on the reclaimed site, was the most dominant woody
species in terms of basal area and density. The density of green ash
saplings was 800/ha within 30 feet (10 m) of the bordering forest edge
and 70/ha at 300 feet (80 m) from the edge [28].

Seed banking:
The length of time green ash seed remains viable in the soil likely
depends on site conditions including
temperature, flooding, and/or soil type. Sutherland and others
[273] suggest that ash seeds are viable for up to 3 to 4 years
in the seed bank. However, no green ash seed germination from seed bank samples in baldcypress-green
ash swamps
along the Cache River of Illinois. Sampling was conducted in April of 1992 and 1993 in
9 intact swamp forests and 51 former swamp sites that have been farmed for the last
1 to 50 years. Under greenhouse conditions, no green ash seedlings emerged from the
swamp soil samples [204]. As sampling and laboratory techniques can affect seed
bank study results [26,171], green ash may have been present in the seed bank
despite its failure to emerge in the greenhouse.

Germination:
Green ash seed requires cold stratification to germinate. Seeds dispersed
in the fall and winter germinate the following spring [22]. Taylor [280]
indicates that approximately 50% of the green ash seeds shed in the
spring initiate germination with those that overwintered on the ground; the other 50%
initiate germination the following spring. The embryos of newly
fallen green ash seed are dormant. Temperatures near 40 °F (5 °C)
are optimal for endosperm digestion, and germination is encouraged at
daily temperatures alternating
between 70 and 90 °F (20-30 °C) [268].

Green ash seeds can also germinate in flooded
conditions. Seed collected in the fall was stratified for 30 days and put in 2
inches (5 cm) of tap water. Thirty percent of immersed seeds germinated [82].

Other research indicates that moisture affects seed viability
and germinability. In a plantation, 500 seeds from 3 green ash trees
were collected weekly from 31 August to 2 November 1970. Seeds slated for
germination testing were stratified for 90 days at 40 °F (5 °C). The
moisture content of other seeds
was evaluated following collection. Researchers found that seed
viability increased with maturity in
consecutive weekly harvests. They also found that seeds with greater
than 71% moisture content may not be
fully mature, but seeds with 9% to 19% moisture were likely
fully mature. The study also revealed that the moisture
content of green ash seeds was influenced by late fall precipitation [70].

Seedling establishment/growth:
Green ash seedlings establish best in partially shaded sites with moist soil or
litter [209]. Researchers found more 1- to 5-year-old seedlings
grew under a partial canopy than in open- or closed-canopy
hardwood river bottom forests of southern Illinois. A greater
number of 1- and 2-year-old seedlings established on sites with low
(0.5 inch (1.3 cm)) litter depths than those with deeper litter (0.5-2
inches (1.3-5 cm)) [151].

From controlled studies, researchers established
that ideal soil temperatures for green ash seedling growth are above
61 °F (16 °C). Green ash seedling growth increased with increasing soil temperatures
from 50 to 70 °F (8-20 °C). Exceedingly low
root zone soil temperatures adversely affected root growth and resource
partitioning [13].

Green ash seedlings studied in 34 stands along North Dakota's Missouri River
floodplain occurred in all sampled stands but average density and frequency were
greatest on sites with "intermediate to high" nutrient levels [161].

Flood tolerance of seedlings:
In southern Illinois, green ash
seedling survival and development were monitored in flooded and nonflooded conditions.
Seedlings developed "well past the cotyledon stage" were exposed to water
levels approximately 1 inch above the soil surface. No green ash seedlings died
after 60 days of flooding; green ash seedlings in saturated soils averaged 7.8
inches (19.9 cm) tall, while those in well-watered, well-aerated conditions
averaged 1.4 inches (3.5 cm) tall [150]. However, no seedlings survived when green ash seedlings were
subjected to flooding levels 1 foot (0.3 m) above the soil surface [149].

Seedling survival and growth:
Seedling establishment, survival, and growth
have been extensively studied. In central Ohio,
researchers followed the establishment and survival of black ash, green ash, and
white ash seedlings in open meadows and deciduous forests.
Ashes made up 69.9% of 2,553 seedlings monitored. Significantly more
(p≤0.05) ash seedlings
emerged on lowland than upland sites and in forests than open meadows. Average ash seedling production
was 241±21(s x)
new seedlings/100 m²/year
from 1984 to 1993. In 1988 and 1990, seedling production peaked at
approximately 800 to 1,000
new seedlings/100 m². Production in 1988 and 1990 was significantly greater
(p≤0.05) than for any other year. Peak production was not correlated
with any observed annual or seasonal climate
events. The average life span of ash seedlings was 5
to 7 months. The seedling population produced in June of 1990 was 916.
By October of the same year, 66.7% were dead; by May of 1991, 96.6% were dead.
Survivorship was likely affected by white-tailed deer browsing;
deer occurred in densities of 0.6 to 0.7
animal/ha in the area [38].

Growth:
Green ash trees produce more than 1
growth flush per season [135], and growth rates may
increase with flooding frequency. Johnson [162] studied 34
stands along 80 river miles (100 km) of North Dakota's Missouri River.
From tree core analyses, Johnson estimated mean total radial tree growth at 26.8
mm for 17 green ash trees grown for 15 years during high flooding frequencies.
Trees grown for a 15-year period in the absence of flooding averaged 20.4 mm
total radial tree growth. From 14 trees,
Johnson estimated that the annual radial growth rate of green ash was 2.1 mm/year.

Asexual regeneration:
Green ash is capable of producing root crown and epicormic sprouts,
and both are typical following disturbances.
Many report "prolific" and "vigorous" root
crown sprouting following fire, logging, or
other events that damage the trunk [167,183,247,248]. Epicormic sprouting is
common following lesser damage to branches. Observations
of green ash trees in Winnipeg, Manitoba, indicate that epicormic shoot
production may not only be stimulated through damage. Researchers
suspect that environmental and/or genetic cues may also signal epicormic shoot
production [232].

The importance of vegetative sprouting following logging is illustrated in
the following 2 studies. On the Tombigbee River floodplain in Choctaw County,
Alabama, green ash trees were cut on 2 sites, 1 in early June and the other in
early October. A total of 83 green ash trees were cut and monitored following
logging. More than 50% of the stumps were sprouting 32 months after the fall
harvest, while less that 50% had sprouted by the 3rd postharvest year in the summer
harvest areas [115]. Secondary succession of mixed-hardwood
forests in southeastern Virginia's Chowan River basin was studied following
logging. Forests were clearcut from 2 and 20 years before the study period and
allowed to regenerate naturally. Early coppice forests were dominated by red
maple and ash, primarily green ash [265].

Flooding may also stimulate vegetative regeneration in green ash. The
north shore forest margin of Quebec's St. Lawrence estuary has experienced an increase
in the frequency of extreme flooding events in the 1950s and 1970s. Green ash trees damaged from these events regenerated
from the root crown and at the point of breakage on damaged stems [179].
On an island in the Chippewa River near Eau Claire, Wisconsin,
96% of the counted green ash stems were sprouts. This finding may indicate a
reliance on asexual
regeneration on sites where the likelihood and/or frequency of
disturbance is high [22].


SITE CHARACTERISTICS:



Green ash is most often described in association with riparian areas,
floodplains, and swamps, but is also found in areas that periodically experience
drought conditions. In the Great Plains states, green ash is described on floodplains,
streambanks, lake margins, and ravines but is also typical on homesteads and in
shelterbelt and windbreak plantings [124,269,294]. Moist to wet habitats are typical
green ash habitats described for the southeastern United States as well [84,110].
In Florida green ash is common on floodplains and calcareous river swamps [62]. In
Michigan sites occupied by green ash are at least
seasonally wet [297]. Green ash occurs on both wet and dry sites in Arkansas [155].

Soils:
Green ash tolerates a variety of soil types. Fertile, clay,
silt, and/or loam soils that range from poorly to well drained are the most common
generic descriptions of green ash soils [10,167,167,269].

Several researchers have described the soils in green ash vegetation types;
soils are described below:

Vegetation type Area of focus Soil description
sugarberry-American elm-green ash major river floodplains from eastern Texas to Atlantic Coast
& southern Illinois clay or silt loams [159]
green ash/chokecherry southwestern North Dakota >35% clay, pH 7.9-8.1
green ash/western snowberry southwestern North Dakota 30-59% clay, pH 8.0-8.3 [106]
green ash/chokecherry central and eastern Montana clay loam to sandy loam, water table <1 m in drought [133]
green ash-American elm western North Dakota pH 6.6-7, chemical ions in
order of decreasing concentrations¹: Ca>Mg>Fe>K>P>Na>Mn>Zn>Sr>Cu
[300]
green ash/chokecherry northwestern South Dakota moderately fertile, P levels low, N moderately low, 4-20% organic matter, neutral pH
[296]

¹
The green ash-American elm forest type when compared to other forest types in the area

had the highest organic matter, total N, and replaceable Ca and Mg levels [300].

On the Missouri River floodplain of North Dakota,
green ash dominates soils with high clay content. Green ash seedlings
and saplings display wide ecological tolerances with respect to soil
nutrients, organic matter, and water capacity [162]. In eastern Texas, soils
supporting green ash are heavy limestone clays, acidic sands, or sandy loams
receiving ample water [257].

Plantations, shelterbelts, and reclaimed farmlands:
Many have studied the relationships between soils
and green ash growth in plantations, shelterbelts, and reclaimed agricultural
areas. Soil analysis of a 6-year-old green ash plantation
on the Neches River terrace in Tyler County, Texas, revealed a positive
correlation between green ash height and pH of the A1
horizon. The pH of the A1 horizon ranged from 4.14 to 6.35 and accounted for 94.6% of the
variation in green ash tree height, which ranged from 4.5 to 18.1 feet (1.4-5.52
m). Green ash height and fine soil materials at a
depth of 2.5 feet (0.76 m) were negatively correlated. Correlations were reported
as significant (significance levels not reported) [307].

In shelterbelts of Swift County, Minnesota, green ash survival and growth
were monitored
for 5 years on 3 different soils. Green ash survival was "excellent"
regardless of soil type. However, trees planted on
excessively drained, droughty, sandy loam soils grew slowly, while trees on
silty, clay loam, calcareous soils with poor drainage grew best. Cloudy and
rainy weather
during the establishment period likely enhanced survival rates [55].

On abandoned farmlands of southwestern Quebec, green
ash seedling survival and growth were compared on sites with
stony littoral, sandy beach, dry-mesic moraine, mesic moraine, morainic ridge,
and wet marine soils. Green ash survival was greater than 70% on all
sites; however, height growth was best on nutrient-rich, fine-textured, well-drained
dry-mesic moraine soils. Green ash displayed wide ecological tolerances of the
soils studied, which ranged from rapidly to imperfectly drained with sand
contents of 31% to 86% and clay contents of 7% to 26% [63].

Flooded soils:
Green ash is flood tolerant, but
studies indicate that green ash is more common on temporarily flooded sites.
The elm-ash-cottonwood forest type is
common along rivers and streams in the north-central states, and the forest
dominants reportedly tolerate
flooding for up to 50% of the growing season [209]. In lowland forests of
southern Ontario, green ash constancy was 90% on temporarily flooded sites, 70%
on sites located 49 feet (15 m) inland from ponds, and 30% on mounds in ponds that
were raised above water level [92]. In the Piedmont of Georgia, researchers indicate
that green ash "rapidly succumbs" to continued inundation during the growing
season [94]. In lower hardwood swamp forests and backwaters or flats, green ash
is typical on sites where flooding is not continuous [250].

Controlled experiments found reduced growth  in green ash seedlings
grown in flooded conditions. Flood levels were 2 inches
(5 cm) above the soil surface and lasted for 32 days. The relative growth
rate of green ash leaves was 46% of well-watered controls.
Root and stem growth of flooded seedlings were 6% and 73% of controls,
respectively. The net photosynthetic rate of flooded green ash seedlings
was 50% of controls by flood-day 8 and 30% by flood-day 32 [123].

Elevation:
Below are the few areas that report elevational tolerances
for green ash:

Area Elevation
Colorado >6,000 feet [120]
western North Dakota
(green ash-American elm type) 1,890-3,200 feet [300]
central and southern Texas >3,000 feet [257]
Utah "lower" elevations [304]
West Virginia "low" elevations [272]
southern Appalachians > 3,000 feet [84]

Climate:
The wide range occupied by
green ash implies a wide tolerance of climatic conditions. In a review of
green ash, Kennedy [167] reports that green ash grows in humid to subhumid
environments with average annual precipitation levels between 15 and 59.8
inches (380-1,520 mm), low average January temperatures of -0.4 to 55 °F
(-18 to 13 °C), mean July temperatures from 64
to 81 °F (18-27°C), and an average number of 120 to 280 frost-free days.

In a 2-year study in the Little Missouri Badlands of North Dakota, where
green ash grows, minimum and maximum temperatures reached -35 °F (- 31°C) and 105
°F (41 °C), respectively, and annual precipitation averaged 15.75 inches (400
mm) [318]. The climate described for green ash habitats in southeastern
Texas is much milder. Reported minimum and maximum temperatures were 51.1
°F (10.6 °C) and 81.7 °F (27.6 °C), respectively, and annual precipitation
averaged 52 inches (1,320 mm) in the Big Thicket National Preserve. However,
the frequency of
tropical storms and hurricanes in this region can be high [194]. A temperate
climate regime is reported for the northern shore of Quebec's St. Lawrence
estuary, which supports an almost pure green ash stand. From 1960 to 1988, the
mean annual precipitation was 38.9 inches (987 mm), 9.1 inches (231 mm) of which
was snow. The average January temperature was 10.9 °F (-11.7 °C), and the mean
July temperature was 67.1 °F (19.5 °C) [179].

Drought tolerance:
Although overwhelmingly described as a riparian, floodplain species, green ash
has survived drought conditions in several areas. In southeastern South Dakota,
green ash survival was 63% over a 5-year period (1934-1939) that included 2 years
described as "the most severe droughts ever to visit" the area.
The author cautioned that
green ash should not be planted on upland sites with fine-textured soils,
suggesting an increased likelihood of green ash tree mortality
during drought conditions on these sites [191].
Green ash trees in windbreaks of western Minnesota suffered
severe drought conditions in 1934.
By the end of that summer, just 8% of
green ash trees were dead or dying. However, in western Kansas,
green ash mortality was 33% at the end of a 4-year-long drought. Trees
investigated were all mature, established green ashes [8].

Cold tolerance:
Green ash survival is
consistently high in shelterbelt plantings of the northern Great Plains, where
winters can be severe. However, green ash may suffer slightly increased
winterkill with age, injury from late-spring frosts, and occasional broken
stems from drifting snow [100]. Green ash seedlings grown from seed
collected in Wisconsin were exposed to low
temperatures and stomatal closure was measured. Green ash seedlings exposed to 3
days of 37 °F (3 °C) temperatures had increased stomatal closure with each successive
day. Treatments of 43 to 48 °F (6-9 °C) did not produce the same response,
suggesting that 37 °F (3 °C) is below green ash's cold tolerance [172].
Dormant 1-year-old twigs collected from an area near Greenville, Mississippi,
and a site in St. Paul, Minnesota, were used to evaluate the freezing resistance
of green ash. Researchers defined freezing resistance
as the lowest temperature at which no injury occurred. Green ash bud and cortex
xylem tissue from Mississippi resisted freezing at temperatures of -20 °F (-30
°C) and -40
°F (-40 °C), respectively. Bud and cortex xylem tissue from Minnesota resisted
temperatures of -40 °F (-40 °C) and -90 °F (-70 °C), respectively [243].


SUCCESSIONAL STATUS:



Green ash is described as a pioneering, early successional, mid-successional,
subclimax, climax, and old-growth species in the literature.
In American beech (Fagus grandifolia)-sugar maple forests of
southern Indiana, green ash is an
early, open-field colonizing species that is later replaced by
American beech and sugar maple
[309]. The hackberry-elm-ash (Celtis-Ulmus-Fraxinus spp.)
vegetation type occupying low flats and sloughs of the
Mississippi River floodplain is considered temporary and typically
follows heavy cutting and/or fire events [221]. Green ash appears
early in the successional development of alluvial soils, sometimes as a pioneer
or as a replacement to cottonwood, quaking aspen, and/or black
willow communities [167]. The quaking aspen-green ash community type on
floodplains of the Missouri River is a mid-seral type that is later replaced by
the green ash/western snowberry type [106].

The cases in which green ash is labeled a late-successional or climax
species are equally abundant. In the successional development of Nebraska's river
floodplains, green ash is identified as a late-seral species [7].
The sugarberry-American elm-green ash cover type
is identified as persistent by several authors [159,250].
Studies of 34 stands along 80 river miles (100 km) of North Dakota's Missouri River
floodplain revealed an increased importance of green ash with
increased substrate depth and increased stand age [162].
Along rivers and streams of the north-central states, the elm-ash-cottonwood
forest type is considered subclimax [209].
After studying a sere along the Yellowstone River from Glendive to Sidney,
Montana, researchers categorized green ash as a climax species [40]. Green
ash also occurs in the old-growth Schnabel Woods of Boone County, central
Missouri. However, the importance of green ash
has declined over the last 40 years in the area [235]. Kindscher and Holah [169]
report that green ash importance increases with increasing stand age in
plains cottonwood-hardwood gallery forests of the Great Plains, and a dense
layer of green ash saplings is common in old-growth stands.

Shade tolerance:
Green ash is often described as moderately shade tolerant. Shade tolerance, however,
decreases with increasing age of green ash trees [159,250].

Several have studied green ash seedling growth under shaded conditions.
Growth and morphological differences were apparent in 2-year-old green ash
seedlings grown under different levels of shading. After 5 weeks, seedlings in 4%,
8%, and 100% of full sun ceased to grow, but growth continued in 20% and 40% of
full sun. Leaf thickness
increased linearly with decreased shading. Trees in heavy shading had poorly
developed crowns, reduced height growth, and fewer and smaller branches. The growth
rate of trees grown in moderate shade and full sun conditions exceeded that of
trees grown in heavy shade [25].

Findings were similar for nursery-grown green ash seedlings subjected to full
sun and shade treatments in Lincoln, Nebraska. Comparisons of seedlings grown in
full sun and shade (18% full sun) revealed that leaf blade area was larger and
leaves were thinner on shade-grown trees. Relative growth rate (pretreatment
growth rate/posttreatment growth
rate) was 1.27 in shade and 2.85 in full sun [196].

General disturbance:
Green ash easily colonizes
disturbed sites when a seed source is available. In a study of green ash
ecology, Taylor [280] reported that green ash frequency increased as the amount of
disturbed area increased. In the Opinicon Lake area of
southeastern Ontario, succession was monitored in 2 hay fields abandoned in 1970. Half of one field was ploughed in
1975. On 3 sides, fields were bordered by forests dominated by American elm, white ash, green ash, and sugar
maple. In all plots, the occurrence of green ash was 54% for all years (1976-1994).
Researchers indicated that green ash seed was likely wind dispersed; birds or small
mammals may have also aided dispersal by caching seed [72].

Canopy release:
Many studies indicate increased green ash growth in forest openings. Sites in several
mixed-hardwood forests of southeastern Virginia's Chowan River basin were
clearcut 2 to 19 years prior to study and allowed to regenerate naturally.
Regeneration in the mixed-hardwood forests was dominated by ash, primarily green ash, and red maple. Most early regeneration was due to sprouting [265]. Green ash
was also identified as the species that most quickly colonized forest openings
in an extensive study of 34 stands along 80 river miles (100 km) of North Dakota's
Missouri River floodplain [162].

In the Little Missouri National Grasslands of southwestern North Dakota's
Custer National Forest, canopy removal experiments were monitored for 7
years in degraded green ash-dominated woody draws. Sites that had 40% of
the overstory canopy removed were compared to those with no removal.
Green ash tree heights were significantly (p=0.04)
greater on sites with partial canopy removal for the 3rd, 4th, 5th, and 6th
posttreatment years [291]. Harvesting 40% of the trees in the area also
stimulated green ash sprouting and seedling growth. Seedling height was greater
on harvested than unharvested sites, and within the harvested sites
increases were greater
on sites closed to grazing [41].

Green ash increased in importance following harvests in
oak-dominated, mixed bottomland hardwood forests
along the Tombigbee River floodplain in Choctaw County,
Alabama. Before harvesting in the summer and
fall of 1992, green ash made up 5% of the preharvest stems. Following harvest,
green ash contributed 22% to the total number of stems in the area
[116].

Secondary and old-growth forest comparisons:
Green ash is found in both secondary and old-growth forests. Researchers
compared 2nd-growth (<150 years old) and old-growth (>150 years old) forests
in the Wayne National Forest of southeastern Ohio. Green ash was present as a canopy
species in only 2nd-growth forests, as a sapling in most forests over 70
years old, and as a seedling in all forest age classes sampled [112]. On Horseshoe Lake Island in
Alexander County, Illinois, green ash was most important in old-growth forests.
Old-growth stands had been relatively undisturbed, while 2nd-growth stands
were undisturbed for just the last 75 years [239].
Researchers predicted that green ash would "gradually diminish" from the
approximately 100-year-old bottomland forests in Virginia's Meherrin River
in Greensville County [251].

Floodplain succession:
The patterns of green ash succession
on alluvial floodplains are similar for many different rivers and
regions. Green ash typically invades pioneer communities early in succession
and remains in mature floodplain communities. Along a sinuous section
of the Bogue Chitto River in Washington Parish, Louisiana, green ash
occurred on the youngest
surfaces referred to as the herb-forest transition zone and the oldest surfaces
on the upper floodplain margin or the cut bank of the upstream river bend
[238]. Studies of a sere along the Yellowstone River from
Glendive to Sidney, Montana, suggest green ash is a climax species.
Newly formed river sandbars
were populated by quaking aspen and willow (Salix spp.) communities.
Willows died out approximately 20 years
following establishment. After about 100 years, quaking aspen declined and
shrubs, primarily Wood's rose (Rosa woodsii) and western snowberry,
increased in importance. Green ash colonized young quaking aspen
communities, persisted through the shrub-dominated stage, and was common as a
seedling in subsequent communities. The researcher expected green ash seedlings
would replace decadent green ash adults, and thus green ash is likely a climax
species [40].

Along the Missouri River of southeastern South Dakota, the 1st established woody
vegetation is a black willow-sandbar willow community that is
soon invaded by quaking aspen. The black willow-quaking aspen community persists for
nearly 15 years before willow trees begin to die. More mesic conditions
prevail after the loss of willows. Quaking aspen growth deteriorates about 50
years following establishment. With the loss of quaking aspen, green ash, American elm, and
boxelder dominate the floodplain [311]. Another reach of the Missouri
River floodplain in North Dakota, extending from the Garrison Dam to the Oahe
Reservoir, has also been well studied. On recent alluvial deposits, quaking aspen
and peachleaf willow are pioneers. Green ash and boxelder are 1st to reach tree
size in the eastern cottonwood-peachleaf willow forests and persist
in intermediate- and old-aged
stands as well. The oldest trees in the study area were 300 to 350 years old,
and green ash seedlings occurred in stands of all ages [161].

Using aerial photographs, ring counts, and/or stem cross sections,
researchers reconstructed and evaluated forest floodplain succession on the
Republican River of Clay County, Kansas. First to invade floodplain alluvium
were sandbar willow, peachleaf willow, and quaking aspen; these species
established on 1- or 2-year-old substrates.
Within 10 years, red mulberry (Morus rubra), American elm, green ash,
and boxelder appeared.
Hackberry established when the floodplain surface was 10 to 30
years old. Sandbar willow survived only about 10 years, peachleaf willow survived for
approximately 30 years, and quaking aspen died within 100 years of establishment. In
100- to over 150-year-old stands, American elm
and hackberry dominated, but green ash was present as well. Below is the average
basal area of green ash
in different-aged stands [31]:

Stand age (years) 0-10 (n=8) 10-30 (n=17) 30-60 (n=7) >60* (n=7)
Trees <6 cm dbh <0.005 0.03 0.03 0.06
Trees >6 cm dbh 0 0.03 1.84 1.41

*Within the >60-year-old-stands, 2 were over 100 years old, 1 was 120 years
old, and 1 was 150 years old.

Flooding: In a review, Hook [144] classified green
ash as
moderately flood tolerant. This tolerance rating suggests that green ash can
develop from a seedling to a mature tree in soils that are waterlogged
approximately 50% of the time. Winter, spring, and/or early summer flooding
are most typical in green ash habitats. For more information on the
survival and growth of green ash seedlings grown in flooded conditions, see the Seedling establishment/growth
discussion above.

Eighteen years of vegetation change were monitored in Hickory Creek
streambank forests of northeastern Illinois. Green ash
dominated the frequently flooded lowland sites from the streambank margin to 3
feet (1 m) above bank level. The researcher described green ash as "very flood
tolerant." Over the course of the 18-year-study, the relative density of green
ash decreased but relative dominance increased [30].

Within the Montezuma National Wildlife Refuge of central New York,
researchers compared 2 seasonally flooded sites to a nonflooded control site.
The eastern pool was flooded in the spring from mid-March to mid- or late July.
The western pool was
flooded from mid-September to mid-November. Vegetation was surveyed in 1965
(before flooding of the western pool
and 1 year following flooding of the eastern pool), in 1979 (2 years after the end
of flooded conditions), and in 1995 (18 years after discontinued flooding in the
area). Researchers found that in 1995 the density of saplings in the eastern and
western pools was 30 to 90/ha, respectively, but was 270/ha in the
control area. Sapling
cores suggested that the majority of sapling recruitment occurred from 1967 to
1973, indicating lower recruitment levels in times of flooding. Green ash density and
basal area are provided below for the flooded and nonflooded periods [76].

Site
East-
flooded 1964-1977
West-
flooded 1966-1977
Control
year density
(trees/ha ± s x) basal area (m²/ha) density basal area density basal area
1965 160 ± 7 ---- 140 ± 0 ---- ---- ----
1979 170 ± 47 8.2 ± 2.4 190 ± 38 5.8 ± 1.8 330 ± 92 6 ± 2.2
1995 170 ± 30 9.3 ± 3.0 ---- 8.7 ± 3.0 530 ± 138 4.7 ± 1.4

Extreme weather events:
Typically a majority of
green ash trees survive the high winds and/or ice that accompany extreme
weather events. In eastern Ontario, the mortality of
62 green ash trees (>3.9 inches (9.9 cm) dbh) was 24.2% for 1996 to 1998
(after ice storms). Mortality was 4.4% from 1999 to
2000, and no green ash trees died in 2001. Damaged trees died relatively quickly [147]. In a "50- to 100-year"
ice storm event that deposited ice 0.8 inch (2 cm)
thick on branches of bottomland forests species in western New York's Till Plain,
the average green ash crown damage was just 10% [246].

Following Hurricane Hugo, researchers evaluated the damage to mixed
bottomland hardwood species in Congaree Swamp National Park of South
Carolina. Winds exceeded speeds of 96.3 miles/hour (155 km/h) in
forests that had been relatively undisturbed for the previous 100 years. In
slough areas, 4 of 29 sampled green ash trees were uprooted; in bottomland
sites, just 2 of 41 green ash trees were uprooted [225]. The
number of recruits, defined as number of individuals to reach 2 cm dbh,
increased significantly (p<0.05) following Hurricane Kate in
old-growth southern mixed hardwood forests
north of Tallahassee, Florida. There were 2 prehurricane (1978 to 1984) green ash
recruits and 11 posthurricane (1985 to 1992) recruits.
Increased recruitment was likely facilitated by the overstory mortality that
followed the high wind speeds of 99 miles/hour (160 km/h) over areas with soils saturated
by the storm [27].


SEASONAL DEVELOPMENT:



Green ash produces flowers before leaves [304]. The process from
the start of inflorescence bud growth to fruit set takes 3
years for green ash trees, and on average 1/3rd of the flower buds initiated
produce flowers [231]. In a review, Farmer and Pitcher [93] report that male
trees flower almost every year, while female trees flower every 2 to 5 years.

From a 5-year study of 5 green ash trees in the Quetico-Superior
Wilderness Center of
northeastern Minnesota, Ahlgren [6] reported an "abrupt" increase in
stem expansion with an "extreme" rise in temperature. Green ash bud swell
coincided with flowering but occurred only after temperatures had reached 70
°F (20 °C) or more. The 1st trees leafed out on 10 April, and the last trees
to leaf out did so on 3 June. The earliest trees to shed their leaves did
so on 19 September, and the latest trees dropped leaves on 3 October [6].
In Ithaca, New York, researchers found that green ash
seedlings initiated root growth in mid- to late May when temperatures were between
54 and 59 °F (12-15 °C); root growth ceased in the fall when
temperatures were 40 to 50 °F (6-8 °C) [135]. In Manitoba, Remphrey
[230] reports that shoot growth begins sometime from mid-April to early
May. Green ash leaf fall is typically earlier
than other associated species including maples (Acer spp.),
elms, plums (Prunus spp.), alders (Alnus spp.), and
oaks [308].

Below are the reported fruiting and flowering dates
for green ash:

State or region Flowering dates Fruiting dates
Florida spring [62,317] ----
Illinois April-May [206] ----
north-central Texas February-March [79] ----
West Virginia April-May [272] ----
Blue Ridge province April-May [312] ----
Carolinas April August-October [227]
Great Plains April-May [124] ----
New England ---- 2July -25
September [249]
north-central Plains mid-April August-September [269]
Quetico-Superior Wilderness Center of northeastern Minnesota 1st flowered on 23 April;
last initiation of flowering on 25 May* Seeds fell 3 October** [6]

*Based on a 5-year-long study of 5
trees; tree age and site occupied varied.

**Based on a single year of study.

Management considerations

provided by Fire Effects Information System Plants
More info for the terms: basal area, codominant, density, hardwood, restoration, tree

Urban landscapes:
Green ash's salt and pollution tolerances make it a likely choice in urban landscapes.
Heisler and others [139] suggest using green ash in parking lot plantings. Lait
and others [178] have researched the growth and survival of
green ash cultivars under a
variety of urban conditions. 'Summit' tolerated ozone,
sulfur dioxide, and a combination
of both pollutants [164]. 'Summit' and 'Marshall's
Seedless' both had high survival in street plantings in Wisconsin cities
[205]. 'Cardan' was best adapted to the northern Great Plains, and would likely do
well in windbreaks, mining reclamations, floodplains, and disturbed areas [290].
In a study conducted in Logan, Utah, 1-year-old green ash seedlings were watered with
an excess-of-salt solution for an entire growing season. Salt solutions provided
a known salinity level without build up. Green ash survived levels
of salt up to 8,000 ppm [207].

Invasive species:
Native ungulate use of green ash-chokecherry
habitat in Theodore Roosevelt National Park, North Dakota was reduced by 32%
when sites were infested with leafy spurge (Euphorbia esula) [284].

Diseases/damaging agents:
Green ash is susceptible to a
number of diseases and damaging agents.
Ash dieback is common; for a description of symptoms, causes, and control see
Hibben and Silverborg [141].
The emerald ash borer, an exotic insect pest identified in Michigan, primarily
attacks green ash trees. For more information on the potential control and means for
mitigating the spread of this species see [121,122,310].
Riffle and Peterson [236] and Solomon and others [262]
provide information on green ash
tree diseases, their symptoms, causes, damaging agents, and potential controls.
Chlorosis, foliar fungi, and wood, root, and stem rots that infect naturally
occurring and managed populations are described and
discussed.

Lesica and others [182] revealed a relationship between decreased annual
precipitation and increased incident of green ash infected with a common stem decay
pathogen. Trees sampled in 17 stands in east-central Montana, together with
precipitation data, suggested that drought conditions may increase the incident of
green ash heartwood decay [182].

Growth relationships:
Many researchers report relationships between growth aspects of green ash that are used in regression
equations and models to gain additional information. Below is a table summarizing the
system of equations and where they are most likely useful:

Data collection area
Related parameters
Additional information
Dependent variable Independent variable
AR, LA, MO, OK, and TX potential relative increment and optimal annual dbh growth min, max, and mean dbh n=3,058 [46]
Gulf and Atlantic Coastal Plain nutrient content dbh and provided regression coefficients hardwood forests [223]
IN projected basal area and tree number initial basal area and number of trees model for growth and yield in elm-ash-cottonwood vegetation type,
used trees with >5 inch dbh [253]
KS site index rating age and height of dominant and codominant trees 3 to 5 uniformly shaped, dominant and codominant
trees [102]
TX, Lewisville Lake Wildlife Restoration Area age dbh bottomland hardwood forests, n=9 [24]
Mississippi, Missouri, Illinois, and Des Moines rivers in
MO, IA, and IL height dbh bottomland hardwood forests, n=110 [64]
MS crown radius dbh equations for dominant, codominant, and intermediate trees [96]
Mississippi River Delta crown radius dbh open-grown trees [113]
West-central MS volume and weight A variety including: age, dbh, height, wood and bark
moisture contents, specific gravity, and density [244] ----


Fraxinus pennsylvanica:

Other uses and values

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More info for the term: natural

Native people of the Great Plains utilized green ash. Bows, arrows, drums, tent poles,
teepee pegs, and meat-drying racks were often
constructed of green ash [136]. It was believed that green ash had beneficial
natural powers and was often used to carry and/or display ceremonial or symbolic
objects of the Omaha and Pawnee tribes [105]. The Cheyenne built
portions of their Sun Dance Lodge with green ash, as they too believed in green
ash's powers [136]. The Cheyenne Contrary Warriors reportedly wore whistles made
of green ash around their necks [137].


Wood Products:
Green ash wood is course grained, heavy, hard, and strong [269,294].
Sapwood is white [269]. Green ash is used to make tool handles,
furniture, and interior furnishings [294].

Plant Response to Fire

provided by Fire Effects Information System Plants
More info for the terms: root crown, seed, tree

While some green ash trees may survive fire, those that are top-killed are
capable of "prolific" root crown sprouting following fire [183,247,248].
The high seed production potential [38,308], wind-dispersed seed [22,167],
and wide ecological tolerance of seedlings [63,162] make green ash
a likely candidate for off-site colonization of burned sites. Seedling recruitment, however, may require a nearby seed-producing tree,
as green ash seed on or near the soil surface likely does not survive fire
[185].

Post-fire Regeneration

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More info for the terms: adventitious, initial off-site colonizer, root sucker, tree

POSTFIRE REGENERATION STRATEGY [270]:




Tree with adventitious bud/root crown/soboliferous species root sucker

Initial off-site colonizer (off-site, initial community)

Regional Distribution in the Western United States

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More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [32]:





7 Lower Basin and Range

9 Middle Rocky Mountains

10 Wyoming Basin

11 Southern Rocky Mountains

12 Colorado Plateau

13 Rocky Mountain Piedmont

14 Great Plains

15 Black Hills Uplift

16 Upper Missouri Basin and Broken Lands

States or Provinces

provided by Fire Effects Information System Plants
(key to state/province abbreviations)


UNITED STATES

AL AR CO CT DE FL GA

IL IN IA KS KY LA ME

MD MA MI MN MS MO MT

NE NH NJ NY NC ND OH

OK PA RI SC SD TN TX

UT VT VA WV WI WY DC



CANADA

AB MB NB NS ON PE PQ
SK

Value for rehabilitation of disturbed sites

provided by Fire Effects Information System Plants
More info for the terms: basal area, density, forest, fuel, hardwood, natural, reclamation, restoration, seed, tree, vines

Green ash is widely used in revegetation,
reclamation, and protection plantings. There is abundant literature on the
multistaged revegetation process of green ash from seed collection
to monitoring success.

Seed collection/storage:
Green ash seed is available commercially [288], and many
guidelines are available for the
successful collection, storage, and germination of green ash seed. Cunningham
[73] provides delineated seed collection zones where soils,
precipitation, and temperature regimes are similar within the Great Plains. Zones
are designed to be matched with the area being revegetated or restored.
Cram and Worden [71] suggest collecting green ash seed only when
its moisture content is below 49%, as seed moisture
content is likely related to seed maturity.
Bonner and Turner [43] suggest ways to rapidly measure the
moisture content of green ash seeds. If stored properly, green ash seed retains
its viability for over 8 years of storage. Cram [69] reports 80% germination of
green ash seed after 8 years of storage at 0° F
(-20 °C). Another researcher provides a green
ash viability equation based on 5 years of seed storage [42].
Comprehensive information on green ash seed
collection, seed storage, and planting is available [308].

Revegetation methods:
Researchers have tested a
variety of green ash planting methods. Researchers found that water level was
most important to green ash survival on
wetland sites from
Louisiana to South Carolina. Green ash survival was
85% to 100% for moderately root-pruned
seedlings on sites with shallow water (0-10 inches (0-30 cm)) and tree shelter.
Survival was
less, 45% to 65%, on shallow water sites without tree shelter. In deep water
(10-20 inches (30-60 cm)), survival ranged from 0% to 100% [66].

Researchers used an underplanting method to
regenerate degraded bottomland hardwood forests on the Atchafalya River basin of
south-central Louisiana. Green ash seedlings were planted before
harvesting the "overmature" eastern cottonwood and black willow overstory.
Bareroot forest nursery seedlings were planted in the winter of 1983 to 1984, and
sites were harvested from April through September of 1985. Green ash survival
before harvesting (1985) was 98.2% (n=589), and in the 1st postharvest year
(1986) survival
was 74.2%. An estimated 9.2% of the mortality was attributed to natural causes,
chiefly animal damage, and 16.7% of the mortality was logging related. Green ash
seedlings grew rapidly. Two years after logging, green ash
seedling height averaged 2.8 feet (0.85 m), and 38.7% of seedlings were over 3
feet (1 m) tall [59].

Some literature provides comprehensive information on the initiation and care
of revegetation projects. Manci [192] provides a thorough review on the
planning, implementing, sustaining, and monitoring of riparian restoration
projects, and Houston and Buckner [152] compare cultural,
mechanical, and chemical treatment
effects on the growth of green ash in reforestations and plantations.

Plantations:
Green ash is often successful in
managed plantations. Typically survival does not require the control of weeds
or other understory vegetation. However, vines can
decrease green ash growth [157]. Baker and Broadfoot [20]
provide a site suitability chart
for green ash plantations based on soil and hydrologic characteristics. Best
green ash soils are typically deep, medium-textured, noncompacted, silts or loams
with a pH of 5.5 to 7.5. Floodplains or stream bottoms with a 2- to 6-foot
(0.6-2 m) water table that experience winter or spring flooding are considered
ideal green ash sites [20]. Seeds of select trees growing in
the National Environmental Research Park of
New Ellenton, South Carolina, were collected in the fall of 1992
and grown in nursery beds
until February 1994. Seedlings were transplanted into a
cleared pine plantation in the Crackerneck
Wildlife Management Area of South Carolina's
Savannah River Research Park. As of
1998, green ash seedling survival was 100% although 1997 and 1998 experienced
drought conditions, and seedlings were browsed by deer. Six seedlings produced
seed in 1998 [170].

Ten years after planting green ash seedlings on a cleared forest site,
an abandoned field, and a
previous plantation in eastern Texas, survival ranged from
95% to 98%. Seedlings were grown from seed collected in 5
eastern Texas locations, and weeds and sprouts of other
species were controlled mechanically [267].

For 20 years, researchers monitored survival and growth of green ash
planted in a cleared hardwood-pine forest along a minor stream bottom
in southeastern Arkansas. When the plantation was 6 years old, green ash was
among the fastest growing of the 8 planted species. However, by age 20, green ash
height growth was negligible or none. Soil tests revealed it was
infertile for hardwood trees and likely explains the poor green ash growth [54].

Abandoned agricultural lands:
Green ash commonly invades and is often actively planted on old fields.
Newling [216] described green ash as a typical volunteer species on
old fields that were previously bottomland hardwood communities. Based on
soils information, Groninger and others [126] suggest
that green ash would be valuable in reforesting poorly
drained sites in the Mississippi Delta region of Arkansas, Mississippi, and
Louisiana cleared for soybean crop production.

Green ash survival was 98% three years following its planting on a
recently abandoned soybean field of southwestern Tennessee. Early
green ash height growth was greatest when weedy species were mechanically
controlled [299]. On an abandoned agricultural field
in Catahoula Parish, Louisiana, green ash survival was approximately 60%.
Seedlings were used in the afforestation effort, and over the
5-year monitoring period, the study area was inundated
by 2 flooding events per year. The maximum consecutive number of flooded days
was 116, and the maximum flood level was 10.3 feet (3.13 m) above flood stage [219]. Green
ash survival was nearly 100% on an improved grass pasture in Poteau, Oklahoma. The
large-scale cultivation methods, site preparation, maintenance, and
hand-planting methods tested are described in the original reference together with
costs involved [260].

Shelterbelts:
The use of green ash in shelterbelts or other protective plantings is extensive.
Often times shelterbelts are needed on sites that would not naturally support
green ash. George [100] followed the successes and failures of shelterbelt
plantings across the northern Great Plains. He found overall that green ash
growth was good and survival was consistently high. Trees grown in deep shade
frequently died back, but growth was generally good in dry conditions [101].
However, green ash suffered slightly increased winterkill with age, injury with
late spring frosts, and occasional broken stems from drifting snow [100].
Winter damage was greatest during severe drought years [101].
In the northern Great Plains, winters and summers can be severe.
Within a 6-month period, 2 North Dakota
weather stations located less than 100 miles (200 km) apart reported a temperature range
of 181° F (100 °C). Average precipitation in
northern and southern zones from 1914 to 1946 ranged from 13.6 to 16.2 inches
(34.6-41.1 cm), and the frost-free period lasted 127 to 139 days [100].

Johnson [160] reported poor green ash
survival on dry sites. The potential use of green ash
in fuel breaks was evaluated near conifer plantations with
high fire frequencies. Study sites in Wexford County, Michigan,
and Bayfield County, Wisconsin,
were dry and sandy. Six years after planting green ash, survival ranged from 37%
to 42%.

Surveys from private landowners and operators
have also provided information on the use and success of green ash
in windbreaks. Thirty-five percent of respondents rated green ash
performance as excellent, 42% rated it as good, 14% rated it fair, and 6%
as poor. Those who planted green ash by machine rated
performance significantly (p≤0.05) higher than those who
hand planted [286].

Abandoned mining sites:
Green ash has been
successfully used in mine reclamations from Wyoming to
Pennsylvania. The Minkers Run Mine of southeastern Ohio was deep mined from 1878 to
1924, surface mined from 1948 to 1950, and revegetated 15 years following abandonment
in 1966. Green ash density was 110/ha in
1966, and 79/ha in 1997 [56].
Green ash survival ranged from 98% to 83% on other Ohio coal mine spoils that
were abandoned from 1 to 7 years prior. The pH of spoils ranged from 3 to 7 or
more. A number of "toxic patches" were noted on
some sites, and rabbit browsing
was common to severe [186]. In southeastern Kansas green ash
was 1 of several species evaluated
on a coal strip-mine site that was mined in 1946 and
planted in 1950. Green ash survival averaged 94% after 10 years, but most trees
were bent with multiple branches, lowering timber
value [245]. On a lignite coal strip in eastern Texas, green ash
survival was an estimated 81% on sites planted 3 to 10
years earlier [119]. Green ash survival on a coal
mine spoil in Campbell County, Wyoming,
was 40% to 80%. Spoils were slightly more
saline than surrounding soils.
Survival rates were higher for bare root than container seedlings, and
interestingly irrigated seedlings grew slower than nonirrigated seedlings [36].

Green ash survival was evaluated on several
surface mined reclamation sites in Colorado and Wyoming.
Seedlings were planted in 1975 on overburden covered with 6 to 18 inches (20-46 cm) of topsoil.
Green ash seedling survival
on coal mine sites ranged from 42% to 100% in 1977. Survival
was 100% on Colorado mine sites at 7,500 feet (2,300 m) elevation that
received an average annual precipitation of 40.2 inches (1,020 mm). The low 42%
survival was on sites in Wyoming at 6,000 feet (1,800 m) that averaged 33.8 inches
(858 mm) of annual precipitation. No green ash seedlings planted on a uranium
mine site in Wyoming survived [153].

Green ash growth and survival were evaluated on mine spoils of
Missouri, Kansas, Oklahoma, Illinois, Indiana, and Pennsylvania. From this
study, Vogel [295] reported a lower pH
limit of 4 and an upper elevation limit of 2,500 feet (760 m)
for green ash seedlings on
mine sites. Growth was considered best on soils with a high proportion of soil
particles greater than 2 mm in size. Presented below are the average survival
percentages and growth characteristics of green ash on 30-year-old mine spoils
[295].

Location Number of sites Survival (%) Dbh (inches) Height (feet) Basal area (ft²/acre)
MO, KS, OK 9 33 3.8 28 23.0
IL, IN 11 53 4.7 ---- 56.8
OH 4 55 4.0 27 42.7
PA* 2 69 2.5 15 ----

*Revegetated mine areas were 10 years old in Pennsylvania.

Landfills:
Researchers have also planted green
ash on backfilled landfill sites
in East Brunswick, New Jersey. Root growth was stunted
compared to control plots when just 20 inches (60 cm) of soil was spread over a
30-foot (9-m)-deep former refuse landfill [104].

Associated Forest Cover

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Green ash is an integral part of the forest cover type Sugarberry-American Elm-Green Ash (Society of American Foresters Type 93) and is an associated species in the following types (22):

16 Aspen
26 Sugar Maple-Basswood
42 Bur Oak
52 White Oak-Black Oak-Northern Red Oak
62 Silver Maple-American Elm
63 Cottonwood
65 Pin Oak-Sweetgum
87 Sweetgum-Yellow-Poplar
88 Willow Oak-Water Oak-Diamondleaf (Laurel) Oak
89 Live Oak
91 Swamp Chestnut Oak-Cherrybark Oak
92 Sweetgum-Willow Oak
94 Sycamore-Sweetgum-American Elm
95 Black Willow
96 Overcup Oak-Water Hickory
101 Baldcypress
102 Baldcypress-Tupelo
103 Water Tupelo-Swamp Tupelo

Species most commonly associated with green ash are boxelder (Acer negundo), red maple (A. rubrum), pecan (Carya illinoensis), sugarberry (Celtis laevigata), sweetgum (Liquidambar styraciflua), American sycamore (Platanus occidentalis), eastern cottonwood (Populus deltoides), quaking aspen (P. tremuloides), black willow (Salix nigra), willow oak (Quercus phellos), and American elm (Ulmus americana).

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Climate

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The climate within the range of green ash is subhumid to humid, with the following ranges: Annual precipitation from 380 to 1520 mm (15 to 60 in), warm season precipitation from 250 to 890 mm (10 to 35 in); average January temperature of -18° to 13° C (0° to 55° F); average July temperature of 18° to 27° C (65° to 80° F); snowfall from 0 to 254 cm (0 to 100 in); average length of frost-free season 120 to 280 days.

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Damaging Agents

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Many insects feed at least occasionally on green ash. One of the most serious is the oystershell scale (Lepidosaphes u1mi), which is distributed throughout the Northeast and can cause serious damage among seedlings and small trees. The carpenterworm (Prionoxystus robiniae) bores into the heartwood of large branches and trunks, permitting the entrance of fungi. The brownheaded ash sawfly (Tomostethus multicinctus) and the blackheaded ash sawfly (Tethida barda) occasionally cause serious damage to shade trees. The ash borer (Podosesia syringae) damages the stems of trees of all sizes, causing lumber degrade in timber-sized trees and contributing to decline and mortality in shelterbelt plantings (23,25).

Several diseases are of general importance. The fungus Mycosphaerella fraxinicola creates a leaf spot which may cause premature defoliation of young trees. Anthracnose (Gloeosporium aridum) also causes premature defoliation. A rust caused by Puccinia peridermiopora results in distortion of petioles and small twigs. Several rots cause minor damage in green ash. In Texas and Oklahoma, green ash has shown intermediate susceptibility to a root rot caused by Phymatotrichum omnivorum (25).

Young trees are subject to damage from deer browsing, and rabbits may sever the stems.

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Flowering and Fruiting

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Green ash is dioecious. The small, usually inconspicuous flowers appear in the spring, with or just before the leaves, in terminal or axillary clusters (4). Flowers are generally borne over the entire outer part of the live crown. Usually, flowering starts when trees are 8 to 10 cm (3 to 4 in) d.b.h. and 6 to 8 in (20 to 25 ft) tall. A high percentage of the male and female trees bear flowers annually, and many female trees bear fruit each year.

Flowers may appear as early as March or April in Florida and from late April to early May in the northern part of its range (25). Male flowers require 1 to 2 weeks to pass from the enlarged winter condition to completion of pollen shedding. Individual trees shed pollen over an interval of 3 to 4 days. Within a stand, range among individual trees in onset of pollen shedding is only 2 to 3 days. The pollen is disseminated by wind and is dispersed relatively short distances, most of it falling within 61 to 91 in (200 to 300 ft) of the source.

Flower bud enlargement starts a few days later on female trees than on male (25). The stigmas of the female flowers are receptive as soon as they emerge from the bud and remain receptive for about a week. Receptivity appears to end just before the stigmas start to wither. The female flowers and young fruit are very sensitive to late spring frosts.

Within a month after pollination, the samaras developing from fertilized flowers reach mature size. Ash fruits are elongated, winged, single-seeded samaras borne in clusters. Unpollinated flowers or flowers pollinated by an incompatible ash species drop off within the first month. Growth and ripening of embryos lag behind growth of samaras and are not completed until late September or early October.

Physiological maturity of green ash seeds can be related to a fully elongated embryo that fills the entire embryonic cavity. When ripe, the embryo should be about 10 min (0.4 in) long and slightly less than I mm (0.04 in) in diameter. Mature embryos have firm, white tissues that break crisply. Physical characteristics indicating seed maturity can be utilized by workers in the field during seed collections (3). Color change in the samaras, from green to yellow or brown, is not complete until after the embryo is fully grown. Samples picked in mid-October in central Mississippi gave excellent germination though samaras were still slightly green. While samaras are still green, they may contain as much as 50-percent moisture, and care must be taken to prevent seed lots from overheating. A little heat damage at this stage may significantly reduce seed quality, especially if long-term storage is contemplated. In seed collections, especially bulk collections, complete change of samaras to a brown color probably is a safer index to maturity than size of the embryo.

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Genetics

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Population Differences Green ash is composed of three or more geographic ecotypes. The trees belonging to these ecotypes are easily distinguishable when growing under uniform conditions in a nursery but not when growing naturally. For that reason, they have not been given Latin varietal or subspecific names.

Three different ecotypes were evident in the Great Plains (25). The population from the arid, northwestern part of the green ash range was more drought resistant than that from the more moist central Great Plains. As compared with the Coastal Plain ecotype, the Northern States ecotype grew more slowly, had greener petioles, was more winter hardy, and was less subject to leaf damage by fall frosts. These ecotypes may or may not be identical with those from the Eastern United States.

Hybrids Attempts have been made to artificially cross green ash with other ash species. Only the cross of green ash with velvet ash (Fraxinus velutina) was consistently successful, yielded viable seed, and produced identifiable hybrids that grew as fast as the eastern parent. The other crosses yielded no identifiable hybrids.

The pumpkin ash (Fraxinus profunda) is a rare hexaploid (2n = 138 chromosomes) species of the Coastal Plain and Mississippi Valley (25). Its leaves, twigs, flowers, and fruit are larger than those of green ash or white ash but qualitatively similar to one or the other of these two species. The patterns of morphological variation and geographic distribution taken together are strong evidence for the view that pumpkin ash is a true-breeding polyploid derivative of a cross between a diploid green ash and tetraploid white ash.

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Growth and Yield

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In shelterbelts in the Great Plains, green ash averaged 0.4 m (1.3 ft) per year height growth for the first 6.5 years (25). Opengrown trees planted on a fertile soil in Pennsylvania grew 14 to 17 m (45 to 55 ft) tall and 20 to 30 cm (8 to 12 in) in d.b.h in 21 years.

In most areas in the northern part of its range, green ash reaches heights of 15 to 18 m (50 to 60 ft) and breast-high diameters of 46 to 61 cm (18 to 24 in). On good sites in the southern part of its range, trees attain a height up to 37 m (120 ft) and a d.b.h. of 61 to 76 cm (24 to 30 in) (20). Diameter growth of dominant crop trees in well-stocked, managed stands is about 6 to 8 cm (2.5 to 3.0 in) in 10 years (5).

Little data exist on growth rates and volumes of trees grown under natural stand conditions. Probably the best information available is contained in results of research conducted in Georgia (6). Four sites included in the study ranged from well-drained sandy loams on levees or terraces to poorly drained, wet, silty flats. Green ash was the dominant species in these stands, comprising about 80 percent of the total stand basal area. Stand ages ranged from 27 to 65 years. Average stand heights for green ash sawtimber ranged from 24 m (78 ft) in the 27-year-old stand to 35 m (116 ft) in the 65-year-old stand.

Volume growth ranged from 2.7 to 4.6 m³/ha (39 to 65 ft³/acre) per year. Growth was related to stand age with better growth rates occurring in the younger stands. Merchantable sawtimber volume ranged from 104.4 m³/ha (1,491 ft³/acre) in the 27-year-old stand to 175.8 m³/ha (2,511 ft³/acre) in the 65-yearold stand. In addition to sawtimber, pulpwood volumes from tops and small trees ranged from 144.8 m³/ha (23 cords/acre) in the younger stand to 245.6 m³/ha (39 cords/acre) in the older stand.

Green ash on most sites in the southern part of its range is characterized by a clear, straight bole for about half the total height (6). Above this point the stem often forks or crooks and has large branches that degrade the lumber. Merchantable height for saw logs averages about two 5-m (16-ft) logs. Merchantable height for pulpwood to a 10-cm (4-in) top may extend to 12 m (40 ft) in younger stands. Its pioneer nature and ability to grow rapidly in relatively pure, even-aged stands indicate green ash is well suited for plantation management. Studies in Mississippi and Arkansas have shown that green ash grows about 1.2 to 1.5 m (4 to 5 ft) in height and 13 mm. (0.5 in) in d.b.h. the first 5 to 10 years under plantation management (fig. 4).

Natural stands appear to support sufficient volume to allow commercial thinnings at 25 to 30 years (6). To ensure reasonable volume production and reduce epicormic branching in the residual stand, basal area should not be reduced below 23.0 to 27.6 m²/ha (100 to 120 ft²/acre). This should be represented by about 250 to 300 trees/ha (100 to 120 trees/acre).

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Reaction to Competition

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Green ash varies from intolerant to moderately tolerant to shade in the northern part of its range. It comes in early in succession on alluvial soils, either as a pioneer species or following cottonwood, quaking aspen, or black willow (25). It is less able to maintain its position in the crown canopy than some of its more rapidly growing associates such as red maple and American elm.

In the southern part of its range, green ash would be considered tolerant when young and moderately tolerant as it grows older. Studies have shown that advanced reproduction of green ash can be maintained in the understory for more than 15 years (12). Green ash may not grow more than 15 cm (6 in) in height yearly, with 12- to 15-year-old trees being 4 to 5 in (12 to 15 ft) tall and 2.5 cm (1 in) in diameter. However, these trees respond well to release and outgrow many of their competitors (13). Other studies of green ash in plantations, where various levels of cultural treatments were applied, showed that green ash could tolerate competition from weeds and vines better than any of the 6 to 10 other species tested (17). Overall, green ash may most accurately be classed as tolerant of shade.

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Rooting Habit

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Root systems were studied in North Dakota on a Fargo clay soil, with a 0.3-m (1-ft) layer of black surface soil overlaying a light-colored, calcareous, clayey soil with no hardpan (25). The soil was poorly drained and wet in the spring; later in the growing season the water table was at a depth of about 5 in (15 ft) or more. Roots had extended laterally for 15 in (48 ft) and 1.1 in (3.6 ft) downward; they were about equally distributed in the upper 0.9 in (3 ft) of soil. Excavations of other root systems have shown green ash roots to penetrate about 1 in (3.2 ft) deep in sandy and clay soils and 1.4 in (4.5 ft) deep along the edges of sloughs. In the southern part of its range, green ash has a root system that is typically saucer-shaped with no distinct taproot; roots penetrate to depths of 0.9 to 1.2 in (3 to 4 ft). The extensive root system of this species makes it relatively windfirm.

Green ash seedlings, and probably older trees, have certain rooting habits or adaptations that enable them to withstand flooding (1,16,21). Young green ash (8) has been shown to have the ability under flooded conditions to regenerate new secondary roots from the primary root, develop adventitious water roots on the submerged stem, accelerate anaerobic respiration rate in the absence of oxygen, and oxidize its rhizospheres. These root adaptations enable it to withstand flooding regimes of several months during the dormant and early growing season that would kill other species (9,10,25). Specific gravity has been shown to be related to flooding in some hardwoods (19).

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Seed Production and Dissemination

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Green ash seeds start to fall as soon as they ripen and continue to fall into the winter (25). Most seeds are dispersed by wind within short distances of the parent tree. Some dispersal by water also may occur, but the importance of water as a long-distance dispersal agent is unknown.

Seed clusters can be collected from trees by hand or with pruners and seed hooks. Fully dried samaras also may be shaken or whipped from limbs of standing trees onto plastic sheets spread under the trees. Fruit should be spread in shallow layers for complete drying, especially when collected early. Dried clusters may be broken apart by hand, by flailing in sacks, or by processing through a macerator. Seeds should be dried to 7- to 10-percent moisture content for storage. No loss in viability for 7 years was found when green ash seeds were stored in sealed containers at 5° C (41° F) with a seed moisture content of 7 to 10 percent.

The epigeal germination may occur in the spring following seedfall, or seeds may lie dormant in the litter for several years before germinating. Dormancy is apparently due to both internal factors and to seedcoat effects (3,4). For the nursery, dormancy may be overcome by cold, moist stratification in a suitable medium, or simply storing in containers of water. Both methods should be used at temperatures of 2° to 4° C (35° to 40° F) for 90 to 120 days. Seeds may be sown in fall and allowed to stratify in the nursery bed.

Seeds should be sown in nursery beds at approximately 80 to 100/m (25 to 30/ft) of row with rows 15 to 30 cm (6 to 12 in) apart (25) and covered with burlap or greenhouse shade cloth until germination starts. Seedbed densities of 110 to 130/m² 10 to 12/ft² ) are recommended for green ash to produce high-quality seedlings.

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Seedling Development

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Under good nursery conditions in the northern part of its range, seedlings grow about 30 cm (12 in) in height the first year and another 46 cm (18 in) the second year. In the southern part of the green ash range, nurseries can produce seedlings 0.8 to 0.9 m (2.5 to 3.0 ft) tall the first growing season.

Uninjured nursery seedlings usually develop no side branches during the first year. On vigorous seedlings, the uppermost one or two pairs of lateral buds develop into branches during the second year.

Apical dominance usually is strong enough in vigorous, uninjured open-grown trees so that they often have a single, straight stem until they are 5 m (15 ft) or more tall. If this dominance is lost by the removal of a terminal bud, the uppermost lateral branch quickly takes over and reasserts dominance over the lower branches (25). In slow-growing shaded specimens, the tendency for quick assertion of apical dominance following deer nipping or other damage to a terminal bud is much less pronounced. As a consequence, understory seedlings frequently have poor form.

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Special Uses

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Green ash wood, because of its strength, hardness, high shock resistance, and excellent bending qualities, is used in specialty items such as tool handles and baseball bats but is not as desirable as white ash. It is also being widely used in revegetation of spoil banks created from strip mining (25). Green ash is very popular as a shade tree in residential areas because of its good form, adaptability to a wide range of sites, and relative freedom from insects and diseases. Seeds are used for food by a number of game and nongame animals and birds.

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Vegetative Reproduction

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Stumps of sapling and pole-size green ash sprout readily. Studies in Mississippi have shown ash, as sprouts, to be one of the dominant species in bottom-land clearings (11,13). Dominants among the ash sprouts were 3.8 cm (1.5 in) d.b.h. and 5 m (15 ft) tall after five growing seasons.

Cuttings made from 1-0 seedlings or 1-year-old sprouts root easily under greenhouse and field conditions (25). Cuttings may be planted horizontally under the soil or vertically with good results(14,15). However, no practical way to root cuttings from older trees has yet been found. Green ash can be successfully bench-grafted or field-grafted (2,18). Understocks; can be stored by severely root-pruning young seedlings and heeling them in by groups of 50 to 100. Most of the seedlings remain alive but grow so little that they supply an assortment of small understocks whenever needed.

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Distribution

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Green ash extends from Cape Breton Island and Nova Scotia west to southeastern Alberta; south through central Montana, northeastern Wyoming, to southeastern Texas; and east to northwestern Florida and Georgia.


-The native range of green ash.


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Brief Summary

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Oleaceae -- Olive family

Harvey E. Kennedy, Jr.

Green ash (Fraxinus pennsylvanica), also called red ash, swamp ash, and water ash, is the most widely distributed of all the American ashes. Naturally a moist bottom land or stream bank tree, it is hardy to climatic extremes and has been widely planted in the Plains States and Canada. The commercial supply is mostly in the South. Green ash is similar in property to white ash and they are marketed together as white ash. The large seed crops provide food to many kinds of wildlife. Due to its good form and resistance to insects and disease, it is a very popular ornamental tree.

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Fraxinus pennsylvanica

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Fraxinus pennsylvanica, the green ash or red ash,[2] is a species of ash native to eastern and central North America, from Nova Scotia west to southeastern Alberta and eastern Colorado, south to northern Florida, and southwest to Oklahoma and eastern Texas. It has spread and become naturalized in much of the western United States and also in Europe from Spain to Russia.[3][4][5]

Other names more rarely used include downy ash, swamp ash and water ash.

Description

 src=
Bark

Fraxinus pennsylvanica is a medium-sized deciduous tree reaching 12–25 m (39–82 ft) (rarely to 45 m or 148 ft) tall with a trunk up to 60 cm (24 in) in diameter. The bark is smooth and gray on young trees, becoming thick and fissured with age. The winter buds are reddish-brown, with a velvety texture. The leaves are 15–30 cm (6–12 in) long, pinnately compound with seven to nine (occasionally five or eleven) leaflets, these 5–15 cm (2–6 in) (rarely 18 cm or 7 in) long and 1.2–9 cm (123 916 in) broad, with serrated margins and short but distinct, downy petiolules a few millimeters long. They are green both above and below. The autumn color is golden-yellow and depending on the climate, Green Ash's leaves may begin changing color the first week of September. The flowers are produced in spring at the same time as the new leaves, in compact panicles; they are inconspicuous with no petals, and are wind-pollinated. The fruit is a samara 2.5–7.5 cm (1–3 in) long comprising a single seed 1.5–3 cm (581 18 in) long with an elongated apical wing 2–4 cm (341 12 in) long and 3–7 mm (18932 in) broad.[6][7][8][9]

It is sometimes divided into two varieties, Fraxinus pennsylvanica var. pennsylvanica (red ash) and Fraxinus pennsylvanica var. lanceolata (Borkh.) Sarg. (syn. var. subintegerrima (Vahl) Fern.; green ash) on the basis of the hairless leaves with narrower leaflets of the latter, but the two intergrade completely, and the distinction is no longer upheld by most botanists.[3]

Ecology

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Bark and leaf

It is the most widely distributed of all the American ashes, although its range centers on the midwestern U.S. and Great Plains. The natural habitat of green ash is almost exclusively stream sides and bottomlands. The large seed crops provide food to many kinds of wildlife.[2]

Green ash is threatened by the emerald ash borer, a beetle introduced accidentally from Asia. Asian ashes have a high tannin content in their leaves which makes them unpalatable to the beetle, while most American species (with the notable exception of blue ash) do not.[10] A common garden experiment showed that green ash is killed readily when exposed to emerald ash borer, while the Asian species F. mandschurica shows resistance against emerald ash borer.[11] The United States Forest Service has discovered small numbers of green ash in the wild that have remained healthy after emerald ash borer swept through the population.[12] The possibility of these trees possessing genetic resistance to the beetle is currently being investigated with the hope that green ash could be restored using the surviving trees.[13]

 src=
Winter twig of Fraxinus pennsylvanica. Green ash can usually be distinguished from white ash (F. americana) by its D-shaped leaf scars. In F. americana, the lateral buds are more deeply recessed within their corresponding leaf scars, giving the latter a more C-shaped appearance.[14]

The spread of emerald ash borer was facilitated by the extensive use of green ash as an ornamental tree in the central U.S. following the loss of American elms in the 1950s–60s due to Dutch elm disease. That epidemic was the result of a similar overuse of elms in urban environments, leading to a monoculture that lacked any disease or pest resistance. Scientifically for green ash this is because modern cultivars utilized regionally were parented from sometimes only four individual trees selected for unique traits and male seedless flowering. Proclaiming a harsh lesson learned, cities like Chicago did not replace dead elms with a 1:1 ash:elm ratio. Instead, Norway, silver, red and sugar maples, honey locust, linden/basswood, redbud, crabapples, and hackberry, among others, were also utilized during this recovery period and in new urban and suburban areas. Fortunately, with these additional species, many cities were able to reduce the percent of ash and other species to much lower levels (20% average) than during the Dutch elm disease era where from 56% to 100% of the trees were elm.

Injections and spraying of ashes with pesticides has been used in city parks to protect valued trees from emerald ash borer.[15]

Record cold temperatures during the winter of 2018–19 are estimated to have killed as much as 80% of ash borer larva in the Upper Midwest.[16]

Both American elm and green ash were extremely popular due to rapid growth and tolerance of urban pollution and road salt, so many housing developments in Michigan were lined from end to end with ashes, a result of which the beetles had an enormous food supply to boost their population well above Infestation thresholds. The tree was also extensively propagated and sold by local nurseries. According to the American Nursery Industry, "Back in the late 1980s, Dr. Frank Santamour Jr., then a research geneticist with the U.S. National Arboretum, proposed the 10-20-30 formula for diversity in the urban forest, limiting the plantings in a community to no more than 10 percent within a single species, 20 percent within a genus and 30 percent within a family." Many communities are using a more strict 5-10-20 rule today, because of the threat posed by emerald ash borer.

The emerald ash borer proved to be a far worse and potentially more serious threat than epidemics of the past such as chestnut blight and Dutch elm disease because those diseases spread at a slower rate, only affected one species, and did not kill the trees before they could attain reproductive maturity. Many areas have banned the sale of ash seedlings in nurseries, although seeds may be sold as they are not a vector for the insect.

Green ash is also vulnerable to many other diseases including ash yellows and dieback that can cause gradual loss of vigor and exhibit similar symptoms to emerald ash borer infestation such as crown dieback, bark cracking, and epicormal sprouts. These conditions are most common on stressed trees in areas of poor soil, urban pollution, and lack of moisture. A wave of ash dieback struck the northeastern United States in the 1950s–60s that killed an estimated 70% of ashes in the region.

Uses

Urban ornamental trees

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Autumn leaf color

Green ash is one of the most widely planted ornamental trees throughout the United States and much of Canada but mostly Alberta, including in western areas where it is not native. It is also widely planted in Argentina. It is very popular due to its good form and resistance to disease. About 40% of boulevard trees in Edmonton, Alberta are green ash.[17]

For the last two centuries American elm and ash, which both belong to the ancient Elm-Ash-Cottonwood Bottomland ecosystem,[18] achieved distinction as North America's two most popularly planted urban species, used primarily for their superior survival traits and slowly maturing 180–300 year majestic natural beauty. Today used as living national monuments, the National Park Service is protecting Thomas Jefferson's 200-year-old planted example, and George Washington's 250-year-old white ash which has a 600-year possible lifespan. Green ash had been widely used as a primary ornamental and long lived monument tree until the elm fad of the 1880s, and regained top position once again after Dutch elm disease arrived.

Other continents learned of American ash species' urban survivability and unique beauty through the worldwide popularity of Midwestern Prairie style ecology and architectural movement. Modernizing cities in Russia and China then began using imported green ash a century ago to line streets and landscape new public parks.Advantages of green ash include its tolerance of harsh urban environmental conditions, ease of propagation, and (in eastern North America) its value for wildlife as a native keystone species.[19]

Usefulness to wildlife

North American native ash tree species are used by North American frogs as a critical food source, as the leaves that fall from the trees are particularly suitable for tadpoles to feed upon in ponds (both temporary and permanent), large puddles, and other water sources.[20] Species such as red maple, which are taking the place of ash due to the ash borer, are much less suitable for the frogs as a food source — resulting in poor frog survival rates and small frog sizes.[20] It is the lack of tannins in the American ash varieties that makes them good for the frogs as a food source and also not resistant to the ash borer. Varieties of ash from outside North America typically have much higher tannin levels and resist the borer. Maples and various non-native invasive trees, trees that are taking the place of American ash species in the North American ecosystem, typically have much higher leaf tannin levels.[20] Ash species native to North America also provide important habit and food for various other creatures that are native to North America.[21]

Other uses

Green ash wood is similar in properties to white ash wood, and is marketed together as "white ash". The commercial supply is mostly in the South. It is very popular, used in making electric guitars because it can be somewhat lighter than white ash without sacrificing too much in tone. It has a bright sound with long sustain, plus the wood grain is aesthetically desirable to many guitar players. Gibson, Fender, Ibanez, Warwick, and many other luthiers use ash in the construction of their guitars.

References

  1. ^ Westwood, M., Oldfield, S., Jerome, D. & Romero-Severson (2016). "Fraxinus pennsylvanica". IUCN Red List of Threatened Species. IUCN. 2016. Retrieved 14 September 2017.CS1 maint: multiple names: authors list (link)old-form url
  2. ^ a b Kennedy, Jr., Harvey E. (1990). "Fraxinus pennsylvanica". In Burns, Russell M.; Honkala, Barbara H. (eds.). Hardwoods. Silvics of North America. Washington, D.C.: United States Forest Service (USFS), United States Department of Agriculture (USDA). 2 – via Southern Research Station (www.srs.fs.fed.us).
  3. ^ a b "Fraxinus pennsylvanica". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA).
  4. ^ "Fraxinus pennsylvanica". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  5. ^ "Fraxinus pennsylvanica". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.
  6. ^ Common Trees of the North Carolina Piedmont: Fraxinus pennsylvanica
  7. ^ Northern Ontario Plant Database: Fraxinus pennsylvanica
  8. ^ Virtual Herbarium of the Chicago Region: Fraxinus pennsylvanica
  9. ^ Oklahoma Biological Survey: Fraxinus pennsylvanica
  10. ^ Emerald ash borer: EAB website
  11. ^ Rebek, Eric J.; Herms, Daniel A.; Smitley, David R. (1 February 2008). "Interspecific Variation in Resistance to Emerald Ash Borer (Coleoptera: Buprestidae) Among North American and Asian Ash (Fraxinus spp.)". Environmental Entomology. 37 (1): 242–246. doi:10.1603/0046-225X(2008)37[242:IVIRTE]2.0.CO;2. PMID 18348816.
  12. ^ Knight, Kathleen S.; et al. (2012). "Dynamics of surviving ash (Fraxinus spp.) populations in areas long infested by emerald ash borer (Agrilus planipennis)". Proceedings of the Fourth International Workshop on the Genetics of Host-parasite Interactions in Forestry: Disease and Insect Resistance in Forest Trees: 143–152.
  13. ^ Koch, J. L.; Carey, D. W.; Mason, M. E.; Poland, T. M.; Knight, K. S. (21 June 2015). "Intraspecific variation in Fraxinus pennsylvanica responses to emerald ash borer (Agrilus planipennis)". New Forests. 46 (5–6): 995–1011. doi:10.1007/s11056-015-9494-4.
  14. ^ "Fraxinus comparison chart". www.uwgb.edu. Retrieved 2018-11-11.
  15. ^ https://www.farmprogress.com/conservation/injecting-ash-trees-protect-emerald-ash-borer?ag_brand=missouriruralist.com
  16. ^ https://www.twincities.com/2019/01/31/one-benefit-of-minnesotas-polar-plunge-ash-borers-took-a-licking/
  17. ^ Edmonton: trees
  18. ^ Cook, Bill. "Forest management guidelines for Michigan". Michigan SAF Home Page. Michigan Society of American Foresters. Retrieved 5 July 2015.
  19. ^ "Ash Tree Identification". New York Invasive Species Information. Cornell University Cooperative Extension. Retrieved 5 July 2015.
  20. ^ a b c Stephens, Jeffrey; Bervan, Keith; Tiegs, Scott (3 May 2013). "Anthropogenic changes to leaf litter input affect the fitness of a larval amphibian". Freshwater Biology. 58 (8): 1631–1646. doi:10.1111/fwb.12155.
  21. ^ Hilty, John (2016). "Black Ash (Fraxinus nigra)". Illinois Wildflowers. Retrieved 27 August 2018.
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Fraxinus pennsylvanica: Brief Summary

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Fraxinus pennsylvanica, the green ash or red ash, is a species of ash native to eastern and central North America, from Nova Scotia west to southeastern Alberta and eastern Colorado, south to northern Florida, and southwest to Oklahoma and eastern Texas. It has spread and become naturalized in much of the western United States and also in Europe from Spain to Russia.

Other names more rarely used include downy ash, swamp ash and water ash.

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