(key to state/province abbreviations)
UNITED STATES

AZ	CA	CO	ID	IN	MN	MT	NE	NV	NM
ND	OR	PA	SD	TX	UT	WA	WY

CANADA

AB	BC	ON

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 [31]:

1 Northern Pacific Border

2 Cascade Mountains

4 Sierra Mountains

5 Columbia Plateau

6 Upper Basin and Range

8 Northern Rocky Mountains

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

Oregon-grape is native to the western United States and Canada. It occurs from central British Columbia and southern Alberta to western South Dakota, south to California, and east to southern Arizona and New Mexico, and Minnesota [34,61,133,207,216]. Isolated populations are also present in western Texas, Indiana, and Pennsylvania [61]. The Flora of North America provides a distributional map of Oregon-grape.

Berberis aquifolium var. repens (Lindl.) Scoggan:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Berberis sonnei (Abrams) McMinn:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Berberis repens Lindl.:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Berberis pumila Greene:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Berberis amplectens (Eastw.) L.C. Wheeler:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Alta., B.C.; Ariz., Calif., Colo., Idaho, Minn., Mont., Nebr., Nev., N.Mex., N.Dak., Oreg., S.Dak., Tex., Utah, Wash., Wyo.

Calif., Oreg.

Calif.

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Mahonia repens ranges from British Columbia and Alberta, Canada and south through California, west to Texas and North Dakota, U.S.

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

More info for the term: rhizome

This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available [3,68,71,85,88,99,100,109,124,214,216].

Oregon-grape is a perennial, evergreen, creeping subshrub [71,100,109,135,157,210,216]. Stem height is 4 to 12 inches (10-30 cm) [61,68,85,88,99,100,109,135,157,216]. Each aerial stem arises from a rhizome that gives rise to other aerial stems at intervals [3,85,110,135,149,181,210,216]. Leaves are pinnately compound with 3 to 7 spine-toothed leaflets [61,68,71,85,100,109,124,135,153,210]. Flowers occur in dense racemes or umbels [3,68,85,99,100,110,124,153,157,210,216]. Fruits are berries, 0.4 inches long (1 cm) and borne in grape-like clusters [3,68,71,85,99,110,124,135,210,216]. Each berry contains 1 to 4 seeds, 0.2 to 0.4 inches (0.6-1.0 cm) long [61,110]. Each Oregon-grape fruit contains several seeds [3,68,71,85,99,110,116,124,135,149,210,216]. Oregon-grape produces 71,120 seeds per pound [96].

Roots: Oregon-grape has fibrous rhizomes and roots that typically grow 0.6 to 2.0 inches (1.5-5 cm) below the mineral soil surface [35,36,88,128,132,147]. Rhizomes can sprout from relatively great depth without the stimulus of fire [35,78]. Bradley [35] found 1 active rhizome branch originating from 5.9 inches (15 cm) below the soil surface that was nearly emergent in Pattee Canyon, in western Montana. In the Black Hills of South Dakota, a 6 ft² study plot identified 31 stems originating from the same root system [32]. Roots can reach a maximum rooting depth of 6 feet (1.8 m), providing adaptability to water stress [40,145].

Shrubs , evergreen, 0.02-0.2(-0.6) m. Stems monomorphic, usually without short axillary shoots. Bark of 2d-year stems grayish or purplish brown, glabrous. Bud scales 3-8 mm, deciduous. Spines absent. Leaves (3-)5-7-foliolate; petioles (1-)3-9 cm. Leaflet blades thin and flexible; surfaces abaxially dull, papillose, adaxially dull, rarely glossy, somewhat glaucous; terminal leaflet stalked, blade 3.2-9.5 × 2.3-6 cm, 1.2-2.2(-2.5) times as long as wide; lateral leaflets ovate or elliptic, 1(-3)-veined from base, base rounded to obtuse or truncate, margins plane, toothed, with 6-24 teeth 0.5-3 mm tipped with spines to 0.6-2.8 × 0.1-0.25 mm, apex rounded, rarely obtuse or even broadly acute. Inflorescences racemose, dense, 25-50-flowered, 3-10 cm; bracteoles membranous, apex rounded to obtuse or broadly acute. Anther filaments with distal pair of recurved lateral teeth. Berries blue, glaucous, oblong-ovoid, 6-10 mm, juicy, solid. 2 n = 28.

Shrubs , evergreen, 0.1-0.4 m. Stems monomorphic, without short axillary shoots. Bark of 2d-year stems gray-brown or purplish, glabrous. Bud scales 3-6 mm, deciduous. Spines absent. Leaves 3-9-foliolate; petioles 0.5-4 cm. Leaflet blades thick and rigid; surfaces abaxially dull, papillose, adaxially dull, glaucous; terminal leaflet stalked, at least on most leaves, blade 4-8 × 2-5 cm, 1.3-1.9 times as long as wide; lateral leaflet blades ovate to oblong-ovate or elliptic, 1(-3)-veined from base, base obtuse, rarely truncate, margins plane or undulate, toothed, with 2-10 teeth 1-3 mm tipped with spines to 1.6-3 - 0.3-0.4(-0.5) mm, apex obtuse or rounded, rarely broadly acuminate. Inflorescences racemose, dense, 30-45-flowered, 2-4 cm; bracteoles membranous, apex rounded or obtuse, sometimes apiculate. Flowers: anther filaments with distal pair of recurved lateral teeth. Berries dark blue, glaucous, oblong-ovoid to spheric, 5-8 mm, juicy, solid. 2 n = 28.

Shrubs , evergreen, 0.2-1.2 m. Stems monomorphic, without short axillary shoots. Bark of 2d-year stems purple, glabrous. Bud scales 3-6 mm, deciduous. Spines absent. Leaves 5-7-foliolate; petioles 1.5-5 cm. Leaflet blades thick and rigid; surfaces abaxially dull, papillose, adaxially dull, ± glaucous; terminal leaflet stalked, blade 4.4-5.5 × 3.1-4.6 cm, 1.1-1.4 times as long as wide; lateral leaflet blades oblong or circular, 1-5-veined from base, base truncate or cordate, margins undulate or crispate, toothed, each with 9-15 teeth 1-3 mm tipped with spines to 1.4-2.4 × 0.2-0.4 mm, apex truncate or broadly rounded. Inflorescences racemose, dense, 25-35-flowered, 3-6 cm; bracteoles membranous, apex obtuse or rounded. Flowers: anther filaments distally with pair of recurved teeth: author had no data available. Berries dark blue, glaucous, ovoid to elliptic, 7-9 mm, juicy, solid. 2 n = 28.

Berberis aquifolium Pursh var. repens (Lindley) Scoggan; B. sonnei (Abrams) McMinn; Mahonia repens (Lindley) G. Don; M. sonnei Abrams

Mahonia pumila (Greene) Fedde

Mahonia amplectens Eastwood, Proc. Calif. Acad. Sci., ser. 4, 20: 145. 1931

Isotype for Mahonia sonnei Abrams
Catalog Number: US 2699
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): C. Sonne
Year Collected: 1885
Locality: Truckee., Nevada, California, United States, North America

More info for the term: xeric

Oregon-grape is abundant on north-facing slopes [133,151]. It occurs in dry to moist foothill shrublands and montane areas [68,85,99,109,110,124,135,157,210,214,216] with sparse understory vegetation [61]. Oregon-grape also occurs in moist sites on plains, low-elevation woodlands [119,133], riparian areas, and occasionally wetland areas [83]. Oregon-grape is among the most resistant plants to winter sun exposure [213].

Elevation: Oregon-grape grows at elevations ranging from near sea level on the Pacific coast to 10,000 feet (3,000 m) in the Rocky Mountains [85,216]. Elevational ranges by state are shown below:

Arizona	5,000- 8,500 feet (1,500-2,600 m) [100]
California	1,000-7,200 feet (300-2,200 m) [88]
Colorado	5,500-10,000 feet (1,700-3,100 m) [85]
Nevada	5,000-10,000 feet (1,500-3,100 m) [99]
New Mexico	6,500-10,000 feet (2,000-3,100 m) [124]
Texas	4,500-8,000 feet (1,400-2,400 m) [157,210]
Utah	3,600-9,800 feet (1,100-3,000 m) [216]

Soil: Oregon-grape is found in medium-textured, well-drained sandy loam, chalky, or granitic soil in coniferous forests [34,71,213] and sometimes on shallow, rocky sites where other vegetation is sparse [46,213]. Oregon-grape grows well on soils derived from limestone and quartzite in western Montana [67]. It is intolerant of poor drainage and high water tables [85,156,213] and is weakly tolerant to saline soils [182]. Oregon-grape is tolerant of very strongly acid to mildly alkaline soils [34,213] with pH ranging from 4.6 to 7.6 [34,182,185,189].

Climate: Oregon-grape tolerates a wide range of climates including xeric continental [81,142], Pacific maritime, core maritime, northern and southern continental [142,176,188], and subhumid montane [217].

Precipitation: Oregon-grape tolerates annual precipitation ranging from 12 inches (305 mm) per year in the Uinta Mountains of Utah [57] to 140 inches (3,556 mm) per year in northwest Oregon [120].

More info for the terms: cover, phase

Oregon-grape is recognized as a dominant species in the following vegetation
classifications:

Arizona:

Douglas-fir (Pseudotsuga menziesii)/Oregon-grape habitat type [7,113]

White fir (Abies concolor)/Oregon-grape habitat type [69,113,125,138]

White fir/Douglas-fir habitat type, Oregon-grape phase

White fir/Rocky Mountain maple (Acer glabrum) habitat type, Oregon-grape phase[7]
Colorado

White fir/Oregon-grape habitat type [125]

Douglas-fir/Oregon-grape habitat type

Quaking aspen (Populus tremuloides)/Oregon-grape habitat type [6]
Idaho

Douglas-fir/Oregon-grape habitat type [88,180,185,187].

Douglas-fir/Oregon-grape habitat type, Oregon-grape phase [180,185,187,189,189]

Subalpine fir (Abies lasiocarpa)/Oregon-grape habitat type, Oregon-grape phase [185]

Ponderosa pine (Pinus ponderosa)/Oregon-grape [180]

Singleleaf pinyon/curlleaf mountain mahogany-mountain snowberry-Oregon-grape/bluebunch wheatgrass ( Pinus monophylla/Cercocarpus
ledifolius-Symphoricarpos oreophilus/Pseudoroegneria spicata) [170]

Ponderosa pine/common snowberry (Symphoricarpos albus), Oregon-grape phase [180]
Montana

Quaking aspen/Oregon-grape habitat type [81,82]

Ponderosa pine/Oregon-grape habitat type [167,180]

Ponderosa pine/common snowberry (Symphoricarpos albus) habitat type, Oregon-grape phase [116,180]

Douglas-fir/Oregon-grape habitat type [180]
Nevada

Subalpine fir/Oregon-grape habitat type [144]
New Mexico

White fir/Oregon-grape habitat type [113,125]

White fir/Rocky Mountain maple habitat type-Oregon-grape phase [4,7]

White fir/sparse habitat type (white fir/Douglas-fir habitat type)-Oregon-grape phase [7]

Douglas-fir/Oregon-grape habitat type [113],
Oregon

Douglas-fir/Oregon-grape community type [42]
South Dakota

Quaking aspen/Oregon-grape/roughleaf ricegrass (Oryzopsis
asperifolia) habitat type [44,136,176]

Ponderosa pine/common juniper (Juniperus communis)-common
snowberry-Oregon-grape habitat type [200]

Ponderosa pine-bur oak (Quercus macrocarpa)/common chokecherry (Prunus virginiana)-common snowberry-Oregon-grape habitat type [200]
Utah

Subalpine fir/Oregon-grape habitat type [57,79,126]

White fir/Oregon-grape habitat type [57,219]

White-fir/Oregon-grape habitat type, Oregon-grape phase [126,219]

Blue spruce (Picea pungens)/Oregon-grape habitat type [57,126,180,219]

Lodgepole pine (Pinus contorta)/Oregon-grape habitat type [126]

Douglas-fir/Oregon-grape habitat type [180,219]

Douglas-fir/Oregon-grape habitat type, Oregon-grape phase [126,180,219]

Subalpine fir/Oregon-grape habitat type [219]

Subalpine fir/Oregon-grape habitat type, Oregon-grape phase [219]
Wyoming

Douglas-fir/Oregon-grape habitat type [5,44,180,185]

Douglas-fir/Oregon-grape habitat type, Oregon-grape phase [185]

Quaking aspen/Oregon-grape cover type [5,136,220]

Quaking aspen/subalpine fir habitat type, Oregon-grape phase [220]

Subalpine fir/Oregon-grape habitat type [5,185]

Subalpine fir/Oregon grape cover type [5]

Subalpine fir/Oregon grape cover type, Oregon-grape phase [185]

Subalpine fir/Engelmann spruce (Picea engelmannii) habitat type, Oregon-grape phase [44]

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 term: cover

SRM (RANGELAND) COVER TYPES [178]:

101 Bluebunch wheatgrass

102 Idaho fescue

109 Ponderosa pine shrubland

110 Ponderosa pine-grassland

207 Scrub oak mixed chaparral

210 Bitterbrush

215 Valley grassland

217 Wetlands

239 Pinyon-juniper

304 Idaho fescue-bluebunch wheatgrass

312 Rough fescue-Idaho fescue

317 Bitterbrush-bluebunch wheatgrass

319 Bitterbrush-rough fescue

401 Basin big sagebrush

402 Mountain big sagebrush

404 Threetip sagebrush

409 Tall forb

411 Aspen woodland

412 Juniper-pinyon woodland

413 Gambel oak

415 Curlleaf mountain-mahogany

416 True mountain-mahogany

418 Bigtooth maple

420 Snowbrush

421 Chokecherry-serviceberry-rose

422 Riparian

612 Sagebrush-grass

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 term: cover

SAF COVER TYPES [56]:

16 Aspen

42 Bur oak

63 Cottonwood

109 Hawthorn

206 Engelmann spruce-subalpine fir

208 Whitebark pine

210 Interior Douglas-fir

211 White fir

212 Western larch

213 Grand fir

215 Western white pine

216 Blue spruce

217 Aspen

218 Lodgepole pine

219 Limber pine

220 Rocky Mountain juniper

224 Western hemlock

226 Coastal true fir-hemlock

227 Western redcedar-western hemlock

228 Western redcedar

229 Pacific Douglas-fir

230 Douglas-fir-western hemlock

234 Douglas-fir-tanoak-Pacific madrone

237 Interior ponderosa pine

239 Pinyon-juniper

243 Sierra Nevada mixed conifer

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

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: shrub

KUCHLER [104] PLANT ASSOCIATIONS:

K001 Spruce-cedar-hemlock forest

K002 Cedar-hemlock-Douglas-fir forest

K004 Fir-hemlock forest

K005 Mixed conifer forest

K008 Lodgepole pine-subalpine forest

K010 Ponderosa shrub forest

K011 Western ponderosa forest

K012 Douglas-fir forest

K013 Cedar-hemlock-pine forest

K014 Grand fir-Douglas-fir forest

K015 Western spruce-fir forest

K016 Eastern ponderosa forest

K017 Black Hills pine forest

K018 Pine-Douglas-fir forest

K019 Arizona pine forest

K020 Spruce-fir-Douglas-fir forest

K021 Southwestern spruce-fir forest

K023 Juniper-pinyon woodland

K033 Chaparral

K037 Mountain-mahogany-oak scrub

K038 Great Basin sagebrush

K050 Fescue-wheatgrass

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 [62]:

FRES19 Aspen-birch

FRES20 Douglas-fir

FRES21 Ponderosa pine

FRES22 Western white pine

FRES23 Fir-spruce

FRES24 Hemlock-Sitka spruce

FRES25 Larch

FRES26 Lodgepole pine

FRES28 Western hardwoods

FRES29 Sagebrush

FRES34 Chaparral-mountain shrub

FRES35 Pinyon-juniper

FRES36 Mountain grasslands

Open forest, shrubland, and grassland; 200-3000m.

Open woods and rocky areas; 300-1200m.

Rocky slopes in chaparral and open forest; of conservation concern; 900-1900m.

Comments: An understory plant in western North America coniferous forests below 2200 m (Vance et al. in press). Relatively shade tolerant and common in second-growth Douglas-fir forests (Vance et al in press).

In Great Britain and/or Ireland:
Foodplant / parasite
Erysiphe berberidis parasitises Mahonia repens

More info for the terms: fuel, prescribed fire, severity

Oregon-grape can recover quickly, remain unchanged or decrease following prescribed fire. The response of Oregon-grape to prescribed fire depends on the habitat type, fuel load, and severity of the burn. Research is needed to determine the seasonal effect of prescribed burning on Oregon-grape.

More info for the terms: cover, duff, fire severity, fire use, frequency, fuel, litter, low-severity fire, prescribed burn, prescribed fire, relative frequency, restoration, severity, shrub, shrubs, stand-replacement fire, succession, tree, underburn, wildfire

The postfire recovery time for Oregon-grape varies according to fire severity, site
characteristics, and climatic factors.

Oregon-grape sprouted 4 months after a fire that
killed all but old growth ponderosa pine trees in a mixed-conifer forest in Zion
National Park, Utah [217].
Oregon-grape sprouted from rhizomes 1 year after fire in old-growth western
hemlock-Douglas-fir forest in the Pacific Northwest [1].
In a 1996 lightning-ignited fire in Mesa Verde National Park, Colorado, 4,781
acres (1,935 ha) burned. Postfire recovery was studied the following year in 3 habitats:
mountain shrublands, pinyon-juniper/shrublands, and pinyon-juniper
woodlands. Oregon-grape occurred in 10 to 20% of all habitat types. The numbers below indicate the
relative frequency of Oregon-grape [60]:

Habitat
Mountain shrublands	0.19
Pinyon-juniper/shrublands	0.12
Pinyon-juniper woodlands	0.14

Severe wildfires:
Oregon-grape increased after severe fires in the following habitats:
Subalpine fir/Engelmann spruce habitat: In a 1974 lightning-ignited fire in
Waterfalls Canyon in Grand Teton National Park, Wyoming, 3,494 ac (1,414 ha) burned before
it was extinguished by snow in late November. Data were collected from
permanent plots in 1975, 1976, 1977, 1983, and 1991 in 60 unburned plots, 60 moderately
burned (40% of the canopy trees alive 1 year after the fire) plots, and 60 severely burned
plots (all trees killed and the aboveground portions of understory species are
consumed). Oregon-grape was considered one of the most important
postfire understory species in the severely burned areas, making up a maximum
cover of 1-3%. The mean percent cover of Oregon-grape is shown below [54]:

Year	1975	1976	1977	1983	1991
Unburned	1	trace (<1% cover)	1	1	t
Moderate burn	t	0	0	0	0
Severe burn	t	1	1	2	1

Engelmann spruce/subalpine fir and lodgepole pine stands: Oregon-grape
appeared 1 year after a severe subalpine wildfire in northern Colorado [30].
Douglas-fir: Oregon-grape was a common undergrowth species 10 years after a
severe fire in an advanced mature/early old-growth Douglas-fir forest in the
Warner Creek Basin on the Willamette National Forest near Eugene, Oregon [160].
Following a severe wildfire in 1977 in a second-growth Douglas-fir forest in
western Montana, the percent cover of Oregon-grape increased over time [204]:

Year	1979	1982	1987
Postfire year	2	5	10
Percent cover	3	5	11

Ponderosa pine/common snowberry, grand fir/queencup beadlily (Clintonia uniflora), grand fir/birchleaf
spirea (Spiraea betulifolia), and grand fir/pinegrass (Calamagrostis
rubescens): Oregon-grape increased after severe fires in
these northeastern Oregon communities and utilized habitat after a
severe burn in a cool, moist grand fir forest [95].
Douglas-fir, quaking aspen, and subalpine fir: Oregon-grape appeared 5 years after a
severe fire in 1998 in Yellowstone National Park [9], perhaps due to seed
dispersal by birds and mammals.
Prescribed burning:
Oregon-grape can have an unfavorable, favorable, or
no response to prescribed burning based on the habitat, severity of the burn,
and how long after fire Oregon-grape is measured.
Unfavorable responses to prescribed burning:

Gambel oak habitat: The frequency of Oregon-grape was higher in
unburned stands versus stands burned within 8 years of the sampling date in central Utah [107]:

Treatment	9 unburned stands	14 burned stands
Average percent frequency	7.7	2.6

Douglas-fir/ponderosa pine habitat: Arno [15] studied the response of
Oregon-grape for 4 years following low and high-consumption prescribed burning in a
shelterwood cutting unit in
western Montana. The average percent cover of Oregon-grape was
highest overall in the no burn areas, and greater in the
high-consumption burns compared to the low-consumption burns. Burn treatment
severity was indicated by the consumption of woody fuels, which ranged from 0% in
the no-burn to 80% in the high-consumption burn treatment. Mineral soil exposure was 4% in
the no-burn, 8% in the low-consumption burn and 9% in the high-consumption burn
[15]:

Postfire year	Pretreatment	1	2	3	4
No burn	3.0	2.6	2.7	3.0	3.9
Low-consumption burn	1.2	1.6	2.0	2.6	2.9
High-consumption burn	2.1	1.7	2.8	3.4	3.9

Mixed conifer: The effectiveness of shelterwood cutting and underburning was
tested on a ponderosa pine-Douglas-fir-grand fir forest on the Priest River
Experimental Forest in northern Idaho. Treatments included a moist fuels underburn, a dry
fuels underburn, and a no burn in the cut units. The percent canopy coverage of
Oregon-grape was measured 1 year following the moist and dry burns. Oregon-grape
changed little after the shelterwood cut in the no burn and moist underburn
areas but decreased after the dry burn [179]:

No burn		Moist burn		Dry burn
Precut	Postcut	Prefire	Postfire	Prefire	Postfire
4.6	4.0	3.8	3.7	3.9	1.3

Favorable responses of Oregon-grape to prescribed burning:

Big sagebrush/grass: The effects of prescribed burning were studied by
Blaisdell [33] in the Snake River Plains in Idaho. Four hundred circular plots,
each having an area of 100 ft², were established at
regular intervals. Immediately after the plots were burned, they were
classified by intensity of burn as follows: "light burn"-smaller branches and
twigs of sagebrush unburned, only leaves consumed by fire; "moderate burn"-
larger branches of sagebrush remaining, but smaller branches and twigs consumed;
and "heavy burn"- trunk or mainstem
of sagebrush plants consumed by fire. Fifteen years following the prescribed burns,
Oregon-grape was favored by the heavy burn treatment [33]:

	Unburned	Light burn	Moderate burn	Heavy burn
Lbs/acre	6.3	4.4	7.0	33.9

Great Basin big sagebrush: The percent cover of Oregon-grape was greater
after prescribed spring and fall fires in 1973 compared to a control site on the
Bridger-Teton National Forest, Wyoming [127]:

Treatment	Spring burn			Fall burn			Unburned control
Year	1974	1975	1976	1974	1975	1976	1974	1975	1976
Cover (%)	trace	1	trace	trace	----	1	----	trace	----
Frequency (%)	3	5	5	3	----	10	----	3	----

Mixed conifer, quaking aspen/mixed conifer and quaking aspen: Oregon-grape responded quickly after
a prescribed burn applied in late September in Manning Basin in the Caribou
National Forest, Idaho. In the mixed conifer stand, the burn severity was
"moderate", indicating that litter was consumed, duff was deeply charred, but
with some remaining charcoal; shrubs were killed and partially consumed; and
most aspen stems were charred and appeared killed. In the upper-elevation and
lower-elevation aspen stands, the burn severity was "high", indicating that
litter and duff were completely consumed and mineral soil exposed; shrubs were
mostly consumed; and all aspen stems were killed. The biomass of Oregon-grape was
2/3rds of prefire quantities 5 years after
fire. The numbers below indicate biomass kg/ha [36]:

Stand	Mixed conifer	Upper-elevation aspen	Lower-elevation aspen
Prefire	60	65	85
Postfire	47	93	47

Ponderosa pine-Douglas-fir:
The Research Project Summary
Vegetation response to restoration treatments in ponderosa pine-Douglas-fir forests of western Montana provides information on prescribed fire and postfire response of plant species
in this community including
Oregon-grape.
Douglas-fir:
Vegetation was compared between clearcuts, uncut, and cut and
burned stands by Lafferty [111] in the Gold Creek drainage, 17 miles northeast
of Missoula, Montana. The clearcuts were burned in the fall between 1961 and 1964, and the study was
conducted in 1967. The burn classifications are as follows: "Unburned"-no
apparent effect of fire on the slash or soil; "lightly burned"-twigs finger-size
and smaller consumed, larger materials partly burned with needles scorched and
fuel components discernible; and "severely burned"-fire consumed most of the
organic layer, all 4 inch materials absent and logs deeply charred.
Oregon-grape was most abundant on south aspects of the
"lightly burned" stand [111]:

Treatment	Unburned			Lightly burned			Severely burned
Aspect	North	East	South	North	East	South	North	East	South
Cover (%)	5	5	13	5	5	13	0	5	5
Frequency (%)	6	9	14	3	4	62	0	1	1

Douglas-fir/globe huckleberry: After spring and
fall prescribed fires in the Lubrecht Experimental forest in western Montana,
the total number of Oregon-grape plants increased in 3 of 5 plots, and
frequency increased in 2 of 5 plots in both
postfire years [130]:

Plot number	Prefire 1973		Postfire 1974		Postfire 1975
	Total no. of plants	No. of sample quadrats with plants	Total no. of plants	No. of sample quadrats with plants	Total no. of plants	No. of sample quadrats with plants
2 (Spring burn)	73	10	109	3	130	5
30 (Spring burn)	39	10	80	14	86	13
1(Fall burn)	135	21	56	10	77	11
3 (Fall burn)	110	6	127	8	180	10
31 (Fall burn)	6	2	2	2	23	5

Douglas-fir/ninebark habitat: On the Coeur d'Alene Indian Reservation in Benewah County, Idaho, Douglas-fir/ninebark habitat was burned in high- and
low-intensity prescription fires. Oregon-grape was nearly absent on high-intensity burn sites, and
unharmed on low-intensity sites. The following table provides the percent cover in unburned, low-intensity,
and high-intensity treatments. Coverages are averaged over 3 postfire years of
data collection [11].

Treatment	Unburned	Low-intensity	High-intensity
Cover (%)	1.1	1.2	0.0
Frequency (%)	8.6	11.1	0.2

The average fuel load on burned sites was 58,200 kg/ha, nearly half of which
was duff [25]. Depth of duff was 1.3 cm on high-intensity sites, 4.0 cm on low-intensity sites,
and 6.6 cm on unburned sites. Three replicated high- and low-intensity fires
were sampled. High- and low-intensity fires had significantly different (p<0.05)
fireline intensities. Energy produced by high-intensity fires was between 30 to
3,034 kcal/m/s and averaged 781 kcal/m/s; energy released on low-intensity fires
averaged 127 kcal/m/s and ranged from 25 to 194 kcal/m/s. Significantly (p value
not reported) more duff was consumed on the high-intensity fire sites (80%) than
on low-intensity fire sites (40%). Flame lengths averaged 0.9 m and ranged from
0.1 to 1.7 m on both sites. On average, duff smoldered longer on high-intensity
sites than on low-intensity sites [11]. See the Research Project Summary
Understory recovery after low- and high-intensity fires in northern Idaho ponderosa pine forests for an extended report on this study.
Lyon's Research Paper
also provides information on prescribed fire use and postfire response of plant
species, including Oregon-grape, in Rocky Mountain Douglas-fir communities.

Grand fir/Oregon boxwood (Pachistima
myrsinites): The percent shrub crown cover of Oregon-grape was studied
before (1967) and after prescribed spring burning in central
Idaho by Leege [118] with little difference [118]:

Year	1967	1969	1970	1970	1972	1977
% crown cover	0.5	0.3	0.5	0.6	0.9	0.6

Grand fir/Oregon boxwood: In a study performed by Zamora [221], 43 stands of vegetation representing various
developmental stages were studied following broadcast-burned clearcut stands in north central Idaho. The average
percent canopy volume of Oregon-grape was greatest 8 years following
the treatment and decreased until Oregon-grape was no longer present in the near-climax stage [221]:

Age class	1 year	3 year	8 year	12 year	23 year	Near-climax
% canopy volume	<0.1	0.1	0.7	<0.1	0.1	0

Mature larch/Douglas-fir: Following spring and fall prescribed burns of "light
intensity" in the Lubrecht Experimental Forest in western Montana, almost no
damage was done to the rhizomes of Oregon-grape, and Oregon-grape sprouted either the same year or the
following year [184].
Grand fir/Oregon boxwood and western hemlock/Oregon boxwood: A 20-year record of shrub
succession in clearcut and clearcut-burned areas
was studied in the Coeur d'Alene National Forest in northern Idaho by Wittinger
and others [218]. Oregon-grape increased following logging and/or burning on 3 sites in
the western hemlock/Oregon boxwood sites and 2 sites in the grand fir/Oregon boxwood habitat
as shown below [218]:
The Jupiter Creek-Diamond Cut site is located in the western hemlock-Oregon boxwood
habitat and was clearcut in 1950 and not burned. Oregon-grape increased 7 years after
clearcutting but decreased 25 years after clearcutting [218]:

Jupiter Creek-Diamond cut site
Unlogged adjacent		7 years after clearcutting	14 years after clearcutting	25 years after clearcutting
% composition	8.7	19.3	2.8	1.6
% cover	3.7	14.1	2.0	2.3

The Jupiter Creek-Power Line site is located in the western hemlock/Oregon boxwood habitat and
was clearcut and burned in 1961. The percent composition and percent cover
changed little 3 years and 14 years after the treatment [218]:

Jupiter Creek-Power Line site
3 years after clearcutting and burning		14 years after clearcutting and burning
% composition	1.3	0.9
% cover	0.9	1.8

The Beetle Creek site is located in the western hemlock/Oregon boxwood habitat and was cut in
1956 and burned in 1958. Oregon-grape increased significantly
(p<0.05) on the clearcut and burned sites compared to the unlogged adjacent site [218]:

Beetle Creek site
Unlogged adjacent		6 years after clearcutting and burning	17 years after clearcutting and burning
% composition	trace	2.2	4.5
% cover	trace	2.2	7.8

The Tourist Creek site is located in the grand fir/Oregon boxwood habitat and was clearcut and burned in 1964.
Oregon-grape increased after 5 years then decreased by 11 years [218]:

Tourist Creek site
5 years after clearcutting and burning		11 years after clearcutting and burning
% composition	8.3	4.7
% cover	6.0	4.0

The Mullan Tree site is also located in the grand fir/Oregon boxwood habitat and was
clearcut in 1956 and burned in 1958. Oregon-grape sustained increases following
logging and burning though the 14-year period [218]:

Mullan Tree site
1964		1975
3 years after clearcutting and burning		14 years after clearcutting and burning
% composition	1.0	2.6
% cover	0.5	4.6

No response to prescribed burning:

Subalpine fir/beargrass (Xerophyllum tenax) habitat type, globe
huckleberry phase: The response of Oregon-grape to different clearcutting treatments
followed by burning in west-central
Montana was studied by Arno and Simmerman [20]. Oregon-grape showed little
change after the following treatments: clearcutting without additional site or slash treatment,
clearcutting with broadcast burning, clearcutting with mechanical scarification and burning in piles,
and low-severity fire, and severe, stand-replacement fire [20].

Oregon-grape sprouts from rhizomes after fire. Seedling regeneration can occur from onsite or offsite sources [147]. Seedling establishment following fire has been reported by Bradley [35], possibly originating from a short-term seedbank. Oregon-grape seeds may be dispersed onto burns by birds and mammals [22,147,169].

Oregon-grape is considered an "endurer," or "survivor" due to its adaptability to survive fire by sprouting, and growth from deep-buried perennating buds [147,193,194,195,196]. Rhizomatous species, such as Oregon-grape, often increase by the end of the 1st year after fire [33,195]. If shallow rhizomes are killed by fire, the remaining rhizomes below the mineral soil surface can survive to form separate plants [35].

More info for the terms: cover, duff, flame length, frequency, resistance

Oregon-grape has "medium" resistance to fire [132,153,158,158,184,212]. This rating is interpreted as a 35-64% chance that 50% of a population will survive or immediately reestablish after a fire with an average flame length of 12 inches (30 cm) [158] and regain its prefire frequency or cover in 5 to 10 years [153,158]. Oregon-grape may be killed by severe fire (over 572º F (300° C)) that removes duff and causes heating of the soil, killing rhizomes [11,35,78,132,158,184,212]. Occasionally, Oregon-grape survives severe fires [9,15,30,33,54,95,160,204,217].

Fire top-kills Oregon-grape. Mortality of the entire plant is induced when sufficient heat is diverted to its rhizomes which are near or below the ground surface [11,78,132,158,184,212].

More info for the terms: adventitious, ground residual colonizer, rhizome, secondary colonizer, shrub

POSTFIRE REGENERATION STRATEGY [195]:
Small shrub, adventitious bud/root crown
Rhizomatous shrub, rhizome in soil
Ground residual colonizer (on-site, initial community)
Secondary colonizer (on-site or off-site seed sources)

More info for the term: rhizome

Fire adaptations: Oregon-grape is adapted to fire due to its well-developed rhizome systems [3,35,36,88,128,132,147,195]; however, plants with rhizomes above the mineral layer may be killed in the case of severe fires [11,35,78,132,158,184,212].

FIRE REGIMES: Oregon-grape occurs in plant communities with a variety of FIRE REGIMES including frequent, low-severity surface fires, mixed-severity fires, and crown fires.

The following table provides fire return intervals for plant communities and ecosystems where Oregon-grape is important. For further information, see the FEIS review of the dominant species listed below.

Community or ecosystem	Dominant species	Fire return interval range (years)
grand fir	Abies grandis	35-200 [16]
basin big sagebrush	Artemisia tridentata var. tridentata	12-43 [171]
mountain big sagebrush	Artemisia tridentata var. vaseyana	15-40 [18,38,131]
curlleaf mountain-mahogany*	Cercocarpus ledifolius	13-1,000 [21,174]
mountain-mahogany-Gambel oak scrub	Cercocarpus ledifolius-Quercus gambelii	<35 to <100
Rocky Mountain juniper	Juniperus scopulorum	<35 [154]
western larch	Larix occidentalis	25-350 [17,29,51]
Engelmann spruce-subalpine fir	Picea engelmannii-Abies lasiocarpa	35 to >200
blue spruce*	Picea pungens	35-200 [16]
pinyon-juniper	Pinus-Juniperus spp.	<35 [154]
whitebark pine*	Pinus albicaulis	50-200 [2,13]
Rocky Mountain lodgepole pine*	Pinus contorta var. latifolia	25-340 [28,29,198]
Sierra lodgepole pine*	Pinus contorta var. murrayana	35-200 [16]
Colorado pinyon	Pinus edulis	10-400+ [59,70,101,154]
western white pine*	Pinus monticola	50-200
Pacific ponderosa pine*	Pinus ponderosa var. ponderosa	1-47 [16]
interior ponderosa pine*	Pinus ponderosa var. scopulorum	2-30 [16,24,115]
quaking aspen (west of the Great Plains)	Populus tremuloides	7-120 [16,72,129]
mountain grasslands	Pseudoroegneria spicata	3-40 (µ=10) [14,16]
Rocky Mountain Douglas-fir*	Pseudotsuga menziesii var. glauca	25-100 [16,18,19]
coastal Douglas-fir*	Pseudotsuga menziesii var. menziesii	40-240 [16,134,165]
oak-juniper woodland (Southwest)	Quercus-Juniperus spp.	<35 to <200 [154]
western redcedar-western hemlock	Thuja plicata-Tsuga heterophylla	>200 [16]

*fire return interval varies widely; trends in variation are noted in the species review

More info on this topic.

More info for the terms: climax, cover, density, frequency, low-severity fire, succession

Oregon-grape is present throughout all successional stages [65,77,120]. It tolerates full sun and partial to deep shade [133,151]. It is considered a "stress tolerator" due to its shade tolerance and longevity, surviving in environments from clearcuts to dense conifer stands. As the overstory increases in density or cover, the establishment and growth of Oregon-grape diminish due to lack of sunlight [112,151,199]. Oregon-grape responds favorably to disturbances and increases after low-severity fire [11,12,183,184] as well as severe fire [9,15,30,33,54,95,160,204,217] and logging [151,175,218].

Oregon-grape is classified by various authors as a seral to climax species throughout its range. In studies by Habeck [75,76] in Glacier National Park, Montana, the forest succession of major understory species, including Oregon-grape, was studied in western redcedar-western hemlock (Thuja plicata-Tsuga heterophylla) communities after the 1967 Flathead Fire. The following table presents the percent frequency of Oregon-grape from pioneer to climax stages of succession. The gradient segments begin with pioneer communities dominated by lodgepole pine that are less than 50 years old and end with a climax community dominated by western hemlock, averaging 400 years old [75,76]:

Gradient segments	I (dominated by lodgepole pine)	II (dominated by Engelmann spruce)	III (dominated by western hemlock)	IV (dominated by western redcedar/western hemlock)	V (dominated by western hemlock)	VI (dominated by western hemlock)
Frequency (%)	7.0	26.7	3.5	2.5	4.3	0.3

Oregon-grape was a pioneer species following the Tillamook Fires in northwestern Oregon, which burned a total of 355,000 acres (143,663 ha) over 20 years. Before the burns, the forests were dominated by Douglas-fir, western redcedar, and western hemlock at medium to high elevations, and Sitka spruce (Picea sitchensis) at lower elevations [120].

On some site types, Oregon-grape is considered seral. Oregon-grape occurs in seral communities of Douglas-fir habitat types in central Idaho [48,187], ponderosa pine communities in the Selway-Bitterroot Wilderness, Idaho [77], Rocky Mountain juniper (Juniperus scopulorum)/roughleaf ricegrass habitat in the northern Great Plains, Engelmann spruce (Picea engelmannii) -subalpine fir forests in northwest Wyoming [26] and quaking aspen woodlands in the West [5,6,44,81,82,136,136,137,176,220]. Oregon-grape occurs in late-seral stages in riparian areas of Zion National Park [84].

After disturbances in a ponderosa pine/common juniper habitat type in the Custer National Forest within the Missouri Plateau of Montana, Oregon-grape quickly invaded, but decreased with time and lack of disturbance [81].

Oregon-grape occurs as a climax understory dominant in the following habitats: Douglas-fir [7,48,64,80,91,113,126,168,185,186,187,187,203], grand fir [64,65,77,168,186,186], western redcedar and western hemlock forests [77,168], subalpine fir [5,44,144,185,185,219], ponderosa pine forests [116,167,168,180,200], white fir [4,7,57,69,113,125,126,138,219], quaking aspen [5,6,44,81,82,136,136,176,220], lodgepole pine [126], and blue spruce [57,126,180,219].

More info for the terms: cover, density, layering, monoecious

Oregon-grape reproduces both sexually and vegetatively.

Pollination: Oregon-grape is pollinated by bees and butterflies. If cross-pollination does not occur, self-pollination may occur, frequently producing no fruits [135].

Breeding system: Oregon-grape is monoecious.

Seed production: Good fruit crops are produced almost annually from cross-pollinated plants [135].

Seed dispersal: Seeds are dispersed by birds and mammals [22,169].

Seed banking: Regeneration from seed banks is common [35,78]. Seed banking of Oregon-grape has not been studied in the field; however, seeds are viable for many years under warehouse conditions. Plummer and others [156] claim that Oregon-grape seeds can be stored up to 5 years with good viability; Jorgensen and Stevens [96] claim that seeds can be kept under uncontrolled warehouse conditions for 13 or more years with good viability and or 16 or more years of dry storage without a great loss in viability [192]. Oregon-grape had a germination rate of 25% for freshly collected seed and decreased to 23% germination after 13 years in an open warehouse, showing no great change in germination percentage [192].

Soils were sampled in mature Douglas-fir/ninebark (Physocarpus malvaceus), grand fir/Rocky Mountain maple, and grand fir/globe huckleberry (Vaccinium globulare) habitat types on the Payette and Boise National Forests in west central Idaho for viable Oregon-grape seeds. In samples covering a total area of 2.28 m², 13 viable Oregon-grape seeds were found-10 seeds in the 0 to 2.0 inch (0-5 cm) layer and 3 seeds in the 2.0 to 3.9 inch (5-10 cm) layer [103].

Germination: Oregon-grape requires stratification. In the laboratory, Oregon-grape is considered a "medium germinator" [96] but is considered a "poor" germinator when planted on game ranges of Utah [156]. According to Jorgensen and Stevens [96], Oregon-grape seeds require cold stratification from 1 to 3 months. Plummer and others [156] claim that seeds can require up to 196 days cold stratification to stimulate germination.

Seedling establishment/growth: Growth of Oregon-grape is rapid after a disturbance but is slow when considered over the life of a forest stand [199]. Individual stems can live for 10 years or more [61]. As the overstory increases in density or cover, the establishment and growth of Oregon-grape generally diminish due to lack of sunlight [112,151,199]; however, in a ponderosa pine habitat in the Fort Lewis National Forest in Colorado, the percent ground cover of Oregon-grape increased as the density of trees increased. This was probably due to the affinity of Oregon-grape to acid soils created by the ponderosa pine needles [143].

Survival measurements and "vigor" estimates were made on Oregon-grape plants planted on road cut and fill slopes on 3 National Forests in eastern Washington. The survival of Oregon-grape was generally low and vigor was fair to poor on all sites [201].

Asexual regeneration: Oregon-grape regenerates by rhizomes [133,135,147,190] and layering [34,96,133].

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More info for the terms: chamaephyte, geophyte

RAUNKIAER [161] LIFE FORM:
Chamaephyte
Geophyte

More info for the term: shrub

Shrub

Berries and leaves are browsed by ungulates and rodents (Tilford 1998). Also, provides significant forage for the white-footed vole in coastal Oregon (Vance et al. in press). This plant aerates and stabilizes soils.

More info on this topic.

More info for the term: phenology

Oregon-grape flowers from early spring to mid-summer. Flower development likely depends on climate and site conditions:

Arizona	April-June
Idaho	March-July
Nevada	March-June
New Mexico	April-June
Uinta Basin	May-June

The fruit of Oregon-grape ripens from June to September in Utah [156] and June in the Great Plains [71].

Schmidt and Lotan [173] provide phenological data on Oregon-grape east of the Continental Divide in Montana and Yellowstone National Park, and in northern Idaho and Montana west of the Continental Divide. The growing season for Oregon-grape generally begins earlier west of the Continental Divide. The table below presents the phenology of Oregon-grape based on observations from 1928 to 1937 [173]:

East of the Continental Divide in Montana and Yellowstone National Park
	leaf buds burst	leaves full grown	flowers start	flowers end	fruits ripe	seeds fall starts	leaves start to color/wither	leaves begin to fall	leaves fallen withered
average date	May 6	June 12	May 28	June 22	Aug. 11	Aug. 9	Sep. 8	Sep. 20	Oct. 15
earliest date	Apr. 20	May 15	Apr. 28	May 15	June 23	July 16	Aug. 25	Sep. 17	Oct. 10
latest date	May 30	June 28	July 4	Aug.2	Sep. 15	Sep. 1	Sep. 15	Sep. 24	Oct. 18
standard error (days)	2	2	3	4	4	6	4	2	2
number of observations	25	24	32	31	22	7	5	4	4
Northern Idaho and west of the Continental Divide in Montana
	leaf buds burst	leaves full grown	flowers start	flowers end	fruits ripe	seeds fall starts	leaves start to color/wither	leaves begin to fall	leaves fallen withered
average date	May 2	May 24	May 6	May 29	Aug. 2	Aug. 12	Sep.27	----	----
earliest date	Mar. 20	Apr. 11	Mar. 20	Apr. 15	June 21	July 16	Sep. 24	----	----
latest date	May 28	July1	May 28	June 16	Sep. 1	Sep. 14	Oct. 1	----	----
standard error (days)	4	4	3	3	3	6	2	----	----
number of observations	23	28	29	30	30	8	3	----	----

Flowering spring (Apr-Jun).

Flowering winter-spring (Mar-May).

Flowering spring (Apr-May).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 1
Species With Barcodes: 1

Oregon-grape is imperiled in North Dakota [146].

Rounded Global Status Rank: G4 - Apparently Secure

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Mahonia repens is widely distributed from western Canada south to California and east to Texas and North Dakota. It is reportedly abundant throughout its range and common in second-growth forests. Closely related Mahonia species are collected for medicinal use, however Mahonia repens is not currently in demand. Trends in demand and future impacts on wild populations should be monitored, since relatively less is known about threats to this species as compared to other economic plants in this genus.

United States

Rounded National Status Rank: NNR - Unranked

Comments: Mahonia species are reportedly used as a substitute for goldenseal (Tilford 1998). Thus, although current demand is apparently relatively small, increased interest is possible. Some experts in the medicinal industry have suggested increased research be conducted on this species, probably because several related species are used medicinally (Robbins 1998). Therefore, commercial interest and collecting activities should be monitored.

More info for the terms: basal area, cover, density, frequency, resistance, wildfire

Recreation: In recreation areas of Montana, Oregon-grape showed moderate
resistance to trampling by humans due to stout stems and branches. Short-term
recovery for Oregon-grape in trampled areas was very low to low, but long-term recovery
was high [43].

Herbicide treatment and browsing:
Oregon-grape neither increased nor decreased after herbicide treatment with
picloram and clopyralid [162].
In a Gambel oak habitat on the Grand Mesa National Forest, Colorado, the percentage of cover for
Oregon-grape decreased slightly 2 years after
spraying with 2,4-5T (now banned by the EPA) [209] and increased slightly after chaining [105].
Following browsing by domestic goats in a Gambel oak habitat in northern
Utah, Oregon-grape increased [163].
Wildlife management:
A study by Pase and Hurd [151] was conducted to
determine the effects of silvicultural thinning on understory vegetation in
ponderosa pine forests in the Black Hills and Bear Lodge Mountains in Wyoming.
Oregon-grape responded favorably to increased and decreased basal area of the
ponderosa pine stands. This was due to Oregon-grape's tolerance to full sun
and shade. The increase in Oregon-grape provided forage for deer in winter [151].
Silviculture:
In a subalpine forest in Colorado, the percent cover of
Oregon-grape decreased 3 years after clearcutting and returned to prelogging percent cover 4 years
after clearcutting [49].
The mean percent cover of Oregon-grape was higher in 50-year-old clearcut forests of
lodgepole pine and Engelmann spruce-subalpine fir compared to adjacent mature
stands of lodgepole pine and Engelmann spruce-subalpine fir in
southeastern Wyoming [175].
Following a 4,000 acre (1,619 ha) wildfire in 1968 in a ponderosa pine-mixed fir habitat
in Oregon, the effects of rehabilitation by seeding versus nonseeding were
studied by Anderson and Brooks [10]. The percent ground cover of
Oregon-grape was greater on the unseeded area than the seeded
area of the pine-mixed fir site, indicating that it may have been suppressed by
the seeded grasses [10]:

Year	1969	1970	1971	1972
Unseeded	1	4	2	7
Seeded	trace	0	0	trace

Slash burning of debris in Douglas-fir/grand fir habitat of northern Idaho
favors early establishment of Oregon-grape, which is a preferred forage species
for deer [155].
Other:
Oregon-grape is an alternate host of black stem rust of cereals [100,135,213].

Oregon-grape is resistant to sulfur dioxide pollutants generated from coal-fired power
plants in southwest desert areas of the U.S. [89].
Fires of low intensity (surface soil <138° F(59°
C)) do not improve the nutrient quality of Oregon-grape browse; however, sprouting may be stimulated
[17].
The influence of prescribed understory burning
and livestock grazing on community structure was studied by Zimmerman [222] in
Douglas-fir/ninebark habitat on
the East Hatter Creek portion of the University of Idaho Experimental
Forest in northern Idaho. The density, cover, and frequency
of Oregon-grape were studied the 1st postfire year. Oregon-grape was most
abundant in the grazed, unburned areas [222]:

	Grazed		Ungrazed
	Burned	Unburned	Burned	Unburned
Density (plants/ha)	0.0	4766.7	1633.4	1100.0
Cover (%)	0.0	2.1	0.5	0.8
Frequency (%)	0	11	3	9

More info for the term: resistance

Medicinal: The leaves, roots, and bark of Oregon-grape were used by Native Americans for medicine. The leaves were chewed for acne [197] and made into a tonic for rheumatic stiffness [55]. The roots were used to cure dysentery, thicken the blood and cure coughs, kidney problems, and venereal diseases [135,164,197]. Liquid from chewed roots was placed on wounds [197], and the bark of Oregon-grape was used to cure stomach troubles, heartburn, and purify the blood [41].

The alkaloid berberine exhibits weak antibiotic properties. Berberis species are not known to be infected by bacterial pathogens, making them useful in medicine [100,191].

Dye: The roots of Oregon-grape were used for yellow dye [52,100,133,135,153,207].

Food: Native Americans used the berries of Oregon-grape to add flavor to soup [197]. The fruit is suitable for preserves [34,52,100,109,116,135,153,164,197,207,210,214] and wine [116,197].

Ornamental: Oregon-grape is an excellent plant for xeriscaping due to its heat and drought resistance [37,74,159,190,213,216] and it has good ornamental potential [157].

More info for the terms: cover, hardwood, layering, reclamation, resistance, restoration

Oregon-grape is an excellent ground cover because it protects against erosion [52,99,100,190,210] and has good resistance to insects and disease [156]. The spreading habit and ability to grow on exposed, dry rocky slopes makes Oregon-grape a useful plant for restoration on disturbed sites such as highways [133,182], recreation areas [133], mined lands [133], including acid mine sites [211], game ranges [133], and reclamation areas [216]. For quicker growth, transplants of Oregon-grape are usually used instead of direct seeding [133].

Propagation: Oregon-grape can be propagated by seeds, layering [34,96], and root cuttings [34]. For seed propagation, seeds must be collected by hand-stripping into hoppers, cleaned, and dried using a fan. A warm pretreatment of seeds is necessary for 0 to 60 days, followed by a wet prechill of 30 to 196 days [34,156]. The container production period (excluding hardening) has a moderate growth of 0-6 months and slow growth after 6 months [156]. For layering, stem cuttings of the hardwood should be harvested in the winter and grown in a greenhouse [96,177]. Propagation by root cuttings is slow and not recommended [34].

More info for the terms: cover, density, shrub

Oregon-grape browse contains toxic alkaloids and is slightly poisonous and unpalatable to livestock [33,52,73,136,207,210]; however, it is an important forage plant for the wildlife:

White-tailed deer and mule deer: White-tailed deer [94,139,140] and mule deer [23,63,73,106,114] eat Oregon-grape primarily in the fall and winter during periods of reduced snow cover in the Rocky Mountain region.

Oregon-grape is lightly used by mule deer in the spring and summer in the Beaver Creek Watershed of the Coconino National Forest, Arizona [141] and Chopaka Mountain, Washington [39].

The diet of mule deer was studied from 1 June to 31 August, 1962 through 1968 by Hungerford [92] in logged mixed conifer, logged ponderosa pine, a burn in mixed conifer habitat, and a control site in northern Arizona. Mule deer ate a small amount of Oregon-grape in the 2nd half of June and 1st half of July, but use was intermittent, depending upon the availability of other foods. The burned area had the highest ground cover density of Oregon-grape and the most use by deer [92].

Elk: In a study by Trout and Leege [205] along the Lochsa and Selway Rivers in northern Idaho, Oregon-grape was the 2nd most important item in the winter diet of elk. In the Threemile and Calf Creek game ranges, Montana, overall shrub use by elk was minimal, but Oregon-grape was the primary shrub used in February [114]. Oregon-grape growing in open areas is an important food for elk in the Rocky Mountains in the spring and fall [117,122].

Birds: Sharp-tailed grouse [66] and various other species of birds [100,123,157,210] eat the fruit of Oregon-grape.

Bighorn sheep: Bighorn sheep eat Oregon-grape during the winter in Montana [45,172,202].

Mountain goat: On Chopaka Mountain in Washington, Oregon-grape comprises 2.1% of mountain goat diet in winter, 2.1% in spring, 0.1% in summer, and 0.8% in the fall [39].

Moose: Oregon-grape is a forage species for moose in the fall in Montana and comprises less than 5% of the fall diet of moose in Fremont County, Idaho [166].

Bear: American black bears rely heavily on the fruits of Oregon-grape and play an important role in seed dispersal [22]. Grizzly bears also eat the berries of Oregon-grape [50,102].

Lagomorphs: Mountain cottontail and snowshoe hare eat Oregon-grape [123]. Oregon-grape comprised <6% of the desert cottontail's diet in the Sugarloaf Mountain area of the Tonto National Forest, Arizona [206].

Palatability: Oregon-grape has low palatability to livestock [47,53,97]. Game animals show low to moderate use, primarily in the fall and winter [150,207].

The percent use of Oregon-grape for big game and livestock in a grand fir/Rocky Mountain maple habitat type in central Idaho are [186]:

Deer		Elk		American black bear			Cattle	Domestic sheep
Summer	Winter	Summer	Winter	Spring	Summer	Fall	Summer	Summer
15-25%	35-45%	15-25%	35-45%	15-25%	15-25%	15-25%	15-25%	35-45%

In the Black Hills of South Dakota, white-tailed deer use of Oregon-grape was measured in winter, spring, summer, and fall. The numbers below are the utilization: availability ratio for use by white-tailed deer to availability of Oregon-grape [90]:

Winter	Spring	Summer	Fall
8.32	.25	.00	2.72

The degree of use shown by livestock and wildlife species for Oregon-grape in several western states is as follows [53]:

	Colorado	Montana	Utah	Wyoming
Cattle	poor	poor	poor	poor
Domestic sheep	poor	poor	fair	fair
Horse	poor	poor	poor	poor
Elk	good	poor	good	good
Mule deer	good	fair	good	good
White-tailed deer	----	good	----	good
Pronghorn	----	----	fair	poor
Upland game birds	----	fair	good	good
Waterfowl	----	----	poor	poor
Small non-game bird	----	fair	good	fair
Small mammal	----	fair	good	fair

Nutritional value: Oregon-grape retains usable energy value and digestible protein moderately well during the fall and winter [83]. In a study by Gastler and others [63], the composition of moisture and nutrients for Oregon-grape was analyzed in the fall, winter, spring, and summer in the Black Hills of South Dakota:

Season	Moisture (%)	Carotene (%)	Crude Fat (%)	Crude Fiber (%)	Crude Protein (%)	Phosphorus (%)	Calcium (%)	Iron (ppm)	Manganese (ppm)
Fall	51.24	42.03	1.96	15.49	4.77	.100	.24	90.06	79.29
Winter	49.16	8.19	2.12	16.33	4.36	.088	.26	84.24	101.13
Spring	47.52	27.21	2.27	15.40	4.32	.11	.28	44.76	84.99
Summer	62.95	66.97	1.43	9.34	5.53	.06	.17	57.74	37.74

Cover value: Oregon-grape provides good cover for small mammals [108,159] and birds [157].

Habitat containing Oregon-grape as a predominant understory species is used by adult sharp-tailed grouse [66], boreal owls [87] and northern goshawks [152] for activities including wintering, breeding, nesting and brood rearing [66,87,152].

In the Black Hills of South Dakota, Oregon-grape comprises 36.5% of white-tailed deer diet [63] but it is considered a poor species for hiding/escape cover, thermal cover and fawning cover [148].

Berberis sonnei was described based on plants with relatively narrow, rather shiny leaflets collected by Sonne in Truckee, California. Subsequent collections from this population show the morphology typical of B . repens ; Sonne's collections evidently are an aberrant form of this species. 

 Berberis repens is resistant to infection by Puccinia graminis .

Various Native American tribes used preparations of the roots of Berberis repens to treat stomach troubles, to prevent bloody dysentary, and as a blood purifier; mixed with whiskey, it was used for bladder problems, venereal diseases, general aches, and kidney problems; and preparations made from the entire plant served as a cure-all and as a lotion for scorpion bites (D. E. Moermann 1986).

Berberis pumila is resistant to infection by Puccinia graminis .

Berberis amplectens is endemic to the Peninsular Ranges of southern California. It is resistant to infection by Puccinia graminis .

Comments: Kartesz (1994 'Synonymized Checklist' and 1999 'Synthesis of the North American Flora') includes Mahonia (or Berberis) sonnei in Mahonia (or Berberis) repens here; USFWS recognizes the 'sonnei' taxon as a distinct species. LEM 18Feb01.