Global Range: ID to N. Mexico, W. to W. AZ, E. to OK, TX. Much narrower in northern half of range, concentrated in N. central UT.
States or Provinces
Regional Distribution in the Western United States
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 :
5 Columbia Plateau
6 Upper Basin and Range
7 Lower 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
Bigtooth maple is a deciduous, small tree or shrub of variable size. Its life form is dependent upon the moisture regime . In canyon bottoms and along streams it grows as a tree with single or multiple trunks reaching 50 feet (15 m) tall and 1 foot (30 cm) in diameter, while on dry canyon slopes it grows as a shrub with 2 or more stems reaching 26 feet (8 m) tall [11,14,31,66,67,108,149,160].
Bigtooth maple leaves are palmately lobed, 1 to 4 inches (2.5-10 cm) wide, and pubescent beneath [31,66,160]. Plants usually flower every 2 or 3 years . Flowers are umbellate or corymbose and have no petals. The fruit is a dry, indehiscent, double-winged samara, each side with 1 small seed 0.16 to 0.20 inch long. The ovary and young fruit have long, straight hairs [31,58,61,66,107,160]. Twigs are glabrous and the bark is thin and smooth or flaky [148,153]. Bigtooth maple has both lateral surface roots and a deep tap root. An extensive root system develops during the first growing season. Reproduction by layering of the lower branches extends the root system radially [11,27].
Comments: Moist soil in canyons of high mountains and plateaus, ponderosa pine forest and scrub, 4700 to 7000 ft.
Bigtooth maple has a broad ecological amplitude . It occurs on a wide range of sites with different aspects, soil types, and soil moisture conditions . Throughout its range it is most often located on cool, moist sites in canyons, ravines, along mountain streams, and on lower slopes [1,3,10,11,28,31,34,60,66]. Physiological research, however, shows that bigtooth maple can grow with oaks on drier, open slopes because it is relatively tolerant of low water potentials .
When bigtooth maple grows together with Gambel oak, it occupies ravines while Gambel oak occupies the slopes. When oak is absent, maples occupy the drier sites as well as the moist ravines . It occupies cool, shaded draws and intermittent stream drainages in the high mountains and plateaus of central and southern Arizona and southern New Mexico [19,80] and has been classified as an obligate riparian species in New Mexico . It is more abundant in the bottom than in the top of snow-melt drainages on the Mogollon Rim in central Arizona . In Idaho, it grows on hillsides, below springs and seeps, and on secondary floodplains of narrow canyon drainages . In Texas, it grows in limestone canyons, along creeks, on canyon slopes, and on floodplain terraces [37,39,51,112,162]. It is primarily a riparian species in Utah, but is also found throughout the mountain brush zone and in white fir and Douglas-fir forests. It is found on upper slopes in the Wasatch Mountains, although it is more common on mesic, north-facing slopes than on drier south-facing slopes [40,43,44,103].Elevation: Bigtooth maple occurs between 4,200 and 9,400 feet (1,280-2,870 m) [1,31,56,60,63,66,67,69,80,112,160]. Elevation ranges by state/region are as follows:
|New Mexico||6,900-9,400 [1,80]|
|Intermountain West||up to 8,900 |
Soils: Bigtooth maple is adapted to a range of soil depths and a variety of soil textures including silt loam, clay loam, sand, gravel, and cobble. It prefers moist, well-drained soil [56,66,69,105,139]. Plants can grow in both moderately acidic and alkaline soils in the 6.0 to 8.0 pH range [11,14,110,139]. In north-central Utah it is abundant on calcium-rich soils .
Moisture: Bigtooth maple is drought tolerant [11,14,131,139,149]. Plants require 16 to 20 inches (40-50 cm) of annual precipitation [32,105]. In southeastern Idaho, the water table is generally well below the surface where bigtooth maple grows but may occur within 24 inches (60 cm) . In Red Butte Canyon, Utah, precipitation is the most important water source for small trees (<20 cm DBH) located away from the stream, while the stream is the major water source for small trees located adjacent to the stream. Larger trees (>20 cm DBH) do not use stream water even if they grow adjacent to the stream. Roots are distributed throughout the soil profile but active sites of water absorption are in the deep soil horizons . The effects of flooding on bigtooth maple are unclear. One source states that plants are intolerant of "prolonged or frequent flooding" , while another states that bigtooth maple can withstand flooding for most of one growing season .
Key Plant Community Associations
Bigtooth maple is listed as a dominant species in the following vegetation classifications:
- bigtooth maple community type 
- Douglas-fir (Pseudotsuga menziesii)/bigtooth maple habitat type [2,97,98]
- ponderosa pine (Pinus ponderosa)/bigtooth maple habitat type [97,98]
- white fir (Abies concolor)/bigtooth maple habitat type [2,19,35,46,92,98,138,141]
- bigtooth maple community type 
- bigtooth maple montane forest alliance 
- narrowleaf cottonwood (Populus angustifolia)/bigtooth maple community type [62,104]
- bigtooth maple cover type 
- Arizona cypress (Cupressus arizonica)/bigtooth maple habitat type 
- bigtooth maple-Buckley oak-chinkapin oak (Quercus buckleyi-Q. muehlenbergii) forest alliance 
- bigtooth maple-Lacey oak (Q. laceyi)-Buckley oak forest 
- bigtooth maple montane forest alliance 
- bigtooth maple-oak series 
- bigtooth maple cover type 
- bigtooth maple montane forest alliance 
- Douglas-fir/bigtooth maple habitat type 
- Gambel oak (Q. gambelii)-bigtooth maple community type 
- maple brush community 
- narrowleaf cottonwood/bigtooth maple community type 
- quaking aspen (Populus tremuloides)/bigtooth maple/bracken fern (Pteridium aquilinum)
community type 
Habitat: Rangeland Cover Types
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 :
402 Mountain big sagebrush
404 Threetip sagebrush
411 Aspen woodland
412 Juniper-pinyon woodland
413 Gambel oak
415 Curlleaf mountain-mahogany
416 True mountain-mahogany
418 Bigtooth maple
503 Arizona chaparral
504 Juniper-pinyon pine woodland
509 Transition between oak-juniper woodland and mahogany-oak association
Habitat: Cover Types
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 :
61 River birch-sycamore
66 Ashe juniper-redberry (Pinchot) juniper
93 Sugarberry-American elm-green ash
210 Interior Douglas-fir
211 White fir
216 Blue spruce
219 Limber pine
220 Rocky Mountain juniper
237 Interior ponderosa pine
240 Arizona cypress
241 Western live oak
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
KUCHLER  PLANT ASSOCIATIONS:
K011 Western ponderosa forest
K012 Douglas-fir 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
K031 Oak-juniper woodland
K032 Transition between K031 and K037
K037 Mountain-mahogany-oak scrub
K055 Sagebrush steppe
K086 Juniper-oak savanna
K098 Northern floodplain forest
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):
FRES21 Ponderosa pine
FRES26 Lodgepole pine
FRES28 Western hardwoods
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 to >300
Fire Management Considerations
The mountain brush vegetation type, dominated by Gambel oak and bigtooth maple, is important for big game winter range in Utah . Prescribed burning can be used to top-kill bigtooth maple and Gambel oak to open up dense stands for easier big game access . Because mature bigtooth maple stands have sparse understories and therefore reduced surface fuel loads to carry fire, burning should take place before maple clones become large . Seeding of mountain brome (Bromus carinatus var. marginatus) and other grasses following burning or mechanical removal of brush reduces the regrowth of bigtooth maple and Gambel oak .
Because flames can spread quickly through Gambel oak and bigtooth maple canopy during dry, windy weather and on steep terrain, fuel reduction is recommended for property owners in the oak-maple zone in Utah . The white fir/bigtooth maple habitat type in Arizona and New Mexico may be important as a fire barrier since it generally occurs along streams in mountain canyons .
Plant Response to Fire
There is little information about immediate or long-term postfire response in bigtooth maple. Limited research suggests that bigtooth maple can survive low- and moderate-severity burns but may be killed by a severe burn [49,58]. In a field experiment near Logan, Utah, clipping of buds, leaves and stems stimulated production of new growth in bigtooth maple. Loss of buds and other plant tissue, therefore, does not cause a meristematic constraint that limits production of new growth, suggesting that bigtooth maple can recover from tissue loss after a fire . In Ephraim Canyon, Utah, bigtooth maple sprouted "vigorously" from the root crown following prescribed burning in the mountain brush vegetation type. There was no mortality in the individuals observed .
Fire does not significantly change the species composition in bigtooth maple and Gambel oak stands in the oakbrush vegetation type in Utah . Burned stands "return quickly" to prefire species composition . Bigtooth maple may become more important in the canopy after fire. A severe fire can spread quickly through Gambel oak and bigtooth maple canopy during dry, windy weather and on steep terrain. After a stand- replacing fire, sprouts of Gambel oak and bigtooth maple appear within a few weeks. Dense clones develop until some stems gain dominance and increase in diameter. With self-thinning, the clones open up, allowing understory production to increase. Although maple and oak codominate in the canopy at this point, oak seedlings are eventually shaded out and maple seedlings and sprouts from stem layering dominate the understory. Over time, bigtooth maple becomes the canopy dominant .
Immediate Effect of Fire
Although bigtooth maple may be top-killed by fire, plants can survive by sprouting from the root crown [21,49,58]. In a severe burn, bigtooth maple would likely be killed . Smaller-diameter stems are more likely to be killed by fire, clearing areas for new tree seedlings and sprouts from surviving larger diameter trees. More research is needed on the response of bigtooth maple to fires of different severities .
POSTFIRE REGENERATION STRATEGY :
Tall shrub, adventitious bud/root crown
Secondary colonizer (on-site or off-site seed sources)
Fire adaptations: Bigtooth maple is generally tolerant of fire. Plants sprout from the root crown when stems are burned [49,56,58,59]. Sprouting after fire is dependent upon tree age and fire severity. Sprouting is most likely to occur from young stems growing on moist sites where high moisture content in fuels results in low severity burns. A severe burn is likely to damage the sprouting response .
FIRE REGIMES: Fire plays a role in many plant communities where bigtooth maple is a common or dominant species. Bigtooth maple is, for example, an important component of montane riparian communities in the Intermountain West and southwest United States. These moist sites burn less frequently than nearby uplands [46,91]. In Big Bend National Park, Texas, fire-scarred Arizona cypress trees provided evidence of historic fire in an Arizona cypress/bigtooth maple canyon bottom community, but fire dates could not be determined . In riparian deciduous forests in the Central Texas Hill Country, fire frequency is "low" to "very low." Crown fires may occur during drought or at long return intervals [36,37].
Bigtooth maple is also a dominant species in montane maple-oak woodlands. In Utah, fire frequency in these communities is low. Historically, more extensive grass cover allowed more frequent fires that inhibited the establishment of Gambel oak and bigtooth maple seedlings and killed smaller stems along the edges of existing clones. Due to a combination of fire suppression, cessation of livestock grazing, and climatic changes, however, Gambel oak and bigtooth maple have increased in these communities. As bigtooth maple increases in the canopy, stands become less susceptible to fire. Shading by bigtooth maple foliage prevents the buildup of understory fuels. Bigtooth maple leaf litter decomposes rapidly, which results in lower surface-fuel loads, making fire spread difficult [21,119].
The following table provides fire return intervals for plant communities and ecosystems where bigtooth maple 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)|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|mountain big sagebrush||Artemisia tridentata var. vaseyana||15-40 [6,23,89]|
|sugarberry-America elm-green ash||Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica||154]|
|curlleaf mountain-mahogany*||Cercocarpus ledifolius||13-1,000 [8,124]|
|mountain-mahogany-Gambel oak scrub||Cercocarpus ledifolius-Quercus gambelii||<35 to <100|
|Arizona cypress||Cupressus arizonica||<35 to 200|
|juniper-oak savanna||Juniperus ashei-Quercus virginiana||<35|
|Ashe juniper||Juniperus ashei||<35|
|Rocky Mountain juniper||Juniperus scopulorum||<35|
|pinyon-juniper||Pinus-Juniperus spp.||<35 |
|Mexican pinyon||Pinus cembroides||20-70 [91,140]|
|Rocky Mountain lodgepole pine*||Pinus contorta var. latifolia||25-340 [16,17,143]|
|Colorado pinyon||Pinus edulis||10-400+ [48,54,68,106]|
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [5,9,77]|
|Arizona pine||Pinus ponderosa var. arizonica||2-15 [9,30,125]|
|quaking aspen (west of the Great Plains)||Populus tremuloides||7-120 [5,55,88]|
|Texas savanna||Prosopis glandulosa var. glandulosa||<10 |
|Rocky Mountain Douglas-fir*||Pseudotsuga menziesii var. glauca||25-100 [5,6,7]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||<35 to <200 |
More info for the terms: climax, cover, shrub, succession, tree
Bigtooth maple is an early- to late-successional species [26,58,101,103,136]. It is abundant in late successional riparian communities in Zion National Park, Utah . Seedlings are shade tolerant and grow under the canopy of mature big sagebrush (Artemisia tridentata)  and Gambel oak .
Bigtooth maple commonly invades Gambel oak stands in Utah and northern Arizona [42,59]. The general trend in these mountain brush communities is toward an increase in bigtooth maple in the canopy along with a decrease in Gambel oak. In a grazing exclosure in Pole Canyon, bigtooth maple increased from 52% to 64% cover between 1949 and 1967 while Gambel oak decreased from 26% to 23% cover . In a review of the literature, Harper and others  state that stream courses, slope bases, and intermittent drainages serve as sites from which bigtooth maple can invade upland Gambel oak stands. Because bigtooth maple leafs and flowers earlier and grows faster in stem and crown diameter than Gambel oak, it becomes more important in the canopy over time [26,42]. On some sites, it may eventually replace Gambel oak [73,101,103]. Bigtooth maple is the dominant climax species in many maple-oak woodlands from north-central Utah to south-central Idaho .
On cooler sites, bigtooth maple may replace Gambel oak, but further succession could lead to dominance by white fir [42,59]. In Arizona, New Mexico, Utah, and Idaho, bigtooth maple occurs as a shade-tolerant, seral understory tree or shrub in Douglas-fir, white fir, and subalpine fir (Abies lasiocarpa) habitat types [21,35,46,85,135]. In Douglas-fir habitat types in Utah, bigtooth maple sprouts are likely to form a dense canopy after fire. Douglas-fir will eventually dominate the canopy, but bigtooth maple often remains in the understory for many years .
Bigtooth maple reproduces sexually and vegetatively. Reproduction by seed is important for establishment of bigtooth maple in new areas. Layering is common in older plants and is a more effective method of reproduction in the mountain brush zone in central Utah [27,28,101]. Bigtooth maple also sprouts from the root crown .
Breeding system: Flowers are either male or female. Plants may bear male flowers only or produce both male and female flowers on the same inflorescence [13,58,76,80,107]. Flowers may be bisexual initially, with ultimate sex expression linked to environmental factors such as moisture or temperature. Flower sex ratios differ between mesic and xeric sites and also from year to year in response to climatic changes. In northern Utah, plants produced more female flowers during wet years and on mesic sites and more male flowers during dry years and on dry sites . Schlessman  argues that the evidence for sex conversion in bigtooth maple is inconclusive, suggesting instead that some trees in a monoecious population may produce only male flowers under poor conditions.
Seed production: Bigtooth maple produces an estimated 235,000 samaras per acre in the mountain brush zone in central Utah. In most double samaras, only one ovary contains a developed seed . Seed production varied with elevation in northern Utah. Seed filled samaras were most abundant between 5,900 and 6,200 feet (1,800-1,900 m) and least abundant below 5,300 feet (1,600 m) and above 6,500 feet (2,000 m) . Bigtooth maple produces many more seeds than Gambel oak, giving it a reproductive advantage in the mountain brush zone [28,101].
Seed dispersal: Bigtooth maple seeds are dispersed by wind and gravity [58,107]. Wind dispersed samaras are important for successful establishment of bigtooth maple in new areas, particularly on shady sites [28,149].
Seed banking: Although bigtooth maple occurred in the extant vegetation at two sites in the Huachuca Mountains, Arizona, it was not present in the soil seed bank at either site . No other information on seed banking in bigtooth maple is available.
Seed viability: Viability of bigtooth maple seeds is low. Out of 412 mature samaras examined in the mountain brush zone of central Utah, no viable embryos were found . Weevil and moth larvae infestation contribute to seed mortality [11,76,149]. Bigtooth maple is, for example, a host plant for Phyllotrox canyonaceris, a weevil that develops in the seeds. Adults lay eggs directly on the seed in the spring and larvae emerge in August. Larvae are most abundant in seeds in early summer .
Germination: Germination in bigtooth maple is epigeal and generally occurs in April and May . Soaking in cold water and exposure to cold temperatures stimulate germination [131,147]. In a greenhouse study, 50% of samaras stratified in moist soil at 40 Â°F (4.4 Â°C) for 4 weeks germinated. Only 8% of samaras not subjected to cold treatment germinated . In a study of seed viability, 8.7% of bigtooth maple seeds remained viable after storage at 68 Â°F (20Â°C) for 25 days .
Seedling establishment/growth: Bigtooth maple samaras exhibit better establishment in new areas than under parent trees where layering is more common . Herbaceous vegetation beneath Gambel oak is often less dense than under bigtooth maple, allowing for easier establishment of bigtooth maple seedlings . Seedling growth in bigtooth maple is slow, especially during the first few growing seasons [131,139]. In a greenhouse study, seedlings averaged 5 inches (13 cm) after 4 months . In another study, seedlings grew only 2 inches (5 cm) in the first growing season . Chilling treatments can accelerate seedling growth .
Mature bigtooth maple samaras were stored for 3 months in a dry, cool room, stratified in moist soil at 40 Â°F (4.4 Â°C) for 4 weeks, then placed in a greenhouse for 3 months. Seedlings emerged during the first 5 weeks after the flats were placed in the greenhouse. Of single samaras, 30.6% developed into "normal" seedlings . Seedling mortality under field conditions is very high. Although bigtooth maple seedlings can grow under the dense canopy of mature Gambel oak and bigtooth maple , only 0.47% of seedlings survived for 5 growing seasons and only 1 new seedling was observed during this time period in an exclosure in Pole Canyon, Utah :
|Seedlings per acre|
Vegetative regeneration: Bigtooth maple reproduces vegetatively by layering  or by sprouting from the root crown when stems are broken off by flooding, beavers, fire, or other disturbances [49,58]. Layering is the most effective means of reproduction in bigtooth maple in the mountain brush zone of central Utah. In a study in Pole Canyon, 1,680 stems per acre originated through layering . In another Pole Canyon study, bigtooth maple vegetative growth from layering made up 78.5% of the total understory canopy coverage of a Gambel oak-bigtooth maple community . Clipping of buds, leaves and stems stimulates production of new growth in bigtooth maple .
Growth Form (according to Raunkiær Life-form classification)
More info for the terms: hemicryptophyte, phanerophyte
RAUNKIAER  LIFE FORM:
Life History and Behavior
Bigtooth maple seeds germinate and cotyledons of new plants emerge in April and May . Throughout much of the range of bigtooth maple, new leaves and flowers appear at the same time in April and May [28,42,108]. Flowering times vary only slightly by region [4,13,28,31,66,67,69,80,112,139]:
|New Mexico ||April|
|Intermountain West ||April-May|
In Green Canyon near Logan, Utah, leaf development proceeded as follows :
|1 June||young leaves fully developed|
|2 July||leaves mature|
|25 September||leaves senescent|
|3 October||leaves fallen|
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: Native in much of the American southwest and Intermountain West. Common (with Quercus gambellii) on lower mountain and foothill slopes in Utah and adjacent southeastern Idaho, Wyoming. Spotty/irregular distribution elsewhere.
Comments: Grazing, housing development pressure at some locations.
Biological Research Needs: Determine what stresses species is subject to, and the reasons for widely scattered distribution.
Riparian forests and woodlands in the southwestern United States where bigtooth maple is often a dominant
species do not cover extensive areas but are ecologically important. These communities are threatened by
degradation from livestock grazing, stream flow regulation, recreation, and invasion of nonnative species .
Logging activity that allows increased light in the understory accelerates growth and development of
bigtooth maple. Although bigtooth maple can be a dominant species in logged areas, it does not restrict
establishment of conifer seedlings .
Since mule deer prefer bigtooth maple over Gambel oak, managers may wish to maintain bigtooth maple stands
in wintering areas . In Arizona, mixed conifer-bigtooth maple communities with horizontal visibility
<45 feet (14 m) should be created or preserved to provide secure cover for black bears . Maintaining
a diversity of stand ages benefits wildlife by providing a balance of forage and cover. Firewood cutting
reduces bigtooth maple density in mature stands .
Bigtooth maple is a grazing increaser .
Information on the susceptibility of bigtooth maple to aerially applied herbicides is available .
Relevance to Humans and Ecosystems
Other uses and values
Syrup can be produced from bigtooth maple sap [12,15,58,63,80,105,149]. Because of its fall coloration and tolerance of alkaline soils, drought conditions, and cold temperatures, bigtooth maple has high potential as a landscaping tree in the western United States [14,105,131,139,149].
Wood Products: Bigtooth maple is a good source of fuelwood [58,63,67,80]. The wood is heavy and hot-burning and regenerates quickly after cutting [21,76,153]. The wood is used for posts, and small amounts can be sawed into lumber . Commercial harvest, however, is not economically viable due to the restricted distribution of the species [35,46,75].
Value for rehabilitation of disturbed sites
Bigtooth maple has deep roots that can stabilize soil on roadcuts, streambanks, and other disturbed sites in the Intermountain West [56,70,86,94,110,136,149]. It is suitable for restoration planting in mountain brush, quaking aspen, and juniper-pinyon (Juniperus spp.-Pinus spp.) vegetation types in Utah . Bigtooth maple is moderately valuable for range restoration in Utah  and is recommended for urban planting on the Colorado Great Plains . Bigtooth maple can be used in restoration plantings on strip-mined areas and on denuded recreation sites . It is best to transplant 2-year-old bare root stock or container-grown seedlings in the early spring when dormant . Bigtooth maple can also be established by seed planted 0.5 inch (1.3 cm) deep in sunny areas and covered by straw mulch . Information on commercial sources of bigtooth maple seed is available [139,150].
Importance to Livestock and Wildlife
Bigtooth maple provides browse for big game and livestock but is generally consumed in small to moderate amounts [72,75,128,153]. Its forage value is "fair" because its tall growth form limits forage availability . Consumption of bigtooth maple by Rocky Mountain mule deer is "light" in the winter and "moderate" in the summer [72,128,129]. Bigtooth maple comprised 9% of fecal material from elk and 8% from mule deer on a northern Utah rangeland . In another northern Utah study, bigtooth maple ranked 12th out of 15 plants in percent of forage consumed by mule deer . Bigtooth maple is an important food source for moose in southeastern Idaho. On Big Bend Ridge in Fremont County, bigtooth maple comprised 5% of moose diet .
Lower elevation Gambel oak-bigtooth maple communities in Utah are regularly used by big game animals for winter range [74,111]. Throughout its range, bigtooth maple provides foraging, nesting, and roosting habitat for a variety of birds [58,99]. Bigtooth maple seeds are an important food source for many wildlife species [56,75]. Squirrels and chipmunks eat maple seeds, storing them in caches after removing the hull and wing .
In Arizona and New Mexico, the white fir/bigtooth maple habitat type typically occurs along stream courses. These riparian areas are considered high quality fish and wildlife habitat . Bigtooth maple is a dominant species in broadleaf riparian woodlands in Arizona which are used by a variety of wildlife including canyon tree frog, leopard frog, Mexican garter snake, Arizona alligator lizard, Sonoran mud turtle, zone-tailed hawk, pygmy owl, downy woodpecker, western flycatcher, red-faced warbler, American dipper, Bullock's oriole, valley pocket gopher, Arizona gray squirrel, black bear, and raccoon [22,116].
Palatability/nutritional value: The palatability of bigtooth maple for livestock and game species is generally poor to fair . Bigtooth maple is less palatable to elk and moose than Rocky Mountain maple (Acer glabrum)  and is undesirable for domestic sheep and deer on Utah rangelands . Although mule deer generally prefer bigtooth maple over Gambel oak in the southwestern United States [110,130], bigtooth maple ranked 24th in preference out of 32 plants eaten by mule deer in the summer in northern Utah . Palatability of bigtooth maple for mule deer and cattle on the Kaibab National Forest, Arizona is 5% (palatability is based on the amount of leaves and annual shoot growth consumed) .
Honey bees near Tuscon, Arizona, preferred bigtooth maple pollen over pollens of Fremont cottonwood (Populus fremontii), dandelion (Taraxacum spp.) and aleppo pine (Pinus halepensis). Bigtooth maple had the highest protein content (>25%) of any of these species, although the effect of protein content on preference in this study was not clear .
Palatability of bigtooth maple in 2 western states has been rated as follows :
|Small nongame birds||----||poor|
|Upland game birds||----||poor|
The protein value of bigtooth maple forage is rated as "poor" and the energy value is rated as "fair" . Crude protein concentration was 9.5% and in-vitro organic matter digestibility was 58.5% in bigtooth maple leaves harvested in mid-September after tissue growth ceased but before the first frost. Mastication of bigtooth maple leaves by cattle resulted in lower tannin levels and significantly (P<0.05) higher crude protein content compared to unmasticated controls . In-vitro organic matter digestibility of leaves decreases as the growing season progresses .
Cover value: Bigtooth maple provides cover for a variety of livestock and wildlife species in canyon bottoms, along riparian zones, and where it occurs in uplands [56,58,63,75]. In the Great Basin, bigtooth maple copses provide cover and bedding grounds for mule deer . In central and southern Arizona and southern New Mexico, the dense cover in white fir-bigtooth maple forests serves as excellent black bear habitat . Although white fir-bigtooth maple forest occurred on only 1% of a study area on the Mogollon Plateau, Arizona, it accounted for 12% of black bear use. The thicker cover created by this forest type provides females with better security than adjacent, open, ponderosa pine ridgetops . Overall, however, bigtooth maple provides poorer cover for large animals than Gambel oak because the leaves fall earlier in the autumn and maple tends to form dense, self-pruning stands .
Of the 392 bird species known from Utah, 67 were found feeding and/or nesting in oakbrush habitat dominated by Gambel oak, bigtooth maple, and chokecherry (Prunus virginiana) in the Wasatch Mountains. California quail, ring-necked pheasant, scrub jay, black-billed magpie, black-capped chickadee, and rufous-sided towhee are all permanent residents of this habitat . Twelve percent of sharp-shinned hawk nests documented in a Utah study were located in bigtooth and Rocky Mountain maple trees . In southern Utah, Mexican spotted owls roost in riparian deciduous woodlands in steep canyons where bigtooth maple is a dominant species [161,163]. In snow-melt drainages on the Mogollon Rim in central Arizona, red-faced and orange-crowned warblers prefer mesic sites dominated by bigtooth maple and small firs (Pseudostuga menzeisii and Abies concolor) . Ruffed and blue grouse use bigtooth maple stands in the spring, summer and fall on the Caribou National Forest in southeastern Idaho. Bigtooth maple provides nesting habitat for black-billed magpies  and is the preferred habitat of blue grouse in the summer [133,134].
The dense canopy formed by bigtooth maple in riparian zones provides shade and helps to maintain cooler stream temperatures for fish and other aquatic biota during hot summer months .
The cover value of bigtooth maple in 2 western states has been rated as follows :
|Small non-game birds||good||good|
|Upland game birds||----||good|
Acer grandidentatum (bigtooth maple) is a species of maple native to interior western North America, occurring in scattered populations from western Montana in the United States south to Coahuila in northern Mexico. It is closely related to Acer saccharum (sugar maple), and is treated as a subspecies of it by some botanists, as Acer saccharum subsp. grandidentatum (Nutt.) Desmarais.
It is a small to medium-sized deciduous tree growing to 10–15 m tall and a trunk of 20–35 cm diameter. The bark is dark brown to gray, with narrow fissures and flat ridges creating plate-like scales; it is thin and easily damaged. The leaves are opposite, simple, 6–12 cm long and broad, with three to five deep, bluntly-pointed lobes, three of the lobes large and two small ones (not always present) at the leaf base; the three major lobes each have 3–5 small subsidiary lobules. The leaves turn golden yellow to red in fall (this trait is less reliable in warmer areas).
The flowers appear with the leaves in mid spring; they are produced in corymbs of 5–15 together, each flower yellow-green, about 4–5 mm diameter, with no petals. The fruit is a paired samara (two winged seeds joined at the base), green to reddish-pink in color, maturing brown in early fall; each seed is globose, 7–10 mm diameter, with a single wing 2–3 cm long.
It commonly grows in limestone soils but can adapt to a wide range of well-drained soils, from sand to clays to even white limestone areas. It prefers valleys, canyons, and the banks of mountain streams, primarily at higher elevations such as the mountain ranges of Utah, Arizona, and New Mexico and some adjacent states. However, bigtooth maple can survive at lower elevations in sheltered canyons, for example in the mountains of west Texas and the Edwards Plateau in Texas (where a population is protected in the Lost Maples State Natural Area). Although continental climates prevail over all of its natural range, it grows well in the maritime climate of Vancouver. It is slow growing when young, and does not have many pests.
It is occasionally planted as an ornamental tree, valued for its drought tolerance and ability to grow in rocky landscapes.
Other vernacular names occasionally used include lost maple, Sabinal maple, western sugar maple, Uvalde big tooth maple, canyon maple, southwestern big tooth maple, plateau big tooth maple, limerock maple, Wasatch maple and Rocky Mountain sugar maple.
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Names and Taxonomy
For bigtooth maple:
Acer saccharum Marsh. subsp. grandidentatum (T. & G.) Desmarais
Acer saccharum Marsh. subsp. grandidentatum (Nutt.) Desmarais [31,65]
Acer saccharum var. grandidentatum (Nutt.) Sudw. [31,65,81,160]
For canyon maple:
Acer saccharum Marsh. var. sinuosum (Rehd.) Sarg. [65,81]
Acer sinuosum Rehd. [65,81]
Acer grandidentatum Nutt. var. grandidentatum , bigtooth maple
Acer grandidentatum Nutt. var. sinuosum (Rehd.) Little [39,65,81,153], canyon maple
A more detailed discussion of bigtooth maple taxonomy, including its relationship to eastern sugar
maple (Acer saccharum), can be found in .
western sugar maple
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