Rocky Mountain Maple (Acer glabrum) – Featured Native Plant of the Week

by J. Thomas Gebauer, ASLA

Each week TLC brings you one featured native plant to highlight the wonderful, beautiful native plants that are available to us here in Teton County. We choose to highlight natives specifically for the adaptations to this climate, their food value to regional wildlife, decreases the damage done by exotic invasive species and we believe they promote the true natural beauty of this land.

This weeks featured native plant to Teton County is the Rocky Mountain Maple (Acer glabrum). Native to the mountains from Alaska to California and occurs along streambanks, canyons, sometimes dry ridges at low to middle elevations and moist sites in high mountains. It usually occurs between 5,000 and 12,000 feet. Rocky Mountain maple is a long-lived, shade-tolerant species that often persists in the understory of coniferous stands.¹

Native American uses

Some Plateau Indian tribes drank an infusion of Douglas maple as a treatment for diarrhea.²

Wildlife Uses

The Rocky Mountain maple is an important species for foraging animals such as moose, deer, elk and big horn sheep. While the plant will be browsed in summer, it is heavily consumed in fall and winter. Grouse will eat the buds and small animals will consume the seeds. The tree is also important for wildlife cover, especially in lowland, or stream bank areas where it provides cover for small animals, birds and even large moose.³

Functioning With Fire

Rocky Mountain maple has been characterized as fire dependent, and may decline with fire exclusion. Prolific sprouting and wind dispersal of seed of Rocky Mountain maple facilitate rapid revegetation of burned areas. In quaking aspen/Rocky Mountain maple communities in Colorado, this rapid regeneration results in postfire vegetation that quickly resembles the prefire community. Following fire, enhanced growth of Rocky Mountain maple may result in moderate growth loss of conifers and mortality of shade-intolerant conifers. Due to aggressive competition, it may also interfere with conifer seedling establishment.

Rocky Mountain maple occurs as a major component or dominant in seral shrubfields in the northern Rockies. These shrubfields result from canopy removal by repeated severe fires. Seral shrubfields have also been maintained with prescribed fire. A lack of seed combined with increased soil temperatures and moisture stress inhibit tree regeneration and maintain the shrubfields. Fuels in persistent shrubfields consist primarily of the shrubs themselves with little large downed woody material and low litter amounts; in one study conducted in northern Idaho, fuel loading averaged 19.7 tons/acre. Persistent shrubfields may burn in any season; if fuels are continuous and dry, spring fires spread readily, and in summer, hot and dry conditions are exacerbated by nighttime inversions.³

Landscape Uses

This tree is tolerant of a wide variety of conditions. Most common in moist, partly sunny areas the tree can also be found on exposed arid sites in rare circumstances, but will show signs of scorch from wind and heat if over exposed. Best to use for it’s small, almost shrub like stature as an understory tree. Consider using next to pathways or stairs where the subtle qualities of the tree can be observed. Qualities such as the red veins and petioles, the reddish winged seeds are attractive in winter and the yellow/red fall color is wonderful in fall. May also be used for function for watershed protection.

Taxonomy and Characteristics

Scientific name: Acer glabrumCommon name: Rocky Mountain MapleDuration: PerennialLife form: Deciduous treeGrowth form: Multiple stemGrowth Rate: RapidFire resistance: NoFire tolerance: HighToxicity: NoneDrought tolerance: MediumCommercial availability: Readily AvailblePalatable to browsing animals: HighPalatable to grazing animals: Lowmoisture use: LowSoils: Sandy, loamy Height: 33ftLeaves: 1-4″, three lobed, coarsely serrated marginFlowers: corymbs of 5 to 10, yellowish-green, in spring when leaves are emerging.Fruit: Samara. Develops in pairs.

Notes:

1. http://www.sevenoaksnativenursery.com/native-plants/trees/acer-glabrum/
2. Hunn, Eugene S. (1990). Nch’i-Wana, “The Big River”: Mid-Columbia Indians and Their Land. University of Washington Press. p. 351. ISBN 0-295-97119-3.
3. http://www.fs.fed.us/database/feis/plants/shrub/acegla/all.html#FIRE ECOLOGY