Populus tremuloides Forest & Woodland Alliance
Aspen groves

USDA Ecological Section Map

Summary Information

  • Primary Life FormTree
  • Elevation1500-3000 m
  • State RarityS3.2
  • Global RarityG5
  • DistributionCAN: AB, BC, MB, NB, ON, QC, SK. USA: AZ, CA, CO, IA, ID, MA, ME, MI, MN, MT, ND, NH, NJ, NM, NV, NY, OR, SD, TX, UT, VT, WA, WI, WV, WY (NatureServe)
  • Endemic to CaliforniaNo
  • Endemic to California Floristic Province and DesertsNo
  • Date Added1995/11/01

Characteristic Species

Populus tremuloides is dominant or co-dominant in the tree canopy with Abies concolor, Abies magnifica, Juniperus grandis, Juniperus occidentalis, Pinus contorta ssp. murrayana, Pinus jeffreyi and Populus trichocarpa.

Vegetation Layers

Trees < 35 m; canopy is open to continuous. Shrub layer is open to continuous. Herbaceous layer is sparse or abundant.

Membership Rules

  • Populus tremuloides > 50% relative cover in the tree canopy; in mixed stands with conifers > 1% absolute cover (Keeler-Wolf et al. 2003b).


Depressions, swales, slopes, meadow margins, stream corridors, elevated stream terraces, and colluvial toe slopes. Soils are typically deep and well developed, often rocky. The USFWS Wetland Inventory (1996 national list) recognizes Populus tremuloides as a FAC+ plant.

Other Habitat, Alliance and Community Groupings

MCV (1995) Aspen series
NVCS (2009) Abies concolor-Populus tremuloides forest alliance, Populus tremuloides forest alliance, Populus tremuloides seasonally flooded forest alliance, Populus tremuloides temporarily flooded forest alliance, Populus tremuloides woodland alliance
Calveg Aspen (shrub), Quaking aspen, Willow-Aspen
Holland Aspen riparian forest, Aspen forest
Munz Not treated
WHR Aspen
CDFW CA Code 61.111.00

National Vegetation Classification Hierarchy

Formation Class Mesomorphic Tree Vegetation (Forest and Woodland)
Formation Subclass Temperate Forest
Formation Cool Temperate Forest
Division Western North America Cool Temperate Forest
Macro Group Rocky Mountain Subalpine and High Montane Conifer Forest
Group Rocky Mountain mesic subalpine forest and woodland