Name:
Populus tremuloides Woodland Alliance
Reference:
Western Ecology Working Group of...
Description:
Woodlands included in this alliance occur from the Great Lakes and northern Great Plains to the interior northwestern United States. Elevations range from up to 2900 m in Montana and Oregon to less than 500 m in the lake states. Climate is temperate, continental and ranges from semi-arid to subhumid. Stands have a sparse to moderately dense canopy of the cold-deciduous broad-leaved tree Populus tremuloides, 5-20 m tall. Other trees may include scattered conifers in the western extent or several deciduous broad-leaved trees from the Great Plains to the Great Lakes. Stands may have irregular canopies of young and old trees, or tall, dense immature trees, or mature trees. Often these stands are found on rocky, dry or disturbed sites that limited the density of tree canopy. The shrub layer can be sparse, but is often dense and diverse especially in the plains. The herbaceous layer is sparse to moderately dense and is typically dominated by graminoids. In the northern Great Plains and western Great Lakes area these Populus tremuloides-dominated stands may have an abundance of Acer rubrum, Populus balsamifera, or Populus grandidentata. Betula papyrifera, Fraxinus pennsylvanica, and Quercus macrocarpa are common associates. The shrub layer is well-developed, with 40-90% cover in northwestern Minnesota. Common shrub species include Amelanchier alnifolia, Corylus spp., Prunus virginiana, Ribes aureum, Rosa spp., and Symphoricarpos occidentalis. Cornus sericea and Salix spp. are common on wetter sites. The herbaceous layer is not as well-developed as the shrub layer but is still significant. Andropogon gerardii, Aralia nudicaulis, Galium boreale, Maianthemum canadense, and Maianthemum stellatum are typically found in the herbaceous layer. In the western United States, scattered conifers of Pinus ponderosa or Pinus contorta may be present in these stands. Shrubs have a sparse to moderately dense layer (10-60% cover) dominated by Symphoricarpos albus, Amelanchier alnifolia or Physocarpus malvaceus with scattered Ribes lacustre. The graminoid layer is also sparse to moderately dense (3-40% canopy cover) and is dominated by the perennial grass Elymus glaucus with Carex spp. The sparse to moderately dense (10-40% cover) and often diverse forb layer includes Achillea millefolium, Fragaria virginiana, Galium spp., Geum macrophyllum, Maianthemum stellatum, Osmorhiza spp., and Veratrum californicum. Exotic grasses, such as the perennial Poa pratensis, are often common in stands disturbed by grazing. Stands are largely limited to gentle (0-20%) slopes but may be steep in mountains and canyons. Canopy cover of these Populus tremuloides woodlands is limited by environmental factors such as aridity, poor site conditions or frequent disturbance. Sites vary with geography. Near the Great Lakes, this alliance occurs on rocky sites with shallow soils and exposed patches of granite bedrock. In the Great Plains, it is found on well-drained, moderately deep to deep loam soils. Along the prairie-forest border, this alliance can be found on dry-mesic to wet-mesic sites on flat to rolling topography. In northwestern Montana, stands are found on steep scree slopes in the Mission Mountains. In Oregon, stands occur in riparian and seepage areas in the mountains, foothills and plains. Sites include floodplains, valley bottoms, footslopes, mesic basins and draws, and at higher elevations rocky slopes on mountains and canyonsides. In more mesic areas sites are often transitional between true riparian and upland. Soils are derived from alluvium, ash and colluvium. Soil texture ranges from fine sandy loam to clay loam. Adjacent vegetation includes deciduous and coniferous forests in more mesic areas, and grasslands and shrublands where more xeric.
Accession Code:
VB.CC.20177.POPULUSTREMULOI
Plot-observations of this Community Concept:
0
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