Print Report
A0422 Abies lasiocarpa - Populus tremuloides Rocky Mountain Moist Forest Alliance
Type Concept Sentence: This mixed evergreen-deciduous forest alliance is codominated by Populus tremuloides and Abies lasiocarpa and has been described from mountain slopes and plateaus in the Rocky Mountains from Alberta, Canada, south to Montana, Wyoming, Colorado, and west into Utah.
Common (Translated Scientific) Name: Subalpine Fir - Quaking Aspen Rocky Mountain Moist Forest Alliance
Colloquial Name: Rocky Mountain Moist Subalpine Fir - Aspen Forest
Hierarchy Level: Alliance
Type Concept: The mixed coniferous and deciduous tree canopy is open to moderately closed and is dominated by Populus tremuloides and Abies lasiocarpa. Several other species of conifers may be scattered within the stands, including Abies concolor, Picea engelmannii, Picea pungens, Pinus contorta, Pinus flexilis, and Pseudotsuga menziesii. Younger stands typically have dense Populus tremuloides, with Abies lasiocarpa or other conifers mixed in. As the stands age in this typically seral forest association, Populus tremuloides is slowly reduced until conifers become dominant. Mixed stands must have at least 25% relative tree cover of both aspen (deciduous) and conifers. The understory is most often composed of a short-shrub layer often dominated by Symphoricarpos oreophilus. Other shrubs may include Amelanchier alnifolia, Mahonia repens, Paxistima myrsinites, Physocarpus malvaceus, and Rosa woodsii. The herbaceous layer is variable and may compete with shrub species for understory dominance or in some stands be dominant over shrubs. It is a mixture of graminoids and forbs. Characteristic herbaceous species may include Delphinium x occidentale, Eucephalus engelmannii, Heracleum maximum, Osmorhiza occidentalis, Pedicularis racemosa, Rudbeckia occidentalis, Thalictrum fendleri, and Valeriana occidentalis. Stands included in this mixed evergreen-deciduous forest alliance have been described from mountain slopes and plateaus in the Rocky Mountains from Alberta, Canada, south to Montana, Wyoming, Colorado and west into Utah. They occur on gentle to steep slopes on all aspects, but are most common on cooler and more mesic, north and east aspects. Soils are derived from alluvium and colluvium from sedimentary, metamorphic and igneous parent materials.
Diagnostic Characteristics: Diagnostic of these seral forests is the open to moderately closed, mixed coniferous and deciduous tree canopy codominated by Populus tremuloides and Abies lasiocarpa that occupy the upper montane and subalpine zones of the Rocky Mountains.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This alliance is composed of five associations for which only two have descriptive material. Further review of undescribed associations will be required to produce a more thorough description of this alliance.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation included in this minor alliance has a moderately dense to dense upper canopy of mixed deciduous broad-leaved and evergreen needle-leaved trees (5-20 m tall). The understory has a moderate to sparse short-shrub layer typically dominated by evergreen scale-leaved or deciduous broad-leaved shrub species. A sparse tall-shrub layer dominated by deciduous broad-leaved shrubs may be present. A moderate to sparse herbaceous layer may also be present, most often dominated by tall perennial forbs.
Floristics: Seral forests are included in this Rocky Mountain alliance. The open to moderately closed, mixed evergreen needle-leaved and deciduous broad-leaved tree canopy is composed of short to moderately tall trees and is codominated by Populus tremuloides and Abies lasiocarpa. Several other species of conifers may be scattered within the stands, including Abies concolor, Picea engelmannii, Picea pungens, Pinus contorta, Pinus flexilis, and Pseudotsuga menziesii. Younger stands typically have dense Populus tremuloides, with Abies lasiocarpa mixed in. As the stands age in this typically seral forest association, Populus tremuloides is slowly reduced until conifers become dominant (Mueggler 1988). Mixed stands must have at least 25% relative tree cover of both aspen (deciduous) and conifers. The understory is typically moderately dense to sparse and becomes sparser as Abies lasiocarpa becomes more dominant. The understory is most often dominated by a short-shrub layer dominated by Symphoricarpos oreophilus. Other shrubs may include Mahonia repens, Paxistima myrsinites, Physocarpus malvaceus, and Rosa woodsii. The herbaceous layer is variable and may compete with shrub species for understory dominance or in some stands be more prominent over shrubs. It is a mixture of graminoids and forbs. Characteristic herbaceous species may include Delphinium x occidentale, Eucephalus engelmannii (= Aster engelmannii), Heracleum maximum, Osmorhiza occidentalis, Pedicularis racemosa, Rudbeckia occidentalis, Thalictrum fendleri, and Valeriana occidentalis.
Dynamics: Stems of Populus tremuloides are thin-barked and readily killed by fire. It is a fire-adapted species that generally needs fire or some other stand-replacing disturbance to establish and maintain dominance in a forest. These mixed forests are seral and in the absence of disturbance will slowly convert to late-successional forests dominated by Abies lasiocarpa or Picea engelmannii (Mueggler 1988).
Environmental Description: Stands included in this mixed evergreen-deciduous forest alliance have been described from mountain slopes and plateaus in the Rocky Mountains from Alberta, Canada, south to Montana, Wyoming and Colorado and west into Utah. Elevations range from 2200 to 3500 m. Climate is temperate with cold winters. Mean annual precipitation is typically greater than 50 cm. Sites occur on gentle to steep slopes on all aspects, but are most common on north and east aspects. Soils are derived from alluvium and colluvium from sedimentary, metamorphic and igneous parent materials.
Geographic Range: Forests included in this alliance are scattered in the Rocky Mountains of Alberta, Canada, Montana, Idaho, Wyoming, Colorado and Utah.
Nations: CA,US
States/Provinces: AB, CO, ID, MT, UT, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.898990
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: parts of A.274, A.422.
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? Abies lasiocarpa Series (Mauk and Henderson 1984) [Early seral stands in this habitat type may have significant Populus tremuloides.]
>< Aspen: 217 (Eyre 1980)
>< Engelmann Spruce - Subalpine Fir: 206 (Eyre 1980)
>< Aspen: 217 (Eyre 1980)
>< Engelmann Spruce - Subalpine Fir: 206 (Eyre 1980)
- Eyre, F. H., editor. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC. 148 pp.
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- Mauk, R. L., and J. A. Henderson. 1984. Coniferous forest habitat types of northern Utah. General Technical Report INT-170. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 89 pp.
- Mueggler, W. F. 1988. Aspen community types of the Intermountain Region. General Technical Report INT-250. USDA Forest Service, Intermountain Research Station, Ogden, UT. 135 pp.
- Mueggler, W. F., and R. B. Campbell, Jr. 1986. Aspen community types of Utah. Research Paper INT-362. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT.