Print Report
A3616 Abies lasiocarpa - Picea engelmannii Rocky Mountain Talus & Scree Woodland Alliance
Type Concept Sentence: These woodlands of the subalpine Rocky Mountains are associated with talus and scree substrates and dominated by Abies lasiocarpa and/or Picea engelmannii.
Common (Translated Scientific) Name: Subalpine Fir - Engelmann Spruce Rocky Mountain Talus & Scree Woodland Alliance
Colloquial Name: Rocky Mountain Subalpine Fir - Engelmann Spruce Talus & Scree Woodland
Hierarchy Level: Alliance
Type Concept: These upper montane or subalpine conifer woodlands are found scattered throughout the Rocky Mountains within cool and relatively dry climate regimes. In mature stands, the association is characterized by Abies lasiocarpa as the dominant tree species, often with Picea engelmannii. In seral stands, other conifers can be important or even dominant, but Abies lasiocarpa is always present in the regeneration layer. Other tree associates include Callitropsis nootkatensis, Larix spp., Pinus albicaulis, Pinus contorta, Picea glauca, Pseudotsuga menziesii, and Tsuga spp. Stands have sparse shrub layers, typically a reflection of dry conditions related to poorly developed soils, and may include species such as Acer circinatum, Holodiscus dumosus, Juniperus communis, Ribes spp., Salix brachycarpa, and Salix glauca. The herbaceous layer is generally sparse. Important forbs include species of Arnica, Fragaria, Lupinus, Pedicularis, and Thalictrum. Graminoids are rarely important in these woodlands. These woodlands are found on scree and talus slopes where marginal growing conditions produce an open tree canopy. Parent materials and soils are variable across the distribution of the alliance.
Diagnostic Characteristics: Abies lasiocarpa and/or Picea engelmannii form open canopies and occur on talus and scree habitats in upper montane and subalpine environments. Diagnostic of woodlands in this alliance is that they are upland (non-flooded) with average tree canopy of less than 60% cover that is either dominated by Abies lasiocarpa or has Abies lasiocarpa as the predominant conifer in the tree-regeneration layer.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This alliance is a subset of associations of a former larger woodland alliance (A.559), but is now considered environmentally unique in occupying scree and talus slopes. Associations in this alliance have been poorly sampled and may prove with further data to be sparsely vegetated types that should be moved into the sparse vegetation class of the USNVC.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: These woodlands are dominated by needle-leaved evergreen trees up to 30 m in height and of low to moderate cover (20-60%). Although cold-deciduous trees are relatively rare, they can be prominent in some regional variants or seral stands. A sparse to moderately dense shrub layer may be present, dominated by ericaceous or, less commonly, cold-deciduous species. The herbaceous layer is variable and is typically dominated by perennial forbs. In some regions, a nonvascular layer dominated by mosses covers the ground surface.
Floristics: Older stands of these woodlands are characterized by Abies lasiocarpa as the dominant tree species in an open tree canopy, often with Picea engelmannii. Total canopy cover averages <60%, but some stands may have somewhat higher cover. In younger stands, other conifers can be important or even dominant, but Abies lasiocarpa is always present in the regeneration layer. Canopy associates may include Pinus contorta, Populus tremuloides, and Pseudotsuga menziesii. Other tree associates include Callitropsis nootkatensis (= Chamaecyparis nootkatensis), Larix spp., Pinus albicaulis, Picea glauca, and Tsuga spp. Associations in this alliance have poorly to well-developed shrub layers, with the herbaceous layer being relatively depauperate and sparse. The shrub layer is typically less than 2 m in height, and can be up to 80% in cover, although in some stands may be under 20% and a reflection of dry conditions and poorly developed soils. Important to dominant species include Acer circinatum, Holodiscus dumosus, Juniperus communis, Ribes spp., Salix brachycarpa, and Salix glauca. Important forbs include Arnica cordifolia, Arnica latifolia, Chamerion angustifolium (= Epilobium angustifolium), Galium triflorum, Orthilia secunda, Polemonium pulcherrimum, Saxifraga bronchialis, and species of Fragaria, Lupinus, Pedicularis, and Thalictrum. Graminoids are rarely important in these woodlands. Where these woodlands occur on sites with some soil development, there may be a nonvascular layer composed primarily of mosses on the ground surface (Steele et al. 1981, Henderson et al. 1989).
Dynamics: No Data Available
Environmental Description: These upper montane or subalpine woodlands are found scattered throughout the Rocky Mountains in cool and relatively dry climate regimes. These woodlands occur on droughty, well-drained substrates such as scree and talus slopes on southerly or westerly slopes and ridgetops. Snowpacks can be deep, and summers are cool. Summer frosts are characteristic, especially in sites where cold air pools. Elevations range from roughly 2200 m in central Idaho to over 3200 m in Utah, Colorado and New Mexico. In some locations where there is cold-air drainage, these woodlands extend down in elevation into the montane zone. Soils are typically shallow, poorly developed, with significant amounts of rock and gravel in the profile.
Geographic Range: The distribution of this alliance is poorly documented. It has been documented primarily from the southern Rocky Mountains of Colorado, Wyoming and New Mexico with occurrences known also from the northern Rocky Mountains in Glacier-Waterton International Peace Park in Montana and Alberta, Canada.
Nations: CA,US
States/Provinces: AB, AZ?, CO, MT, NM, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899674
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: A.559
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Abies lasiocarpa-Picea engelmannii Series (Johnston 1987)
>< Engelmann Spruce - Subalpine Fir: 206 (Eyre 1980)
>< Western Needleleaf Forests: 15: Western Spruce-Fir Forest (Picea-Abies) (Küchler 1964)
>< Western Needleleaf Forests: 21: Southwestern Spruce-Fir Forest (Picea-Abies) (Küchler 1964)
>< Engelmann Spruce - Subalpine Fir: 206 (Eyre 1980)
>< Western Needleleaf Forests: 15: Western Spruce-Fir Forest (Picea-Abies) (Küchler 1964)
>< Western Needleleaf Forests: 21: Southwestern Spruce-Fir Forest (Picea-Abies) (Küchler 1964)
- 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.
- Henderson, J. A., D. A. Peter, R. Lesher, and D. C. Shaw. 1989. Forested plant associations of the Olympic National Forest. R6-ECOL-TP-001-88. USDA Forest Service, Pacific Northwest Region, Portland, OR. 502 pp.
- Johnston, B. C. 1987. Plant associations of Region Two: Potential plant communities of Wyoming, South Dakota, Nebraska, Colorado, and Kansas. R2-ECOL-87-2. USDA Forest Service, Rocky Mountain Region. Lakewood, CO. 429 pp.
- Küchler, A. W. 1964. Potential natural vegetation of the conterminous United States. American Geographic Society Special Publication 36. New York, NY. 116 pp.
- Steele, R., R. D. Pfister, R. A. Ryker, and J. A. Kittams. 1981. Forest habitat types of central Idaho. General Technical Report INT-114. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 138 pp.