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A3366 Pinus contorta Rocky Mountain Forest Alliance
Type Concept Sentence: This alliance is characterized by forests dominated by Pinus contorta and occurs in the upper montane and subalpine zones of the Rocky Mountains and the eastern Cascade Range.
Common (Translated Scientific) Name: Lodgepole Pine Rocky Mountain Forest Alliance
Colloquial Name: Rocky Mountain-East Cascadian Lodgepole Pine Forest
Hierarchy Level: Alliance
Type Concept: This alliance is found in the upper montane and subalpine zones of southern Rocky Mountains, north to the Canadian Rocky Mountains and west into the Cascade Range. Forests included in this alliance are characterized by a closed to open tree canopy that is dominated (>90% cover) by the conifer Pinus contorta. Stands may be even-aged or multi-aged depending on geographic location, edaphic characteristics, and how the stands were established following wildfire. Shrub and herbaceous layers may be present or absent depending on tree canopy. Other tree species such as Abies lasiocarpa, Picea engelmannii, Pinus albicaulis, Pinus flexilis, Populus tremuloides, Pseudotsuga menziesii, Tsuga heterophylla, or Tsuga mertensiana may be present to abundant as seedlings and saplings, or as trees, but with low abundance. On warmer sites, Abies grandis, Thuja plicata, and Tsuga heterophylla may be also present. Associated shrub and herbaceous species vary across the range of this alliance. Common subalpine and montane shrub species include Arctostaphylos nevadensis, Arctostaphylos patula, Arctostaphylos uva-ursi, Ceanothus velutinus, Linnaea borealis, Mahonia repens, Purshia tridentata, Ribes spp., Spiraea betulifolia, Spiraea douglasii, Shepherdia canadensis, Symphoricarpos albus, Vaccinium cespitosum, Vaccinium membranaceum, and Vaccinium scoparium. Herbaceous cover is very sparse. The cover of the herbaceous stratum can be dominated by either graminoids or perennial forbs and tends to vary inversely with shrub cover. Important graminoids include Achnatherum occidentale, Carex pensylvanica, Carex geyeri, Carex rossii, Calamagrostis rubescens, Danthonia californica, and Elymus glaucus. Important forbs are Arnica cordifolia, Chimaphila umbellata, Orthilia secunda, Osmorhiza berteroi, Pedicularis racemosa, Thalictrum spp., and Xerophyllum tenax. Elevations range from just over 900 m in the eastern Cascades to well over 3100 m in the Rocky Mountains. This alliance occurs in a broad array of habitats.
Diagnostic Characteristics: Forests of the Rocky Mountains and eastern Cascades with canopies primarily dominated by Pinus contorta. Canopy cover is typically dense, and understories are variable depending on substrate and density of the canopy. Diagnostic of this upland forest alliance is the dominance of Pinus contorta in the tree canopy (>90% cover), without significant regeneration of Abies lasiocarpa or similar shade-tolerant species.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This alliance is initially derived from a series concept, in which associations are distinguished by the dominance of Pinus contorta in the tree canopy and the near total lack of regeneration of other conifers. In the habitat-typing classification system, stands dominated by Pinus contorta but with significant regeneration of other conifers, such as Abies grandis, Abies lasiocarpa, Picea engelmannii, Pseudotsuga menziesii, Thuja plicata, or Tsuga heterophylla, have typically been placed into series named for those conifers. There are undoubtedly several to many associations which should be placed in this alliance, but which have been classified as belonging to other series because of the lack of regeneration of Pinus contorta. Future work will need to review this issue and identify additional associations belonging to this alliance.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: These are closed-canopy (>60% cover), densely stocked stands of needle-leaved evergreen trees from 10-30 m in height. Stands can be so dense that little light penetrates the tree canopy, and understory vegetation is sparse or absent. In younger stands, the tree canopy often has a structure of same-size and even-aged classes. In older stands, there may be a taller, older, larger size class, with a relatively dense shorter tree layer composed of saplings and pole-sized conifers, often of different species than the older trees. Where densities are lower, or where canopy gaps occur, ericaceous or cold-deciduous shrubs may be locally abundant. The herbaceous layer is typically sparse and can be dominated by either shade-tolerant forbs, grasses or sedges.
Floristics: Pinus contorta is almost always the only mature tree in stands of this alliance, with greater than 90% cover, but other conifers are occasionally present. In some stands, species such as Abies grandis, Abies lasiocarpa, Picea engelmannii, Pseudotsuga menziesii, or Tsuga mertensiana may be present to abundant as seedlings and saplings, or as trees with low abundance. On warmer sites Abies grandis, Thuja plicata, and Tsuga heterophylla may be also present. In the eastern Cascades, northern Utah, and Rocky Mountains, Pinus contorta forests occupy large areas in the upper montane to lower subalpine elevation zones. Stand structure can vary from dense "dog-hair" stands established following wildfire, to a more multi-aged structure with widely spaced large older trees and a subcanopy of younger Pinus contorta. The dominance of Pinus contorta may be maintained in some of these stands by recurring surface fires that kill seedlings and saplings of other shade-tolerant conifers but allow reproduction of Pinus contorta (Pfister et al. 1977, Chappell et al. 1997). The shrub stratum may be conspicuous to absent depending upon canopy closure and soil moisture, but where shrubs are present, common species include Arctostaphylos nevadensis, Arctostaphylos patula, Arctostaphylos uva-ursi, Ceanothus velutinus, Linnaea borealis, Mahonia repens, Purshia tridentata, Ribes spp., Spiraea betulifolia, Spiraea douglasii, Shepherdia canadensis, Symphoricarpos albus, Vaccinium cespitosum, Vaccinium membranaceum, and Vaccinium scoparium. The cover of the herbaceous stratum tends to vary inversely with shrub cover. Where there is a significant herbaceous layer, it can be dominated by either graminoids or perennial forbs. Important graminoids include Achnatherum occidentale (= Stipa occidentalis), Calamagrostis rubescens, Carex geyeri, Carex pensylvanica, Carex rossii, Danthonia californica, or Elymus glaucus. Important forbs are Arnica cordifolia, Chimaphila umbellata, Orthilia secunda, Osmorhiza berteroi (= Osmorhiza chilensis), Pedicularis racemosa, Thalictrum spp., and Xerophyllum tenax.
Dynamics: Pinus contorta is aggressively colonizing and shade-intolerant. Establishment is episodic and linked to stand-replacing disturbances, primarily fire. The incidence of serotinous cones varies within and among varieties of Pinus contorta, being most prevalent in Rocky Mountain populations. Closed, serotinous cones appear to be strongly favored by fire and allow rapid colonization of fire-cleared substrates (Burns and Honkala 1990a). Hoffman and Alexander (1980, 1983) report that in stands where Pinus contorta exhibits a multi-aged population structure, with regeneration occurring, there is typically a higher proportion of trees bearing nonserotinous cones. Chappell et al. (1997) report that where these forests are found on pumice, Pinus contorta dominance is maintained by periodic disturbance from both fires and insect infestations. Without fires and insects, stands will become dense forests and quite barren. Unlike most Pinus contorta forests, most of these stands are not seral to another tree species (Chappell et al. 1997). Fire is infrequent in coastal stands, but shifting sand substrates and wind-borne salt spray act to discourage competition and provide suitable conditions for perpetuation of Pinus contorta (Jenny et al. 1969, Kumler 1969, Chappell et al. 1997).
Environmental Description: Pinus contorta occupies the broadest array of habitats of any coniferous species in the western United States, and forests dominated by this species occur in widely varying ecological settings. This includes upland plant associations found in the montane and subalpine zone of the Rocky Mountains and eastern Cascades. Elevations range from just over 900 m in the Cascades to well over 3100 m in the Rockies. Temperature regimes are extreme throughout this region and frequent growing-season frosts occur. Annual precipitation in these montane and subalpine habitats ranges from less than 40 cm to over 150 cm, usually with the majority falling as snow. Late-melting snowpacks provide the majority of growing-season moisture, particularly in the Cascades. The dominance of Pinus contorta in associations in this alliance is related to fire history and topo-edaphic conditions (Pfister et al. 1977, Hoffman and Alexander 1980, Steele et al. 1981, Mauk and Henderson 1984). Following stand-replacing fires, Pinus contorta will rapidly colonize and develop into dense stands of even-aged trees. Over time, many of these stands can succeed to dominance by other more shade-tolerant conifer species. Most forests in this alliance are early- to mid-successional forests which developed following fires.
Some Pinus contorta forest associations occur, and will persist, on sites that are too extreme for other conifers to establish. These include excessively well-drained pumice deposits (Volland 1976), glacial till and alluvium on valley floors where there is cold air accumulation (Steele et al. 1981), warm and droughty shallow soils over fractured quartzite bedrock (Mauk and Henderson 1984), well-drained to xeric stabilized sand dunes (Jenny et al. 1969, Kumler 1969), and shallow moisture-deficient soils with a significant component of volcanic ash (Cooper et al. 1987). Some Pinus contorta forests can be persistent for hundreds of years, a result of a lack of seed source or the competitive exclusion of other conifer species (Moir 1969a, Pfister et al. 1977, Despain 1983, Hoffman and Alexander 1983, Cooper et al. 1987), or the frost tolerance of Pinus contorta seedlings and mature trees, which allows the development of monotypic stands in frost-prone areas (Steele et al. 1981, Burns and Honkala 1990a). Soils supporting these forests are typically well-drained, gravelly, and have textures ranging from silty to sands and gravels. They are acidic and rarely are formed from calcareous parent materials.
Some Pinus contorta forest associations occur, and will persist, on sites that are too extreme for other conifers to establish. These include excessively well-drained pumice deposits (Volland 1976), glacial till and alluvium on valley floors where there is cold air accumulation (Steele et al. 1981), warm and droughty shallow soils over fractured quartzite bedrock (Mauk and Henderson 1984), well-drained to xeric stabilized sand dunes (Jenny et al. 1969, Kumler 1969), and shallow moisture-deficient soils with a significant component of volcanic ash (Cooper et al. 1987). Some Pinus contorta forests can be persistent for hundreds of years, a result of a lack of seed source or the competitive exclusion of other conifer species (Moir 1969a, Pfister et al. 1977, Despain 1983, Hoffman and Alexander 1983, Cooper et al. 1987), or the frost tolerance of Pinus contorta seedlings and mature trees, which allows the development of monotypic stands in frost-prone areas (Steele et al. 1981, Burns and Honkala 1990a). Soils supporting these forests are typically well-drained, gravelly, and have textures ranging from silty to sands and gravels. They are acidic and rarely are formed from calcareous parent materials.
Geographic Range: These forests occur from the southern Rocky Mountains north to the Canadian Rocky Mountains, east to the Big Horn Mountains of Wyoming and west to the eastern Cascade Range of Washington and Oregon.
Nations: CA,US
States/Provinces: AB, BC, CA?, CO, ID, MT, NM, NV?, OR, UT, WA, WY, YT
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899490
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: A.118, in part
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Lodgepole Pine Series (Sawyer and Keeler-Wolf 1995)
>< Lodgepole Pine: 218 (Eyre 1980)
>< Lodgepole Pine: 218 (Eyre 1980)
- Barrows, J. S., E. W. Mogren, K. Rowdabaugh, and R. Yancik. 1977. The role of fire in ponderosa pine and mixed conifer ecosystems. Final report, Cooperative report between the National Park Service and Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 101 pp.
- Burns, R. M., and B. H. Honkala, technical coordinators. 1990a. Silvics of North America: Volume 1. Conifers. Agriculture Handbook 654. USDA Forest Service, Washington, DC. 675 pp.
- Chappell, C., R. Crawford, J. Kagan, and P. J. Doran. 1997. A vegetation, land use, and habitat classification system for the terrestrial and aquatic ecosystems of Oregon and Washington. Unpublished report prepared for Wildlife habitat and species associations within Oregon and Washington landscapes: Building a common understanding for management. Prepared by Washington and Oregon Natural Heritage Programs, Olympia, WA, and Portland, OR. 177 pp.
- Cooper, S. V., K. E. Neiman, R. Steele, and D. W. Roberts. 1987. Forest habitat types of northern Idaho: A second approximation. General Technical Report INT-236.USDA Forest Service, Intermountain Research Station, Ogden, UT. 135 pp. [reprinted in 1991]
- Despain, D. G. 1973b. Major vegetation zones of Yellowstone National Park. USDI National Park Service, Yellowstone National Park. Information Paper No. 19.
- Despain, D. G. 1983. Nonpyrogenous lodgepole pine climax communities in Yellowstone National Park. Ecology 63:231-235.
- 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.
- Harrington, F. A., Jr. 1978. Ecological segregation of ungulates in alpine and subalpine communities. Unpublished dissertation, Colorado State University, Fort Collins. 142 pp.
- Hoffman, G. R., and R. R. Alexander. 1980. Forest vegetation of the Routt National Forest in northwestern Colorado: A habitat type classification. General Technical Report RM-221. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 41 pp.
- Hoffman, G. R., and R. R. Alexander. 1983. Forest vegetation of the White River National Forest in western Colorado: A habitat type classification. Research Paper RM-249. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 36 pp.
- Jenny, H., R. J. Arkley, and A. M. Schultz. 1969. The pygmy forest-podsol ecosystem and its dune associates of the Mendocino coast. Madrono 20:60-74.
- Kumler, M. L. 1969. Plant succession on the sand dunes of the Oregon coast. Ecology 50:695-704.
- 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.
- Moir, W. H. 1969a. The lodgepole pine zone in Colorado. The American Midland Naturalist 81(1):87-99.
- Pfister, R. D., B. L. Kovalchik, S. F. Arno, and R. C. Presby. 1977. Forest habitat types of Montana. General Technical Report INT-34. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 174 pp.
- Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 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.
- Volland, L. A. 1976. Plant communities of the central Oregon pumice zone. USDA Forest Service R-6 Area Guide 4-2. Pacific Northwest Region, Portland, OR. 113 pp.