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G221 Pinus flexilis - Pinus aristata Rocky Mountain Subalpine-Montane Woodland Group
Type Concept Sentence: This group is composed of open, patchy woodlands dominated by Pinus flexilis and/or Pinus aristata usually on dry, rocky, wind-blasted, mostly west-facing slopes and exposed ridges near upper treeline and is known from throughout the Rocky Mountains and west into the southern Colorado Plateau.
Common (Translated Scientific) Name: Limber Pine - Bristlecone Pine Rocky Mountain Subalpine-Montane Woodland Group
Colloquial Name: Rocky Mountain Subalpine-Montane Limber Pine - Bristlecone Pine Woodland
Hierarchy Level: Group
Type Concept: This group is found throughout the Rocky Mountains and extends west into the southern Colorado Plateau. Stands occur on dry, rocky ridges and slopes near upper treeline above the matrix spruce-fir forest and extend down to the lower montane zone. Sites are harsh, exposed to desiccating winds, with rocky substrates and a short growing season that limit plant growth. Higher elevation occurrences are found well into the subalpine-alpine transition on wind-blasted, mostly west-facing slopes and exposed ridges. Calcareous substrates are important for Pinus flexilis-dominated communities in the northern Rocky Mountains and probably elsewhere. The open tree canopy is often patchy and is strongly dominated by Pinus flexilis and/or Pinus aristata with the latter restricted to southern Colorado, northern New Mexico and the San Francisco Mountains in Arizona. Other trees such as Juniperus scopulorum, Picea engelmannii, Pinus contorta, Pinus ponderosa, or Pseudotsuga menziesii are occasionally present, but do not dominate. Arctostaphylos uva-ursi, Cercocarpus ledifolius, Juniperus communis, Mahonia repens, Purshia tridentata, Ribes montigenum, or Vaccinium spp. may form an open shrub layer in some stands. The herbaceous layer, if present, is generally sparse and composed of xeric graminoids, such as Calamagrostis purpurascens, Festuca arizonica, Festuca idahoensis, Festuca thurberi, or Pseudoroegneria spicata, or more alpine plants.
Diagnostic Characteristics: Pinus flexilis and/or Pinus aristata are the dominant and diagnostic species of this woodland group. The understory is variable, but is characterized by xeric shrubs and grasses found in montane and subalpine zones in the Rocky Mountains.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This montane-subalpine group occurs on higher elevation mountains of the Rocky Mountains. It is distinguished from ~Rocky Mountain Foothill-Rock Outcrop Limber Pine - Juniper Woodland Group (G209)$$ largely by life zone, which for the most part is restricted to isolated low mountains, hills, and escarpments of the western Great Plains where soil moisture is slightly higher than surrounding grasslands, and lower foothills in northern Colorado, Wyoming and Montana. The foothill stands are typically juniper-dominated and occur below the zone of continuous Pinus ponderosa or Pseudotsuga menziesii woodlands and forests.
~Rocky Mountain Subalpine-Montane Limber Pine - Bristlecone Pine Woodland Group (G221)$$ is also similar to ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ because Pinus flexilis can dominate stands; however, the groups are geographically separate with ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ restricted to the eastern Sierra Nevada and ranges in the northern Mojave Desert and Great Basin extending east to the high plateaus of southwestern and central Utah, roughly following the range of distribution for Pinus longaeva.
Stands may occur adjacent to ~Rocky Mountain Subalpine Dry-Mesic Spruce - Fir Forest & Woodland Group (G219)$$ and ~Southern Rocky Mountain White Fir - Douglas-fir Dry Forest Group (G226)$$, but are distinguished by dominance of Pinus flexilis or Pinus aristata.
~Rocky Mountain Subalpine-Montane Limber Pine - Bristlecone Pine Woodland Group (G221)$$ is also similar to ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ because Pinus flexilis can dominate stands; however, the groups are geographically separate with ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ restricted to the eastern Sierra Nevada and ranges in the northern Mojave Desert and Great Basin extending east to the high plateaus of southwestern and central Utah, roughly following the range of distribution for Pinus longaeva.
Stands may occur adjacent to ~Rocky Mountain Subalpine Dry-Mesic Spruce - Fir Forest & Woodland Group (G219)$$ and ~Southern Rocky Mountain White Fir - Douglas-fir Dry Forest Group (G226)$$, but are distinguished by dominance of Pinus flexilis or Pinus aristata.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Conifer-dominated woodlands with a typically open tree canopy that is often patchy. Shrub and herbaceous layers, if present, generally have low cover as substrates are characteristically rocky. Higher elevation stands often have cushion plants present.
Floristics: This woodland group is characterized by an open tree canopy that is often patchy and dominated by Pinus flexilis and/or Pinus aristata with the latter restricted to southern Colorado, northern New Mexico and the San Francisco Mountains in Arizona. Other trees such as Juniperus scopulorum, Picea engelmannii, Pinus contorta, Pinus ponderosa, or Pseudotsuga menziesii are occasionally present, but do not dominate. Arctostaphylos uva-ursi, Cercocarpus ledifolius, Juniperus communis, Mahonia repens, Purshia tridentata, Ribes montigenum, or Vaccinium spp. may form an open shrub layer in some stands. The herbaceous layer, if present, is generally sparse and composed of xeric graminoids, such as Calamagrostis purpurascens, Festuca arizonica, Festuca idahoensis, Festuca thurberi, Leucopoa kingii, Muhlenbergia filiculmis, Muhlenbergia montana, Poa fendleriana, and Trisetum spicatum. Highest elevation stands have a floristic component of typically subalpine and alpine plants, such as Sedum lanceolatum, Trifolium dasyphyllum, Carex rupestris, Carex elynoides, or Phlox pulvinata. Other scattered forbs may include species of Achillea, Antennaria, Artemisia, Arenaria, Arnica, Astragalus, Campanula, Erigeron, Hymenoxys, Penstemon, Polemonium, Senecio, and Thalictrum.
Dynamics: Natural regeneration of Pinus flexilis appears to be closely associated with caching of the large wingless seeds, primarily by Clark''s nutcracker (Nucifraga columbiana) (Lanner and Vander Wall 1980). Germination of cached seeds often results in the multi-stemmed clumps characteristic of these sites, although the species may produce multiple stems from boles damaged near the ground. Germination and rooting will sometimes be restricted to crevices in rock. Pinus longaeva has smaller winged seeds and should be wind-disseminated. However, caching by nutcrackers does take place, especially when other Pinus species are also available (Dr. R. Lanner pers. comm.). Fires seldom destroy these woodlands due to the sparse nature of the canopy cover of trees and abundant bare ground. Peet (1978, 1981) notes that Pinus aristata is dominant at higher elevations in much of the southern Rocky Mountains, where Pinus flexilis is restricted to lower elevations. This is attributed to apparent competitive exclusion, because Pinus flexilis is dominant at high elevations in northern Colorado, Wyoming and Montana.
Environmental Description: This woodland group is found throughout the Rocky Mountains and extends west into the southern Colorado Plateau. Stands occur on dry, rocky ridges and slopes near upper treeline above the matrix spruce-fir forest and extends down to the lower montane zone. Sites are harsh, exposed to desiccating winds, with rocky substrates and a short growing season that limit plant growth. Higher elevation occurrences are found well into the subalpine-alpine transition on wind-blasted, mostly west-facing slopes and exposed ridges. Calcareous substrates are important for Pinus flexilis-dominated communities in the northern Rocky Mountains and possibly elsewhere.
Climate: Elevations range from 2400-3670 m. Climate is semi-arid, cold temperate with cool summers. Annual precipitation patterns and amounts vary with latitude, but locally the sites are typically xeric on exposed, windswept rocky slopes and ridges. Soil/substrate/hydrology: Soils are typically well-drained, shallow, skeletal and coarse-textured such as gravelly, sandy loams or loams. Stands occur most frequently on igneous, metamorphic and volcanic substrates such as andesite, granite, gneiss, breccia, tuff, and conglomerate, but also occur on sedimentary rocks like sandstone. Exposed bedrock is common. Soil pH is 4.5-6.9, acidic to slightly acidic. Calcareous substrates are important for Pinus flexilis-dominated communities in the northern Rocky Mountains and possibly elsewhere.
Climate: Elevations range from 2400-3670 m. Climate is semi-arid, cold temperate with cool summers. Annual precipitation patterns and amounts vary with latitude, but locally the sites are typically xeric on exposed, windswept rocky slopes and ridges. Soil/substrate/hydrology: Soils are typically well-drained, shallow, skeletal and coarse-textured such as gravelly, sandy loams or loams. Stands occur most frequently on igneous, metamorphic and volcanic substrates such as andesite, granite, gneiss, breccia, tuff, and conglomerate, but also occur on sedimentary rocks like sandstone. Exposed bedrock is common. Soil pH is 4.5-6.9, acidic to slightly acidic. Calcareous substrates are important for Pinus flexilis-dominated communities in the northern Rocky Mountains and possibly elsewhere.
Geographic Range: This group is found throughout the Rocky Mountains, including the Uinta and northern Wasatch mountains, and the Jarbridge Mountains in northeastern Nevada, and extends west into the southern Colorado Plateau. It also occurs farther east, in the Bighorn Range of north-central Wyoming, although it is not common there. Montane limber pine communities probably occur in the mountains of Alberta as well.
Nations: CA,US
States/Provinces: AB, AZ, CO, ID, MT, NM, NV, OR, UT, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.836512
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 1 Forest & Woodland Class | C01 | 1 |
| Subclass | 1.B Temperate & Boreal Forest & Woodland Subclass | S15 | 1.B |
| Formation | 1.B.2 Cool Temperate Forest & Woodland Formation | F008 | 1.B.2 |
| Division | 1.B.2.Nb Rocky Mountain Forest & Woodland Division | D194 | 1.B.2.Nb |
| Macrogroup | 1.B.2.Nb.5 Subalpine Fir - Engelmann Spruce - Whitebark Pine Rocky Mountain Forest Macrogroup | M020 | 1.B.2.Nb.5 |
| Group | 1.B.2.Nb.5.e Limber Pine - Bristlecone Pine Rocky Mountain Subalpine-Montane Woodland Group | G221 | 1.B.2.Nb.5.e |
| Alliance | A0537 Bristlecone Pine Woodland Alliance | A0537 | 1.B.2.Nb.5.e |
| Alliance | A0540 Limber Pine Rocky Mountain Woodland Alliance | A0540 | 1.B.2.Nb.5.e |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: < Bristlecone Pine: 209 (Eyre 1980)
>< Limber Pine: 219 (Eyre 1980)
>< Limber Pine: 219 (Eyre 1980)
- Baker, W. L. 1992. Structure, disturbance, and change in the bristlecone pine forests of Colorado. Arctic and Alpine Research 24(1):17-26.
- Beasley, R. S., and J. O. Klemmedson. 1980. Ecological relationships of bristlecone pine. The American Midland Naturalist 104(2):242-252.
- Brunstein, C. R., and D. K. Yamaguchi. 1992. The oldest known Rocky Mountain bristlecone pines (Pinus aristata Engelm.). Arctic and Alpine Research 24:253-256.
- 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, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Knight, D. H. 1994. Mountains and plains: Ecology of Wyoming landscapes. Yale University Press, New Haven, MA. 338 pp.
- Krebs, P. H. 1972. Dendrochronology and the distribution of bristlecone pine (Pinus aristata Engelm.) in Colorado. Unpublished dissertation, University of Colorado, Boulder. 211 pp.
- Lanner, R. M., and S. B. Vander Wall. 1980. Dispersal of limber pine seed by Clark''s nutcracker. Journal of Forestry 78(10):637-639.
- Peet, R. K. 1978a. Latitudinal variation in southern Rocky Mountain forests. Journal of Biogeography 5:275-289.
- Peet, R. K. 1981. Forest vegetation of the Colorado Front Range. Vegetatio 45:3-75.
- Ranne, B. M. 1995. Natural variability of vegetation, soils, and physiography in the bristlecone pine forests of the Rocky Mountains. University of Wyoming, Laramie, WY. 68 pp.
- Ranne, B. M., W. L. Baker, T. Andrews, and M. G. Ryan. 1997. Natural variability of vegetation, soils, and physiography in the bristlecone pine forests of the Rocky Mountains. Great Basin Naturalist 57(1):21-37.
- Steele, R., S. V. Cooper, D. M. Ondov, D. W. Roberts, and R. D. Pfister. 1983. Forest habitat types of eastern Idaho - western Wyoming. General Technical Report INT-144. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 122 pp.