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G224 Pinus flexilis - Pinus longaeva Intermountain Basins Subalpine Woodland Group
Type Concept Sentence: This group consists of open woodlands ranging from krummholz to over 10 m in height with Pinus flexilis and/or Pinus longaeva as the dominant conifer with an herbaceous layer that is typically sparse. It is commonly found on steep slopes and ridges between 2530 and 3600 m (8300-12,000 feet) elevation, and extends from the Mojave Desert and eastern Sierra Nevada across the central Great Basin to the high plateaus of southwestern and central Utah.
Common (Translated Scientific) Name: Limber Pine - Great Basin Bristlecone Pine Intermountain Basins Subalpine Woodland Group
Colloquial Name: Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland
Hierarchy Level: Group
Type Concept: This group extends from the Mojave Desert and eastern Sierra Nevada across the central Great Basin to the high plateaus of southwestern and central Utah. These open woodlands are typically found on high-elevation ridges and rocky slopes above subalpine forests and woodlands, sometimes extending down into the montane zone. Site are harsh, exposed to desiccating winds with rocky substrates and a short growing season that limit plant growth. Parent materials include dolomitic, limestone or granitic rocks. Occurrences can be found on all aspects but are more common on southwestern exposures on steep convex slopes and ridges between 2530 and 3600 m (8300-12,000 feet) elevation. Vegetation is characterized by a typically open tree canopy (<25% cover) with heights ranging from 1-2 m (krummholz) to over 10 m. Pinus flexilis and/or Pinus longaeva dominate the tree canopy, alone or in combination. Pinus longaeva stands tend to occur at higher elevation with less mixed canopies. Other trees present to codominant include Picea engelmannii, Pseudotsuga menziesii, Populus tremuloides, or Abies concolor. In the Sierra Nevada stands, Pinus albicaulis, Pinus balfouriana, and/or Pinus contorta var. murrayana may be present. Understory layers, if present, are sparse to moderately dense and composed of xeric shrubs, graminoids and cushion plants. Characteristic shrubs include Arctostaphylos patula, Artemisia arbuscula, Artemisia tridentata ssp. vaseyana, Ericameria discoidea, Juniperus communis, Ribes cereum, and Ribes montigenum. Cercocarpus intricatus, Cercocarpus ledifolius, or Chrysolepis sempervirens frequently occur in stands in the Sierra Nevada. The herbaceous layer is typically sparse. Associated herbaceous species are diverse given the wide elevational range, with alpine species occurring near the upper treeline and montane and subalpine species below.
Diagnostic Characteristics: Pinus flexilis and/or Pinus longaeva are the dominant and diagnostic species of this woodland group. The understory is variable, but is characterized by xeric shrubs and grasses found in subalpine zones in the Sierra Nevada and ranges of the Great Basin.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: ~Rocky Mountain Subalpine-Montane Limber Pine - Bristlecone Pine Woodland Group (G221)$$ is similar to ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ because Pinus flexilis can dominate stands; however, the groups are geographically separate. ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ is restricted to the eastern Sierra Nevada and ranges into the northern Mojave Desert and Great Basin, extending east to the high plateaus of southwestern and central Utah, roughly following the range of distribution for Pinus longaeva, and ~Rocky Mountain Subalpine-Montane Limber Pine - Bristlecone Pine Woodland Group (G221)$$ is limited to the Rocky Mountains extending west into the southern Colorado Plateau.
~Rocky Mountain Foothill-Rock Outcrop Limber Pine - Juniper Woodland Group (G209)$$ is also similar to ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ in that stands may be dominated by Pinus flexilis, but are geographically separate, occurring mostly in 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.
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 Foothill-Rock Outcrop Limber Pine - Juniper Woodland Group (G209)$$ is also similar to ~Intermountain Basins Subalpine Limber Pine - Bristlecone Pine Woodland Group (G224)$$ in that stands may be dominated by Pinus flexilis, but are geographically separate, occurring mostly in 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.
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 a typically open tree canopy (<25% cover) with heights ranging from 1-2 m (krummholz) to over 10 m. Pinus flexilis and/or Pinus longaeva dominate the tree canopy, alone or in combination. Pinus longaeva stands tend to occur at higher elevation with less mixed canopies. Other trees present to codominant include Picea engelmannii, Pseudotsuga menziesii, Populus tremuloides, or Abies concolor. In the Sierra Nevada stands, Pinus albicaulis, Pinus balfouriana, and/or Pinus contorta var. murrayana may be present. Scattered Pinus monophylla may also be present in lowest elevation stands. Understory layers, if present, are sparse to moderately dense and composed of xeric shrubs, graminoids and cushion plants. Characteristic shrubs include Arctostaphylos patula, Artemisia arbuscula, Arctostaphylos patula, Artemisia tridentata ssp. vaseyana, Ericameria discoidea, Juniperus communis, Ribes cereum, and Ribes montigenum. Acer glabrum, Cercocarpus intricatus, Cercocarpus ledifolius, and Chrysolepis sempervirens frequently occur in stands in the Sierra Nevada. The herbaceous layer is typically sparse. Associated herbaceous species are diverse given the wide elevational range, with alpine species occurring near the upper treeline and montane and subalpine species below. Common species may include Antennaria rosea, Aquilegia scopulorum, Arabis drummondii, Arenaria congesta, Arenaria kingii, Astragalus kentrophyta, Astragalus platytropis, Calamagrostis rubescens, Carex rossii, Cirsium eatonii, Cymopterus cinerarius, Cymopterus nivalis, Elymus elymoides, Eriogonum gracilipes, Eriogonum holmgrenii, Eriogonum ovalifolium, Erigeron pygmaeus, Erigeron tener, Festuca brachyphylla, Koeleria macrantha, Linanthus pungens (= Leptodactylon pungens), Packera werneriifolia, Penstemon leiophyllus, Poa fendleriana, Phlox pulvinata, Trifolium gymnocarpon, and Trisetum spicatum. Selaginella watsonii is common in some high-elevation stands.
Dynamics: Both Pinus longaeva and Pinus flexilis are slow-growing, long-lived trees that are intolerant of shade. Pinus longaeva may attain nearly 4900 years in age and 12 m in height, whereas Pinus flexilis may live 1000 years and attain 18 m in height. Bristlecone pine branches retain needles for as long as 30 years, whereas limber pine needles are lost after several years. Bristlecone pine trees produce dense, resinous wood that is resistant to rot and disease. Mature trees have massive, contorted trunks with mostly dead and gnarled wood. (Sawyer et al. 2009).
Natural regeneration of both species 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.). The longevity of individuals enables stands to persist for centuries between times of favorable seedling establishment (Keeley and Zedler 1998). Fires seldom destroy this group due to the sparse nature of the canopy cover of trees and abundant bare ground.
Natural regeneration of both species 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.). The longevity of individuals enables stands to persist for centuries between times of favorable seedling establishment (Keeley and Zedler 1998). Fires seldom destroy this group due to the sparse nature of the canopy cover of trees and abundant bare ground.
Environmental Description: The bristlecone pine-limber pine woodland group denotes some of the driest and windiest sites capable of supporting trees other than Juniperus. Sites are typically xeric on exposed, windswept rocky slopes and ridges. It can be found on all aspects but is more common on southwestern exposures on steep convex slopes and ridges between 2530 and 3600 m (8300-12,000 feet) elevation. It commonly represents a topographic or edaphic climax within the Abies lasiocarpa and upper Pseudotsuga menziesii zones.
This group occurs on a variety of substrates but is best represented on colluvium derived from limestone and dolomite or Tertiary and Cretaceous sandstone. A characteristic feature is the predominance of bare soil; almost all sites have between 25 and 50% bare ground. Consequently, litter accumulations are slight and intermittent. Most sites are droughty, with gravel in the shallow subsurface horizons. Surface textures vary depending upon parent material. Steep slopes, high-intensity summer convection storms, and only partial ground cover for interception often result in severe sheet erosion of fine particles. This usually leads to the development of gravel pavements. Additional erosion can be expected from wind action. High insolation and wind during the winter usually result in reduced snowpack accumulations. However, soils can be expected to freeze.
The sparsity of shrubs, forbs, grasses, and litter in addition to the widely spaced trees usually means that fire does not carry easily. Individual trees may be ignited from lightning, but seldom is an entire occurrence burned.
This group occurs on a variety of substrates but is best represented on colluvium derived from limestone and dolomite or Tertiary and Cretaceous sandstone. A characteristic feature is the predominance of bare soil; almost all sites have between 25 and 50% bare ground. Consequently, litter accumulations are slight and intermittent. Most sites are droughty, with gravel in the shallow subsurface horizons. Surface textures vary depending upon parent material. Steep slopes, high-intensity summer convection storms, and only partial ground cover for interception often result in severe sheet erosion of fine particles. This usually leads to the development of gravel pavements. Additional erosion can be expected from wind action. High insolation and wind during the winter usually result in reduced snowpack accumulations. However, soils can be expected to freeze.
The sparsity of shrubs, forbs, grasses, and litter in addition to the widely spaced trees usually means that fire does not carry easily. Individual trees may be ignited from lightning, but seldom is an entire occurrence burned.
Geographic Range: This woodland group extends from mountains ranges in the Mojave Desert and Sierra Nevada across the Great Basin to the high plateaus of southwestern Utah, central Wasatch and extreme western Uinta Mountains.
Nations: CA,US
States/Provinces: CA, ID, MT, NV, UT, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.836523
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.h Limber Pine - Great Basin Bristlecone Pine Intermountain Basins Subalpine Woodland Group | G224 | 1.B.2.Nb.5.h |
| Alliance | A0518 Great Basin Bristlecone Pine Forest & Woodland Alliance | A0518 | 1.B.2.Nb.5.h |
| Alliance | A2035 Limber Pine Intermountain Basins Forest & Woodland Alliance | A2035 | 1.B.2.Nb.5.h |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: > Bristlecone Pine Forest (#86400) (Holland 1986b)
> Bristlecone Pine Series (Sawyer and Keeler-Wolf 1995)
< Bristlecone Pine: 209 (Eyre 1980)
> Limber Pine Forest (#86700) (Holland 1986b)
> Limber Pine Series (Sawyer and Keeler-Wolf 1995)
>< Limber Pine: 219 (Eyre 1980)
> Bristlecone Pine Series (Sawyer and Keeler-Wolf 1995)
< Bristlecone Pine: 209 (Eyre 1980)
> Limber Pine Forest (#86700) (Holland 1986b)
> Limber Pine Series (Sawyer and Keeler-Wolf 1995)
>< Limber Pine: 219 (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, 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]
- Graybosch, R. A., and H. Buchanan. 1983. Vegetative types and endemic plants of the Bryce Canyon Breaks. Great Basin Naturalist 43:701-712.
- Holland, R. F. 1986b. Preliminary descriptions of the terrestrial natural communities of California. Unpublished report prepared for the California Department of Fish and Game, Nongame-Heritage Program and Natural Diversity Database, Sacramento. 156 pp.
- Holland, V. L., and D. J. Keil. 1995. California vegetation. Kendall/Hunt Publishing Company, Dubuque, IA. 516 pp.
- Keeley, J. E., and P. H. Zedler. 1998a. Evolution of life histories in Pinus. Pages 219-250 in: D. M. Richardson, editor. Ecology and biogeography of Pinus. The Press Syndicate of the University of Cambridge, Cambridge, UK.
- LaMarche, V. C., Jr., and H. A. Mooney. 1972. Recent climatic change and development of the bristlecone pine (P. longaeva (Bailey)) krummholz zone, Mount Washington, Nevada. Arctic and Alpine Research 4(1):61-72.
- Lanner, Dr. Ronald. Personal communication. Professor Emeritus of Forest Resources, Utah State University, Logan.
- 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.
- Nachlinger, J. L., and G. A. Reese. 1996. Plant community classification of the Spring Mountains National Recreation Area, Clark and Nye counties, Nevada. Unpublished report submitted to USDA Forest Service, Humboldt-Toiyabe National Forest, Spring Mountains National Recreation Area, Las Vegas, NV. The Nature Conservancy, Northern Nevada Office, Reno, NV. 85 pp. plus figures and appendices.
- Sawyer, J. O., T. Keeler-Wolf, and J. Evens. 2009. A manual of California vegetation. Second edition. California Native Plant Society, Sacramento CA. 1300 pp.
- Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.