Home/Ecosystems/ California Subalpine Woodland

California Subalpine Woodland

EVT 7033Mediterranean California Subalpine Woodland

CES206.910GNRTreeConifer

Summary

This ecological system occurs on ridges and rocky slopes around timberline at 2900 m (9500 feet) elevation in the southern Sierra Nevada and Transverse and Peninsular ranges, up to 3500 m (11,500 feet) in the Sierra Nevada, and 2450 m (8000 feet) in the southern Cascades. Tree species often occur as krummholz growth forms with a wind-pruned, prostrate, and/or shrublike appearance, but in more protected sites they form true woodland physiognomy. Stands are dominated by Pinus albicaulis and/or Pinus contorta var. murrayana; other important conifers and locally dominant species include Pinus balfouriana (only in the Klamath Mountains and southern Sierra Nevada where it may replace Pinus albicaulis), Pinus flexilis (but only in small patches on the eastern flank of the Sierra Nevada escarpment when it does occur), Pinus monticola (not in Transverse or Peninsular ranges), and Juniperus grandis (mostly in the central and southern Sierra Nevada but not in the Klamath Mountains). Important shrubs include Arctostaphylos nevadensis, Chrysolepis sempervirens, and Holodiscus discolor. Grasses and forbs include Carex rossii, Carex filifolia, Poa wheeleri, Eriogonum incanum, Penstemon newberryi, and Penstemon davidsonii. Due to landscape position and very thin soils, these are harsh sites exposed to desiccating winds with ice and snow blasts, and rocky substrates. In addition, a short growing season limits plant growth. The highest tree diversity occurs in the Klamath Mountains, with sometimes five or more conifers sharing codominance in one stand.

Source: NatureServe Explorer

Vegetation

Stands are dominated by Pinus albicaulis and/or Pinus contorta var. murrayana; other important conifers and locally dominant species include Pinus balfouriana (only in the Klamath Mountains and southern Sierra Nevada where it may replace Pinus albicaulis), Pinus flexilis (but only in small patches on the eastern flank of the Sierra Nevada escarpment when it does occur), Pinus monticola (not in Transverse or Peninsular ranges), and Juniperus grandis (= Juniperus occidentalis var. australis) (mostly in the central and southern Sierra Nevada but not in the Klamath Mountains). Important shrubs include Arctostaphylos nevadensis, Chrysolepis sempervirens, and Holodiscus discolor (= Holodiscus microphyllus). Grasses and forbs include Carex rossii, Carex filifolia, Poa wheeleri, Eriogonum incanum, Penstemon newberryi, and Penstemon davidsonii.

Source: NatureServe Explorer

Environment

Dry, thin soils and exposure to winds are key ecological environmental factors that drive the structure and appearance of this subalpine forest. These forests are at the limit of tree growth in terms of exposure to cold and desiccating winds in the winter (Arno and Huff 1990). Climate is predicted to get warmer in the Sierra Nevada (Fried et al. 2004, as cited in Barbour et al. 2007). This may lead to reduced growth and vigor of trees in this already stressed environment. However, it is the winter cold and desiccating winds that keep trees in a krummholz form. If winter low temperatures increase, these woodlands may increase in growth and vigor, if adequate moisture continues to be available. Soils are thin and poorly developed, usually low in nitrogen-fixing bacteria which is apparently restricted by low soil temperature and high acidity of many sites. Increased temperatures may increase soil nitrogen availability (Arno and Huff 1990). However, this may result in increased competition from invading native tree species rather than an increase in those typically dominant on these sites.

Source: NatureServe Explorer

Dynamics

Due to landscape position and very thin soils, these are harsh sites exposed to desiccating winds with ice and snow blasts, and rocky substrates. In addition, a short growing season limits plant growth. The highest tree diversity occurs in the Klamath Mountains, with sometimes five or more conifers sharing codominance in one stand.

Source: NatureServe Explorer

Distribution

This system occurs on ridges and rocky slopes around timberline at 2900 m (9500 feet) elevation in the southern Sierra Nevada and Transverse and Peninsular ranges and 2450 m (8000 feet) in the southern Cascades.

Source: NatureServe Explorer

Ecologically Associated Plant Species

Plant species that characterize this ecosystem type, organized by vegetation stratum. These are species ecologically associated with the ecosystem, not confirmed present in any specific area.

Tree canopy

Juniperus grandis, Pinus albicaulis, Pinus balfouriana, Pinus contorta var. murrayana, Pinus flexilis, Pinus monticola

Shrub/sapling (tall & short)

Arctostaphylos nevadensis, Chrysolepis sempervirens, Holodiscus discolor

Herb (field)

Carex filifolia var. filifolia, Carex rossii, Eriogonum incanum, Penstemon davidsonii, Penstemon newberryi, Poa wheeleri

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (6)

Animal species ecologically associated with this ecosystem type based on NatureServe assessment. These are species whose habitat requirements overlap with this ecosystem, not confirmed present in any specific roadless area.

Mammals (2)

Common Name	Scientific Name	G-Rank
Alpine Chipmunk	Neotamias alpinus	G4
North American Deermouse	Peromyscus maniculatus	G5

Birds (4)

Common Name	Scientific Name	G-Rank
Cassin's Finch	Haemorhous cassinii	G5
Clark's Nutcracker	Nucifraga columbiana	G5
Pine Grosbeak	Pinicola enucleator	G5
White-crowned Sparrow	Zonotrichia leucophrys	G5

Source: NatureServe Ecological System assessment

At-Risk Species Associated with this Ecosystem (1)

Species with conservation concern that are ecologically associated with this ecosystem type. G-Rank indicates global conservation status: G1 (critically imperiled) through G5 (secure). ESA status indicates U.S. Endangered Species Act listing.

Common Name	Scientific Name	G-Rank	ESA Status
Whitebark Pine	Pinus albicaulis	G3G4	Threatened

Source: NatureServe Ecological System assessment

Component Associations (11)

Plant community associations that occur within this ecological system. Associations are the finest level of the U.S. National Vegetation Classification (USNVC) and describe specific, repeating assemblages of plant species. Each association represents a distinct community type that may be found where this ecosystem occurs.

Name	G-Rank
Juniperus grandis / Artemisia tridentata Woodland	G3	NatureServe
Juniperus grandis - Cercocarpus ledifolius / Artemisia tridentata Woodland	G3	NatureServe
Juniperus grandis / Holodiscus discolor Woodland	GNR	NatureServe
Juniperus grandis / Sparse Understory Woodland	GNR	NatureServe
Pinus albicaulis / Carex filifolia Woodland	G3	NatureServe
Pinus albicaulis / Carex rossii Woodland	G3	NatureServe
Pinus albicaulis - Pinus contorta / Penstemon laetus Forest	G2	NatureServe
Pinus contorta var. murrayana - Pinus albicaulis / Carex filifolia Forest	G3	NatureServe
Pinus contorta var. murrayana - Pinus albicaulis / Carex rossii Forest	G4	NatureServe
Pinus monticola / Achnatherum occidentale Woodland	G3	NatureServe
Pinus monticola - Pinus contorta var. murrayana / Sparse Understory Woodland	GNR	NatureServe

State Conservation Ranks (3)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

State	S-Rank
CA	SNR
NV	SNR
OR	SNR

Roadless Areas (114)

Inventoried Roadless Areas where this ecosystem is present, identified from LANDFIRE 2024 Existing Vegetation Type spatial analysis. Coverage indicates the proportion of each area occupied by this ecosystem type.

California (91)

Area	Forest	Coverage	Hectares
Hat Mtn.	Modoc National Forest	52.4%	2,010.6
Tioga Lake	Inyo National Forest	22.9%	76.95
Bear Camp Flat	Modoc National Forest	22.7%	227.34
Mill	Modoc National Forest	20.7%	26.91
Hoover - Mt.olsen	Humboldt-Toiyabe National Forest	20.3%	51.48
Jennie Lake	Sequoia National Forest	18.5%	178.83
Castle Peak	Tahoe National Forest	12.8%	772.38
Night	Stanislaus National Forest	12.5%	159.93
Granite Chief S	Lake Tahoe Basin Management Unit	12.3%	28.17
Woodpecker	Sequoia National Forest	11.3%	543.96
Granite Chief N	Lake Tahoe Basin Management Unit	10.9%	26.01
Lakes Basin	Tahoe National Forest	10.6%	23.76
Mt. Hoffman	Modoc National Forest	8.9%	353.61
Mt. Shasta A	Shasta-Trinity National Forest	8.6%	23.49
Eagle	Stanislaus National Forest	8.4%	547.47
Hoover - Cattle Ck	Humboldt-Toiyabe National Forest	8.2%	19.89
Granite Chief	Tahoe National Forest	7.9%	208.53
Mt. Eddy	Shasta-Trinity National Forest	7.5%	218.16
Hoover - North	Humboldt-Toiyabe National Forest	7.3%	46.26
Log Cabin Saddlebag	Inyo National Forest	7.0%	429.12
Sherwin	Inyo National Forest	6.9%	88.02
Hoover - Virginia Lks	Humboldt-Toiyabe National Forest	6.6%	135.54
Freel	Lake Tahoe Basin Management Unit	6.5%	401.31
Iceberg - Mill Creek	Humboldt-Toiyabe National Forest	6.4%	697.95
Mt. Shasta B	Shasta-Trinity National Forest	6.3%	71.82
Dardanelles	Lake Tahoe Basin Management Unit	6.3%	362.34
Dinkey Lakes	Sierra National Forest	6.1%	844.2
Wheeler Ridge	Inyo National Forest	5.9%	377.46
Domeland Add.	Sequoia National Forest	5.9%	72.54
Buckeye Ridge	Humboldt-Toiyabe National Forest	5.7%	51.75
Hoover - Emma Lake	Humboldt-Toiyabe National Forest	5.7%	23.31
Mt. Reba	Stanislaus National Forest	5.6%	88.2
Hall Natural Area	Inyo National Forest	5.6%	118.8
Tragedy - Elephants Back	Eldorado National Forest	5.6%	468.9
South Sierra	Sequoia National Forest	5.5%	179.55
Horse Mdw.	Inyo National Forest	5.5%	126.99
Carson - Iceberg	Stanislaus National Forest	5.5%	1,253.52
Table Mtn.	Inyo National Forest	5.3%	90.81
Poison Hole	Eldorado National Forest	5.2%	55.71
Coyote North	Inyo National Forest	5.2%	249.3
Slate Mtn.	Sequoia National Forest	5.0%	250.92
Iceberg - Slinkard	Humboldt-Toiyabe National Forest	4.9%	30.69
Nessie	Inyo National Forest	4.8%	16.2
Whisky Creek	Inyo National Forest	4.8%	16.83
Raymond Peak	Eldorado National Forest	4.7%	47.97
San Joaquin	Inyo National Forest	4.6%	366.84
Laurel Mcgee	Inyo National Forest	4.6%	162.63
South Sierra	Inyo National Forest	4.5%	768.96
Dexter Canyon	Inyo National Forest	4.4%	306.18
Dardanelles	Eldorado National Forest	4.3%	141.12
Glass Mountain	Inyo National Forest	4.3%	914.31
Raymond Peak	Stanislaus National Forest	4.2%	62.37
Rose - Iceland	Humboldt-Toiyabe National Forest	4.1%	19.26
Mt. Bidwell	Modoc National Forest	4.0%	189.63
Caples Creek	Eldorado National Forest	4.0%	288.45
Mokelumne - Mt. Bullion	Humboldt-Toiyabe National Forest	3.9%	216.63
Bell Meadow	Stanislaus National Forest	3.8%	122.58
Pyramid	Lake Tahoe Basin Management Unit	3.7%	116.19
Bald Mountain	Tahoe National Forest	3.5%	83.25
Pyramid	Eldorado National Forest	3.5%	343.71
North Lake	Inyo National Forest	3.4%	32.94
Jobs Peak (CA)	Humboldt-Toiyabe National Forest	3.4%	307.17
Mokelumne - Hawkins Pk	Humboldt-Toiyabe National Forest	3.2%	215.28
Robinson Peak	Humboldt-Toiyabe National Forest	2.9%	67.5
Mt. Raymond	Sierra National Forest	2.8%	79.11
Dome	Stanislaus National Forest	2.8%	123.84
Grouse Lakes	Tahoe National Forest	2.8%	212.4
Rincon	Sequoia National Forest	2.7%	606.42
Grizzly Peak	Plumas National Forest	2.6%	64.8
Onion Springs	Lassen National Forest	2.6%	25.02
San Joaquin	Sierra National Forest	2.6%	231.93
Hoover - Green Ck No	Humboldt-Toiyabe National Forest	2.4%	70.56
Russian	Klamath National Forest	2.3%	202.95
Rock Creek West	Inyo National Forest	2.2%	31.59
Waterhouse	Stanislaus National Forest	2.0%	36.45
Coyote Southeast	Inyo National Forest	1.8%	393.48
Independence Creek	Inyo National Forest	1.7%	94.77
Shuteye	Sierra National Forest	1.5%	44.64
East Yuba	Tahoe National Forest	1.5%	108.72
Wonoga Pk.	Inyo National Forest	1.4%	64.89
Barney Riley	Humboldt-Toiyabe National Forest	1.4%	46.17
Mt. Vida	Modoc National Forest	1.4%	43.65
Agnew	Sequoia National Forest	1.2%	47.7
West Yuba	Plumas National Forest	1.1%	28.08
Moses	Sequoia National Forest	1.1%	95.31
Channell	Sequoia National Forest	1.0%	192.51
Powley	Modoc National Forest	1.0%	26.1
Heart Lake	Lassen National Forest	0.8%	31.05
Tinemaha	Inyo National Forest	0.8%	82.44
North Fork American River	Tahoe National Forest	0.6%	98.82
Kings River	Sierra National Forest	0.5%	108.9

Nevada (9)

Area	Forest	Coverage	Hectares
Rose - Bronco	Humboldt-Toiyabe National Forest	9.4%	32.85
Rose - North Notch	Humboldt-Toiyabe National Forest	7.3%	4.14
Rose - Galena	Humboldt-Toiyabe National Forest	6.0%	90.81
Rose - Gray Creek	Humboldt-Toiyabe National Forest	5.6%	8.19
Mt. Rose Roadless	Lake Tahoe Basin Management Unit	5.0%	10.71
Mystic (NV)	Humboldt-Toiyabe National Forest	5.0%	114.12
Rose - Dutch Louie	Humboldt-Toiyabe National Forest	4.5%	6.57
Rose - Davis Mdw.	Humboldt-Toiyabe National Forest	3.4%	32.94
Lincoln	Lake Tahoe Basin Management Unit	1.9%	50.49

Oregon (14)

Area	Forest	Coverage	Hectares
Antler	Fremont National Forest	42.8%	953.1
Buck Creek	Fremont National Forest	39.0%	1,561.23
North Paulina	Deschutes National Forest	37.6%	2,994.57
Yamsay Mt.	Winema National Forest	33.6%	910.17
South Paulina	Deschutes National Forest	23.5%	861.39
Drake - Mcdowell	Fremont National Forest	11.1%	259.92
Crane Mountain	Fremont National Forest	4.7%	438.75
Hanan Trail	Fremont National Forest	2.8%	91.08
Coleman Rim	Fremont National Forest	2.1%	92.34
Mt. Bidwell	Fremont National Forest	2.0%	36.36
Bend Watershed	Deschutes National Forest	1.7%	100.26
Deadhorse Rim	Fremont National Forest	1.3%	70.02
Three Sisters	Deschutes National Forest	1.0%	30.06
Mcdonald Peak	Rogue River National Forests	0.9%	35.28

Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.