Print Report

A0156 Picea breweriana - Abies lowiana Forest Alliance

Type Concept Sentence: This alliance is dominated by several conifer trees: Abies spp., Picea breweriana, and Pseudotsuga menziesii with Chamaecyparis lawsoniana or Pinus lambertiana codominating in some stands. Picea breweriana is the diagnostic species as it has the most limited geographic range, without which stands belong to a different alliance. These forests occur at high elevations of the Klamath Mountains in southwestern Oregon and northern California.

Common (Translated Scientific) Name: Brewer Spruce - Sierra White Fir Forest Alliance

Colloquial Name: Northwestern Brewer Spruce - White Fir Forest

Hierarchy Level:  Alliance

Type Concept: This is a mixed conifer alliance dominated by Abies lowiana, Abies procera, Abies magnifica var. shastensis, Picea breweriana, and Pseudotsuga menziesii with Chamaecyparis lawsoniana or Pinus lambertiana codominating in some stands. Picea breweriana is diagnostic of these stands, because it has the most limited geographic range, without which stands belong to a different alliance. Broad-leaved trees may also be present and include Quercus sadleriana, Quercus vacciniifolia, Quercus kelloggii, Chrysolepis chrysophylla, and Notholithocarpus densiflorus. Shrub layers include Arctostaphylos nevadensis, Chimaphila umbellata, Holodiscus discolor, Mahonia nervosa, Paxistima myrsinites, Rosa gymnocarpa, Vaccinium membranaceum, or Vaccinium parvifolium. The herbaceous layer is typically sparse with 12-25% cover. Forests are found at relatively high (subalpine) elevations (1170-1560 m) within the rainshadow of the Coast Ranges. Stands occur on steep rugged mountain slopes and benches but not in valleys. Slopes are moderate to steep, and aspects range from southwesterly to northern. Parent materials are primarily granitics, gabbro, diorite, granodiorite and andesite with some metamorphics. These forests occur in the Klamath Mountains of southwestern Oregon and northern California.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Abies lowiana (= Abies concolor var. lowiana) is typically the codominant, but Abies procera or Abies magnifica var. shastensis may replace Abies lowiana in some stands (J. Evens pers. comm. 2014). Picea breweriana is the most famous relict of the Klamath Mountains (Sawyer 2006). It grows on high-elevation, cool sites in the montane and subalpine belts as local, isolated groves of varying size, as single individuals invading forests and montane chaparral, and as scattered individuals in dense, mixed conifer forests (Cope 1992c). Ecologists in Oregon have recognized the alliance (Kagan et al. 2004); ecologists in California have focused on the species (Cheng 2004), or they have considered the tree to be a secondary species of other forest types (Jimerson et al. 1996).

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Tall evergreen forests (>50 m) with a subcanopy of conifers and broad-leaved trees and tall shrubs. It is structurally diverse, typically closed-canopy coniferous forest, with a continuous vertical structure difficult to categorize as layers.

Floristics: This is a mixed conifer alliance dominated by Abies lowiana (= Abies concolor var. lowiana), Abies procera, Abies magnifica var. shastensis, Picea breweriana, and Pseudotsuga menziesii with Chamaecyparis lawsoniana or Pinus lambertiana codominating in some stands. Picea breweriana is diagnostic of these stands and forms a moderately dense (40-60% cover) subcanopy less than 25 m in height, under the other conifers, which average over 50 m in height. Other species that may be present to codominate in the subcanopy include the broad-leaved trees Quercus sadleriana, Quercus vacciniifolia, Quercus kelloggii, Chrysolepis chrysophylla (= Castanopsis chrysophylla), and Notholithocarpus densiflorus (= Lithocarpus densiflorus). These forests are diverse with as many as 7 other tree species occurring in some stands, most often with <10% cover. Total tree cover averages 75%. Both tall- and short-shrub layers are usually present. The tall layer is dominated by conifer regeneration, especially of Picea breweriana and Abies lowiana, with the broad-leaved evergreen small tree/tall shrubs Quercus sadleriana or Quercus vacciniifolia often codominant. The short-shrub layer is dominated by a mix of broad-leaved deciduous and evergreen species such as Arctostaphylos nevadensis, Chimaphila umbellata, Holodiscus discolor, Mahonia nervosa, Paxistima myrsinites, Rosa gymnocarpa, Vaccinium membranaceum, or Vaccinium parvifolium. Although diverse in species, average shrub cover ranges from relatively sparse to moderately dense (22-46% cover) depending on the community. The herbaceous layer is typically sparse with 12-25% cover. Common species include Arnica cordifolia, Galium ambiguum, Goodyera oblongifolia, and Pyrola picta. Nonvascular ground cover, of mostly mosses, varies from 2% to over 70% depending on site conditions.

Dynamics:  Low-intensity surface fires kill Picea breweriana because it has thin bark, drooping branches, and a shallow root system. Recovery from fire takes several decades or centuries if seed sources exist. Seedlings establish in shaded conditions with reduced moisture stress (Sawyer and Thornburgh 1977, Thornburgh 1990). The most developed stands tend to occur on very steep, rocky, fire-protected sites.
Environmental Description:  These forests occur at high elevations (subalpine 1170-1560 m) on rugged, deeply dissected terrain. The climate of the region is maritime, with wet, mild winters, and cool, relatively dry summers at higher elevations. Precipitation is less than 75 cm annually on the eastern slope, where a rainshadow effect is pronounced and summers are very dry. Stands occur on mountain slopes and benches but not in valleys. Slopes are moderate to steep, and aspects range from warm, being southwesterly to westerly, to northern aspects which are cooler and result in cool soil temperatures and slow warming during the growing season. Local topographic effects result in increased fog and humidities, as well as orographically produced summer precipitation. Most sites with Chamaecyparis lawsoniana have abundant soil moisture or high atmospheric moisture as a result of fog. Parent materials are primarily granitics, gabbro, diorite, granodiorite and andesite with some metamorphics. Soils derived from the granitics are very infertile and are low in most essential elements. Soils derived from the metamorphics are shallow and rocky.
Geographic Range: Forests in this alliance have been described from southwestern Oregon and the adjacent region of northern California.

Nations: US

States/Provinces:  CA, OR


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G3

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.Nd Vancouverian Forest & Woodland Division D192 1.B.2.Nd
Macrogroup 1.B.2.Nd.2 Incense-cedar - Jeffrey Pine - Sierra White Fir Forest Macrogroup M023 1.B.2.Nd.2
Group 1.B.2.Nd.2.a Incense-cedar - Sugar Pine - Sierra White Fir Forest & Woodland Group G344 1.B.2.Nd.2.a
Alliance A0156 Brewer Spruce - Sierra White Fir Forest Alliance A0156 1.B.2.Nd.2.a
Association CEGL000041 Sierra White Fir - Port Orford-cedar - Douglas-fir / (Cascade Barberry) / Sweet After Death Forest CEGL000041 1.B.2.Nd.2.a
Association CEGL000049 Sierra White Fir - Port Orford-cedar - Brewer Spruce / Huckleberry Oak Forest CEGL000049 1.B.2.Nd.2.a
Association CEGL000050 Sierra White Fir - Brewer Spruce / Pipsissewa Forest CEGL000050 1.B.2.Nd.2.a
Association CEGL000051 Sierra White Fir - Brewer Spruce / Western Teaberry / Sidebells Wintergreen Forest CEGL000051 1.B.2.Nd.2.a
Association CEGL000052 Sierra White Fir - Brewer Spruce / Thinleaf Huckleberry / Western Rattlesnake-plantain Forest CEGL000052 1.B.2.Nd.2.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Picea breweriana (Brewer spruce forest) Alliance (Sawyer et al. 2009) [83.300.00]
= Picea breweriana Forest Alliance (CNPS 2017) [83.300.00]
? Enriched stands in the Klamath Mountains (Sawyer and Keeler-Wolf 1995)
>< Salmon-Scott Enriched Coniferous Forest (#85420) (Holland 1986b)
>< Siskiyou Enriched Coniferous Forest (#85410) (Holland 1986b)
Concept Author(s): K.A. Schulz, in Faber-Langendoen et al. (2013)

Author of Description: G. Kittel and K.A. Schulz

Acknowledgements: No Data Available

Version Date: 12-18-14
  • Atzet, T. A., D. E. White, L. A. McCrimmon, P. A. Martinez, P. R. Fong, and V. D. Randall. 1996. Field guide to the forested plant associations of southwestern Oregon. Technical Paper R6-NR-ECOL-TP-17-96. USDA Forest Service, Pacific Northwest Region, Portland, OR.
  • Atzet, T., and D. L. Wheeler. 1982. Historical and ecological perspectives on fire activity in the Klamath Geological Province of the Rogue River and Siskiyou national forests. R6-Range-102-1982. USDA Forest Service, Pacific Northwest Region, Portland, OR.
  • Atzet, T., and D. L. Wheeler. 1984. Preliminary plant associations of the Siskiyou Mountains Province, Siskiyou National Forest. USDA Forest Service, Pacific Northwest Region, Portland, OR.
  • CNPS [California Native Plant Society]. 2015-2017. A manual of California vegetation [online]. California Native Plant Society, Sacramento, CA. [http://vegetation.cnps.org/].
  • Cheng, S. 2004. Forest Service research natural areas in California. General Technical Paper PSW-GTR-188. USDA Forest Service, Pacific Southwest Research Station, Albany, CA.
  • Cope, A. B. 1992c. Picea breweriana. In: Fire Effects Information System [Online]. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). [http://www.fs.fed.us/database/feis/]
  • Eckert, A. J., and M. L. Eckert. 2007. Environmental and ecological effects on size class disturbations of foxtail pine (Pinus baulforiana, Pinaceae) in the Klamath Mountains, California. Madroño 54:117-125.
  • 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.
  • Hawk, G. M. 1977. A comparative study of temperate Chamaecyparis forests. Unpublished dissertation, Oregon State University, Corvallis. 194 pp.
  • 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.
  • Jimerson, T. M., E. A. McGee, D. W. Jones, R. J. Svilich, E. Hotalen, G. DeNitto, T. Laurent, J. D. Tenpas, M. E. Smith, K. Hefner-McClelland, and J. Mattison. 1996. A field guide to the tanoak and Douglas-fir plant associations in northwestern California. Technical Paper R5-ECOL-TP-009. USDA Forest Service, Pacific Southwest Region, San Francisco, CA.
  • Reid, M. S., L. S. Engelking, and P. S. Bourgeron. 1994. Rare plant communities of the conterminous United States, Western Region. Pages 305-620 in: D. H. Grossman, K. L. Goodin, and C. L. Reuss, editors. Rare plant communities of the conterminous United States, an initial survey. The Nature Conservancy, Arlington, VA.
  • Sawyer, J. O. 2006. Northwest California: A natural history. University of California Press, Berkeley, CA.
  • Sawyer, J. O. 2007. Forests of northwestern California. Pages 253-295 in: M. G. Barbour, T. Keeler-Wolf, and A. Schoenherr, editors. Terrestrial vegetation of California, third edition. University of California Press, Berkeley, CA.
  • 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 D. A. Thornburgh. 1977. Montane and subalpine vegetation of the Klamath Mountains. Pages 699-732 in: M. G. Barbour and J. Major, editors. Terrestrial vegetation of California. John Wiley and Sons, New York.
  • Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.
  • Thornburgh, D. A. 1990. Picea breweriana, Brewer spruce. Pages 181-186 in: R. M. Burns and B. H. Honkala, editors. Silvics of North America. Volume 1: Conifers. Agriculture Handbook 654. USDA Forest Service, Washington, DC.