Picea breweriana Forest & Woodland Alliance
Brewer spruce forest and woodland
Brewer spruce forest and woodland
USDA Ecological Section Map
Summary Information
- Primary Life FormTree
- Elevation1150-2700 m
- State RarityS2
- Global RarityG3
- DistributionUSA: CA, OR (NatureServe)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsYes
- Date Added2009/09/01
Characteristic Species
Picea breweriana is dominant or co-dominant in the tree canopy with Abies concolor, Abies procera, Abies ×shastensis, Calocedrus decurrens, Chamaecyparis lawsoniana, Pinus contorta ssp. murrayana, Pinus lambertiana, Pinus monticola, Pinus ponderosa, Pseudotsuga menziesii, Taxus brevifolia and Tsuga mertensiana.
Vegetation Layers
Trees < 60 m; canopy is intermittent to continuous. Shrub layer is sparse to intermittent. Herbaceous layer is sparse or abundant.
Membership Rules
- Picea breweriana is > 30% relative cover and > 5% absolute cover in the tree layer (NatureServe 2007).
Habitats
North slopes and rocky ridges. Parent materials and soils are highly variable.
Other Habitat, Alliance and Community Groupings
| MCV (1995) | Enriched stands in the Klamath Mountains |
| NVCS (2009) | Picea breweriana forest alliance |
| Calveg | Brewer spruce |
| Holland | Siskiyou enriched coniferous forest, Salmon-Scott enriched coniferous forest |
| Munz | Red fir forest |
| WHR | Klamath mixed conifer |
| CDFW CA Code | 83.300.00 |
National Vegetation Classification Hierarchy
| Formation Class | Mesomorphic Tree Vegetation (Forest and Woodland) |
| Formation Subclass | Temperate Forest |
| Formation | Cool Temperate Forest |
| Division | Western North America Cool Temperate Forest |
| Macro Group | Californian-Vancouverian Montane and Foothill Forest |
| Group | Californian montane conifer forest |
Remarks
Picea breweriana is a conifer with distinctive, drooping branches endemic to the Klamath Mountains. Trees attain 50 m in height. They begin producing cones about 20 years, and produce seeds annually or in 2-year cycles. Seeds are dispersed by the wind. Most seeds germinate on decaying logs, forest humus, loose soil, and leaf litter under trees and shrubs. Trees are shade tolerant, and plants can endure decades of suppression under closed tree canopies. Suppressed trees may grow rapidly when tree canopy openings are created. Plants can withstand considerable soil drought, but they are extremely sensitive to high evaporation demands (Cope 1992d, Thornburgh 1990a, Sawyer 2007).
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 1992d). Ecologists in Oregon have recognized the alliance (Kagan et al. 2000); 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).
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 1992d). Ecologists in Oregon have recognized the alliance (Kagan et al. 2000); 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).
Life History Traits of the Principal Species
| Picea breweriana | |
|---|---|
| Life forms | Tree; evergreen |
| Seed storage | Transient |
| Seed longevity | Short |
| Mode of dispersal | Gravity; wind |
| Germination agents | Stratification—winter |
| Mode of sprouting | None |
| Survivability after fire/disturbance | Fire-sensitive; thin epidermis; no/low sprouter; canopy architecture susceptible |
| Disturbance-stimulated flowering | No |
| Reproductive range | 20-900 years |
| Recruitment | Episodic (variable) |
| Regional variation | Low |
Fire Characteristics
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 1990a). The most developed stands tend to occur on very steep, rocky, fire-protected sites.
| Fire return interval | Medium to long |
| Seasonality | Summer-early fall |
| Size/extent | Small to medium |
| Complexity | Low to moderate |
| Intensity | Multiple |
| Severity | Moderate to very high |
| Type | Surface to passive-active crown fire |
| Regional knowledge | Klamath Mountains |
Regional Status
- Klamath Mountains (M261Aa, Ad-g, Aj, An-q, At). Stands occur at montane and subalpine elevations in the Trinity Alps and the Marble, Salmon, Scott, Siskiyou, and Trinity mountains (Sawyer 2006, 2007). The easternmost stands are near Castle Crags, the westernmost is to the west of Red Mountain in the Siskiyou Mountains, and the southernmost is on Weaverville Bolly in the Trinity Alps. The northernmost stand is in the Siskiyou Mountains in Oregon. Some of the largest inventoried stands occur in the Sugar Creek drainage in the Salmon Mountains (Bingham 1993, Keeler-Wolf 1984d, see Cheng 2004, Sawyer 2007).
Management Considerations
Fire sensitivity and logging practices have limited the range of Picea breweriana. Extinction of P. breweriana could result from the increasing potential of forest fires combined with climate change, loss of seed sources, and inability of seedlings to tolerate high moisture stress (Thornburgh 1990a). However, as with Pinus balfouriana (Eckert and Eckert 2007), the range of Picea breweriana is currently expanding down in elevation.
Associations
- Picea breweriana - Abies concolor / Chimaphila umbellata - Pyrola picta [1]
References
- [1] Atzet, T.A.;White, D.E.;McCrimmon, L.A.;Martinez, P.A.;Fong, P.R.;Randall, V.D. 1996
- Atzet, T.;Wheeler, D.L. 1982
- Bingham, P.B. 1993
- Cope, A.B. 1992d
- Kagan, J.S.;Christy, J.A.;Murray, M.P.;Titus, J.A. 2004
- Sawyer, J.O. 2006
- Sawyer, J.O. 2007
- Sawyer, J.O.;Thornburgh, D.A. 1977
- Thornburgh, D.A. 1990a