Calocedrus decurrens Forest & Woodland Alliance
Incense cedar forest and woodland
Incense cedar forest and woodland
USDA Ecological Section Map
Summary Information
- Primary Life FormTree
- Elevation500-2100 m
- State RarityS3
- Global RarityG4
- DistributionUSA: CA, NV, OR (USDA Plants)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsNo
- Date Added1995/11/01
Characteristic Species
Calocedrus decurrens is dominant in the tree canopy . Other tree species present at low cover include Abies concolor, Pinus contorta ssp. murrayana, Pinus coulteri, Pinus jeffreyi, Pinus lambertiana, Pinus ponderosa, Pseudotsuga menziesii, Quercus chrysolepis and Quercus kelloggii.
Vegetation Layers
Trees < 65 m; canopy is open to continuous. Shrubs are infrequent to common. Herbaceous layer is variable.
Membership Rules
- Calocedrus decurrens > 50% relative cover in the tree canopy; there may be abundant Quercus chrysolepis and/or Q. kelloggii in the understory (Klein and Evens 2005, Evens and San 2005).
- Calocedrus decurrens > 60% relative cover in the tree canopy; Pinus jeffreyi, P. ponderosa, and Pseudotsuga menzeisii are absent (Ratchford et al. 2023a).
Habitats
Raised stream benches, terraces, around wet meadows, upper slopes, ridges.
Other Habitat, Alliance and Community Groupings
| MCV (1995) | Incense-cedar series |
| NVCS (2009) | Calocedrus decurrens forest alliance |
| Calveg | Incense-cedar |
| Holland | Sierran mixed coniferous forest, Sierran white fir forest |
| Munz | Yellow pine forest |
| WHR | Sierran mixed conifer |
| CDFW CA Code | 85.100.00 |
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
Calocedrus decurrens is a conifer that attains 50 m in height and an age of over 500 years. Seed crops vary in 3-6 year cycles, with seed production lacking in some years. Seeds are wind dispersed. Germination is best under partial shade on fresh mineral soil or very light litter. Established seedlings are both shade and drought tolerant. Plants develop well when released. C. decurrens grows on a wide variety of parent materials. Trees grow fastest on deep, well-drained, productive sites, but they commonly occur on unproductive ones as well (Habeck 1992a, Powers and Oliver 1990). Plants can extract soil phosphorus and calcium and exclude surplus magnesium, allowing it to grow on ultramafic substrates (Alexander et al. 2007).
Stands are characterized by a dominance of C. decurrens and do not include stands that have a mixed dominance of pines, Douglas fir, or alder. Stands with mixed dominance belong to the respective alliance of the codomiant species. Additional data and analysis is needed to better understand this alliance.
The ecology of C. decurrens varies greatly among different sections. Much of the literature involves the role of C. decurrens and fire in the mixed-conifer forests of the montane Sierra Nevada (see the Pinus ponderosa - Calocedrus decurrens - Pseudotsuga menziesii alliance), but it may not apply to other sections. C. decurrens stands are often small and restricted and in a mosaic within stands of other forest alliances (Barbour et al. 2007a). Stands are often found near riparian areas, on serpentine soils, or on rocky outcrops protected from fire.
Stands are characterized by a dominance of C. decurrens and do not include stands that have a mixed dominance of pines, Douglas fir, or alder. Stands with mixed dominance belong to the respective alliance of the codomiant species. Additional data and analysis is needed to better understand this alliance.
The ecology of C. decurrens varies greatly among different sections. Much of the literature involves the role of C. decurrens and fire in the mixed-conifer forests of the montane Sierra Nevada (see the Pinus ponderosa - Calocedrus decurrens - Pseudotsuga menziesii alliance), but it may not apply to other sections. C. decurrens stands are often small and restricted and in a mosaic within stands of other forest alliances (Barbour et al. 2007a). Stands are often found near riparian areas, on serpentine soils, or on rocky outcrops protected from fire.
Life History Traits of the Principal Species
| Calocedrus decurrens | |
|---|---|
| Life forms | Tree; evergreen |
| Seed storage | Transient |
| Seed longevity | Short |
| Mode of dispersal | Wind |
| Germination agents | Stratification—winter |
| Mode of sprouting | None |
| Survivability after fire/disturbance | Fire-hardy; thick epidermis; low flammability; canopy architecture resistant |
| Disturbance-stimulated flowering | No |
| Reproductive range | 20-500+ years |
| Recruitment | Episodic; high |
| Regional variation | Low |
Fire Characteristics
Saplings of Calocedrus decurrens are highly susceptible to even low-severity fires. Saplings have very flammable bark and foliage. Mature trees have a thick bark that protects them from ground fires. Moderate-to high-severity surface fires damage trunks, however, making trees prone to rots and root disease (Habeck 1992a, Powers and Oliver 1990). Riparian or semiriparian stands exist throughout its range and on fire-sheltered, moist sites that naturally favor this alliance. Fire histories are similar to that of other mid-elevation forest types. Underburning would allow older trees to survive repeated fires (Sugihara et al. 2007).
| Fire return interval | Short to medium (5-30 years) |
| Seasonality | Summer-early fall |
| Size/extent | Small to medium |
| Complexity | Low to moderate |
| Intensity | Low to moderate |
| Severity | Low to moderate |
| Type | Surface-passive crown fire |
| Regional knowledge | Klamath, Cascade, and North Coast ranges; Modoc Plateau; Sierra Nevada and foothills; southern California |
Regional Status
Calocedrus decurrens stands are likely small and scattered throughout the range. Additional surveying and data are needed to better understand this alliance and its range extent in California.
- Central California Coast (261Aj). Scattered individual trees and groves occur near streams in the Santa Lucia Mountains.
- Central California Coast Ranges (M262Ac). Scattered individual trees and groves occur at the higher elevations on serpentine substrates (Alexander et al. 2007). Evens et al. (2006) did not sample any during the San Benito Mountain study.
- Klamath Mountains (M261Ac-g, Ai-j, Ap-u). Local and extensive stands occur on and off serpentine substrates, commonly at montane elevations on exposed ridges and at meadow margins (Sawyer 2007).
- Modoc Plateau (M261Gf). The range of the alliance includes the higher elevations in the section (Griffin and Critchfield 1972). Isolated, upland stands, pure or mixed with Abies concolor, occur in the northern Warner Mountains .
- Northern California Coast (263Ag). Scattered trees and small groves occur on serpentine substrates at even low elevations (Alexander et al. 2007, Sawyer 2007).
- Northern California Coast Ranges (M261Ba-b, Bf). At low elevations, individual trees and groves occur on serpentine substrates. Stands at Doll Basin RNA (Keeler-Wolf 1986b, see Cheng 2004) and in the Yolla Bolly Mountains (Keeler-Wolf and Keeler-Wolf 1974, Muldavin 1982) are among the largest known. They are adjacent to moist montane meadows and the southernmost stand of Populus tremuloides in the section.
- Sierra Nevada (M261Ef-g, Em, Ep-q, Eu). Stands found in riparian settings in Yosemite National Park (Keeler-Wolf et al. 2003b). Stands in this region may be codominanting with white alder and belong to that alliance.
- Sierra Nevada Foothills (M261Fa-b). Stands sampled on serpentine soils in this region (Klein et al. 2007). Small stands may also occur at higher elevations in riparian settings.
- Southern California Mountains and Valleys (M262Ba, Be, Bh, Bm, Bo). Trees mix as a secondary component in several montane forest alliances, but groves and local stands do occur throughout the Transverse and Peninsular ranges (Minnich 2007). Descriptions exist for stands in the Hall Canyon RNA (Keeler-Wolf 1986c, see Cheng 2004), in the San Jacinto Mountains (Klein and Evens 2005), and for Volcan Mountain (Evens and San 2005).
- Southern Cascades (M261Dd, Dj, Dl-m). Stands were surveyed in Lassen Volcanic National Park (NPS, 2016). Stands are expected elsewhere in the section, especially in the southern subsections (see Fites-Kaufman et al. 2007).
Management Considerations
Fire exclusion has led to a buildup of fuels, an increase in stem density, and a change in composition in montane zones of California. Additionally, logging practices have selectively taken the large trees. Like fire exclusion, these practices encourage stands to change in composition toward shade-tolerant conifers, such as Calocedrus decurrens (Sugihura et al. 2007).
Associations
- Calocedrus decurrens - Abies concolor / Senecio triangularis [5]
- Calocedrus decurrens / Listera convallarioides [5]
- Calocedrus decurrens - Quercus chrysolepis - Quercus kelloggii [1], [2], [3]
References
- [1] Evens, J.;San, S. 2005
- [2] Ratchford, J.;Harbert, B;Boul, R.;Keeler-Wolf, T.;Evens, J. 2024a
- [3] Klein, A.;Evens, J. 2006
- [5] Muldavin, E.H. 1982
- Alexander, E.B.;Coleman, R.G.;Keeler-Wolf, T.;Harrison, S. 2007
- Atzet, T.A.;White, D.E.;McCrimmon, L.A.;Martinez, P.A.;Fong, P.R.;Randall, V.D. 1996
- Barbour, M.G. 1988
- Barbour, M.G.;Keeler-Wolf, T.;Schoenherr, A.A. 2007a
- Brooks, R.R. 1987
- Coleman, R.G.;Kruckeberg, A.R. 1999
- Griffin, J.R.;Critchfield, W.B. 1972
- Kruckeberg, A.R. 1984
- Powers, R.F.;Oliver, W.W. 1990
- Sawyer, J.O. 2007
- Sugihara, N.G.;van Wagtendonk, J.W.;Shaffer, K.E.;Fites-Kaufman, J.;Thode, A.E. 2006