Picea sitchensis Forest & Woodland Alliance
Sitka spruce forest and woodland
Sitka spruce forest and woodland
USDA Ecological Section Map
Summary Information
- Primary Life FormTree
- Elevation0-20 m
- State RarityS2
- Global RarityG5
- DistributionCAN: BC. USA: AK, CA, OR, WA (NatureServe)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsNo
- Date Added1995/11/01
Characteristic Species
Picea sitchensis is dominant in the tree canopy with Abies grandis, Alnus rubra, Sequoia sempervirens and Tsuga heterophylla.
Vegetation Layers
Trees < 75 m; canopy is intermittent to continuous. Shrub layer is sparse to continuous. Herbaceous layer is usually abundant, especially with ferns.
Membership Rules
- Picea sitchensis > 50% relative cover in canopy (NatureServe 2007).
Habitats
Bottomlands, upland steep slopes, and seaward bluffs and ravines near the ocean. Sandstone or schist-derived soils are seasonally flooded to permanently saturated, and they are sandstone or schist-derived. The USFWS Wetland Inventory (1996 national list) recognizes Picea sitchensis as a FAC plant.
Other Habitat, Alliance and Community Groupings
| MCV (1995) | Sitka spruce series |
| NVCS (2009) | Picea sitchensis giant forest alliance, Picea sitchensis seasonally flooded forest alliance, Picea sitchensis temporarily flooded forest alliance |
| Calveg | Sitka spruce-Grand fir, Sitka spruce, Sitka spruce-Redwood |
| Holland | Freshwater swamp, Sitka spruce-grand fir forest, Sitka spruce forest |
| Munz | North Coast coniferous forest |
| WHR | Redwood |
| CDFW CA Code | 83.200.00 |
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 | Vancouverian Rainforest |
| Group | Vancouverian hypermaritime lowland rainforest |
Remarks
Picea sitchensis is a conifer that attains a height of 70 m and an age of 800 years. The root system is usually shallow, except on well-drained alluvium. Plants produce cones between 20 and 40 years of age. Dispersal of seeds is moisture dependent, with mature, dry cones dispersing numerous seeds. Seeds can travel over 750 m from parent plants. They germinate on almost any substrate, although mineral soil, a mixture of mineral soil and organic soil, and nurse logs are considered the best seedbeds (Harris 1990b, Griffith 1992b).
Picea sitchensis occurs in coastal forests in a narrow band along the northern Pacific Coast. It is an early colonizer of disturbed soils and a late-seral species of coastal forests. Old-growth stands of P. sitchensis are rare along the northern coast of California, as most stands are in shrub or young tree stages. The alliance often occurs adjacent to Sequoia sempervirens, Tsuga heterophylla, Alnus rubra, and Abies grandis alliance stands. Successional stands occur adjacent to wetlands of Salix hookeriana and Deschampsia cespitosa alliances. P. sitchensis also quickly invades stands of Corylus cornuta, Malus fusca, Frangula purshiana, Rhododendron occidentale, and other shrubs, such as at Azalea State Reserve and Stagecoach Hill Azalea Reserve in Humboldt Lagoons State Park. These areas are managed to maintain blooming populations of Rhododendron occidentale. Young forests of these settings also support stands of Alnus rubra.
Picea sitchensis occurs in coastal forests in a narrow band along the northern Pacific Coast. It is an early colonizer of disturbed soils and a late-seral species of coastal forests. Old-growth stands of P. sitchensis are rare along the northern coast of California, as most stands are in shrub or young tree stages. The alliance often occurs adjacent to Sequoia sempervirens, Tsuga heterophylla, Alnus rubra, and Abies grandis alliance stands. Successional stands occur adjacent to wetlands of Salix hookeriana and Deschampsia cespitosa alliances. P. sitchensis also quickly invades stands of Corylus cornuta, Malus fusca, Frangula purshiana, Rhododendron occidentale, and other shrubs, such as at Azalea State Reserve and Stagecoach Hill Azalea Reserve in Humboldt Lagoons State Park. These areas are managed to maintain blooming populations of Rhododendron occidentale. Young forests of these settings also support stands of Alnus rubra.
Life History Traits of the Principal Species
| Picea sitchensis | |
|---|---|
| Life forms | Tree; evergreen |
| Seed storage | Transient |
| Seed longevity | Short |
| Mode of dispersal | Wind |
| Germination agents | None |
| Mode of sprouting | Buds on large branches or trunks; underground structures |
| Survivability after fire/disturbance | Fire-sensitive; thin epidermis; shallow roots |
| Disturbance-stimulated flowering | No |
| Reproductive range | 20-800 years |
| Recruitment | Low |
| Regional variation | Low |
Fire Characteristics
Picea sitchensis has relatively thin bark and shallow roots, and is very susceptible to mortality from fire. Many stands develop in moist to wet areas that are not associated with fire on stream bottoms or on seepy slopes. Fire intervals are long (150-350+ years). Fires are severe when they occur and result in stand replacement (Parminter 1991). After a fire, off-site, unburned trees provide wind-dispersed seed to re-colonize.
| Fire return interval | Truncated long |
| Seasonality | Summer-early fall |
| Size/extent | Small to medium |
| Complexity | Moderate |
| Intensity | Moderate |
| Severity | Multiple |
| Type | Passive-active crown |
| Regional knowledge | North Coast |
Regional Status
- Northern California Coast (263Aa-b, Ad-i). Three disjunct stands occur between Fort Bragg and Big River in Mendocino Co., and Westman and Whittaker (1975) define an association in this county. Stands occur more regularly along the coast north of Cape Mendocino from Humboldt to Del Norte Cos. These represent the southernmost continuous range of the species. Some of the best old-growth stands are in the Gold Bluffs area of Redwood National Park. Imper et al. (1987) define stands at Table Bluff Ecological Reserve, and VegCAMP (1993) and CNPS (2005) have plot data for Prairie Creek Redwood State Park and Redwood National Park in Humboldt Co.
Management Considerations
Picea sitchensis stands have been logged in California for over 100 years, and virtually all the original large stands have been cut at least once. Second-growth stands are common within several state parks and in Redwood National Park. Management for coastal scrub and grassland (including associated rare species, such as the western lily) may require burning and clearing of P. sitchensis stands in some areas (Imper et al. 1987).
Associations
- Picea sitchensis / Maianthemum dilatatum [1]
- Picea sitchensis / Polystichum munitum [1]
- Picea sitchensis / Rubus spectabilis [1]
- Picea sitchensis - Tsuga heterophylla [2]
References
- [1] Imper, D.K.;Hoovey, G.E.;Sawyer, J.O.;Carlson, S.A. 1987
- [2] Westman, W.E.;Whittaker, R.H. 1975
- Franklin, J.F. 1988
- Griffin, J.R.;Critchfield, W.B. 1972
- Griffith, R.S. 1992b
- Harris, A.S. 1980a
- Harris, A.S.;Johnson, D.L. 1983
- Minore, D. 1980
- Sawyer, J.O. 2007
- Zinke, P.J. 1977