Picea sitchensis Forest & Woodland Alliance
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).


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