Pseudotsuga macrocarpa Forest Alliance
Bigcone Douglas fir forest

USDA Ecological Section Map

Summary Information

  • Primary Life FormTree
  • Elevation275-2400 m
  • State RarityS3.2
  • Global RarityG3
  • DistributionUSA: CA (NatureServe) (Calflora)
  • Endemic to CaliforniaYes
  • Endemic to California Floristic Province and DesertsYes
  • Date Added1995/11/01

Characteristic Species

Pseudotsuga macrocarpa is dominant or co-dominant in the tree canopy with Arbutus menziesii, Notholithocarpus densiflorus, Pinus coulteri, Pinus jeffreyi, Quercus agrifolia, Quercus chrysolepis, Quercus wislizeni and Umbellularia californica.

Vegetation Layers

Trees < 30 m; canopy is continuous or two tiered in older stands. Shrub layer is sparse to intermittent. Herbaceous layer is sparse.

Membership Rules

  • Pseudotsuga macrocarpa > 30% relative cover in the tree canopy (Evens and San 2005, Klein and Evens 2005, Buck-Diaz and Evens 2015).


Deep, convex canyons, draws, benches, hillsides, and cliff faces favoring rapidly eroding, north-facing slopes. Soils are shallow and well drained.

Other Habitat, Alliance and Community Groupings

MCV (1995) Bigcone Douglas fir series, Bigcone Douglas fir-canyon live oak series
NVCS (2009) Pseudotsuga macrocarpa forest alliance, Pseudotsuga macrocarpa-Quercus chrysolepis forest alliance
Calveg Bigcone Douglas-fir
Holland Bigcone spruce-canyon oak forest
Munz Mixed evergreen forest
WHR Montane hardwood-conifer
CDFW CA Code 82.100.00

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