Acer negundo Forest & Woodland Alliance
Box-elder forest and woodland

USDA Ecological Section Map

Summary Information

  • Primary Life FormTree
  • Elevation0-600 m
  • State RarityS2.2
  • Global RarityG5
  • DistributionUSA: CA, CO, ID, UT, WY (NatureServe)
  • Endemic to CaliforniaNo
  • Endemic to California Floristic Province and DesertsNo
  • Date Added2009/09/01

Characteristic Species

Acer negundo is dominant or co-dominant in the tree canopy with Alnus rhombifolia, Fraxinus latifolia, Juglans hindsii, Juglans hindsii × regia, Platanus racemosa, Populus fremontii, Populus trichocarpa, Quercus lobata, Salix gooddingii and Salix spp.

Vegetation Layers

Trees < 20 m; cover is intermittent to continuous, and it may be two tiered. Shrub layer is open to intermittent. Herbaceous layer is sparse to abundant.

Membership Rules

  • Acer negundo > 50% relative cover in the tree canopy (Stillwater Sciences 2001).
  • Acer negundo > 50% relative cover in the tree canopy, with Fraxinus latifolia, Populus fremontii, Quercus lobata, and Salix gooddingii at < 5% cover (Hickson and Keeler-Wolf 2007).


Streams, bottomlands. Soils are deep alluvium. The USFWS Wetland Inventory (1996 national list) recognizes Acer negundo as a FACW plant.

Other Habitat, Alliance and Community Groupings

MCV (1995) Not treated
NVCS (2009) Acer negundo seasonally flooded forest alliance
Calveg Fremont cottonwood
Holland North Coast riparian forests, Central Coast riparian forest, Great Valley mixed riparian forest
Munz Not treated
WHR Fresh emergent wetland, Valley foothill riparian
CDFW CA Code 61.440.00

National Vegetation Classification Hierarchy

Formation Class Mesomorphic Tree Vegetation (Forest and Woodland)
Formation Subclass Temperate Forest
Formation Temperate Flooded and Swamp Forest
Division Western North America Warm Temperate Flooded and Swamp Forest
Macro Group Southwestern North American Riparian, Flooded and Swamp Forest
Group Southwestern North American riparian evergreen and deciduous woodland