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Red Alder

The Alnus Rubra is commonly known as Oregon Alder, Pacific Coast Alder, Red Alder, as well as Western Alder

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Growing Regions

Red alder is confined to the Pacific Coast region from southeast Alaska to southern California. Although there is an isolated population growing along streams in northern Idaho, it ordinarily occurs no further inland than 100 miles (160 km) at elevations below 2,500 feet (762 m) [16,24,33]. Red alder is cultivated in Hawaii [71].

     

General Information

The currently accepted scientific name of red alder is Alnus rubra Bong. [31,34,40]. There are no recognized subspecies, varieties, or forms.

Red alder communities, both upland and riparian, generally are found
within coniferous forests dominated by Douglas-fir (Pseudotsuga
menziesii), western redcedar (Thuja plicata), western hemlock (Tsuga
heterophylla), grand fir (Abies grandis), and Sitka spruce (Picea
sitchensis) [18,19,67], or as components of deciduous forests of
floodplains or swamps [18,19].  Generally, five types of red alder
communities have been described [18,19,21,32,67]:

 (1)  Upland, pure even aged stands of red alder, with a dense shrub
      undergrowth dominated by salmonberry (Rubus spectabilis) or
      elderberry (Sambucus melanocarpa), occurring within coniferous
      forests.

 (2)  Upland mixed stands of red alder/other deciduous trees and
      shrubs/conifers within coniferous forests less than 100 years
      old, with red alder occurring as a dominant or codominant.       
      
 (3)  Riparian red alder communities within coniferous forests. 

 (4)  Mixed stands within deciduous riparian forests, red alder
      occurring as codominant with black cottonwood (Populus trichocarpa)
      and bigleaf maple (Acer macrophyllum).

 (5)  In swamps often occurring with, or codominant with, western
      redcedar.  In this type of community, red alder appears to be a
      climax species.

Red alder communities were primarily restricted to streams and wet areas
during presettlement times.  Since then, disturbances such as logging
have provided an abundance of open sites with bare mineral soil, which
favor red alder colonization.  Today red alder communities are common
throughout much of coastal Oregon and Washington.

Published classification schemes listing red alder as an indicator
species or as a dominant part of the vegetation in community types (cts)
or plant associations (pas) are presented below:

    Area            Classification              Authority

AK                  general veg. cts            Viereck & others 1992

CA                  hardwood forest &           Barbour 1987
                    woodland cts
    
CA                  general veg. cts            Thorne 1976

s CA                general veg. cts            Paysen & others 1980

nw CA,w Or,w WA     general veg. cts            Franklin 1979

OR: Siuslaw NF      general veg. pas            Hemstrom & Logan 1986

OR                  postburn veg. cts           Bailey & Poulton 1968

s OR: Cascade Mtns  forest pas                  Atzet & McCrimmon 1990

OR, WA              general veg. cts            Franklin & Dyrness 1973 

Pacific NW          general veg. cts            Hall 1984

Much of the information presented here is attributed to:
Uchytil, Ronald J. 1989. Alnus rubra. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available at USDA Forest Service.

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