Red alder (Alnus rubra), also called Oregon alder, western alder, and Pacific coast alder, is the most common hardwood in the Pacific Northwest. It is a relatively short-lived, intolerant pioneer with rapid juvenile growth. The species is favored by disturbance and often increases after logging and burning.
The commercial value of alder has traditionally been lower than that of its associated conifers, most forest managers have tried to eliminate the species from conifer stands. On the other hand, red alder is the only commercial tree species west of the Rocky Mountains with the capability to fix atmospheric nitrogen, and the species is now being considered for deliberate use in some management systems.
Forestryimages.org provides several images of parts of northern red alder. The tree is a hardwood and the lineal taxonomy is Magnoliopsida > Fagales > Betulaceae > Alnus rubra Bong. Red alder is also commonly called Oregon alder, western alder, and Pacific coast alder.
3. The Range of Red Alder
Red alder is most often observed as a lowland species along the northern Pacific coast. Its range extends from southern California (lat. 34° N.) to southeastern Alaska (60° N.). Red alder is generally found within 125 miles of the ocean and at elevations below 2,400 ft. It seldom grows east of the Cascade Range in Oregon and Washington or the Sierra Nevada in California, although several isolated populations exist in northern Idaho.
Leaf: Alternate, simple, deciduous, ovate, 3 to 6 inches long, prominently penniveined leaf with doubly serrate margins that are tightly rolled under at the edges (revolute); petiole 1 inch long and grooved; green to yellow green above and paler green below.
Twig: Young twigs are distinctly triangular in cross-section; olive to reddish brown; prominent lenticels; clearly stalked buds.