Red Alder (Alnus rubra), so named for the reddish-brown color of its inner bark, is a member of the Birch family and native to the western United States. Often associated with the mixed evergreen and redwood forests of the Pacific Northwest, its range extends from southeastern Alaska to San Luis Obispo County, California.A shade-intolerant, medium-sized deciduous tree, Red Alder typically reaches heights between 80 and 100 feet, with widths ranging from 1 to 2 feet across at the base. In the first 20 years of its 100-year lifespan, 3 feet of growth per year is not uncommon. Leaves are elliptical, serrated, and slightly rolled under with sharp, pointed tips. Upper surfaces of the leaves appear dark green, while lower surfaces are paler green and feature rust-colored veins. The bark is thin and gray with grayish-white mottling, and is commonly colonized by white lichen and moss. Red Alder is a monoecious tree, meaning individuals bear both female flowers and male catkins — a cylindrical flower cluster.Thanks to symbiotic bacteria that form nodules in Red Alder roots, these trees are a great boon to soil enrichment and fertility, fixing atmospheric nitrogen in a form that can be used by other plants. For this quality, as well as soil erosion control, Red Alder has become an integral species in wetland restoration planting.Native American peoples valued Red Alder for its use as a medicine, fish net dye, and salmon-smoking wood.