( Alnus spp. ) , members of the birch family, grow in the cool regions of North America, Asia, and Europe, and in high mountains of Central America and south America. Many of the 30 or so kinds are shrubs. Nine are the natives of continental United States, and one of these only Red and White alders grow to tree size. Alders prefer moist soil. They grow rapidly and often are “pioneers” on burned-over land. Alder leaves are oval, coarsely toothed, and alternately arranged on twigs. They have prominent, hairy veins. Yellowish-green cat-kins, similar to those birches, appear in early spring. The seeds are contained in thick, woody cones, called strobiles. At first green, the strobiles change black over the many months they hang on the tree. The Red Alder is the most t common deciduous tree in a narrow coastal strip from Central California northward to Alaska. It may grow to a height of a 100 feet or more, and its trunk may be two or three feet in diameter. Once considered a “weed tree” the Red Alder is becoming increasingly important commercially as new uses for its wood are discovered. The White Alder is also commonly found along the Pacific Coast but farther inland and at elevations as high a 8,000 feet in the Sierra Nevada Mountains. Its wood is of little value. Most common of the alders in eastern United States is the Speckled Alder, which seldom grows taller the 20 feet. It is chiefly of value in checking erosion along the the streams where it grows thickly. The Green Alder, a small shrub, grows in eastern North America and Europe, and the Sitka Alder, often large, the Rocky Mountain region. European Black, Japanese, and Golden alders are sometimes planted as ornamentals. Alder bark is eaten by beavers, rabbits, and other animals.