Alnus rhombifolia

Description

White alder is a medium-sized deciduous tree that typically grows 15 to 25 meters tall, though it can occasionally reach 35 meters. Its bark is pale gray, smooth when the tree is young but turning scaly as it ages. The leaves are arranged alternately and are rhombic to narrow elliptic in shape, measuring 4 to 10 centimeters long and 2 to 5 centimeters wide. They have finely serrated edges, a rounded to pointed tip, and a thin layer of hairs on the underside.

The tree produces flowers in catkins. The male catkins are slender, drooping, yellowish, and 3 to 10 centimeters long, appearing in clusters of two to seven; they release pollen in early spring before the leaves come out. The female catkins are oval, maturing in autumn to 10 to 22 millimeters long and 7 to 10 millimeters wide on a short stem, looking much like small conifer cones. Tiny winged seeds scatter over winter, while the old, woody, blackish cones may stay on the tree for up to a year. White alder is closely related to red alder, but its leaf margins are flat rather than curled under.

Uses

The Chumash people used white alder wood, though less extensively than oak or sycamore. Early Spanish expedition reports noted that the Chumash made wooden platters from alder and oak roots. Ethnologist J. P. Harrington's consultants stated that alder wood was used to produce bowls, trays, and spoons; the spoons were described as about a foot long with straight handles and round hollowed bowls. The Chumash word for white alder, mow, was also applied to a kind of sugar called panocha de carrizo traded by the Yokuts, made from native Phragmites australis.

Alder bark was employed as a dye: in northern California, it colored woodwardia ferns used in baskets by the Yurok, Karuk, and Hupa. The Ohlone used the bark as a dye and are also reported to have consumed the inner bark. Chumash people dyed cordage by soaking it in a bark solution for a day and a night. The Maidu produced a bright orange dye by chewing the bark, with salivary enzymes possibly helping to set the color.

Some Plateau Indian tribes used white alder for female health treatment needs. Alder-bark tea was reportedly used medicinally by some California indigenous people.