tanoak

Tanoak (Notholithocarpus densiflorus) is an evergreen tree in the beech family (Fagaceae) native to the Pacific coast of North America. It is the sole living species in the genus Notholithocarpus and was historically classified in Lithocarpus; it is closely related to the oaks (Quercus). The common name derives from its oak-like form and tannin-rich nuts.

Distribution and habitat

Tanoak occurs from southwestern Oregon through coastal and foothill regions of central California. It favors moist, mesic sites within mixed evergreen forests and oak woodlands, often growing on foothill slopes and near streams.

Description

The tree typically reaches 15–25 meters in height, with a broad, irregular crown. Leaves are evergreen, alternate, simple, 6–13 cm long and 2–5 cm wide, leathery, with wavy or finely serrated margins. Bark is brown to gray and develops shallow fissures with age. The fruit is an acorn about 1–2 cm long, with a scaly cupule that covers part of the nut. Acorns mature after about 18 months and are produced in variable but sometimes abundant crops.

Ecology and threats

Tanoak forms mixed stands with other oaks and conifers, and its acorns provide food for wildlife such as birds and mammals. A major threat is Phytophthora ramorum, the pathogen responsible for sudden oak death, which has caused significant tanoak mortality in parts of California and Oregon and altered forest composition in affected areas.

Uses

The wood is dense and heavy and used for lumber and woodworking. The nuts are edible after leaching tannins and have historically been used as a food resource by Indigenous peoples and early settlers.