Notholithocarpus

Notholithocarpus is a genus in the beech family (Fagaceae) that contains a single living species, Notholithocarpus densiflorus, commonly known as the tanbark oak or California tanbark oak. The genus was established to accommodate distinctive features of this species that differ from Lithocarpus, and modern classifications often treat the two as separate. The genus name means “false stone oak.”

Notholithocarpus densiflorus is an evergreen tree that can reach substantial size, with a broad, rounded crown and thick, corky bark. Leaves are evergreen, simple, and alternately arranged, typically oblong to lanceolate with fine serrations. The fruit is an acorn enclosed in a tight, scaly cupule that partially covers the nut; acorns mature in roughly six to seven months.

Distribution and habitat: The species is native to western North America, from southwestern Oregon to central California, where it grows in mixed conifer and oak woodland communities on mesic, well-drained sites, often along canyons and at foothill elevations.

Ecology and uses: Acorns provide an important seasonal food source for wildlife. The bark was historically rich in tannins, giving the tanbark oak its common name and supporting tanning industries in California. Notholithocarpus densiflorus is vulnerable to Phytophthora ramorum, the pathogen that causes Sudden Oak Death, which affects many coastal populations. The species is valued for its timber and as a component of native plant communities in applicable ecosystems.