Tanoak Notholithocarpus densiflorus
Tanoak is not a true oak — it belongs to its own unique genus, Notholithocarpus. Its range runs from just north of the Umpqua River in southwestern Oregon south through the California Coast Ranges (USFS Silvics of North America). It is an evergreen hardwood and an ectomycorrhizal host.
Tanoak bears acorns and has thick, stiff, leathery leaves with fine star-shaped hairs, and they stay on the tree for three to four years (Silvics). Mature bark is thick and furrowed. In closed stands the trees are tall with narrow crowns; in the open they branch freely and grow broad and short-trunked (Silvics).
For mushroom hunters working southwestern Oregon, tanoak is one of the hardwood hosts to know. It often grows in mixed stands with Douglas-fir and other conifers.
Tanoak faces a serious threat from sudden oak death (Phytophthora ramorum), which has devastated populations in northern California and is present in parts of Curry County, Oregon.
Associated Mushrooms
Fungi recorded with tanoak include the queen bolete (Boletus regineus), which in California north to Oregon grows with hardwoods, tanoak especially (Arora). The California golden chanterelle (Cantharellus californicus) grows with coast live oak and other oaks, and also with tanoak (Arora). The California black trumpet (Craterellus calicornucopioides) is more common with tanoak in southwest Oregon, and western matsutake (Tricholoma murrillianum) is also fond of tanoak in the southern part of our range (Siegel & Schwarz, Mushrooms of Cascadia). Spring coccora (Amanita vernicoccora) is associated with tanoak and oaks (Tulloss); like other Amanita, it has deadly look-alikes. None of these is the king bolete of the Sitka spruce coast and the Cascades (Boletus edulis), and the Pacific golden chanterelle (Cantharellus formosus) is a conifer species.
Find Tanoak Forests on Forayz
Overlay precipitation data and ecoregion boundaries to locate the mixed hardwood-conifer forests of southern Oregon where tanoak drives mushroom production. Free environmental layers included.
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Distribution in Washington & Oregon
Photos: Tanoak — GinaGPark (CC0) · Queen Bolete — moorebuesing (CC0).
Sources: Mushrooms of Cascadia (Siegel & Schwarz, 2024); MycoMatch (© Ian Gibson), a compilation of published descriptions through which most other field-guide authors named here are quoted.