Notholithocarpus densiflorus aka Tanoak

Notholithocarpus densiflorus is an evergreen tree known as tanoak or tanbark-oak. It belongs to the beech family, but is not a true oak. Its native range runs from southwest Oregon through California. It grows along the coast and in nearby mountain ranges. Older sources call it Lithocarpus densiflorus. Garden trees reach 20–80 feet [6.1–24.4 metres] tall. They can spread to 50 feet [15.2 metres] wide. Other accounts report trees reaching 100 feet [30.5 metres]. Growth is slow, and wild trees may live over 300 years.

The crown can form a cone or a rounded dome. Large branches extend out from the trunk. Sprouts from underground burls can form clumps with several stems. Trees in shade may have narrow crowns. Mature bark is reddish brown, with grooves and raised ridges. Young stems have a thick coat of rusty hairs. The leaves grow in an alternate pattern and feel leathery. They measure 3–5 inches long and have smooth or toothed edges. Mature leaves shine dark green above, with pale blue-white undersides. Each leaf can remain on the tree for three or four years.

Flowers appear from April to August, with most bloom in summer. Some trees also flower again in autumn. Upright male catkins start white, then turn a rusty shade. They measure 2–4 inches long and have an unpleasant smell. Small greenish-yellow female flowers sit at their bases. Wind carries the pollen. The oval acorns grow alone or in pairs. Their shallow cups have dense bristles. Acorns take two growing seasons to ripen. They fall from September into November.

Tanoak grows best in sun or partial shade. It prefers rich, moist soil that drains well. Mild weather and humid air suit it. Established trees can cope with some drought. North Carolina State lists it for USDA zone 7. Plants For A Future reports that it survives at Kew. Its broad crown suits a woodland canopy and gives wildlife shelter. Deer, squirrels, chipmunks, and several birds eat the acorns. Butterflies and moths also visit the tree.

Oak worms may eat its leaves, though most insects cause few problems. Sudden oak death can infect and kill tanoaks. The tree also has a high fire risk. People have used its hard wood for fuel, lumber, and pulp. Bark supplied tannin for leather and dye. Indigenous peoples used prepared acorns for soups, mush, and bread. The seeds contain bitter tannins that need removal before cooking. Plants For A Future lists no known hazards. That does not establish pet safety.