Alnus rubra

Red alder is in the birch or Betulaceae family and is native to western North America from Skagway, Alaska south to central California, along mountainous coastal areas and in valley bottoms. It is a fast-growing early pioneer species, growing into a broadly-conical tree reaching up to 27 m tall and often out-competing conifers in wetter areas.

• Leaves are alternate, simple, doubly serrated, oval to elliptical, up to 10 cm long and 7.5 cm across, pointed at the tip. Petiole is 2.5 cm long. The leathery foliage becomes deep green above, blue-green with some rusty-brown hairs beneath.
• Species is monoecious. Male catkins are drooping and yellow-orange, up to 15 cm long, new ones forming in late summer and lasting over winter. Female catkins are small, red and upright, groups of 2 to 5, becoming green and swollen by mid-summer, brown and woody (non-disintegrating) by winter.
• Buds are stocked, red, flatter in one direction, 2 bud scales (valvate).
• Bark is pale gray; when bark is removed, stem becomes reddish-orange. Roots are nitrogen-fixing.