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Sitka alder Betulaceae Alnus viridis ssp. sinuata (Chaix) DC. ssp. (Regel) Á. Löve & D. Löve Listen to the Latin Print a QR link to this factsheet symbol: ALVIS
Leaf: Alternate, simple, deciduous, ovate or oval, variable sized, 2 to 5 inches long, margins are sharply and doubly serrate or slightly lobed and serrated (but not revolute); green to yellow-green above and paler green below; thin and papery.
Flower: Species is monoecious but flowers are borne in unisexual aments (catkins); preformed male aments are long, slender, and pendent; female catkins are small and hang in long clusters from long stalks.
Fruit: A small semi-woody cone 1/2 to 1 inch long, persists through the winter; brown, seeds are tiny winged nutlets, shed in the fall.
Twig: Slender, zig-zag and spreading; orange-brown and sticky when young but turning gray and smooth with age; conspicuous lenticels; buds are slender and pointed with valvate scales, slightly stalked or sessile.
Bark: Gray to grayish green with warty lenticles, otherwise smooth.
Form: A thicket forming erect shrub or small tree, 20 to 40 feet tall and 5 to 10 inches in diameter. Common in avalanche tracks so they are often crooked or leaning.
 Looks like: thinleaf alder - red alder - white alder - speckled alder

Sitka alder leaf image
Sitka alder flower image
Sitka alder fruit image
Sitka alder twig image
Sitka alder bark image
Sitka alder form image
Sitka alder map image

Additional Range Information: Alnus viridis ssp. sinuata is native to North America. Range may be expanded by planting. Download the full-size PDF map.
External Links: USDAFS FEIS Silvics - USDA Plants Database - USDAFS Forest Products Lab
All material 2025 Virginia Tech Dept. of Forest Resources and Environmental Conservation; Photos and text by: John Seiler, Edward Jensen, Alex Niemiera, and John Peterson; Silvics reprinted from Ag Handbook 654; range map source information