Sitka Alder - Alnus viridis var. sinuata
ost often shrublike, but occasionally a tree, this is a Northwestern alder, growing as far north as southern Alaska and east throughout British Columbia. It prefers moist slopes and is tolerant of rocky substrates. The leaf is thin and shiny above and below. This alder is often encountered in thickets and helps to stabilize sites, such as avalanche-prone areas; it is often found as a pioneering species on deglaciated terrain, sprouting quickly from roots and stumps. It is a nitrogen-fixing species, enabling it to thrive in impoverished sites.