Thin-leaf Alder - Alnus incana ssp. tenuifolia
Shrubby or sometimes a small tree, this is a widely-distributed alder, growing from low elevations to nearly 10,000 feet in the mountains. It is widespread throughout western Canada, growing above the Arctic circle in Alaska, and ranges south to the Rocky Mountains. The bark is smooth and gray, and the leaves are doubletoothed, and hairy beneath. The female catkin is small. A pioneering tree often growing on poor soils, it tolerates dry substrate. As are other alders, it is a nitrogen-fixer, and thus enhances the soil for many plants.