Alnus rubra, or Red Alder, is a deciduous broadleaf tree that is native to western North America. It is widely employed in traditional medicine by indigenous North American tribes, who mainly use the bark to treat a variety of complaints like headaches, rheumatic pains, internal injuries, and diarrhea. Red Alder is the largest species of alder in North America and one of the world's largest, growing up to 100 ft tall, with bright rusty red bark when bruised or scraped. It produces yellow fall foliage and has seeds that are shed in the autumn and winter. Red Alder is an important early colonizer of disturbed forests and riparian areas, as it can fix nitrogen in the soil and grow rapidly. It is also used for dye, woodworking, fish smoking, and is being increasingly used for furniture and cabinetry. As an environmental indicator, Red Alder leaves react to the presence of high ozone levels by developing red to brown or purple discolorations. Alder continues to attract interest as log values approach and often exceed those of Douglas-fir.