White Alder

White alder is a fast-growing deciduous tree native to riparian areas, streambanks, and moist valleys of California and the Pacific Northwest. It typically reaches 30–80 feet tall, with smooth gray bark that whitens with age and diamond-shaped, serrated leaves that give the species its name. In early spring, it produces dangling catkins that release pollen before the leaves emerge, followed by small woody cones that persist into winter. Like other alders, white alder forms symbiotic relationships with nitrogen-fixing bacteria, enriching soils and supporting surrounding plant communities. It is also tolerant of wet, poor, disturbed soils and seasonal inundation. Ecologically, it stabilizes streambanks, provides shade that moderates water temperature for fish, and offers habitat and food for birds, insects, and other wildlife.