White Alder

You encounter white alder in riparian settings from British Columbia to Baja California, where its whitish or light gray bark and open, rounded crown mark it as distinct from red alder. Its rhombic (diamond-shaped) leaves give it the species name; they are thinner and smoother than those of red alder, and mature trees often develop multiple trunks in forest conditions. Growing to 50-80 feet, it reaches substantial size quickly along streambanks and canyon bottoms.

White alder is a riparian specialist thriving in wet, frequently inundated soils where its nitrogen-fixing roots improve soil quality and enrich bare substrates. It is fast-growing (50 feet in 20 years) and moderately long-lived (100+ years in good conditions), making it more suitable for long-term riparian restoration than purely pioneer roles. Monitor for the same suite of alder diseases: collar rot, drippy dieback, and leaf spot. Its relatively long lifespan makes it valuable for riparian buffer strips and recovery projects.