A shade-intolerant, submontane to montane, Western North American deciduous broad­leaved tree distributed more in the Pacific than the Cordilleran region. Occurs in maritime to submaritime summer-dry cool mesothermal climates on very dry to moderately dry soils; its occurrence decreases with increasing latitude, elevation, precipitation, and continentality. Sporadic to scattered on southeastem Vancouver Island and islands of Georgia Strait (less frequent on adjacent mainland). Usually forms open-canopy stands on water-shedding (rock outcrops) sites. Its calcium-rich bark supports corticolous moss communities. Characteristic of dry mesothermal forests.

Source: Indicator Plants of Coastal British Columbia (Information applies to coastal locations only)