Western Hemlock Zone
Mantling both the Coast Range and western slopes of the Cascades, this zone is one of the most extensive in the region, stretching from British Columbia to California. Although named for the shade-tolerant western hemlock characterizing the persistent vegetation, the dominant tree is often the seral Douglas-fir. Extensive logging has occurred throughout the area. Communities within this zone have been studied in detail and have been related to site characteristics. Some important species are western redcedar in moist sites and, in the south, ponderosa pine (Pinus ponderosa) and incense cedar (Calocedrus decurrens). In disturbed moist sites, red alder and bigleaf maple (Acer macrophyllum) are common. Western hemlock gives way to Douglas-fir in drier sites and Pacific silver fir (Abies amabilis) at higher elevations.