Overview
Spire-like evergreen conifer of the high mountains, becoming twisted and mat-like at the windy edge of treeline.
Ecology
Spruce forms the backbone of the mountain boreal ecosystem. Its dense stands create cool, shaded habitat for mosses and shade-tolerant understory plants. Spruce seeds feed birds like crossbills and red squirrels, and its boughs shelter snowshoe hares and the endangered Bicknell's Thrush, a rare songbird that breeds only in high-elevation spruce - fir forests. In the krummholz, prostrate spruce catch and hold drifting snow, which insulates the ground and provides moisture for alpine plants. Spruce are shallow-rooted in thin mountain soils and thus prone to blowdown; in some areas you'll see "fir-wave" patterns of fallen trees and regrowth. Historically, high-elevation red spruce suffered heavy damage from acid rain and winter freeze injury, but with cleaner air some stands are rebounding. As climate warms, however, the cool, moist zone they occupy is expected to contract upslope, potentially reducing spruce extent in the Whites.