Sarah Tharp, a wiry biologist for the U.S. Forest Service, hoists a small ax, takes aim and delivers an angled blow to an aspen trunk, peeling off a sample of diseased bark. "Sometimes," she says ...

Admirers frequently note the striking white bark of quaking aspen. This bark lives and carries out photosynthesis, attributes that make it unique among North American trees and likely contribute ...

Cottonwoods, along with related big-toothed and trembling aspens, are poplars — some of New England’s fastest-growing tree ...