FLAGSTAFF — Beneath the scenic yellow and red leaves of soaring aspen trees in the Kachina Wilderness, forest ecologist Mike Stoddard is looking down. His concern isn’t the brilliant fall foliage but ...

It's fall in Arizona, which means it's time to head for the hills to hike colorful forests and drive winding roads littered with fallen leaves.

In parts of Arizona like Flagstaff and Sedona, leaves on the trees are changing color. Here's your guide to fall colors and where to visit.

While the Valley is slowly changing seasons and easing into fall, it’s not so subtle in eastern Arizona’s White Mountains. At ...

Aspen forests help slow the spread of wildfires and could serve as fire breaks in Colorado and other southwestern states, according to a peer-reviewed study by Western Colorado University researchers.

DENVER — Something is killing the quaking aspen trees of the Rocky Mountain West. The slender, white-barked trees that paint the hills gold every autumn are dying, some scientists say, leaving bald ...

The restoration of gray wolves in Yellowstone National Park has helped revive an aspen tree population unique to the region, a new study has found. Quaking aspen, one of the few deciduous tree species ...