The U.S. Postal Service celebrates the colorful sights of autumnal walks with the release of five new Vibrant Leaves postcard stamps. Each stamp showcases a single leaf from the aspen, sassafras, oak, ...

Aspen has distinctive, almost-circular leaves with flattened petioles or stems. This flattening causes the leaves to tremble or flutter in the slightest breeze, thereby giving the tree one of its ...

The ability of aspen to produce whole stands of "trees" vegetatively provides yet ... Why do quaking aspen leaves quake and tremble? The leaves of this species quake, shake and tremble in the ...

I slammed my laptop shut and zoomed out the door — escaping the office for a weekend of nonstop music. The brisk winter air ...