trees

Guess which U.S. state spawned a worldwide tree-planting sensation.

In certain conditions, tree sap may reach extreme negative pressures and emit popping sounds.

Petrified trees have been unearthed that are nearly as tall as the world's highest trees today. Here's the story of their discovery and what it tells us about tall trees in general.

Tundra is by definition treeless, but in Eurasia recently, its shrubs have turned to trees.

Hurricane Irene may add kick to fall's colorful leaves.

The interplay between opposing forces that act on trees define their theoretical maximum height.

Evidence is mounting that vines are becoming more abundant in tropical forests of the Americas, raising the possibility of major ecosystem change.

Decline is reverse of earlier boost from warmer temperatures, longer growing season.

Even though plants absorb some greenhouse gas, rising CO2 levels make leaves contribute to global warming.

Forests in the north region are facing increasing threats.