Climate change blamed for fading foliage - Yahoo! News: "Forested hillsides usually riotous with reds, oranges and yellows have shown their colors only grudgingly in recent years, with many trees going straight from the dull green of late summer to the rust-brown of late fall with barely a stop at a brighter hue.
Warming climate affects trees in several ways.
Colors emerge on leaves in the fall, when the green chlorophyll that has dominated all spring and summer breaks down.
The process begins when shorter days signal leaves to form a layer at the base of their stems that cuts off the flow of water and nutrients. But in order to hasten the decline of chlorophyll, cold nights are needed.
In addition, warmer autumns and winters have been friendly to fungi that attack some trees, particularly the red and sugar maples that provide the most dazzling colors."
Sunday, October 21, 2007
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment