Stress may cause trees leaves to turn red

greenspun.com : LUSENET : Current News - Homefront Preparations : One Thread

used under fair use

Link

Stress May Cause Some Tree Leaves To Turn Bright Red

Report To Be Published In Tree Physiology

BURLINGTON, Vt. -- The U.S. Forest Service and University of Vermont will soon publish a study showing that screaming red leaves on sugar maples are caused by tree stress.

Scientists long have known leaves are green because of chlorophyll, a pigment that helps a plant capture light and create its own food.

And fall's lower temperatures and less sun drain the coloring, exposing a palette of yellow.

"The question is what is the deal with this red?" said Paul Schaberg, a plant physiologist with the U.S. Forest Service in Burlington.

The service teamed with the university in 1998 to uncover an answer.

A report soon to be published in the scientific journal Tree Physiology shows low nutrient levels appear to fuel the flaming color.

"Specifically, nitrogen stress resulted in earlier and greater proportion of red foliage in sugar maples in our study," Schaberg said. "We suspect in a drought year, low water availability does the same thing, but we haven't tested that yet. We've only just started to scratch the surface."

Sugar maples dominate not only the state's landscape but also its economy through fall sightseeing and winter and spring syrup production.

"The trees probably turn red because it's a helpful coping response for them to deal with stress," Schaberg said. "One theory is the red is like a sunscreen. It allows the leaf to linger long enough for the tree to absorb more nutrients. That's our guess."

The service will continue to use sugar maples at its Burlington lab to study other tree "stressers" ranging from animal chewing to car crashes.

Schaberg said scientists some day may be able to forecast fall color by monitoring tree health.

"In nature there are always stresses, and it does add some spark to have a patch of red here and there," he said. "The question is, is it just nature or is there something else here, too? Are we adding to that stress over time via pollution or climate change? What does that mean for the long term? We're hoping this red analysis will help us look at that."

-- Anonymous, September 30, 2002

Answers

So will they feed them Prozac? LOL!

-- Anonymous, October 01, 2002

Moderation questions? read the FAQ