The mysterious deaths of hundreds of trees along Arizona's Santa Cruz River has prompted an investigation by environmentalists and scientists.
The experts want to determine if drought, disease, insects or some other factor is killing the trees, the Arizona Daily Star reported Thursday.
The dead trees, which might number in the thousands, are barren or covered only partially with leaves, the newspaper said. The mystery is compounded by the fact that stands of dead trees alternate with live stands.
"It's not one or two types of trees that are dying, it's every type that occurs in a riparian habitat," John Hays, flood plain coordinator for Santa Cruz County, told the Daily Star. "There's cottonwood, willow, hackberry, elderberry and mesquite. I've even seen a few salt cedars that are distressed."
"It's drought," said Jack Kelly, a commercial horticulture agent with the Pima County Cooperative Extension Service. "It's typically dieback -- the crown or top of the trees thins out."
But Ben Lomeli, a professional hydrologist, told the newspaper it's important not to jump to conclusions or dismiss any possibilities.
"It is a call for help. It's a strange case," he said.
Copyright 2005 by United Press International
Explore further: SpaceX mile-high escape test will feature 'Buster' the dummy