"They don't need to be very selective," he said.

According to the letter, there are currently 140 chip mills in the United States, more than 100 of which were constructed in the last decade.

The scientists described the areas affected as extremely important from an ecological perspective--"[they are] some of the richest temperate forests on earth," they wrote.

"The main value is the maintenance of biological diversity," said Wilson. "When you cut a natural forest and replace it with farmland or a tree farm, you go from thousands of flowering plant species...to perhaps one tree species and a tiny number of organisms associated with it."

"The system is not only impoverished, but it is less stable," he said.

The World Wildlife Fund recently ranked the long-leaf-pine regions of the Southeast as one of the world's 200 "most outstanding and diverse" ecosystems.

"These are one-of-a-kind ecosystems," said Dominick A. DellaSala, former director of U.S. forest conservation for the World Wildlife Fund and currently the director of its Klamath-Siskiyou regional office, who drafted the letter. "We lose these ecosystems, there's nothing to replace them."

The call for a study comes as the pulp and paper industry shifts its center of production from the Pacific Northwest to the Southeast.

"There's been an explosion of chip mill operations in the South in the last couple of decades," DellaSala said.

According to Danna Smith, executive director of the Dogwood Alliance, a North Carolina-based forest advocacy group, Southern forests are already beginning to show the strains of increased logging.

"The U.S. Fish and Wildlife Service admits that removal of pines and softwoods has already exceeded growth," she said. Smith said the agency predicts that removal of hardwoods such as oak and maple in the Southeast will exceed growth within 12 to 15 years.

But according to Cathy A. Dunn, vice president of corporate communications for Willamette Industries, forest products companies that own the chip mills do not encourage any specific type of logging. Private landowners harvest the timber and then sell it to the chip mill for processing, she said. Willamette owns 10 chip mills.

"Willamette's position is that it really should have a very healthy impact on our forests because some of the Eastern forests have been overmanaged in the past with selective cutting," she said.

She said the logging that often occurs to feed chip mills instead produces "a good, diverse, representative forest" as no group of trees are favored over others.

Wilson, however, said he views that theory with "mild amusement."