But I feel the photographic images of Carleton Watkins deserve more credit than they are currently afforded by environmental historians.

Rome fell, in the view of many modern environmental historians, because it simply expanded to the point of being an unsustainable beast.

As the preeminent environmental historian in the Southeast, Dr. Booker brings years of experience and knowledge to the project.

Muir, an environmental historian, is a critic of American choice of "profitability over sustainability."

Many environmental historians are occupied with local, regional and national histories.

"Bill's real influence is that his work often gets translated into a larger American history," said Richard White, a Western and environmental historian at Stanford.

"Virtually all early environmental historians considered themselves environmentalists," Mr. White said.

Paul Hirt, an environmental historian at Arizona State University, said that the early 1980's was a time of "real historic crisis" in the national forests.

Adam Ward Rome is an American environmental historian.

She is an assistant professor of history at Iowa State University in Ames, and is also an environmental historian.