Brazil's Amazon rain forest is being destroyed or badly damaged more than twice as fast as normally believed, according to a study that relied on airplane surveys and on-the-ground interviews instead of satellite images.
The researchers said their method more accurately measured the effects of logging and burning in the 1.3 million-square-mile rain forest.
"It's perhaps even more frightening," said Bill Mankin, director of the Global Forest Policy Project of two major environmental groups. "It's going to creep up on us, and people may not even be crafting a solution because they don't realize there's a problem."
The study was carried out largely by ecologist Daniel C. Nepstad of the Woods Hole Research Center in Massachusetts, and colleagues at the Institute of Environmental Research in Belem, Brazil. They interviewed 1,393 wood mill operators and 202 landholders, and checked the effect of fires from an airplane at 1,104 sample points.
Their findings were published in Thursday's issue of the journal Nature.
They concluded that analysts who study satellite images -- the main tool for gauging deforestation -- are missing much of the damage from logging and fires set to clear land for farming or pasture. Selective logging is difficult to detect by satellite, and new growth quickly hides fire damage as viewed from above.
Nepstad put the loss at 17,000 square miles last year, or three times the official Brazilian estimate of 5,700. But 1998 was an especially bad year because of an El Nino drought. He estimated that in an average year, actual damage is at least twice the official, satellite-based estimate.
Nepstad estimated that 217,000 square miles, or 16 percent, of the original rain forest has been spoiled over the years. The official Brazilian estimate is 13 percent.
"All these estimates are quite conservative. The problem could be bigger," Nepstad said.
The findings trouble some scientists and environmentalists because perhaps a third of the world's plant and animal species live in the rain forest.
"As we lose species, we don't know which one is the critical one, the keystone species that results in the whole system falling apart," said Robert L. Sanford Jr., a University of Denver ecologist.
The researchers also worry about huge quantities of carbon dioxide entering the atmosphere from the fires and rotting wood left by loggers. Carbon dioxide is thought to cause global warming.
Also, some scientists fear that damage to the rain forest, which gives off enormous amounts of water vapor and keeps the ground from drying out, could throw the Earth's climate out of balance.
The researchers called for more judicious logging, more prevention of accidental fires, and curbs on roads, power grids and water systems.
But some experts are doubtful about the prospects of controlling development in the rain forest, where the law of the jungle often prevails.
"How can you control evelopment in an area where there's no control? It is the Wild West," said Compton Tucker, a NASA biologist.
Written By Jeff Donn