Bush had planned to go to the Cades Cove wildlife area in the Great Smoky Mountains National Park to help out on a trail restoration project, but heavy rains forced him to scrap a plan to become the first president since Franklin Roosevelt to stop in the country's most visited park.

Many environmentalists consider the Bush administration to be the most anti-environmental in the modern era, dismantling the framework of environmental laws, standards, and enforcement that underpins environmental protection in the United States.

"This administration, in catering to industries that put America's health and natural heritage at risk, threatens to do more damage to our environmental protections than any other in US history," the National Resources Defense Council said on its Web site.

But Bush said his administration had moved to protect the environment while encouraging economic growth.

He cited a rule aimed at cutting pollution from diesel engines by 90 percent, and said 90 percent of Americans have water that meets stringent health standards. He also cited moves he has taken to expand wetlands and guard against forest fires by removing downed trees.

'WISE STEWARDS'

"My point is, it's possible to have economic growth and jobs and opportunity and at the same time be wise stewards of the land," he said.

Bush urged the US Congress to approve his "Clear Skies Initiative," which he said would cut air pollution from coal-fired power plants by 70 percent.

A Republican-written version of the plan stalled in a Senate committee last month after Democrats and a lone Republican panel member objected to its omission of measures to cut heat-trapping greenhouse gases.

The Environmental Protection Agency advanced more limited rules that would reduce utility emissions of sulfur dioxide and nitrogen oxides -- linked with smog and acid rain -- in 28 eastern US states over the next decade, and a separate rule to cut mercury emissions.

The Great Smoky Mountains National Park is visited by 9 million people a year but its spectacular vistas are impaired by a polluted haze.

The National Parks Conservation Association says 30 plant species in the Smokies are showing signs of damage from ozone pollution.

Bush said ozone levels have dropped since 2000, "but there's more to be done to make sure the Smoky Mountains and the Smoky Mountain National Park's as beautiful as possible."

An environmental group, the Environmental Defense, called on Bush to give up the Clear Skies Initiative and support strong Environmental Protection Agency clean air standards as a way to improve the Smokies'

"Great Smoky Mountains National Park is a national treasure that must be protected as a sacred American legacy for future generations," said Environmental Defense senior attorney Vickie Patton.