WASHINGTON - Kathleen Clarke, the first woman to head the Interior Department's Bureau of Land Management, resigned Thursday to return to her home state of Utah.

Interior Secretary Dirk Kempthorne said Clarke had created more recreational opportunities for Americans and sped up "environmentally sensitive" oil and natural gas production on federal lands since taking over the agency in January 2002.

BLM manages 258 million acres, about one-eighth of the land in the United States. Most of that land - grasslands, forests, high mountains, arctic tundra and deserts - is in the West. It also oversees about 700 million acres of minerals below the land's surface.

"Our public lands, our forests and our landscapes are better off" because of Clarke's service, Kempthorne said Thursday.

Jim Magagna, executive vice president of the Wyoming Stock Growers Association, said Clarke "has been a great friend of the public land livestock industry."

"She's been very accessible to us," he said. "She has been a staunch defender of keeping responsible livestock grazing on BLM land."

Magagna said he knows Clarke faced tremendous pressure to "keep the focus on minerals," and he appreciated the support she gave to the livestock industry.

Clarke has been heavily criticized by conservationists for opening up sensitive areas of public lands to oil and gas activities. In Wyoming, areas in the Red Desert and the Upper Green River Valley area have been opened to oil and gas drilling under Clarke's tenure.

Conservation groups say Clarke and BLM officials aren't doing enough to maintain multiple use and are instead clearing the ground for exclusive use by energy.

Under her tenure, the BLM rewrote grazing rules in part giving ranchers joint ownership of improvements to the range and amending public comment guidelines. Those rules were litigated and have been halted by a federal judge.

Before taking over BLM, Clarke had worked as executive director of the Utah Department of Natural Resources and as a top aide to former Rep. James Hansen, a Utah Republican who once headed the House Resources Committee.

She also had co-owned a construction and real estate business in Kaysville, Utah, and had been on the staff of Sen. Wallace F. Bennett, who is now deceased.

BLM was headed during the Clinton administration by another Utah resident, Patrick Shea, who had been a lawyer, educator and businessman before taking over the agency.