A federal judge has upheld a project to thin trees and conduct prescribed burns on about 25,000 acres of the Kaibab National Forest in northern Arizona.

The project surrounding Jacob Lake first was proposed in 1998 and has been revised numerous times as environmental groups objected to the size of trees that would be cut.

The groups contend the thinning would damage habitat needed by the northern goshawk, a bird of prey, and remove too much of the forest canopy.

This week's ruling from the U.S. District Court in Phoenix found that the project doesn't violate federal environmental and forest management laws.

Kaibab forest officials says less than 2 percent of the trees that will be cut are greater than 16 inches in diameter. The project is expected to begin this year.