A fierce debate has cropped up in recent months over the White River National Forest in Colorado — not about logging but about recreation. The U.S. Forest Service has made a controversial proposal to limit recreational use of the forest, which is roughly the size of Delaware and home to some of the nation’s top ski resorts. The proposal is endorsed by enviros but decried by ski resort operators, snowmobilers, mountain bikers, and other recreationists. Enviros who once saw recreation as a benign way to offset economic losses from declining logging, grazing, and mining operations now are worried about the impact of so many people on public lands. Colorado’s population is booming, and as more of the state’s residents come out to play in the White River National Forest, biologists say that wildlife habitat is being fragmented, putting a number of species at risk.