At Yosemite, a preservation plan that calls for chain saws

Central to the thinking of scientists looking for ways to protect forests is research showing that the “natural state” of America’s wild lands was for millenniums influenced by humankind.

Decades of research have shown that the wilderness appreciated by early European settlers, as well as 19th century naturalists like John Muir, was often a highly managed landscape. Core samples from beneath a pond in Yosemite, retrieved in the way that scientists might bore deep into a glacier, showed centuries of layers of pollen and ash. The findings suggested a long history of frequent fires in Yosemite and buttressed the oral histories of Native American tribes who have long seen fire as a tool.