blowdown

In forests damaged by high wind, the resulting tree debris is called blowdown. In the summer of 1999, for instance, violent storms laid waste to 400,000 acres of forest in northern Minnesota’s Superior National Forest. In May 1980, the blast from Mount St. Helens in Washington State’s Cascade Mountains “mowed trees down like blades of grass,” according to one scientist who studied the volcano; in the end, more than four million board feet of timber dropped to the ground. Consisting of formerly living organisms, this blown down material—utterly natural—has at times instantly become fodder for deeply divisive controversy. To the U.S. Forest Service, blowdown represents potential fuel for catastrophic fire. To the timber industry, its quick collection equals salvage revenue. To environmentalists, tampering with the downed trees symbolizes the government’s wish to manipulate rather than protect wilderness. One of the sticky issues surrounding blowdown is that the dried and rotting timber becomes forest duff, which in turn is part of the fuel that burns in a forest fire. Most scientists consider such burns an integral part of the forest system, regenerating plants and increasing light levels to allow young plants to survive, but the timber industry and those who live in heavily timbered areas are more invested in preventing fire—which leads inevitably to a quagmire about how to best take care of the toppled trees.

Antonya Nelson