Recent research shows that forests with too many trees are vulnerable to intense forest fires, increasing pollution. So save the planet: cut a tree.
For decades environmentalists have equated saving trees with saving the planet. Now Jamie Workman of the Environmental Defense Fund says it’s not that simple. Writing for Mother Nature Network (May 23, 2013), Workman argues that overcrowded forests are in fact a cause of pollution.
If Mother Nature had her way, Workman explains, there would only be a few dozen trees per acre, even in forests. The rest would burn in occasional wildfires started by lightning (or Native Americans, before colonization). Then, the cycle of growth would start over again.
But from the Rockies to Sierra Nevada, the typical forest in today’s American West contains 112 to 172 trees per acre. Aside from intercepting rain and snow that would otherwise enter the groundwater supply, an overabundance of trees threatens native species. “Deprived of low-intensity, naturally occurring fires, aspen, lupine, sequoia and fireweed can’t reproduce,” writes Workman. “Deer lose edge habitat. Threatened owls and raptors can’t navigate through increasingly dense thickets.”
The problem dates back to 1910, when a series of wildfires led to (what else?) a war on forest fires. Policy changes brought us Smokey the Bear and a fear of natural fires, eventually leading to too many trees and a firefighting tab of $2 billion a year. The cost is high, in part, because when a forest fire inevitably starts, all those trees become fuel, causing it to burn bigger and hotter than it would’ve 100 years ago. What’s more, writes Workman, pollution-wise “a big fire is like setting a coal-fired power plant in the middle of a forest.”
There is a way to prevent these raging forest fires: thinning. “We need to surgically remove the bulk of the excess, small-diameter ‘trash’ trees,” says Workman. He estimates that the process could pay for itself, explaining that for every $1,000 invested by local public or private institutions, $1,500 worth of water would re-enter the supply. Done right, thinning would mitigate fires, cut carbon emissions, replenish area waterways, expand wildlife habitat, and create jobs in rural areas. Looks like saving a tree isn’t the right answer every time.