Studies question wisdom of thinning forests to stop fires

By Staci Matlock
The New Mexican | 20 comments

In 2011, a downed power line sparked the massive Las Conchas wildfire that roared through homes and scorched 156,000 acres of forest in the Jemez Mountains. And that was just the beginning of the damage. In the weeks that followed, rains washed tons of ash and sediment off the blistered slopes into the Rio Grande, forcing the city of Santa Fe to shut down a river diversion system for six weeks.

The fire’s impact on a major Santa Fe drinking water source is a big reason city officials are now considering joining a collaborative brought together by The Nature Conservancy to thin and burn thousands of acres over the next 20 years in mountain ranges that drain water into the Rio Grande. The partnership hopes the plan will reduce the kind of catastrophic wildfires that wreaked havoc in the West over the last several years.

“Our interest is managing the watershed for water quality,” said Rick Carpenter, the city’s source of supply manager.

But as city officials consider joining the group, known as the Rio Grande Fire and Water Source Protection Collaborative, the science is still changing. New studies question how, and where, fire and tree thinning in Western forests should be used to restore forest health and protect watersheds. The studies, and the move toward treating forests across large landscapes, are fueling some old debates over the best way for people to manage forests that have been dramatically altered during decades of fire suppression, logging and overgrazing.