Study: Protected Forests on Public Land Burn Less Severely Than Logged Areas

A new study published in the scientific journal Ecosphere finds that public forests that are protected from logging burn less severely than logged forests. The study is the most comprehensive investigation of its kind, spanning more than 23 million acres and examining three decades' of forest fire data in the West. Among the major findings were that areas undisturbed by logging experienced significantly less intensive fire compared with areas that have been logged.

The findings come as many federal land managers and members of Congress claim that more logging will reduce wildfires. Several bills have been introduced in Congress to increase logging on vast areas of public land; these have typically been presented under the guise of addressing forest fire concerns, but eliminate most analysis of environmental impacts and reduce environmental protections.

"We were surprised to see how significant the differences were between protected areas managed for biodiversity and unprotected areas, which our data show burned more severely," said lead author Curtis Bradley, with the Center for Biological Diversity.

For this study scientists set out to determine whether reduced forest protections and increased logging are associated with lower fire severity. They analyzed fires that burned in pine and mixed-conifer forests starting about 30 years ago, at the earliest point for which comprehensive data were available, to compare where and how fires burned using satellite imagery and maps from the U.S. Geological Survey's "protected areas database." The results demonstrated that fires burned relatively cooler in areas managed for biodiversity (Gap 1 in figure below), including national parks and wilderness areas where fires are generally allowed to proceed naturally versus areas managed for multiple use (Gap 3) and areas with little to no mandate for protection (Gap 4) such as private forest lands managed for timber production.

The study focused on forests with relatively frequent fire regimes, ponderosa pine and mixed-conifer forest types; used multiple statistical models; and accounted for effects of climate, topography and regional differences to ensure the findings were robust.

"The belief that restrictions on logging have increased fire severity did not bear out in the study," said Dr. Chad Hanson, an ecologist with the John Muir Project. "In fact, the findings suggest the opposite. The most intense fires are occurring on private forest lands, while lands with little to no logging experience fires with relatively lower intensity."

"Our findings demonstrate that increased logging may actually increase fire severity," said Dr. Dominick A. DellaSala, chief scientist of Geos Institute. "Instead, decision-makers concerned about fire should target proven fire-risk reduction measures nearest homes and keep firefighters out of harm's way by focusing fire suppression actions near towns, not in the back country."

The authors noted that even in protected forests they found an appropriate mix of low, moderate and high-intensity fire, which is ecologically beneficial since many wildlife species depend on post-fire habitat, especially "snag forest habitat" created by patches of high-intensity fire. Many studies indicate that significant damage to wildlife habitat can result from logging of both unburned mature forests and snag-forest habitat.