Salvage logging does more harm than good, according to new CU-Boulder study

By Jim Scott, CU News Services
summer, 2003

Cristina Rumbaitis Del-Rio sits among trees felled by a catastrophic storm in the Routt National Forest and the Mount Zirkel Wilderness Area. Note the diversity of groundcover and presence of seedlings compared to the bare soil in the lower photograph that shows a portion of the devastated area that has been logged.

Salvage logging after rare, hurricane-force winds blow down western coniferous forests can cause more damage than the original wind disturbance, according to a recent study.

CIRES researchers have evaluated the ecological effects of salvage logging following an astounding tree "blow-down" in Routt National Forest in northwestern Colorado during October 1997, said doctoral student Cristina Rumbaitis-del Rio and Professor Carol Wessman, a CIRES fellow.

The catastrophic storm snapped, toppled and uprooted millions of trees on 25,000 acres in the Routt National Forest and the Mount Zirkel Wilderness Area. U.S. Forest Service officials opened up areas outside of the wilderness to salvage logging operations in 1999-2001 in hopes of accelerating forest regrowth.

But according to research by Rumbaitis-del Rio, a CU-Boulder graduate student, the salvage-logging made matters worse, not better. "The salvage-logged areas look like a lunar landscape in some places," she said. "The land is barren, the soil is sun-baked and dry, and only weedy, disturbance-loving plants seem to survive in this harsh environment."

Blow-down in the Mount Zirkel Wilderness Area.

Rumbaitis-del Rio, who has been comparing rates of forest growth in logged and unlogged blow-down areas in the Routt National Forest for the past four years, said salvage logging the blown-down areas resulted in a large amount of soil erosion and the loss of soil nutrients needed to support the regrowth of trees and vegetation in the devastated areas. The logging operations also destroyed tree seedlings that survived the ferocious windstorm.

Rumbaitis-del Rio's research shows that in summer, soils in the salvage-logged areas are 5 degrees Fahrenheit warmer on average than soils in unlogged, blow-down areas, where the downed trees provide shade to vegetation and tree seedlings that survived the blow-down.

"The blow-down areas are doing just fine on their own," said Rumbaitis-del Rio. Soils in blow-down areas have a higher amount of nutrients available for plant growth than do adjacent undisturbed forest areas. In particular, they have twice as much nitrogen available than do undisturbed areas. Nitrogen is a limiting nutrient in these forests, she said.

Results also show that blow-down areas support a greater diversity of plants and higher density of tree seedlings. These tree seedlings also are growing at a faster rate than tree seedlings in adjacent, undisturbed forest areas. "While the blow-down looks very messy and devastating, it seems that the ecosystem is adapted to deal with this disturbance quite readily," said Rumbaitis-del Rio. "From an ecosystem point of view, it's really no big deal."

Rumbaitis-del Rio hopes that her research will make forest managers think twice before recommending salvage logging as a mitigation tool following wind disturbance. Salvage logging is often undertaken to help forests recover from catastrophic disturbances such as wind and fire.

The blow-down area is marked by a yellow tab in the upper right corner of this photo.

Catastrophic wind disturbances may be more frequent and more destructive in the future, according to some climate change models. If this occurs, forest managers will have to decide if they will log or leave disturbed areas to recover on their own more frequently in the future.

Rumbaitis-del Rio's research is funded by the Environmental Protection Agency and CIRES.

The study area was affected by two large fires in summer 2002, the Hinman fire and the Burn Ridge fire. Together, these two fires consumed more than 31,000 acres, including logged and unlogged blow-down areas. The research continues in Routt National Forest in summer 2003.

"Specifically, we hope to determine if salvage-logged areas have trouble regenerating after the fire compared to unlogged blow-down areas," she said. "Or, alternatively, we will address the question if fire simply resets the system and 'erases' the pre-burn disturbance history."