Forest health versus global warming: Fuel reduction likely to increase carbon emissions

December 20, 2011

CORVALLIS, Ore. - Forest thinning to help prevent or reduce severe wildfire will release more carbon to the atmosphere than any amount saved by successful fire prevention, a new study concludes.

There may be valid reasons to thin forests - such as restoration of forest structure or health, wildlife enhancement or public safety - but increased carbon sequestration is not one of them, scientists say.

In research just published in Frontiers in Ecology and the Environment, Oregon State University scientists conclude that even in fire-prone forests, it's necessary to treat about 10 locations to influence fire behavior in one. There are high carbon losses associated with fuel treatment and only modest savings in reducing the severity of fire, they found.

"Some researchers have suggested that various levels of tree removal are consistent with efforts to sequester carbon in forest biomass, and reduce atmospheric carbon dioxide levels," said John Campbell, an OSU research associate in the Department of Forest Ecosystems and Society. "That may make common sense, but it's based on unrealistic assumptions and not supported by the science."

A century of fire suppression in many forests across the West has created a wide range of problems, including over-crowded forests, increased problems with insect and pathogen attack, greater risk of catastrophic fire and declining forest health.

Forest thinning and fuel reduction may help address some of those issues, and some believe that it would also help prevent more carbon release to the atmosphere if it successfully reduced wildfire.

"There is no doubt you can change fire behavior by managing fuels and there may be other reasons to do it," said Mark Harmon, holder of the Richardson Chair in Forest Science at OSU. "But the carbon does not just disappear, even if it's used for wood products or other purposes. We have to be honest about the carbon cost and consider it along with the other reasons for this type of forest management."

Even if wood removed by thinning is used for biofuels it will not eliminate the concern. Previous studies at OSU have indicated that, in most of western Oregon, use of wood for biofuels will result in a net loss of carbon sequestration for at least 100 years, and probably much longer.

In the new analysis, researchers analyzed the effect of fuel treatments on wildfire and carbon stocks in several scenarios, including a single forest patch or disturbance, an entire forest landscape and multiple disturbances.

One key finding was that even a low-severity fire released 70 percent as much carbon as did a high-severity fire that killed most trees. The majority of carbon emissions result from combustion of surface fuels, which occur in any type of fire.

The researchers also said that the basic principles in these evaluations would apply to a wide range of forest types and conditions, and are not specific to just a few locations.

"People want to believe that every situation is different, but in fact the basic relationships are consistent," Campbell said. "We may want to do fuel reduction across much of the West, these are real concerns. But if so we'll have to accept that it will likely increase carbon emissions."
-end-
Editor's Note: A digital image of thinning operations is available online: http://bit.ly/upeu4y

The study this story is based on is available in ScholarsArchive@OSU: http://bit.ly/vqSGMY

Oregon State University

Related Wildfire Articles from Brightsurf:

Researchers find confusion over masks for wildfire, COVID-19 crises
Drawing from studies on human behavior and responses to past epidemics and wildfire smoke, researchers outline recommendations for communicating correct mask use and suggest areas for further research.

Post-wildfire hazards: Toward an understanding of when & how slope failure may occur
Across the western US, severe wildfires fueled by tinder-dry vegetation have already burned more than 3.2 million hectares (8 million acres [as of the time of this press release]) -- an area the size of Maryland -- in 2020, and nearly six times that area burned this year in Australia.

Wildfire smoke more dangerous than other air pollutants for asthma patients
For people who suffer from asthma, wildfire smoke is more hazardous than other types of air pollution, according to a new study from the Desert Research Institute (DRI), the Renown Institute for Health Innovation (Renown IHI) and the Washoe County Health District (WCHD).

Unexpected wildfire emission impacts air quality worldwide
During wildfires, nitrous acid plays a leading role--spiking to levels significantly higher than scientists expected, driving increased ozone pollution and harming air quality, according to a new study led by the University of Colorado Boulder and the Belgian Institute for Space Aeronomy.

Wildfire on the rise since 1984 in Northern California's coastal ranges
High-severity wildfires in northern coastal California have been increasing by about 10 percent per decade since 1984, according to a study from the University of California, Davis, that associates climate trends with wildfire.

Many forests scorched by wildfire won't bounce back
A study of 22 burned areas across the Southern Rocky Mountains found that forests are becoming less resilient to fire, with some converting to grasslands after burning.

Study finds less impact from wildfire smoke on climate
New research revealed that tiny, sunlight-absorbing particles in wildfire smoke may have less impact on climate than widely hypothesized because reactions as the plume mixes with clean air reduce its absorbing power and climate-warming effect.

Wildfire smoke has immediate harmful health effects: UBC study
Exposure to wildfire smoke affects the body's respiratory and cardiovascular systems almost immediately, according to new research from the University of British Columbia's School of Population and Public Health.

Stanford researchers forecast longer, more extreme wildfire seasons
Stanford-led study finds that autumn days with extreme fire weather have more than doubled in California since the early 1980s due to climate change.

Wildfire perceptions largely positive after hiking in a burned landscape
Results from pre- and post-hike surveys of a burned landscape indicate that people understand and appreciate the role of fire in natural landscapes more than is perceived.

Read More: Wildfire News and Wildfire Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.