. Earth Science News .
Wildfire Drives Carbon Levels In Northern Forests

Second in size among forests only to the tropical rainforests, the boreal forests form a massive green band spanning the higher latitudes of Canada, Alaska, Siberia, China, and Scandinavia.
by Staff Writers
Madison WI (SPX) Nov 01, 2007
Far removed from streams of gas-thirsty cars and pollution-belching factories lies another key player in global climate change. Circling the northern hemisphere, the conifer-dominated boreal forests - one of the largest ecosystems on earth - act as a vast natural regulator of atmospheric carbon levels.

Forest ecologists at the University of Wisconsin-Madison are studying how environmental factors such as forest fires and climate influence carbon levels in this forest system. Their most recent findings, reported in the Nov. 1 issue of the journal Nature, offer insight into the balance of carbon uptake and release that contribute to atmospheric carbon dioxide levels worldwide.

Second in size among forests only to the tropical rainforests, the boreal forests form a massive green band spanning the higher latitudes of Canada, Alaska, Siberia, China, and Scandinavia. Their sheer size, coupled with the fact that they are expected to experience the greatest warming of any forest biome as global temperatures rise, means that climate-related changes here are likely to resonate well beyond the forest boundaries, says S. Tom Gower, UW-Madison professor of forest ecology and management and primary investigator of the project.

In the new study, Gower and his colleagues used a computer model to simulate the carbon balance of one million square kilometers of the Canadian forest over the past 60 years, to determine the relative impacts of climate and disturbance by wildfire.

The group found that the effects of carbon dioxide and climate - temperature and precipitation - varied from year to year but generally balanced out over time and area. Instead, forest fires during the 60-year period had the greatest direct impact on carbon emissions from the system.

However, "because fire frequency and fire intensity are directly controlled by climate change, it doesn't mean that we shouldn't be focusing on climate change," Gower says. "Climate change is what's causing the fire changes. They're very tightly coupled systems."

The researchers believe that fires shift the carbon balance in multiple ways. Burning organic matter quickly releases large amounts of carbon dioxide. After a fire, loss of the forest canopy can allow more sun to reach and warm the ground, which may speed decomposition and carbon dioxide emission from the soil. If the soil warms enough to melt underlying permafrost, even more stored carbon may be unleashed.

A trend toward hotter and drier conditions is likely to exacerbate the effects of fire by increasing the frequency, intensity, and size of burns. "All it takes is a low snowpack year and a dry summer," Gower says. "With a few lightning strikes, it's a tinderbox."

Historically, scientists believe the boreal forest has acted as a carbon sink, absorbing more atmospheric carbon dioxide than it releases, Gower says. Their model now suggests that, over recent decades, the forest has become a smaller sink and may actually be shifting toward becoming a carbon source.

"The soil is the major source, the plants are the major sink, and how those two interplay over the life of a stand really determines whether the boreal forest is a sink or a source of carbon," he says.

Though the model is not currently designed to forecast future conditions, Gower says, "Based on our current understanding, fire was a more important driver (of the carbon balance) than climate was in the last 50 years. But if carbon dioxide concentration really doubles in the next 50 years and the temperature increases 4 to 8 degrees Celsius, all bets may be off."

Community
Email This Article
Comment On This Article

Related Links
University of Wisconsin-Madison
Forestry News - Global and Local News, Science and Application



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


Biodiversity said to be key to healthy forests: study
Chicago (AFP) Oct 15, 2007
Forests planted with a diverse species of trees will be better able to withstand pest infestation than those that are sown plantation-style with just one species, a study released Monday said.







  • California gets new 'Big One' reminder
  • New Computer Architecture Aids Emergency Response
  • Acoustic Sensor Being Developed In New Anechoic Chamber
  • California fire victims get lush treatment in shelter

  • Climate controversy heats up Australian election
  • Drought in southeast US fuels battle over water resources
  • White House defends 'health benefits' of climate change
  • Like It Or Not, Uncertainty And Climate Change Go Hand-In-Hand

  • DMCii Satellite Imaging Helps Dramatically Reduce Deforestation Of Amazon Basin
  • NASA Views Southern California Fires And Winds
  • A Roadmap For Calibration And Validation
  • GeoEye Contract With ITT Begins Phased Procurement Of The GeoEye-2 Satellite

  • Analysis: U.S. OK's Saddam law oil deals
  • China to raise price of fuel: report
  • Let There Be Light: New Magnet Design Continues Magnet Lab's Tradition Of Innovation
  • China launches counter-protest against Japan in island dispute

  • Staph-Killing Properties Of Clay Investigated
  • AIDS stunting southern Africa's prospects: Malawi president
  • After extinction fears, Botswana learns to live with AIDS
  • West Nile Virus Spread Through Nerve Cells Linked To Serious Complication

  • Dead Clams Tell Many Tales
  • Could Hairy Roots Become Biofactories
  • Dinosaur Deaths Outsourced To India
  • Ancient Amphibians Left Full-Body Imprints

  • Time Spent In Car Drives Up Air Pollution Exposure
  • Birth defects soar in polluted China
  • Sakhalin II Operator Vows To Fix Environmental Damage In Year
  • Space Sensors Shed New Light On Air Quality

  • World Toilet Summit opens in India
  • Europeans face mob anger over child 'abductions' in Chad
  • India's toilet champion sees human liberation in loos for all
  • Video Game Shown To Cut Cortisol

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2007 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement