Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fire Frequency Determines Forest Carbon Storage

24.03.2003


Canadian land cover map / study areas

The BOREAS-follow on Project to determine how carbon storage in boreal forests change in response to wildfire was set in the northern edge of the Canadian boreal forest in Manitoba, Canada, the former Northern Study Area (NSA) in Thompson Manitoba from BOREAS. CREDIT: Canadian Model Forest Program


Northern study area

This satellite image of the Northern Study Area, Manitoba, Canada was taken by the Landsat satellite on July 25, 1990. The bodies of water can be seen in blue. The landscape is a mosaic of different aged stands that are in various stages of recovery from wildfire. Each of the colored patches corresponds to a different aged stand. The years corresponding to the areas indicate the last year of forest fire. CREDIT: NASA/USGS


Scientists studying trees ranging from saplings to 130 years old in Canada’s northern forests have discovered that the period since a fire last swept through an area determines how much carbon the forest can store. Twenty to forty year old stands absorb more carbon than those 70 years old and older, despite being smaller and having less biomass or plant material.

Boreal or northern forests account for close to 25 percent of total carbon stored in vegetation and soils in the Earth’s biosphere. Wildfires burn down individual areas every 40 to 250 years and are an important part of this ecosystem. Whether or not these forests are likely to lower or raise levels of carbon dioxide in the atmosphere depends on how these carbon reserves respond to, and recover from, both climate change and disturbances such as wildfires.

NASA funded part of this study under its Earth Science Enterprise (ESE), whose mission is to understand and protect our home planet. Earth Science in NASA seeks to understand trends in land cover and land use, such as forest fires, that drive global climate. Another Earth Science program objective is to understand the Earth system’s response to natural and human-induced changes, and effects on global carbon cycle.



Marcy Litvak, plant ecologist at the University of Texas at Austin and lead author of the study that appeared in a recent issue of the Journal of Geophysical Research -
Atmospheres, said that the ability of tree stands to store carbon changes as they regenerate from fire. Forests will store more or less carbon depending on the dominant tree species, the amount of moss cover, and changes in forest structure due to fire. Those factors determine how much total carbon is exchanged with the atmosphere.

Carbon is transferred from the atmosphere to the forest through the process of photosynthesis. Carbon is returned to the atmosphere through the process of respiration as soil microorganisms decompose dead organic matter, and trees and mosses metabolize the products of photosynthesis. It is the balance between these two processes, taking in carbon during photosynthesis and "exhaling" carbon through respiration, that determines how much carbon is stored in the forest.

Between 1999-2000, Litvak and her colleagues, Scott Miller and Michael Goulden of the University of California, Irvine, and Steve Wofsy of Harvard University, used solar-powered anemometers and infrared gas analyzers mounted on towers to monitor carbon emissions over five black spruce stands in Manitoba, Canada. These stands ranged in age from 11 to 130 years old. Results indicate that the ability to store carbon is almost zero in the 11 year-old stand, increases to a maximum in the 36 year-old stand, then gradually falls back down to zero in the 130-year old stand. They concluded that most of the net carbon absorption appears to take place from 20-50 years after a fire.

"Seedlings of Aspen, Jack Pine, and Black Spruce all regenerate simultaneously following wildfire in areas once dominated by mature black spruce forests in this region of Manitoba. Aspen and Jack Pine tend to dominate in young stands where light is not limited. Black Spruce grow the slowest, but eventually out-compete the Aspen and Jack Pine by blocking the sunlight available to these species. By 70 years following a burn, these forests are dominated by Black Spruce once again," Litvak said.

Stands less than 20 years old store less carbon than older trees because they lack sufficient leaf area for rapid carbon accumulation. Carbon storage is highest in stands 20-50 years old that are dominated by rapidly growing aspen trees that take up carbon at higher rates than black spruce and jack pine trees.

"Stands [of trees] older than 70 years are dominated by black spruce trees and thick moss cover that ‘exhale and inhale’ equal amounts of carbon. That means stands older than 70 years are in near carbon balance with the atmosphere," she said.

Knowing the rate at which trees respire will help scientists to better estimate the trees’ contributions to the global carbon cycle. This is especially important because of the changing climate. "Increased fire frequency, as predicted from global warming scenarios, has the potential to significantly impact the contribution boreal forests make to the global carbon cycle," Miller said.

NASA data from the Boreal Ecosystem-Atmosphere Study (BOREAS) was also used in the study. BOREAS was a large-scale international experiment in the northern forests of Canada between 1993 and 1996, whose goal was to improve understanding of interactions between the boreal forest and the atmosphere, and clarify their roles in global change.

This work was supported by NASA, the National Science Foundation, and U.S. Department of Energy.

Rob Gutro | NASA / Goddard Space Flight Cent
Further information:
http://www.gsfc.nasa.gov/topstory/2003/0311firecarbon.html

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>