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 Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>