Featured Research

from universities, journals, and other organizations

Forests Damaged By Hurricane Katrina Become Major Carbon Dioxide Source

Date:
November 16, 2007
Source:
NASA/Goddard Space Flight Center
Summary:
With the help of NASA satellite data, a research team has estimated that Hurricane Katrina killed or severely damaged 320 million large trees in Gulf Coast forests, which weakened the role the forests play in storing carbon from the atmosphere. The damage has led to these forests releasing large quantities of carbon dioxide to the atmosphere.

The devastation of southern Gulf Coast forests by Hurricane Katrina was documented in before-and-after images from the Landsat 5 satellite. The Interstate 10 "twin-span" bridges that cross Lake Pontchartrain east of New Orleans is seen here pre- and post-Katrina. Bayou Sauvage National Wildlife Refuge is the large patch of forest (green) the lower left portion of the LEFT image, which suffered heavy tree mortality (seen in red in the RIGHT image after the storm).
Credit: USGS

With the help of NASA satellite data, a research team has estimated that Hurricane Katrina killed or severely damaged 320 million large trees in Gulf Coast forests, which weakened the role the forests play in storing carbon from the atmosphere. The damage has led to these forests releasing large quantities of carbon dioxide to the atmosphere.

Related Articles


The August 2005 hurricane affected five million acres of forest across Mississippi, Louisiana and Alabama, with damage ranging from downed trees, snapped trunks and broken limbs to stripped leaves.

Young growing forests play a vital role in removing carbon dioxide, a greenhouse gas, from the atmosphere by photosynthesis, and are thus important in slowing a warming climate. An event that kills a great number of trees can temporarily reduce photosynthesis, the process by which carbon is stored in plants. More importantly, all the dead wood will be consumed by decomposers, resulting in a large carbon dioxide release to the atmosphere as the ecosystem exhales it as forest waste product.

"The loss of so many trees will cause these forests to be a net source of carbon dioxide to the atmosphere for years to come," said the study's lead author Jeffrey Chambers, a biologist at Tulane University in New Orleans, La. "If, as many believe, a warming climate causes a rise in the intensity of extreme events like Hurricane Katrina, we're likely to see an increase in tree mortality, resulting in an elevated release of carbon by impacted forest ecosystems."

Young forests are valued as carbon sinks, which remove carbon dioxide from the atmosphere and store it in growing vegetation and soils. In the aftermath of a storm as intense as Katrina, vegetation killed by the storm decomposes over time, reversing the carbon storage process, making the forest a carbon source.

"The carbon cycle is intimately linked to just about everything we do, from energy use to food and timber production and consumption," said Chambers. "As more and more carbon is released to the atmosphere by human activities, the climate warms, triggering an intensification of the global water cycle that produces more powerful storms, leading to destruction of more trees, which then act to amplify climate warming."

Chambers and colleagues from the University of New Hampshire in Durham, N.H., studied Landsat 5 satellite data captured before and after Hurricane Katrina to pull together a reliable field sampling of tree deaths across the entire range of forests affected by Katrina. They found that some forests were heavily damaged while others like the cypress-tupelo swamp forests fared remarkably well.

The NASA-built Landsat 5, part of the Landsat series of Earth-observing satellites, takes detailed images of the Earth's surface. Chambers combined results from the Landsat image sampling with data from the Moderate Resolution Imaging Spectroradiometer instrument on NASA's Terra satellite to estimate the size of the entire forested area affected by Katrina. The instrument can detect minute changes in the color spectrum on the land below, enabling it to measure differences in the percentage of live and dead vegetation. This helps researchers improve their estimates of changes in carbon storage and improves their ability to track the location of carbon sinks and sources.

The field samples and satellite images, along with results from computer models that simulate the kind of vegetation and other traits that make up the forests, were used to measure the total tree loss the hurricane inflicted. The scientists then calculated total carbon losses to be equivalent to 60-100 percent of the net annual carbon sink in U.S. forest trees.

"It is surprising to learn that one extreme event can release nearly as much carbon to the atmosphere as all U.S. forests can store in an average year," said Diane Wickland, manager of the Terrestrial Ecology Program at NASA Headquarters in Washington. "Satellite data enabled Chambers' research team to pin down the extent of tree damage so that we now know how these kinds of severe storms affect the carbon cycle and our atmosphere. Satellite technology has really proven its worth in helping researchers like Chambers assess important changes in our planet's carbon cycle."

The team's findings were published Nov. 15 in the journal Science.


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center. "Forests Damaged By Hurricane Katrina Become Major Carbon Dioxide Source." ScienceDaily. ScienceDaily, 16 November 2007. <www.sciencedaily.com/releases/2007/11/071115164458.htm>.
NASA/Goddard Space Flight Center. (2007, November 16). Forests Damaged By Hurricane Katrina Become Major Carbon Dioxide Source. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2007/11/071115164458.htm
NASA/Goddard Space Flight Center. "Forests Damaged By Hurricane Katrina Become Major Carbon Dioxide Source." ScienceDaily. www.sciencedaily.com/releases/2007/11/071115164458.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nations Pledge $9.3 Bn for Green Climate Fund

Nations Pledge $9.3 Bn for Green Climate Fund

AFP (Nov. 20, 2014) — Nations meeting in Berlin pledge $9.3 billion (7.4 bn euros) for a climate fund to help poor countries cut emissions and prepare for global warming, just shy of a $10bn target. Duration: 00:46 Video provided by AFP
Powered by NewsLook.com
What's The Point Of Climate Conferences?

What's The Point Of Climate Conferences?

Newsy (Nov. 20, 2014) — There's optimism about the U.N.'s climate conference in Paris next year, and if climate conferences past are anything to go off, that's notable. Video provided by Newsy
Powered by NewsLook.com
Giant Panda at Toronto Zoo Loves Somersaulting in the Snow

Giant Panda at Toronto Zoo Loves Somersaulting in the Snow

Buzz60 (Nov. 19, 2014) — A giant panda at the Toronto Zoo named Da Mao is celebrating the northeast snowfall by playing and tumbling in the snow in his outdoor enclosure. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Scientists Find Out What's Been Killing Millions Of Starfish

Scientists Find Out What's Been Killing Millions Of Starfish

Newsy (Nov. 18, 2014) — Scientists have found the cause of the biggest marine epidemic in history: the virus behind starfish wasting disease. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins