Deforestation captures more headlines than afforestation. But a latest UN study has pointed out that rising forest density in many countries around the world is helping to counterbalance climate change. The study released on Sunday in the online journal PLoS One mentions that the size of the trees and not only the area covered should be taken into account to calculate carbon capture.
Experts said – “Higher density means world forests are capturing more carbon.”
The study is significant because the UN is leading efforts to put a tangible value on forests as part of a nascent market to slow global warming. Deforestation worldwide, from the Amazon to Indonesia is contributing to release of carbon as trees release the captured carbon dioxide when they burn or rot. Estimates put it at a high of 12 to 20 percent.
The findings of the report based on a survey of 68 nations, found that the amount of carbon stored in forests went up in Europe and North America from 2000-10 despite little change in forest area. In Africa and South America, the total amount of carbon stored in forests fell at a slower rate than the loss of area, suggesting that they had grown denser. Though, some countries still had big losses of carbon, including Indonesia and Argentina.
Lead author Aapo Rautiainen of the University of Helsinki told Reuters that China had a greater density which could be co-related to previous forest plantings.
“Forests that were established in China a few decades ago are now starting to reach their fast-growing phase. That is a reason for rising density now.”
The study found other indicators as well. In the United States, timberland area increased by just one percent between 1953 and 2007 but the volume of growing stock surged by 51 percent. The explanation proffered was that a shift toward farming in the Midwestern United States meant that forests in the east had been left to grow, and get denser.
As the United Nations sets out to put a value on denser forest covers, it could face a few hurdles. Measuring the density of a forest requires more complex monitoring than just measuring the extent of a forest by photographing it from a plane or by satellite.
Iddo Wernick, a co-author at the Rockefeller University in New York said – “There does need to be a greater sampling to be able to come to a legitimate and credible number for the carbon.”