A new estimate of the extent of dryland forests suggests that the global forest cover is at least 9% higher than previously thought. The study , published in the May 12 issue of Science, will help reduce uncertainties surrounding how much carbon dioxide plants absorb from the atmosphere globally. As carbon dioxide is a key driver of climate change, the study's results are important for climate modeling.
Given the vastness of land across the globe, researchers rely on satellite data to estimate the amount of forest cover. Yet dryland biomes — as their name suggests — are arid ecosystems where precipitation is outweighed by evaporation, making them particularly difficult places to spot and measure forests via satellite.
A new estimate of the extent of dryland forests suggests that the global forest cover is at least 9% higher than previously thought. The study , published in the May 12 issue of Science, will help reduce uncertainties surrounding how much carbon dioxide plants absorb from the atmosphere globally. As carbon dioxide is a key driver of climate change, the study's results are important for climate modeling.
Given the vastness of land across the globe, researchers rely on satellite data to estimate the amount of forest cover. Yet dryland biomes — as their name suggests — are arid ecosystems where precipitation is outweighed by evaporation, making them particularly difficult places to spot and measure forests via satellite.
"First, the vegetation is quite sparse, so the signal is often a mix between vegetation and non-vegetation, like soil or even tree shadow," explained Jean-François Bastin of the United Nations Food and Agriculture Organization and co-author of the study. "Second, the vegetation in drylands is quite particular. To adapt to arid conditions, and therefore limit evapotranspiration, trees are leafless most of the year which makes it difficult to detect with classic mapping approaches."
This uncertainty can have huge implications for quantifying global forest cover, as dryland biomes cover about 40% of the Earth's land surface. It also raises question about the real contribution made by forests to the global carbon cycle.
Read more at American Association for the Advancement of Science
Image: A Coolabah (Eucalyptus victrix) forest in the Pilbara region of Western Australia. This material relates to a paper that appeared in the 12 May 2017, issue of Science, published by AAAS. The paper, by J.-F. Bastin at Food and Agriculture Organization, United Nations in Rome, Italy, and colleagues was titled, "The extent of forest in dryland biomes." (Credit: TERN Ausplots)
