February 15, 2012
The research was led by Greg Asner of the Carnegie Institution’s Department of Global Ecology, whose team has developed advanced sensors that provide data on carbon and biodiversity from thousands of feet above the forest canopy. The GoodPlanet Foundation and the World Wide Fund for Nature (WWF) also participated in the project, which mapped some 2.4 million hectares (9,160 square miles) using a combination of field data, airplane-based sensors, and satellite imagery.
To test the range of the technology, the scientists mapped two radically different regions: the humid tropical rainforests of the northern part of the country and an area which included desert-like "spiny" forest in the south. They were able to quantify carbon stocks across multiple ecosystems and vegetation types.
Madagascar with the 659,592 ha northern and 1,713,088 ha southern study regions. Courtesy of Asner et al.
Example LiDAR-based maps of aboveground carbon stocks highlighting: (A) effects of deforestation on humid, low elevation forests in the northern region, and (B) a natural gradient in elevation and plant available water, from dry forests with low canopy height in the lowlands to humid forests in the uplands.
“We found that humid mountain forests had the highest carbon densities, while there was less carbon in dry forests and in the lowlands with more human activity,” said Asner in a prepared statement. “Despite widespread human activity, we found that large-scale natural controls over carbon stocks were heavily driven by the type of terrain and vegetation cover.”
Unsurprisingly the study found the highest levels of carbon in old-growth forests, which have lately been targeted by illegal loggers seeking precious hardwood timber like ebony and rosewood. Regrowing forests stored variable amounts of carbon.
Asner says the results show that carbon stocks can be accurately and rapidly quantified remotely once calibrated with on-the-ground fieldwork.
"These results show that we can obtain verifiable carbon assessments in remote tropical regions, which will be a boon not only to science and conservation, but to potential carbon-offset programs," he added.
Madagascar presently has several REDD pilot projects, which aim to provide economic incentives for leaving forests standing. One project is run by GoodPlanet and WWF Madagascar in partnership with Air France.
Aboveground carbon density (ACD) across the (A) northern and (B) southern region of Madagascar. Median ACD reflects the median value for a habitat class as measured within the LiDAR coverage for that class. Black areas are unobserved or water bodies.
CITATION: Asner et al.: Human and environmental controls over aboveground carbon storage in Madagascar. Carbon Balance and Management 2012 7:2.
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