Asian Scientist (Jul. 18, 2013) – A new satellite imaging system has determined that more than 80% of tropical forests in Malaysian Borneo have been heavily impacted by logging.
The Malaysian states of Sabah and Sarawak are global hotspots of forest loss and degradation due to timber and oil palm industries, but the rates and patterns of change have remained poorly measured by conventional field or satellite approaches.
Now, in a study published in PLOS ONE, an international research team has documented the full extent of logging in this region.
The team analyzed satellite images to reveal the vast and previously unmapped extent of heavily logged forest. These high-resolution satellite images uncovered logging roads in Brunei and in the Malaysian states of Sabah and Sarawak on the island of Borneo.
Using a tool called CLASlite (The Carnegie Landsat Analysis System Lite) developed for this purpose, the team was able to convert satellite images of seemingly dense tropical forest cover into highly detailed maps of deforestation and forest degradation.
Analysis of satellite imagery collected from 1990 and 2009 over Malaysian Borneo showed approximately 364,000 km of roads constructed throughout the forests of this region.
The researchers found that nearly 80% of the land surface of Sabah and Sarawak was impacted by previously undocumented, high-impact logging or clearing operations.
This finding contrasted strongly with neighboring Brunei, where 54% of the land area maintained intact (unlogged) forest. This is because Brunei has largely excluded industrial logging from its borders.
“There is a crisis in tropical forest ecosystems worldwide, and our work documents the extent of the crisis on Malaysian Borneo,” said Jane Bryan, leader of the research team.
“Only small areas of intact forest remain in Malaysian Borneo, because so much has been heavily logged or cleared for timber or oil palm production.”
“Rainforests that previously contained lots of big old trees, which store carbon and support a diverse ecosystem, are being replaced with oil palm or timber plantations, or hollowed out by logging.”
Only 8% and 3% of land area in Sabah and Sarawak, respectively, was covered by intact forests in designated protected areas. Very few forest ecosystems remain intact in Sabah or Sarawak.
“The problem with previous monitoring reports is that they have been based on satellite mapping methods that have missed most of the forest degradation in Malaysian Borneo, and elsewhere throughout the tropics,” said Greg Asner, who led the development of the CLASlite system.
“I’m talking about heavy logging that leaves a wake of forest degradation, even though the area may still look like forest in conventional satellite imagery.”
“With the CLASlite system, we can see the effects of logging on the inner canopy of the forest. The system revealed extremely widespread degradation in this case.”
Source: Carnegie Institution for Science; Photo: Ben Sutherland/Flickr.
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