Tropical forests in Borneo are disappearing much faster than previously thought, according to a new study.
A team of Indonesian and US researchers has found that lowland forests in Kalimantan, the Indonesian part of the island, declined by more than 29,000 square kilometres between 1985 and 2001 — even though much of the forest was protected.
"Many of these forests may be too damaged to fully recover," warns one of the researchers, Lisa Curran of the Yale School of Forestry and Environmental Studies, United States. "They are so degraded that the ecological processes of regeneration will be so slow as to be essentially nonexistent."
Indonesia contains 10 per cent of the world's tropical rainforest, and it is disappearing even faster than the Brazilian Amazon. Scientists are now calling for action both in Indonesia and abroad to save Borneo's forests, which they say are critical in maintaining the island's biodiversity and sustaining rural livelihoods.
The researchers used field, aerial and remote-sensing surveys to assess forest loss, and found that more than half of protected lowland forests have disappeared in less than two decades through logging and human land use. Their findings are reported in this week's Science.
Concession-based logging and the establishment of plantations — both activities partly supported by the authorities — are the main reasons for this loss.
Since 2001, new regulations have allowed districts to issue logging leases for small parcels of land. The result has been "virtually uncontrolled harvest", say the scientists.
In addition, oil palm plantations are being established in logged areas outside the forests, increasing the pressure on protected areas.
"Stemming the flow of illegal wood from Borneo requires international efforts to document a legitimate chain-of-custody from the forest stand to consumers," the researchers write in Science.
The scientists urge that penalties be strictly enforced to prevent unsustainable exploitation of protected forests. Areas that have not yet been converted to plantations could recover, but it could take anywhere from 75 to 150 years, they say.
Reference: Science 303, 1000 (2004)