Dramatic Increase In Fires, Rate Of Forest Loss In Sumatra, Borneo - Mongabay

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Destruction of rainforests and peatlands is making Indonesia more susceptible to devastating forest fires, especially in dry el Niño years, report researchers writing in the journal Nature Geoscience.

Constructing a record of fires dating back to 1960 for Sumatra and Kalimantan (on the island of Borneo) using airport visibility records to measure aerosols or "haze" prior to the availability of satellite data, Robert Field of the University of Toronto and colleagues found that the intensity and scale of fires has increased substantially in Indonesia since the early 1990s, coinciding with rapid expansion of oil palm plantations and industrial logging. The researchers' data shows dramatic spikes in haze coinciding with el Niño years, when dry conditions facilitate cutting, clearing, and burning of vegetation.

"We've had a good understanding of fire events since the mid 1990s, but little before this due to the absence of fire data from satellites," said Field, who collaborated with Guido van der Werf of VU University Amsterdam and Sam Shen of San Diego State University. "However, one of the major impacts of large-scale fires is a reduction in visibility due to the smoke produced. Visibility is recorded several times a day at airports in the region, and these records proved to be an excellent indicator of severe fire activity. We were able to piece together visibility observations back to the 1960s, and hence develop a longer term record of the fires."

The authors found that Sumatra has suffered from large fires since the at least 1960s, but Indonesian Borneo — where industrial conversion of forests was delayed by geography and politics — didn't begin to experience massive fires until 1982. "During the late 1970s, Indonesian Borneo changed from being highly fire-resistant to highly fire-prone during drought years, marking the period when one of the world's great tropical forests became one of the world's largest sources of pollution," said Field. "Ultimately, this abrupt transition can be attributed to rapid increases in deforestation and population growth. The resulting occurrences of haze currently rank among the world's worst air pollution episodes, and are a singularly large source of greenhouse gas emissions."

EDIT

http://news.mongabay.com/2009/0022-fires_indonesia.html