BOGOR, Indonesia (2 July 2013)_CIFOR has made an analysis of new satellite imagery for the area in Riau Province, Sumatra, which appears to have been worst affected by recent fires causing haze problems over Sumatra, Singapore and Malaysia. Although several recent assessments have used NASA’s daily fire alerts to locate the fires, we have additionally used higher-resolution imagery from the recently launched Landsat 8 satellite to map fire scars. The Landsat images were recorded on 25 June 2013.
While our analysis is preliminary, it raises a number of interesting and important questions and insights about the location, context and causes of the fire incidents.
We would like to share these observations and associated hypotheses below, and we encourage your feedback.
1. There was a distinct peak in NASA’s daily fire alerts during a very short period of time, between 17 and 25 June (Figure 1).
2. We found a strong spatial correspondence between fire alert locations and observed burned areas in the Landsat 8 imagery of 25 June (Figure 2). A total of 100,000 hectares (1,000 km2) of fire scars were mapped within the worst-affected Landsat scene, corresponding to 3% of the total area studied.
3. A very high proportion of the fire scars are on peatland, as opposed to mineral soil (Figure 3).
4. Fire scars are predominantly observed in areas of established plantation land use, both large and small scale. Most June 2013 fires in the studied area have occurred outside natural forests (Figure 4). However, some of the fires appear to have advanced from plantations into adjacent natural forest.
5. Fires occurred both on acacia and oil palm plantation sites with little or no tree cover and on sites that carried standing plantation trees (Figure 5).
6. Observed fire scars were both inside and outside boundaries of concession areas, as determined from available official maps (Figure 6). Some fire scars outside of these concession areas contain patterns that indicate plantation establishment.
7. Many of the June 2013 fire scars are in areas that were classified as natural forest in 2007 (Figure 7).
1. Many of the June 2013 fires are part of the processes of plantation establishment and management. The very short period over which fire incidents peaked, the high proportion of fires occurring on peatlands, typical patterns of plantation management in fire areas, and the lack of updated concession maps support this hypothesis.
2. Weather conditions (including wind patterns) exacerbated the haze problem in June 2013 compared with previous fire incidents.
The very rapid availability of Landsat 8 data allowed us to make a timely assessment of fire scars and correlate the data with known land uses. However, more field data are needed to confirm the precise events and processes that caused the fires.
This research is carried out as part of the CGIAR Research Program on Forests, Trees and Agroforestry.
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