Land cover change monitoring after forest fire in northeast China

Abstract

The forest fire during May 6 - June 4, 1987 in Northeast China burned 1.14 million hectares of forests and nearly 25 million cubic meters of timber. The land cover has changed dramatically during the last 15 years. In this study, the Landsat-5 TM, Landsat-7 ETM+ data and JERS-1 SAR data were used to analyze land cover change and forest recovery from burned scar in Changqing Forest Farm of this region. The post-classification change detection method was used. The results from remote sensing data were compared with forest maps based on field inventory. Comparisons of the classification results of 1987 and 2000 Landsat images have revealed several distinctive land cover change patterns: most of the burned scars have recovered and become either forests or shrubs, but some of the scars have turned into other land use types. The NDVI of some recovered areas are even higher than unburned forests. But the timber volume inferred from JERS-1 SAR data shows that even for the best recovered area, the volume is still much less than the unburned forests. The results show that Landsat data can be used to monitor land cover change, but is not sensitive to forest timber volume. On the other hand, L-band SAR data can be used to separate different forest volume levels, but it is not easy to be used to identify different land cover types. Therefore, combined use of Landsat TM and L-band SAR data has high potential to monitor land cover changes and forest recovery after fire.