Assessment of increasing threat of forest fires in Rajasthan, India using multi-temporal remote sensing data (2005-2010)

摘要

Rajasthan is the largest state of India experiencing recurrent forest fires. The present study determines forest burnt areas through remote sensing-based time series analysis. IRS P6 AWiFS satellite data covering March, April and May of six years (2005-2010) were used to cover all forest-fire events. The total forest burnt area was assessed as 53,023.5 ha in 2005; 44,681.5 ha in 2006; 57,689 ha in 2007; 89,655.2 ha in 2008; 199,837 ha in 2009 and 144,816 ha in 2010. Forest fires were observed only in the southern Aravallis. Of the total forest cover in southern Aravallis, burnt area proportionately represents 6.8% in 2005, 5.6% in 2006, 7.3% in 2007, 11.1% in 2008, 23.0% in 2009 and 17.6% in 2010. Forest fires were severe during 2009, which was the warmest year since 1901. Small sized (<25 ha) forest burnt area patches contributed to 44% of the total count during 2010. Among the vegetation types, fire prevalence in the dry deciduous forest was higher and it always contributed to >90% of the burnt area. GIS analysis demonstrated highest burnt area in occasional category (70%) followed by frequent fire area (24%). The abundance of fires in edge forests in relation to interior forests clearly indicates significant anthropogenic influence on the forest edges. The fires in Rajasthan are mainly attributed to ethnic culture, collection of non-timber forest produce and grazing pressure. The study provides critical spatial information of increased forest fire threat in Rajasthan. Long-term planning for forest fire management is necessary for effective conservation of biodiversity and bioresources.