Date of Award
Master of Environmental Management (MEM)
Environmental Science and Management
Forest fires -- Climatic factors -- Sri Lanka, Forest management -- Sri Lanka, Climatic changes -- Sri Lanka, Forests and forestry -- Sri Lanka
Forest fire is one of the main causes for forest degradation and deforestation which affect ecosystem services provided by the given landscapes. Weather variables like temperature, wind speed and direction, rainfall, and relative humidity also govern the forest fire regime and vulnerability. On the other hand, forest fuel characteristics, human impacts, population density, forest canopy density, slope, elevation, road density, closeness to the human settlement areas are other factors that determine the forest fire impact and potential of damage. Annually, 100 to 2500 hectares of forest resources are damaged due to forest fires in Sri Lanka. From the past few years, forest fire impacts on the forest resources have increased. This increase of forest fire damages may be closely related to climate change. In order to assess the impact of climate change on forest fire damage, this study analyzed the occurrence and distribution of forest fires in Sri Lanka using forest fire simulation techniques. The variability of dry weather patterns in Sri Lanka have increased in the last few years, especially during North East monsoon season, which is the season of highest rainfall in the dry zone. This has caused the dry warm conditions in the dry zone to have increased. In Sri Lanka the weather pattern is strongly associated with the El Nino Southern oscillation (ENSO). As a result of climate change and global warming, the Indian ocean surface temperature varies, which changes the pattern and duration of ENSO, warmer conditions and dry weather patterns. In that context, there has been an increase of dry conditions throughout the inland, which has created the worst impact for the dry zone of Sri Lanka.
The simulation algorithm called FconstMTT was used in this study to identify the baseline condition and future projected climate change impact on forest fire damages. Under both conditions, 1000 time iterations for each scenario were done. Sri Lankan forest types were categorized into six categories based on the elevation, rainfall and fuel characteristics. For each and every forest type, custom fuel models were prepared and the numbers 30 to 36 were assigned to these models. Baheveplus application was utilized to produce custom fuel models. The ArcFuel extension of ArcGIS 10.4 was used to derive landscape file using three geographic raster layers (elevation, slope, aspect) and five forest characteristics raster layers. Findings from this research suggested that the forest fire hazards in the dry zone of Sri Lanka could significantly increase for the near future under projected climate change conditions. Most interestingly, fire damage under the future projected climate change scenario in the Mulaitive district has significantly increased. Out of the total forest fire damages, about 53% was reported in Monaragala districts under climate change conditions and this would be about 50% in baseline level in Badulla districts. Based on the fire damages, number of fires, and fire damage per fire occurrence, 25 districts in Sri Lanka were classified into risk, moderate and low risk areas. Fire simulation output results of burn probability, damage areas and fire intensity level provide evidence that under the projected climate condition fire severity, fire intensity is significantly increased in the dry zone of Sri Lanka, especially in the Monaragala, Anuradhapura, Polonnaruwa, Badulla districts. Moreover, forest types like dry monsoon forest, shrublands, open and spare forest, and savannah forest have higher forest fire vulnerability and hazardous levels under the climate change.
© 2021 Mohan Heenatigala
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Heenatigala, Mohan, "Influence of Climate Change on Forest Fire Occurrence and Distribution of Sri Lanka and Modeling of Forest Fire" (2021). Environmental Science and Management Professional Master's Project Reports. 68.