Assessment of drought index response to changes in forest cover across different climate zones

Drought is a complex climatic hazard with major impacts on both human and natural system. It is very likely leading to agricultural loss, forest mortality and drinking water scarcity. In recent years, the occurrence frequency and intensity of droughts has been increasing within a warming climate. This poses serious threats to future food security, ecosystem (e.g., changing the forest structure and carbon content) and fresh water stress for small islands. Precipitation, temperature and other atmospheric factors have an influence on the drought conditions. Furthermore, the impact of land cover change on climate mostly on precipitation and temperature has been established in previous studies. To our best knowledge, the effect of change in land cover, especially in large forest cover, on droughts is largely unexplored. This, however, is important to understand the impact of land cover on climate variability and the sensitivity of the droughts to changes in the climate. This study aims at quantifying the effect of forest cover change and changing meteorological factors  on long-term and short-term droughts across four different climate regions (i.e. equatorial, arid, temperate and snow region).

We analyse the influence of forest cover changes to droughts. Meteorological data (precipitation and temperature), land cover dataset, and drought indices (the Palmer Drought Severity Index and the Standardized Precipitation Evapotranspiration Index) for almost 30 years are used to study the influence of forest cover fraction variability on droughts for different time scales and across different climate zones. Linear model and analysis of variance (ANOVA) have been used in the analysis to explore how forest cover changes impact on the drought occurrence frequency and intensity. Our findings can be used in making policy decision involved in forest management and water resource planning.