Spatio-temporal characterization of landscape fire in relation to anthropogenic activity and climatic variability over the Western Himalaya, India

The frequent occurrence of a forest fire can be detrimental to the functioning of ecologically fragile regions such as the Western Himalaya. This study assesses the spatio-temporal variability and trends of fire occurrence in forests, shrubland, and grassland in relation to anthropogenic activities and climate oscillations over Uttarakhand and Himachal Pradesh; the most fire-affected states in the Western Himalaya. The Pre-monsoon (March to June) temporal distribution of fire occurrence is bimodal with the first and second fire peaks occurring in the last week of April and late May/early June, respectively. The length of fire season was found to have reduced by similar to 10 days in 2010s compared to 2000s with the increasing burned area concentration over a shorter period (similar to 110 days). The Mann-Kendall Tau (tau) and Sen's-slope suggested an increasing trend (tau = 0.3, Sen's slope = 46.78 km(2) year(-1), p = 0.02) of burn area over Uttarakhand where most fire activity occurs. The Getis-Ords (Gi*) statistic was derived by using Fire Radiative Power (FRP) data to infer the spatial distribution of hot and cold clusters which were found to be greatest (Gi* = 1-10) in evergreen needleleaf forest which also accounted for a marginally higher mean per-pixel FRP than other land cover types. Analyses of the role of climatic variables on fire activity revealed moderate positive and negative correspondence between the burned area and average maximum-temperature (R = 0.57, p = 0.01) and total precipitation (R = - 0.53, p = 0.02), respectively. Assessment of the variation of fire activity with global climatic oscillation indices found the Nino-3.4 index to have the strongest, albeit modest, relationship (R = 0.51) with burned area anomalies. This study highlights the increase in fire intensity in the fragile forests of the Western Himalayan region and the requirement for further research into the role of climate and anthropogenic activities on fire occurrence in order to best preserve regional biodiversity and develop an effective forest management strategy.