Synergetic relation of Forest fire, vegetation proportion and Leaf area index over Western Himalaya

Abstract:

The Western Himalaya is one of the substantial hotspot areas of forest fire in India during summer (per-monsoon, March to June) season and it has a large impact on the fragile mountain ecosystem. Present study used Fire CCI v5.1 fire product (250 m spatial resolution) over the span of 2001 to 2019 and computed the percentage of burn area or fire fraction in 5 sq. km grid. The mean 19-year burn area percent showed ~20% (SD = 17%), spatial coverage of burn area was mostly situated over southern and central parts of Uttarakhand, Himachal Pradesh, and some scattered patches in south-western parts of Jammu and Kashmir. The differential (pre and post fire) LAI (Leaf Area Index) and proportion of vegetation calculated using Advanced Very High Resolution Radiometer (AVHRR) LAI and NDVI (Normalized difference Vegetation Index) data, respectively. The trends (2001-2019) of differential proportion of vegetation and LAI (using Sen’s Slope and Mann-Kendall Tau) exhibited browning trends mostly over forest ecosystems in southern and central parts of Uttarakhand, Himachal Pradesh and south-western hilly areas of Jammu and Kashmir. The statistical correlation (r) and relation (β) between Sen’s Slope of percent burn area and differential LAI (2001-2019) showed -0.27 and -0.002, respectively over 90% significant level (p>0.1). The relationship between trends percent burn area and differential LAI exhibited significant (p>0.01) negative correlation (r = -0.36, β = -1.78). The southern and central part of Uttarakhand and Himachal Pradesh and south-western forest parts of Jammu Kashmir has been significantly facing pre-monsoonal forest fire and simultaneously these areas reflect a browning trend of proportion of vegetation and LAI.