Spatiotemporal Impacts of Forest Fires on Mountain Vegetation: A Case Study From Langtang National Park, Nepal Himalaya

TL;DR

This study examines how forest fires affect vegetation in Langtang National Park, Nepal, over two decades, finding that rising temperatures and land cover types influence fire risk and resilience.

Contribution

The study introduces a spatiotemporal framework linking climate, land cover, and fire activity in the Himalayas, proposing targeted fire management strategies.

Findings

Maximum temperature strongly correlates with burned area extent (r = 0.62, p < 0.01).

Grasslands and needle-leaf forests are disproportionately affected by fires, while closed broadleaf forests show resilience.

Vegetation Condition Index (VCI) is the strongest predictor of vegetation health (β = 0.6285, p < 0.001).

Abstract

Forest fires in the Himalayan region are increasing under climate change, yet their interactions with vegetation dynamics and anthropogenic drivers in protected areas remain poorly understood. This study presents a two decade (2000–2020) spatiotemporal assessment of these interactions in Langtang National Park, Nepal. We integrated MODIS‐derived active‐fire and burned‐area data with vegetation indices, including the Normalized Difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI), along with climatic variables (CHIRPS precipitation and land surface temperature, LST). Trends and drivers were validated through field ecological surveys and stakeholder interviews. Our analysis revealed a significant long‐term greening trend (increasing max NDVI; Z = 2.2044, p = 0.0275) alongside a stable fire regime. Fire activity showed strong land‐cover specificity, disproportionately affecting grasslands and needle‐leaf forests, whereas closed broadleaf forests exhibited high resilience. Maximum temperature was the primary climatic driver of burned‐area extent (r = 0.62, p < 0.01), and VCI was the strongest predictor of overall vegetation health (β = 0.6285, p < 0.001). Field evidence confirmed fire‐mediated ecological succession and highlighted intentional burning as a key anthropogenic ignition source. These findings advance understanding of Himalayan fire ecology, demonstrating that climatic warming and land cover interact to shape fire risk even in a greening landscape. We propose a stratified management framework targeting high‐risk zones, leveraging resistant forests as natural firebreaks, carrying out controlled burning in areas where artificial firebreaks can be created, conducting early season burns in key sensitive zones, and incorporating VCI into early warning systems to enhance the resilience of Himalayan‐protected areas.

A good positive correlation was found between maximum temperature and burn area; increased temperature relates to an increase in fire activity and larger burn areas. Grassland and needle leaf forests are the major land cover types with relatively high fire frequency, likely due to flammable biomass and seasonal dryness, while broad leaved closed forests displayed better fire resilience.

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