Climate change patterns reshaping India’s central forests

A new study finds that the Panchmarhi Biosphere Reserve (PBR) in India lost about 13% of its forest cover between 1972 and 2020, driven by both climate shifts and human pressures. As highlighted by a Mongabay-India (MI) report, the study is part of a larger project studying the diversity of 762 forest plots in Central India, to generate an ecological baseline for the region.

The MI report points out that over decades, the tropical deciduous forests of central India have weathered the impacts of a quietly changing climate. New research sheds light on the extent to which long-term changes in temperature and precipitation transformed a protected area in the Indian state of Madhya Pradesh, in addition to the anthropogenic pressures caused by tree felling, extraction, and grazing. The forests of central India occupy a vast landscape, stretching over an area of more than 40,837 square kilometres across Madhya Pradesh, Maharashtra, and Chhattisgarh. Though famed for having a robust tiger population, this region is also home to some of the country’s largest contiguous forested tracts. The PBR sits at the heart of this landscape.

Predictable monsoons and stable temperatures have helped this region’s forests sustain and regenerate for centuries, the MI report adds. The lifecycles of tropical deciduous forests are deeply tied to seasons — typically shedding leaves in the dry seasons and greening in the wetter months, depending on the species. Researchers from the Central University of Jharkhand and Banaras Hindu University analysed 50 years of climate data and examined its relationship with the PBR, which is also facing pressures from encroachments and extraction. Between 1972 and 2020, the PBR lost approximately 13% of its forest cover, amounting to 391 sq. km. Among the most notable findings attributed to climate change is an increase in forest fires in the PBR, driven by consistently warming temperatures and lower levels of precipitation over the last five decades.

As the abstract of the study states, tropical deciduous forests face increasing threats of rising temperatures, erratic rainfall patterns, and anthropogenic disturbances, making it more susceptible to forest fires and invasion. To understand the climate sensitivity of tropical deciduous forests, the present study attempts to bridge the significant research gaps by systematically evaluating the long-term trends and patterns of precipitation and temperature over the past five decades (1971–2020) and examining their potential linkages with forest cover and canopy density in highly diverse forests of the PBR.

The study says that the PBR, with its unique forest properties, including heterogeneous terrain and diverse microclimatic zones, exemplifies the challenges faced by such ecosystems. These characteristics not only support rich biodiversity but also render the forest highly vulnerable to the cascading impacts of climate change, threatening long-term ecosystem stability, and carbon sequestration potential. The research focussed on temperature and rainfall data because they are two major drivers of forest health, although other factors such as soil moisture and topography also play a role. The study revealed that since 1971, the PBR has experienced statistically significant temperature increases both annually and across seasons, with the highest increase in mean temperature observed during the post-monsoon period.

When maximum temperatures soared above 32°C, it increased the risk of forest fire occurrence, the MI report highlights. Higher maximum temperatures “altered species niches, as well as the vitality and health, leading to decreasing forest cover and canopy density over the past five decades,” the study says, adding that higher temperatures were the dominant factor driving fires. Changes in precipitation affected forest health too. The analysis revealed a shift in precipitation away from the post-monsoon period to the pre-monsoon period. Combined with rising temperatures, changes in rainfall also caused disruptions to the forest’s phenology. Changes in phenology have also been found to cause differences in forest productivity in the Western Ghats, putting into question their ability to act as long-term sinks.

The study emphasizes that strengthening conservation strategies, promoting sustainable land-use practices, and enhancing adaptive forest management are urgently needed to mitigate future risks and safeguard the ecological integrity of these forests. Apart from restoration and preservation, the adaptation and long-term resilience of India’s central forests will also require the support of local communities who depend on its resources.