Less oak cover in Himalayas could threaten biodiversity: Study

Express News Service

DEHRADUN: Decreasing cover of oak forests and their replacement by chir pine in the Western Himalayan landscape could render a large number of flora and fauna vulnerable to local extinction, revealed a joint study.

The key reason for the replacement of oak forests was attributed to the presence of more pines in the surrounding landscape, lower levels of winter precipitation, and Topographic Wetness Index (TWI), a measure which quantifies terrain-driven variation in soil moisture. 

Citing ornithologist Ghazala Shahabuddin’s work, the study stated that pine forests harbour only 54–67% of all bird species found in proximal dense oak forests.

The study titled ‘Expansion of pine into mid-elevation Himalayan oak forests: Patterns and drivers in a multiple-use landscape’, published in Forest Ecology and Management, was conducted jointly by the Center for Ecology Development and Research, IISc Bengaluru and the National Remote Sensing Centre.

The study revealed that Oak forests in Uttarakhand have reduced by 29% while pine forests increased up to 74% between years 1991 and 2017. 

Ban on tree cutting could have led to the spread of pine stands, even as oak forests continued to be lopped and grazed. The pine plantations in the lower elevation areas could have expanded laterally and upslope after 1990, added the study.