Building up carbon sinks in northeast India’s shifting cultivation landscape

Text by Sahana Ghosh

  • Mizoram University scientists have identified two tree species that could be planted in shifting cultivation fallows to speed up their regeneration into secondary forests and enhance carbon sinks.

  • The study finds that fallow age contributed the most to the recovery of carbon. The findings are in agreement with other studies in the region. Abandoned fallows are also known to have a high potential for carbon storage.

  • Secondary forests are gaining importance in the tropics as pristine forests are cleared. And it is vital to understand the impacts of changing patterns of shifting cultivation on carbon storage.

Angami Naga tribe innovated the Alder coppicing system by retaining and pollarding nitrogen fixing Alder trees that facilitate fallow regrowth in Khonoma village, Nagaland. Photo by Joli R. Borah.

Chestnut and olive trees that occur naturally in the wild in Manipur have the potential to speed up fallow regrowth in shifting cultivation (jhum) sites and enhance carbon sinks as the fallows regenerate into secondary forests, according to a study.

Olive (Elaeocarpus floribundus Blume) and chestnut (Castanopsis hystrix) can be collected from the surrounding forests or germinated and planted in jhum fallows to accelerate natural succession, said Mizoram University researchers who identified the two species that strike roots in early fallows.

The study’s corresponding author Uttam K. Sahoo of Mizoram University told Mongabay-India that fallow age was the key contributor to carbon recovery in fallow stands. Experts suggest the successful implementation of carbon-based payment for ecosystem services (PES) schemes, such as REDD+ (Reducing Emissions from Deforestation and Forest Degradation), can also conserve landscape-level carbon stocks and biodiversity in shifting cultivation landscapes.

Researchers measured tree height and girth at four shifting cultivation fallow lands (left unplanted for 5, 10, 15, and 20 years) owned by local community members in Ukhrul and Chandel districts of Manipur. Ukhrul is locate