Farms or Forests? Understanding and Mapping Shifting Cultivation Using the Case Study of West Garo Hills, India

Kurien Kurien,Nagendra Nagendra,Lele Lele

doi:10.3390/land8090133

Abstract

Attempts to study shifting cultivation landscapes are fundamentally impeded by the difficulty in mapping and distinguishing shifting cultivation, settled farms and forests. There are foundational challenges in defining shifting cultivation and its constituent land-covers and land-uses, conceptualizing a suitable mapping framework, and identifying consequent methodological specifications. Our objective is to present a rigorous methodological framework and mapping protocol, couple it with extensive fieldwork and use them to undertake a two-season Landsat image analysis to map the forest-agriculture frontier of West Garo Hills district, Meghalaya, in Northeast India. We achieve an overall accuracy of ~80% and find that shifting cultivation is the most extensive land-use, followed by tree plantations and old-growth forest confined to only a few locations. We have also found that commercial plantation extent is positively correlated with shortened fallow periods and high land-use intensities. Our findings are in sharp contrast to various official reports and studies, including from the Forest Survey of India, the Wastelands Atlas of India and state government statistics that show the landscape as primarily forested with only small fractions under shifting cultivation, a consequence of the lack of clear definitions and poor understanding of what constitutes shifting cultivation and forest. Our results call for an attentive revision of India’s official land-use mapping protocols, and have wider significance for remote sensing-based mapping in other shifting cultivation landscapes.

Highlights

Shifting cultivation is a widely practiced form of agriculture important for livelihood, nutrition and as a safety net for millions of people in the tropics [1,2]
Given the concern about possible declines in fallow periods, we propose the use of fallow: active shifting cultivation ratios to estimate the fallow duration in different sub-regions and the possibility of relating the variation in these ratios across the landscape with other land-uses in and demography of these sub-regions
We present the results in four stages: the overall land-use map, estimates of its accuracy, the land-use statistics emerging from it, the fallow period estimation for different parts of the district, and the patterns in and correlates of land-use intensity in shifting cultivation

Summary

Introduction

Shifting cultivation ( known as swidden) is a widely practiced form of agriculture important for livelihood, nutrition and as a safety net for millions of people in the tropics [1,2]. The understanding of the extent and form of shifting cultivation, how much it is intensifying, and whether it causes deforestation, remains limited [8]. A large proportion of the world’s forest-agricultural frontier is still occupied by shifting cultivation [9]. The persistence of this practice in the face of focused efforts to eradicate and replace it, as well as pressures of population increase and market penetration has elicited scholarly interest

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