Forests, weeds and farms

Understanding a shifting cultivation system in the Eastern Himalaya

The shifting cultivation system of the Adi community in the Eastern Himalaya in Arunachal Pradesh is unique in many ways. A forest-fallow matrix in such a landscape also provides opportunities to explore vegetation succession patterns and mechanisms following a disturbance. 

  • A temporary jhum hut in a currently cultivated patch with a mosaic of a forest-fallow matrix in the background in the Upper Siang district, Arunachal Pradesh.

  • Wet rice cultivation fields along the Siang river valley and shifting cultivation farms on the hill slopes (Photo by Anirban Datta-Roy)

  • Wet rice cultivation patches on gentle slopes along the Siang river in the Upper Siang district, Arunachal Pradesh (Photo by Anirban Datta-Roy)

  • Mikania micrantha flowers during the months of November and December in the Upper Siang district in Arunachal Pradesh

Forests, weeds and farms

Shifting cultivation has been described as a form of forest farming in which land under crops, located a practicable distance from a farming village, is often rotated annually. In north-east India, where shifting cultivation or jhum is widespread among diverse tribal communities, increasing human population density and forest loss have resulted in short fallow cycles (4-5 years is the period between two cultivation cycles) and arrested succession in many areas, often due to exotic weedy species.

The Adi community in the Upper Siang district of central Arunachal Pradesh state, largely practice subsistence shifting cultivation, with a relatively lesser area under terrace cultivation. The objectives of this research are: 1) to understand the diversity of the shifting cultivation practice of the Adi community in selected villages and to examine if this affects the forest cover surrounding the villages, 2) to understand the patterns and processes of vegetation recovery following shifting cultivation, 3) to investigate effects of an invasive exotic species Mikania micrantha on native plant regeneration and to explore ways to control invasion by the species.

The 20landscape

Hill slopes show a mosaic of shifting cultivation sites (bare slopes) and forest patches

Role of Shifting cultivation in the Adi Culture

Although shifting cultivation is a widespread practice in several parts of India, government policies have attempted to replace it with other land uses, specifically settled agriculture and monoculture plantations. What factors determine if a community can make the shift? Through interviews with the Adi tribe in Central Arunachal, we tried to identify these factors.  Our research shows that although settled cultivation was initiated in the 60s, about 90 % of the families still practise shifting cultivation. We documented 13 festivals, following an annual agricultural calendar, associated with this activity. Furthermore, we found that the economic status of a household may determine whether a family shifted to  settled cultivation. Disregarding this, government policies since the British colonial period have focused on introducing settled cultivation and cash crop options, unmindful that local institutions have internally regulated the practice. The shift to settled cultivation may entail significant economic and cultural costs, which are ignored in the Government policies. Future policies should be mindful of these factors and not use a one-size-fits-all strategy.

Kebang 20meeting

Members of the Adi community at Kebang meeting. A Kebang is a local council that governs shifting cultivation practices in the community.

Forest recovery following a cultivation cycle

What is the impact of a cycle of clear-felling and cultivation on forest regeneration in Asian tropical forests? We examined forest recovery patterns by comparing species composition, richness and forest structure in early and late fallows formed following shifting cultivation in the Siang region. We examined changes in functional traits of tree species to understand recovery processes with succession. Tree species richness and basal area was higher in fallows with longer cycles. Species composition recovery, however, was low; with even the oldest fallow (50-year fallow) being less than 50% similar to uncut forest in terms of composition. Successional sites that recover over long periods may differ compositionally from uncut forest within a shifting cultivation landscape as these forests are often prone to other anthropogenic disturbances. Functional trait analysis revealed that early fallows were colonized by tree species that are animal-dispersed, insect-pollinated with small fruits and seeds, whereas uncut forest and late successional forests were dominated by species that were tall, self-dispersed, wind-pollinated and of high wood density that are dominant mature forest species in the Himalaya.

My 20plot

Experimental plots measuring the impact of shade and herbivory on forest recovery in cultivated sites

People

Funding

  • Adit Jain Foundation
  • ATREE Small Grants for Research in North-east India
  • Idea Wild
  • Ravi Sankaran Inlaks Grant
  • Rufford Foundation, UK

Publications

  • Book Chapter
    In press
    Top-down or bottom-up: the role of the government and local institutions in regulating shifting cultivation in the Upper Siang district, Eastern Himalaya, India (in press)
    Shifting Cultivation and Environmental Change: Indigenous People, Agriculture and Forest Conservation (Ed: Malcolm Cairns), Published by Routledge.
  • Journal Article
    2016
    Field to a forest: Patterns of forest recovery following shifting cultivation in the Eastern Himalaya
    Forest Ecology & Management http://dx.doi.org/10.1016/j.foreco.2016.01.006

    The patterns of vegetation recovery in shifting cultivation landscapes that undergo a cycle of clearing, cultivation and forest regeneration are not well understood in Asian tropical forests. We determined for- est recovery patterns by comparing species composition, richness and forest structure in early and late fallows formed following shifting cultivation and in an uncut forest site in a mid-elevation subtropical forest in the Indian Eastern Himalaya. We also examined changes in functional traits of tree species to understand recovery processes with succession. Tree species richness in the 12, 25 and 50-year old sites was 37%, 54% and 82% the value of the richness in uncut forest, respectively, while basal area was 33%, 25% and 41% of the value in uncut forest, respectively. Species composition recovery, however, was low; with even the oldest fallow (50-year fallow) being less than 50% similar to uncut forest in terms of composition. Successional sites that recover over long periods may differ compositionally from uncut forest within a shifting cultivation landscape as these forests are often prone to other anthropogenic dis- turbances. Functional trait analysis revealed that early fallows were colonized by tree species that are animal-dispersed, insect-pollinated with small fruits and seeds, whereas uncut forest and late succes- sional forests were dominated by species that were tall, self-dispersed, wind-pollinated and of high wood density that are dominant mature forest species in the Himalaya. These results are in contrast with the patterns in functional traits of tree species in successional sites from the Neotropics. This points to the importance of site-specificity in succession following shifting cultivation.

  • Journal Article
    2016
    Shifting to settled cultivation: Changing practices among the Adis in Central Arunachal Pradesh, north-east India
    Ambio doi 10.1007/s13280-016-0765-x

    In the hilly tropics, although shifting cultivation is a widespread practice, government policies have attempted to replace it with other land-uses. However, several factors determine whether farming communities can make the shift. We tried understanding the factors that facilitate or impede the shift to settled cultivation through interviews with the Adi tribe in north-east India. Although settled cultivation was initiated in the sixties, about 90 % of the families practice shifting cultivation, observing 13 festivals associated with the annual agricultural calendar. Our results indicate that the economic status of a household affected the ability to undertake settled cultivation, while labour availability is important for shifting cultivation. Often, these nuances are ignored in government policies. We conclude that future policies should be mindful of cultural and socio-economic factors that affect the community and of the social-ecological resilience of the landscapes and not use a one-size-fits-all strategy.

  • Dataset
    2016
    Data from: Field to a forest: patterns of forest recovery following shifting cultivation in the eastern Himalaya. Dryad Digital Repository.
    doi:10.5061/dryad.k83h6
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