Use of models to analyse land-use changes, forest/soil degradation and carbon sequestration with special reference to Himalayan region: A review and analysis

Land use-changes and forest/soil degradation affect emissions of green house gases (GHGs) rather strongly, thereby causing global warming. These processes have led to a deep concern among the policy makers, scientists and public alike. For analysing causes and impacts of this complex problem, modelling has become increasingly more important, as evidenced by a plethora of models developed particularly during the last decade. This study reviews and synthesises the available models relating to land-use changes, forest/soil degradation and C sequestration in developing countries in general and the Hindu Kush Himalayan (HKH) region in particular. The major findings of these models in terms of factors affecting land-use changes especially, deforestation or agricultural expansion, are agricultural and timber prices, wage rates, risks in agriculture, population density in the rural areas, access to forestland, and titling security in frontier areas, and some of the government policies of economic reforms in the developing world. These findings, however, are space and time specific, and hence suggest for different policy options. A number of modelling techniques have been used in the past, such as, conceptual, analytical, empirical regression, and programming/simulation models. Both static and dynamic models have been used at different scales from household to global levels. Most studies in the HKH region are based on qualitative/descriptive methods using conceptual modelling techniques. Integrated models for analysing C sequestration dynamics as a function of land-use changes and forest/soil degradation in a holistic approach are emerging. Based on the review and synthesis of different techniques, a conceptual modelling framework is presented. This consists of a dynamic bio-economic modelling framework capable of capturing both socio-economic behaviour and bio-physical processes combined with geographical information systems/remote sensing techniques. Such modelling efforts have the potential of assisting policy makers and planners to identify and implement sustainable agriculture and forestry practices, leading to mitigation of CO2 emissions in developing countries in general and the HKH region in particular.