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What drives land use/cover change? : some evidence from a remote central Vietnamese district | |
Author | Thiha |
Call Number | AIT Diss. no.NR-07-04 |
Subject(s) | Land use--Vietnam |
Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Natural Resources Management, School of Environment, Resources and Development |
Publisher | Asian Institute of Technology |
Series Statement | Dissertation ; no. NR-07-04 |
Abstract | Conservation in a dynamic setting requires understanding the processes, trends and factors leading to landscape change. This study integrated Remote Sensing and Geographic Information Systems and analysis of household survey data to (i) quantify the land cover dynamics between 1975 and 2004; to (ii) evaluate the factors influencing household livelihood strategies and land use change; and to (iii) predict the locations of deforestation and forest degradation in a remote central Vietnamese district. Firstly, classification of time series Landsat imagery quantified the (1975-2004) land cover dynamics, and subsequently transition matrix analysis identified major land cover transitions since 1975. Secondly, biophysical and policy driving factors of the major land cover transitions were analyzed in a multivariate analysis combined with narrative approach that analyzed the qualitative data collected through key informant interviews in the four purposely selected study communes. Whereas binomial logistic regression was used to estimate the probabilities of forest degradation and land cover conversion towards tree plantations observed in the period 1989-2004. Narrative synthesized the policy landmarks in Nam Dong and central Vietnam since 1975 to describe the context and processes of landscape transformation, and identified proximate causes and underlying forces of major land cover transitions observed in three study periods: state forest management (1975-85), implementation of Doi Moi renovation (1986-2000) and the era of forest decentralization and socioeconomic development (2001-present). Thirdly, factors affecting household livelihood strategies and land use change since 2001 were analyzed in a multivariate analysis on the basis of household survey data collected through face-to-face interviews with 103 households in the four study communes. Finally, GEOMOD, a raster-based land change model simulated the locations of deforestation and forest degradation forward in time to predict the locations of forests that are threatened using biogeospatial drivers and time series land cover maps. On the course of 29-year period, the total forest cover of Nam Dong district did not decrease very rapidly. However, there were dynamic class-wise changes and transitions in land cover within and outside forest. Land cover transitions, particularly conversion of closed canopy forest into other forest conditions, accelerated after 2001; coinciding with implementation of forest decentralization policies and major socio-economic investments in Nam Dong. At the landscape level, biophysical models explained only small portions of forest degradation and land cover conversion towards tree plantations. However, narratives improved the quantitative finding and described the link between observed local outcomes (as measured by landscape transformation) of policy, particularly recent forest decentralization initiatives in Nam dong. Rapid conversion rates of closed canopy forest to other forest conditions observed from the quantitative analysis since 2001 were due allegedly to state-sponsored commercial logging and small scale timber extraction by local households responding to improved forest access on logging roads, opening up market opportunities and increasing local and regional market demands for selected timber and non-timber forest products. Rapid conversion rates of upland crop areas and degraded forests into tree plantations since the early 2000s were linked to demonstrated profits from first-rotation harvests of Acacia plantations, increased market demand for pulpwood and raw rubber and availability of plantation loans and seedlings from the State Forest Enterprises. Accelerated degradation events in forests that were in the process of being allocated reflected significant levels of land speculation by local households responding to oversight of government policy and substantial delays in natural forest allocation process introduced in the early 2000s. Findings suggested that in the long run, those landscape outcomes of policy will impose important threat to forest conservation activities. Analysis of household survey data revealed that the choice of household following particular livelihood strategies was influenced by both household's tangible resources (for example, size of landholding) and household characteristics (for example, residential period and educational status of household head), and was relatively independent of exogenous factors (for example, policy). Household land use change toward tree plantations since 2001 was well explained by socioeconomic factors (for example, size of landholding) and policy (for example, presence of secure land tenure), implying that larger landholdings and lack of secure land tenure encouraged households to covert lands to rotational tree crops. Overall findings concluded that rapid change in farmers' land uses in the landscape of Nam Dong since the early 2000s was linked with policy factor. The findings of the research identify specific recommendations that logging quotas of SFEs need to be reduced to lessen economic pressure on forest and to decrease small-scale logging by local households, law enforcement should be increased to protect degraded forests located near forest edges from further depletion, agroforestry should be promoted to improve allocated forest and to generate extra income and the current approach of forest decentralization policy should be refined to ensure people's active participation. This integrated approach of data collection and analysis will serve as the basis for the development of a standard methodology to studying land cover/use change in other Vietnamese uplands. The research outputs can be used as important baseline information for future forest conservation planning in Hue province and central Vietnam. Whereas, quantitative and qualitative data and visual tools (for example, maps) are useful for policy makers to identify the priority areas where conservation policies should be focused |
Year | 2007 |
Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. NR-07-04 |
Type | Dissertation |
School | School of Environment, Resources, and Development (SERD) |
Department | Department of Development and Sustainability (DDS) |
Academic Program/FoS | Natural Resources Management (NRM) |
Chairperson(s) | Webb, Edward L.; |
Examination Committee(s) | Schmidt-Vogt, Dietrich ;Honda, Kiyoshi ;Gautam, Ambika P.; |
Scholarship Donor(s) | The John D. and Catherrine T. MacArthur Foundation ;Asian Institute of Technology; |
Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2007 |