Forest transition in Vietnam : evidence, theory and social-ecological feedbacks

Meyfroidt, Patrick [UCL]

(eng) Prospects for forest transitions – regional or national turnarounds in forest cover trend, from net deforestation to net reforestation – in tropical regions would have wide implications for biodiversity, carbon stocks, and human livelihoods. The objectives of this thesis are to answer three questions: (i) Is there a forest transition in Vietnam, and what are its main characteristics? (ii) What are the causes of the reforestation in Vietnam – at local, national and international levels, and did local land managers perceive and react to forest degradation and/or scarcity? (iii) What are the environmental impacts of the forest transition, for forests in Vietnam and abroad? Firstly, existing land cover data were compiled and compared with recent tools of map comparison. A forest transition occurred in Vietnam during the 1990s. The forest cover dropped to 25–31% in 1991–1993, and then increased to 32–37% in 1999–2001 and 34–42% in 2005. About half of the reforestation was due to plantations of mainly fastgrowing exotic species. Secondly, spatial lag multiple regressions at the national scale and a review of local case studies were used to analyze the causes of spatial variations in the reforestation. Forest regrowth in Vietnam was not due to a single process or policy but to a combination of economic and political responses to forest and land scarcity, economic growth, and market integration. The distribution of forestry land to households, new forest management practices, and food crop intensification were combined in “push and pull” effects to decrease the footprint of agriculture on hillsides. A smallholder agricultural intensification path of forest transition partly explains the reforestation. Population growth and land scarcity drove an intensification of agriculture, mainly based on increased labor inputs on the most suitable plots of the marginal regions, and contributed to the abandonment of the least suitable plots and their reforestation. Thirdly, a material flows analysis quantified and characterized the displacement of deforestation abroad that accompanied the transition. From 1987 to 2006, displacement of forest extraction to other countries represented 49 (34– 70) Mm3, or around 40% of the regrowth of Vietnam’s forests. Leakage due to policies restricting forest exploitation and displacement due to growing domestic consumption and exports contributed respectively to an estimated 58% and 42% of total displacement. About half of wood imports during this period were illegal. Exports of wood products from Vietnam also grew rapidly, amounting to 84% of the displacement. Around 60% of the regrowth in Vietnam was thus not associated with displacement abroad. Fourthly, the main environmental effects of this forest transition at the national scale were studied. The outcomes of the transition are contrasted, and not highly beneficial. The carbon stock in forests followed a transition similar to forest area, decreasing to 903 (770–1307) TgC in 1991–1993, and then increasing to 1374 (1058–1744) TgC in 2005. However, forest density declined during the same period, with an increasing proportion of young and degraded forests. The effects on habitats measured with landscape pattern indices varied between ecoregions: in several regions, the reforestation decreased forest fragmentation, while in others, clearing of oldgrowth forests continued and/or forest fragmentation increased. Fifthly, four village case studies were used to understand feedbacks from local environmental degradation on land use practices of local land managers, their roles in the forest transition and the conditions under which they occur. This showed that forest scarcity is perceived, interpreted and evaluated before possibly affecting land use practices. In one case, beliefs and attitudes of the actors did change because of environmental degradation. Vietnam is one of the few tropical countries that experienced a forest transition, but similar dynamics occur in other countries. Knowledge about this case is, therefore, important to understand forest and land use transitions elsewhere.

(fre) La thèse s'intéresse à la notion de « transition forestière », c'est à dire un basculement d'une tendance nette de déforestation à une tendance nette de reforestation à une échelle spatiale relativement vaste (nationale ou régionale). De tels évènements se sont produits entre autres dans plusieurs pays européens au cours du 19ème siècle. L'idée de départ de la thèse était d'étudier, dans le contexte de pays tropicaux contemporains en développement, la possibilité d'une transition de ce type et la pertinence des théories explicatives développées pour les pays occidentaux tempérés en cours de modernisation. La thèse poursuit trois objectifs: (i) établir la présence éventuelle d'une transition forestière au Vietnam et décrire ses principales caractéristiques, (ii) étudier les causes de cette transition, à l'échelle locale, nationale et internationale, et (iii) dresser le bilan des principaux effets environnementaux de cette transition. Le travail a établi qu'une transition forestière a effectivement eu lieu au Vietnam au cours des années 90, ce qui en fait l'un des rares pays tropicaux dans lequel cette transition s'est produite. La reforestation s'est faite autant par régénération naturelle des forêts que par plantations, et le couvert forestier en 2005 était supérieur à celui de 1980. La reforestation a été causée par une combinaison de processus dans les domaines agraires et forestiers, sous-tendus par des politiques de d'allocation des terres aux ménages, de libéralisation, et de renforcement des règlementations forestières, par des changements dans les marchés agricoles et forestiers, ainsi que par la dégradation des forêts et des terres de montagne et les réactions des acteurs locaux à celle-ci. Selon les contextes, les effets de ces changements sur la situation des habitants des régions reboisées est variable. La reforestation s'est également accompagnée d'un déplacement de la déforestation à l'extérieur du pays, pour combler la demande croissante de bois du Vietnam, qui représente environ 40% de la reforestation dans le pays. L'importation de bois est composée pour moitié de bois illégal coupé dans les forêts naturelles des pays voisins, et la majeure partie de ce bois n'est pas consommée sur place, mais réexportée après transformation. La transition a permis de séquestrer annuellement dans les forêts vietnamiennes plus de carbone que la quantité émise par la consommation d'énergies fossiles au Vietnam. Par contre, la dégradation des forêts continue, et la transition n'a dans l'ensemble pas permis de stopper l'érosion de la biodiversité des forêts vietnamiennes.