Vietnam’s Forest Transition in Retrospect: Demonstrating Weaknesses in Business-as-Usual Scenarios for REDD+ Jeppe Ankersen • Kenneth Grogan • Ole Mertz • Rasmus Fensholt • Jean-Christophe Castella • Guillaume Lestrelin • Dinh Tien Nguyen • Finn Danielsen • Søren Brofeldt • Kjeld Rasmussen Received: 17 October 2013 / Accepted: 2 January 2015 / Published online: 15 January 2015 Ó Springer Science+Business Media New York 2015 Abstract One of the prerequisites of the REDD? mechanism is to effectively predict business-as-usual (BAU) scenarios for change in forest cover. This would enable estimation of how much carbon emission a project could potentially prevent and thus how much carbon credit should be rewarded. However, different factors like forest degradation and the lack of linearity in forest cover tran- sitions challenge the accuracy of such scenarios. Here we predict and validate such BAU scenarios retrospectively based on forest cover changes at village and district level in North Central Vietnam. With the government’s efforts to increase the forest cover, land use policies led to gradual abandonment of shifting cultivation since the 1990s. We analyzed Landsat images from 1973, 1989, 1998, 2000, and 2011 and found that the policies in the areas studied did lead to increased forest cover after a long period of decline, but that this increase could mainly be attributed to an increase in open forest and shrub areas. We compared Landsat classifications with participatory maps of land cover/use in 1998 and 2012 that indicated more forest degradation than was captured by the Landsat analysis. The BAU scenarios were heavily dependent on which years were chosen for the reference period. This suggests that hypothetical REDD? activities in the past, when based on the remote sensing data available at that time, would have been unable to correctly estimate changes in carbon stocks and thus produce relevant BAU scenarios. Keywords Deforestation Á Reforestation Á Forest degradation Á REDD? Á Vietnam Á Land use change Á Shifting cultivation Introduction During the last century tropical forest cover has declined rapidly, and even though the speed of deforestation slowed over the period 2000–2010, annual forest losses still occur (FAO 2010; Hansen et al. 2013). Part of the explanation for the reduced rate of forest loss after the turn of the mil- lennium is that some developing countries have experi- enced a forest transition resembling that of most developed countries and are now experiencing net reforestation (Meyfroidt and Lambin 2011). However, since reforesta- tion in some cases has occurred through secondary forest growth and establishment of forest plantations, sometimes with a continuing loss of old growth forest (Mather 1992, 2007; Meyfroidt and Lambin 2011), forest degradation continues in these regions (Mertz et al. 2012). The release of greenhouse gases (GHG) from tropical deforestation and forest degradation has led to continued negotiations on developing a mechanism for Reduced Emissions from Deforestation and Forest Degradation and forest conser- vation, sustainable forest management, and enhancement J. Ankersen Á K. Grogan Á O. Mertz (&) Á R. Fensholt Á K. Rasmussen Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350, Copenhagen K, Denmark e-mail: om@ign.ku.dk J.-C. Castella Á G. Lestrelin Institut de Recherche pour le De ´veloppement (IRD), UMR 220 GRED, Vientiane, Lao PDR D. T. Nguyen Center for Agricultural Research and Ecological Studies (CARES), Vietnam National University of Agriculture, Gia Lam, Hanoi, Vietnam F. Danielsen Á S. Brofeldt NORDECO, Skindergade 23, 1159, Copenhagen K, Denmark 123 Environmental Management (2015) 55:1080–1092 DOI 10.1007/s00267-015-0443-y