ORIGINAL ARTICLE Agroforest’s growing role in reducing carbon losses from Jambi (Sumatra), Indonesia Grace B. Villamor • Robert Gilmore Pontius Jr. • Meine van Noordwijk Received: 18 January 2013 / Accepted: 25 August 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract This paper examines the size and intensity of changes among five land categories during the two time inter- vals in a region of Indonesia that is pioneering negotiations concerning reducing emissions from deforestation and forest degradation (REDD). Maps at 1973, 1993, and 2005 indicate that land-cover change is accelerating, while carbon loss is decelerating in Jambi Province, Sumatra. Land dynamics have shifted from Forest loss during 1973–1993 to Agroforest loss during 1993–2005. Forest losses account for most reductions in aboveground carbon during the both time intervals, but Agro- forest plays an increasingly important role in carbon reductions during the more recent interval. These results provide motiva- tion for future REDD policies to count carbon changes asso- ciated with all influential land categories, such as Agroforests. Keywords Agroforest  Carbon  Indonesia  Intensity analysis  Land-cover change  REDD Introduction Land change The most important form of land conversion is the expansion of crops and pasture in natural ecosystems (Lambin and Meyfroidt 2011). The main driver of defor- estation in Indonesia is agricultural expansion, such as transitions to rubber and oil palm (Miyamoto 2006, 2007). The rampant deforestation on the island of Sumatra was 12 million ha during 1985–2007 (Laumonier et al. 2010). Indonesia has been reported as one of the main contributors of greenhouse gases from deforestation and forest degra- dation (Baumert et al. 2004; Achard et al. 2004; Parker 2011). If we are to understand and mitigate the possible negative impacts caused by land change, then it is essential to detect the patterns of land change, so that we can better grasp the pro- cesses of land change. Lambin (1997) points out that research concerning land change should be aimed at addressing the questions of why, where, and when? This paper answers the following questions: (1) During which time intervals is annual change area relatively slow versus fast? (2) Which land cat- egories are relatively dormant versus active during a given time interval, and is the pattern stationary across time inter- vals? (3) Which transitions are targeting versus avoiding during a given time interval, and is the pattern stationary across time intervals? Simultaneously, we estimate carbon- stock change resulting from land-cover change to provide insights and recommendations for ongoing policy discussions concerning Indonesia’s participation in reducing emissions from deforestation and degradation (REDD). Sumatra’s landscape history The Dutch introduced rubber trees (Hevea brasiliensis) to Indonesia from Brazil at the beginning of the twentieth century. The climate of Sumatra is similar to the climate of Brazil, so these trees thrived and rapidly replaced shifting cultivation on the island (Gouyon et al. 1993). Forests transitioned to Agroforests, facilitated through policies that G. B. Villamor (&) Center for Development Research, University of Bonn, Bonn, Germany e-mail: gracev@uni-bonn.de G. B. Villamor  M. van Noordwijk World Agroforestry Centre, Southeast Asia Regional Office, JL. CIFOR, Situ Gede, Bogor, Indonesia R. G. Pontius Jr. Graduate School of Geography, Clark University, Worcester, MA, USA 123 Reg Environ Change DOI 10.1007/s10113-013-0525-4