1. European Forest Institute, 08025 Barcelona, Spain;,
2. Center for International Forestry Research, Lima 12, Peru
3. Institute for Food and Resource Economics and Center for Development Research, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany;
4. CIRAD, Unité Propre de Recherche Forêts et Sociétés (FORETS), Campus de Baillarguet, 34090 Montpellier, France;
5. Department of Environment and Natural Resources, World Bank, Washington, DC 20433, USA;