Agradecimentos: We are greatly thankful to the field crew at FMU 11.001 and the staff of the TRC logging company, for their invaluable support with the preparations for fieldwork and great help with tree identification and sampling. In particular, we would like to thank David Zakamdi and the villagers of Okoroba and Abat for welcoming us. Additionally, Prof. Dr. Martin Tchamba and the Department of Forestry of the University of Dschang are acknowledged for their support. Finally, we would also like to thank Peter van der Sleen, Mart Vlam, Wouter Berendsen, Fintan Kelly, William Mbia Nanga, Moïse Guy Singha, Thomas Voswinkel, Evelien Louwers, Katrui Veldhuijzen, Irene Bender and Richard Peters for their dedication with field work, ring-measurements, and discussions. Tree-ring data available at the Dryad Data Repository http://dx.doi.org/10.5061/dryad.22vg4 (Sheil et al., 2016). This study was supported by a European Research Council grant to PAZ (ERC, grant #242955) Ver menos

Worldwide, over 400 million hectares of tropical forests are set aside for timber production. Several certification schemes exist to ensure more sustainable exploitation and large areas of production forests are currently certified. Under such schemes, logging companies are required to evaluate whether species are not overexploited and, if necessary, adapt their logging activities. However, the data needed to project exploitation intensities – growth, mortality and regeneration rates of trees – are scarce or non-existent. Tree-ring analysis provides lifetime species-specific growth data that can be used to allow or improve the projections of timber availability during following logging cycles. In this study, we integrated growth data from tree rings with logging inventory data to forecast timber yields in the next harvest round for four timber species in Cameroon. We compared projections using tree-ring data with projections using fixed growth rates, as set by law and customarily applied in Cameroon. Additionally, we assessed the effect of increasing logging cycles and of using filed-based species-specific logging intensities on the next cycle’s yield projections. Under current logging practices, timber volumes available at next logging cycles are projected to be 21–36% of the volumes obtained at first harvest. Simulations using fixed rates often resulted in lower yields with lower volume ingrowth from trees that were below minimum cutting diameters in the first harvest. Lengthening the logging cycle increased yield predictions during the next harvests, but yields were still not sustained over time. This problem can be resolved by using species-specific logging intensities, which led to projected yields of up to 73% of the initial harvested volume. The growth data provided by tree-ring analysis allows conducting such species-specific projections and thus helps to provide the knowledge base necessary for sustainable forest management. Yet, the low overall yields are a concern to forest conservation, as loss of economic value may lead to conversion of forests to other land uses Ver menos