Time for an update on how the rainforests in Africa are doing? Have a look at the recent Phil Trans R Soc B theme issue on “Change in African rainforests: past, present and future” (link). Since some of us are working on analyzing deforestation rates and patterns we chose to read Mayaux et al.’s paper: “State and evolution of the African rainforests between 1990 and 2010” for our journal club discussion.

The authors present a map of Africa’s rainforests in 2005 and estimate deforestation rates between 1990, 2000 and 2010, based on sampling Landsat images. They report net deforestation to have decreased from 0.28 % per year for 1990-2000 to 0.14 % per year for 2000-2010. There are clear regional differences, with West Africa and especially Madagascar having much higher deforestation rates than the Congo Basin. The authors also try to assess the underlying drivers of deforestation but this part of the study seems superficial and basically only identifies relationships between already known key factors (such as population, travel time to closest city, cropland and logging concessions) and deforestation. A bit surprisingly, proportion of logging concessions seems to have little or no direct influence on forest cover.

It was interesting to read about the technical details of formatting the Landsat data and the sampling done for assessing the deforestation rates. We remained a bit uncertain of how biased the sampling process was; what was the effect of the places with clouds always being left out? How much do differences between reported deforestation rates depend on the thresholds used to identify classes and can deforestation rates between different studies be compared (as they compare their results to rates in Latin America)?

We also spotted some loose ends that the authors mentioned but never really addressed or discussed further; such as REDD or the aspect of the threatened species. Finally, we would have liked to see some more discussion on the importance of capacity building in dealing with the problem of deforestation in Africa.

Mayaux et al. 2013. State and evolution of the African rainforests between 1990 and 2010. Phil Trans R Soc B 368: 20120300.

DOI: 10.1098/rstb.2012.0300

* Note that the authors represent big international research institutions such as the European Commission’s IES, FAO and CIFOR.