In recent decades networks of permanent research plots has been established in tropical forests around the world, providing many fascinating insights into tropical forest ecology and the response of these ecosystems to environmental change (see for example http://www.rainfor.org/en). However, these networks obviously only cover relatively small areas of forest, and require huge effort (and money!) to regularly monitor.
This interesting new study uses a different approach, utilising several datasets from satellites to detect changes in forest dynamics. They show that in the Congo basin, a recent drying trend has led to a decline in "forest greenness" (a slightly ambiguous measure that probably reflects a change in photosynthetic capacity and some structural characteristics of the forest canopy).
Despite this "browning" of the Congo rainforest, biomass in this region has been increasing (see some of the work that has come out of the the AfriTRON project http://www.afritron.org/en), so while changes are occurring, it still isn't clear what will happen to the forests in this region over the coming decades...
The central African rainforests, the second-largest on Earth, have experienced a long-term drying trend10, 11 whose impacts on vegetation dynamics remain mostly unknown because in situ observations are very limited... ...our results suggest that a continued gradual decline of photosynthetic capacity and moisture content driven by the persistent drying trend could alter the composition and structure of the Congolese forest to favour the spread of drought-tolerant species