A new economic model has been developed by researchers to predict the waves of forest degradation that emanate from African cities in search of nearby resources. The model is based on the assumption that the local resources will be targeted in order of their intrinsic value.
An important study for progressing knowledge of forest degradation rather than deforestation by clear felling, it shows how the highest value resources will generally be targeted by a first wave of exploitation and forest degradation. Published late May in the Proceedings of the National Academy of Sciences, the paper says that the first wave selects the most expensive timber trees, usually for the export market. In Tanzania, where the research was focussed on the years 1991 to 2005, most of this high value timber has been sucked in to the booming Chinese markets.
“This is very similar to what we find in South America,” explained Matthew Owen, Director of Cool Earth Action. “In Peru, for example, the area where we work to avoid deforestation with Asháninka communities was first hit by a wave of illegal loggers in 2004. They were only interested in the mahogany stands. Three years later, legal loggers turned up at the communities trying to negotiate for the next most valuable trees, like nogal (Juglans neotropica, a large wild Peruvian walnut) and tornillo (Cedrelinga catenaeformis, a tall rainforest pine).”
“The African study shows how waves expand in line with urban growth and migration,” continued Owen. “In Tanzania, the third and most destructive wave involved local people collecting wood to make cooking charcoal, while in Peru the final wave usually transforms the remaining forest into agricultural fields for ranching, cash cropping or citrus production.”
Understanding forest degradation drivers is essential for the best management of forests to mitigate climate change and predicting degradation patterns can inform policy makers and baseline calculations for programmes like the UN REDD (Reduced Emissions from Deforestation and Forest Degradation) initiative.