Rain-forest area with timber cut and ready to load for export central Ghana AfricaCredit: Robert_Ford/iStock/ Getty Images Plus
Tree conservation in Africa has been focused on national parks and other protected areas, with trees in urban or peri-urban areas left vulnerable to being cut down for heating or cooking fuel.
A study published in Nature Communications shows that over a quarter of Africa’s tree cover could be outside forests, and raises concerns that the impact of tree cutting could be more damaging than previously estimated.
The study used images from nanosatellites to produce a new detailed and large scale research map of the entire continent’s tree cover that traced individual tree canopies.
Lead author, Florian Reiner, from the University of Copenhagen’s Department of Geosciences and Natural Resource Management, told Nature Africa that the tree cover in the study area was compared with the tree cover in the European Space Agency World land cover map at 10m resolution. “This highlights the need for monitoring and sustainable management of these non-forest trees,” he said.
The study provides a more robust and complete evaluation of tree cover in Africa compared to previous measurements, and may have implications for biomass monitoring, sustainable land management, conservation, and landscape ecology. The trees found outside areas classified as forests were in croplands and grasslands. In Libya, Mali, Niger, and Sudan, more than half the tree cover was outside forests.
The study also found surprisingly high numbers of trees in regions with little rainfall across the continent. Another study in Rwanda, published in Nature Climate Change, suggested that Sub-Saharan Africa will need complete mapping of its individual trees to guide planning and monitoring of restoration interventions and optimise their carbon stock as a measure to combat climate change.
Maurice Mugabowindekwe, from the University of Copenhagen and colleagues used satellite imagery and deep learning to map the carbon stock of each individual tree in Rwanda. The team found that trees outside forested areas accounted for almost half of the national carbon stock in the country. They called for comprehensive tree monitoring on the continent to help fulfil climate commitments.
