Reduction of tree cover in West African woodlands and promotion in semi-arid farmlands

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Woody vegetation in farmland acts as a carbon sink and provides ecosystem services for local people, but no macroscale assessments of the impact of management and climate on woody cover exist for drylands. Here we make use of very high spatial resolution satellite imagery to derive wall-to-wall woody cover patterns in tropical West African drylands. Our study reveals that mean woody cover in farmlands along all semi-arid and sub-humid rainfall zones is 16%, on average only 6% lower than in savannahs. In semi-arid Sahel, farmland management promotes woody cover around villages (11%), while neighbouring savannahs had on average less woody cover. However, farmlands in sub-humid zones have a greatly reduced woody cover (21%) as compared with savannahs (33%). In the region as a whole, rainfall, terrain and soil are the most important (80%) determinants of woody cover, while management factors play a smaller (20%) role. We conclude that agricultural expansion causes a considerable reduction of trees in woodlands, but observations in Sahel indicate that villagers safeguard trees on nearby farmlands which contradicts simplistic ideas of a high negative correlation between population density and woody cover.


  • Martin Brandt
  • Kjeld Rasmussen
  • Pierre Hiernaux
  • Stefanie Herrmann
  • Compton J. Tucker
  • Xiaoye Tong
  • Feng Tian
  • Ole Mertz
  • Laurent Kergoat
  • Cheikh Mbow
  • John L. David
  • Katherine A. Melocik
  • Morgane Dendoncker
  • Caroline Vincke
  • Rasmus Fensholt
Enheter & grupper
Externa organisationer
  • University of Copenhagen
  • Géosciences Environnement Toulouse
  • University of Arizona
  • National Aeronautics and Space Administration
  • START International Inc
  • European Commission
Sidor (från-till)328-333
Antal sidor6
TidskriftNature Geoscience
Utgåva nummer5
StatusPublished - 2018 maj 1
Peer review utfördJa