Sahel zone The semi-arid southern border of the Sahara in western Africa, which supports a very dry type of savannah including scattered, thorny trees. In recent years the desert has advanced appreciably into the Sahel zone, partly at least as the result of poor land management. Compare Guinea zone.

Sahel zone The semi-arid southern border of the Sahara in western Africa, which supports a very dry type of savannah including scattered, thorny trees. In recent years the desert has advanced appreciably into the Sahel zone, partly at least as the result of poor land management. Compare GUINEA ZONE.