Concept:Forests in arid regions act as windbreaks and stabilise soil to stop the spread of deserts.
Explanation:The main objective of establishing forests in arid regions is to check desert encroachment.
Arid areas are highly prone to wind erosion because rainfall is low and vegetation is scarce.
Trees planted in such zones reduce wind velocity at ground level.
Their roots bind the soil particles firmly, preventing them from being carried away.
Forests in these areas also help retain soil moisture and improve microclimate conditions.
This forms a protective green barrier against the southward advance of the Sahara desert.
Providing firewood, bush meat, or improving the beauty of the environment are only incidental secondary benefits.
They are not the primary reason for afforestation in dry regions.
Answer:A. check desert encroachment