Why has the National Forest Commission of India recommended a relatively larger forest cover for hills than for plains?

Explanation

It is our moral duty to protect, restore and conserve/ preserve the forest as they are highly beneficial for mankind.
In India, around 30% of land was covered by forest in early 2000. National Forest Commission of India (1988) recommended at relatively large forest cover, i.e. 67% for the hills and 33% for the plains. Recommendation of a large forest area for hills is due to its properties like checking soil erosion, percolation and recharging groundwater, checking landslide and other natural calamities and to maintain the original flora and fauna of hills.