Why has the National Forest Commission of India recommended

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

It is our moral duty to protect, restore and conserve/preserve the forests as they are highly beneficial for mankind.
In India, around 30% of land was covered by forest in early 20th century, which was reduced to 18-19% by the year 2000.
National Forest Commission of India (1988) recommended a 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.