Which forestry practice decreases competition and improves the overall health and productivity of a forest?

A. Desertification

B. Clear-cutting

C. Slash-and-burn

D. Thinning

Answer is (D) Thinning

Thinning is the forestry practice of selectively removing certain trees to increase the productivity of the forest. Example eucalyptus trees have a higher water consumption and demand. Now if there are several such trees in a forest, it will affect the water demand of the other trees. It will be competing for resources. Hence by selective removal of such trees, the health of a forest can be boosted.

D-Thinning that's the forestry it decreases and improves the overall health and productivity of a forest.