Positive effects

1. Wind brings fresh supplies of carbon dioxide to the foliage of trees and thus helps in photosynthesis
2. Wind helps in pollination of anemophilous flowers
3. Wind helps in the dispersal of seed of many forest trees. Eg. Toonaciliata, Bombaxceiba, etc

Harmful effects

Direct harmful effects: Tapering in the boles, bending, uprooted, branches damaged, growth affected, etc
Indirect harmful effects: Fans up forest fire resulting in fire damage; increase evaporation; wind erosion and removes fertile soil depositing sand, etc.