Question

1. Forests have greater impacts than small crops over wind flows because of their more dense canopies. With depth below the canopy, wind speed

a) exponentially decays but gets a secondary maximum near the surface

b) increases

c) none of the above

Answer 1

Wind speed below forest canopies exponentially decays due to the resistance to the airflow from the dense canopy. However, the speed increases near the surface as there is a lesser resistance to the flow due to the spaces between tree trunks and fewer amount of foliage in such spaces. So option a) is correct.

Wind speed does not increase as the resistance to the wind flow due to dense foliage in the canopy tends to decrease the speed. So options (b) and (c) are incorrect.

Thus, the correct option is a) which specifies that the wind speed exponentially decays but gets a secondary maximum near the surface.