Georgia Burn Manager Certification Practice Test

The wind’s behavior is governed by roughness and drag created by obstacles. When air moves through a forest, the many branches, leaves, and trunks act like a maze of obstructions that the air must squeeze around. This friction and obstruction slow the average wind speed and produce a lot of turbulence, so the flow inside the trees is slower and more chaotic.

At the tree line, the wind meets a sharp change in surface roughness. It has to negotiate around the edge of the canopy, causing flow separation, eddies, and strong shear near the boundary. Because the trees present substantial drag, the wind behaves differently there than it does moving through the dense interior or in open air.

So the key idea is that vegetation adds drag and roughness, altering wind flow, which is why wind moves differently through trees than at the tree line.