The edges have it

You can use the shape of a leaf to help you identify a tree. But not all trees play fair! Some have leaves whose shape varies depending on their age, exposure to the sun, and even the season. You can see three types of leaves in this photo: simple, lobed and dentate (toothed).

Leaves' shape also affects the boundary layer (Interface area between the air and the leaf, in which a thin layer of stagnant air sticks to the leaf, more or less saturated with water.) that surrounds them. Dentate and lobed leaves are less aerodynamic than simple ones. When the wind strikes their surface, small eddies stir the air and reduce the impact of the boundary layer, effectively providing a breath of fresh air!