Surprisingly, the best windbreaks are also, typically, permeable. Permeable windbreaks, such as trees, will let just enough of breeze through so as to significantly reduce wind speeds in a given place without causing significant turbulence nearby. Impervious walls and fences work as windbreaks, too, but impervious windbreaks can also create significant turbulence on the leeward side of the solid surface, and this kind of turbulence can cause more problems than you had before the “windbreak” was ever constructed. It’s helpful to realize, too, that winds don’t blow. They suck. Atmospheric pressure changes create vacuums that draw “wind” toward the pockets of lower pressure.