Before revision: Windbreak aerodynamics An East German windbreak promotion poster, 1952 In essence, when the wind encounters a porous obstacle such as a windbreak or shelterbelt, air pressure increases (loosely speaking, air piles up) on the windward side and (conversely) air pressure decreases on the leeward side.
After revision: Windbreak aerodynamics An East German windbreak promotion poster, 1952 When wind encounters a porous obstacle such as a windbreak or shelterbelt, air pressure increases on the windward side and , decreases on the leeward side.