Agroforestry: Enhancing Water Use Efficiency = James R. Brandle, Xinhua Zhou and Laurie Hodges

More porous barriers, for example, single rows of deciduous species, result in less wind speed reduction but also less turbulence. The downwind extent of the protected area is generally greater for more porous barriers. As a result, narrow, less dense barriers (4060% density) are typically used to protect crop fields.