 a windbreak or shelterbelt is a plantation usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. they are commonly planted around the edges of fields on farms. if designed properly, windbreaks around a home can reduce the cost of heating and cooling and save energy. windbreaks are also planted to help keep snow from drifting onto roadways and even yards. other benefits include providing habitat for wildlife and in some regions the trees are harvested for wood products. windbreaks and intercropping can be combined in a farming practice referred to as alleycropping. fields are planted in rows of different crops surrounded by rows of trees. these trees provide fruit, wood, or protect the crops from the wind. alley cropping has been particularly successful in india, africa, and brazil, where coffee growers have combined farming and forestry.withgott & brennan 2008, p.249 a further use for a shelterbelt is to screen a farm from a main road or motorway. this improves the farm landscape by reducing the visual incursion of the motorway, mitigating noise from the traffic and providing a safe barrier between farm animals and the road. the term "windbreak" is also used to describe an article of clothing worn to prevent wind chill. americans tend to use the term "windbreaker" whereas europeans favor the term "windbreak". fences called "windbreaks" are also used. normally made from cotton, nylon, canvas, and recycled sails, windbreaks tend to have three or more panels held in place with poles that slide into pockets sewn into the panel. the poles are then hammered into the ground and a windbreak is formed. windbreaks or "wind fences" are used to reduce wind speeds over erodible areas such as open fields, industrial stockpiles, and dusty industrial operations. as erosion is proportional to wind speed cubed a reduction of wind speed of 1/2 (for example) will reduce erosion by over 80%. == windbreak aerodynamics ==  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. as a result the airstream approaching the barrier is retarded, and a proportion of it is displaced up and over the barrier, resulting in a jet of higher wind speed aloft. the remainder of the impinging airstream, having been retarded in its approach, now circulates through the barrier to its downstream edge, pushed along by the decrease i
Agriculture Agroforestry Forestry_and_the_environment Landscape_ecology