Editing Windbreak

{{Short description|Rows of trees or shrubs planted to provide shelter from the wind}}
{{use dmy dates |date=July 2023}}
{{for|crops left to dry in the wind with the appearance of hedgerows|windrow}}{{Distinguish|breaking wind}}
[[File:Shea_Butter_Trees_Planted_Near_Residential_Areas_to_Serve_as_Windbreaks.jpg|thumb|[[Shea tree|Shea butter tree]]s planted near residential areas to serve as windbreaks]]
A '''windbreak''' (shelterbelt) is a [[planting]] usually made up of one or more rows of [[tree]]s or [[shrub]]s planted in such a manner as to provide shelter from the [[wind]] and to protect soil from [[erosion]]. They are commonly planted in [[hedge]]rows around the edges of fields on [[farm]]s. 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 or yards.<ref>{{cite web|title=Windbreaks|url=https://www.fs.usda.gov/nac/practices/windbreaks.shtml|website=National Agroforestry Center|access-date=29 April 2015}}</ref> Farmers sometimes use windbreaks to keep snow drifts on farm land that will provide water when the snow melts in the spring. Other benefits include contributing to a [[microclimate]] around [[crop]]s (with slightly less [[drying]] and chilling at night), providing [[habitat]] for wildlife,<ref>{{Cite news|url=http://www.blue-berry.pl/index.php/blog/role-of-trees-in-agriculture|title=Role of trees in agriculture|access-date=2018-02-13}}</ref> and, in some regions, providing [[wood]] if the trees are harvested.

Windbreaks and [[intercropping]] can be combined in a farming practice referred to as [[alley cropping]], or being deployed along riparian buffer stripes.<ref>{{cite journal |last1=Englund |first1=Oskar |last2=Börjesson |first2=Pål |last3=Mola-Yudego |first3=Blas |last4=Berndes |first4=Göran |last5=Dimitriou |first5=Ioannis |last6=Cederberg |first6=Christel |last7=Scarlat |first7=Nicolae |title=Strategic deployment of riparian buffers and windbreaks in Europe can co-deliver biomass and environmental benefits |journal=Communications Earth & Environment |date=2021 |volume=2 |issue=1 |page=176 |bibcode=2021ComEE...2..176E |s2cid=237310600 |doi=10.1038/s43247-021-00247-y |doi-access=free }}</ref> 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.<ref>{{cite book |last=Withgott |first=Jay |author2=Scott Brennan |year=2008 |title=Environment: The Science Behind the Stories |edition=3rd |location=San Francisco |publisher=Pearson Benjamin Cummings |page=249 |isbn=978-0131357051}}</ref>

A further use for a shelterbelt is to screen a farm from a main road or motorway.<ref>{{Cite book|last=Hetlzer|first=Robert|title=Soil Survey of Walsh County, North Dakota|publisher=United States NRCS Soil Conservation Service|year=1972|url=https://books.google.com/books?id=LUfYcK7fpBoC|pages=75}}</ref> This improves the farm landscape by reducing the visual incursion of the motorway, [[Noise mitigation|mitigating noise]] from the traffic and providing a safe barrier between farm animals and the road.

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 87.5%.{{Citation needed|date=June 2021}}

Sheltered, windless areas created by windbreaks are called wind shadows.<ref>{{Citation|last=Matthews|first=John A.|title=WIND SHADOW|date=2014|url=http://sk.sagepub.com/reference/dictionaryenvirochange/n4179.i1.xml|encyclopedia=Encyclopedia of Environmental Change|pages=1175|publisher=SAGE Publications, Ltd.|doi=10.4135/9781446247501 |isbn=9781446247112 |access-date=2020-03-30|url-access=subscription}}</ref>

Windbreaks can mitigate the effects of [[pesticide drift]].<ref>{{cite journal |doi=10.1002/ps.341 |title=Windbreaks as a pesticide drift mitigation strategy: A review |date=2001 |last1=Ucar |first1=Tamer |last2=Hall |first2=Franklin R. |journal=Pest Management Science |volume=57 |issue=8 |pages=663–675 }}</ref>

<gallery widths="200px" heights="200px">
Image:FieldWindbreaks.JPG|Aerial view of field windbreaks in [[North Dakota]]
Image:Svappavaara 1965a.jpg|One of the original buildings at [[Svappavaara]], designed by [[Ralph Erskine (architect)|Ralph Erskine]], which forms a long windbreak
File:Lesja leplanting.JPG|Windbreaks in [[Lesja]], Norway, also used to collect snow in a dry area.
</gallery>

== Windbreak aerodynamics ==
[[Image:Bundesarchiv Bild 183-15117-0005, Infografik, Windschutz, Ertragssteigerung.jpg|thumb|An [[East Germany|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. As a result, the airstream approaching the barrier is interrupted, and a portion of it moves over the barrier, resulting in a jet of higher wind speed. The remainder of the airstream then moves through the barrier to its edge downstream, pushed along by the decrease in pressure across the shelterbelt's width; as it emerges again, that airstream is interrupted further as its air pressure adjusts to the surrounding area. This results in slower wind speed further downwind, reaching a minimum at a distance of about 3 to 5 times the windbreak's height. Beyond that point wind speed recovers, aided by the overlying, faster-moving stream. From the perspective of the [[Reynolds-averaged Navier–Stokes equations]], these effects can be understood as resulting from the loss of momentum caused by the drag of leaves and branches and would be represented by the body force ''f<sub>i</sub>'' (a distributed momentum sink).<ref>{{cite journal |doi=10.1016/0167-6105(85)90001-7 |title=Numerical studies of flow through a windbreak |year=1985 |last1=Wilson |first1=John D. |journal=Journal of Wind Engineering and Industrial Aerodynamics |volume=21 |issue=2 |pages=119–154 }}</ref>

Windbreaks reduce the wind's average air speed and make it less variable, resulting in the wind mixing less effectively than it does upwind. Additionally, all these changes to the wind's behavior result in changes to the region's environment. For instance, the [[surface energy budget]] of the ground may be impacted, as the slowed wind dissipates heat from the sun less effectively; this trend may reverse further downwind, and about 8 times the windbreak's height downstream, the windbreak may result in cooler surface temperatures.<ref>{{cite journal |doi=10.1016/0168-1923(89)90016-6 |title=The microclimate in the centre of small square sheltered plots |year=1989 |last1=Argete |first1=J.C |last2=Wilson |first2=J.D |journal=Agricultural and Forest Meteorology |volume=48 |issue=1–2 |pages=185–199 |bibcode=1989AgFM...48..185A }}</ref>

== Windbreak organizations ==
* The [[Great Plains Shelterbelt]] was an American initiative to create shelterbelts on the prairies in the USA during the [[Dust Bowl]] of the 1930s.
* The [[Prairie Farm Rehabilitation Administration]] in Indian Head, Saskatchewan, Canada, subsidized seedlings to prairie farmers for almost 100 years to reduce soil erosion and increase quality of life on the prairies.

==See also==
{{Div col|colwidth=15em}}
* [[Agroforestry]]
* [[Buffer strip]]
* [[Dead hedge]]
* [[Desertification]]
* [[Energy-efficient landscaping]]
* [[Erosion control]]
* [[Hedgerow]]
* [[Macro-engineering]]
* [[Rain shadow]]
* [[Sahara Forest Project]]
* [[Sand fence]]
* [[Seawater Greenhouse]]
* [[Tugay]]
{{Div col end}}

==References==
{{Reflist}}

==External links==
{{commons category|Windbreaks}}
* [https://www.fs.usda.gov/nac/practices/windbreaks.shtml National Agroforestry Center (USDA)]
* {{URL|https://data.mendeley.com/datasets/675gwk5jp7/1|The Bibliography of Aeolian Research}}

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[[Category:Agriculture]]
[[Category:Agroforestry]]
[[Category:Forestry and the environment]]
[[Category:Landscape ecology]]