Windbreak

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Aerial view of field windbreaks in North Dakota FieldWindbreaks.JPG
Aerial view of field windbreaks in North Dakota
One of the original buildings at Svappavaara, designed by Ralph Erskine, which forms a long windbreak Svappavaara 1965a.jpg
One of the original buildings at Svappavaara, designed by Ralph Erskine, which forms a long windbreak

A windbreak (shelterbelt) is a planting 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 in hedgerows 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 or yards. [1] 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 crops (with slightly less drying and chilling at night), providing habitat for wildlife, [2] and, in some regions, providing wood if the trees are harvested.

Contents

Windbreaks and intercropping can be combined in a farming practice referred to as alleycropping, or being deployed along riparian buffer stripes. [3] 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. [4]

A further use for a shelterbelt is to screen a farm from a main road or motorway. [5] 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.

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 ]

Sheltered, windless areas created by windbreaks are called wind shadows. [6]

Windbreaks can mitigate the effects of pesticide drift. [7]

Windbreak aerodynamics

An East German windbreak promotion poster, 1952 Bundesarchiv Bild 183-15117-0005, Infografik, Windschutz, Ertragssteigerung.jpg
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. 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 windspeed 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 fi (a distributed momentum sink). [8]

Windbreaks reduces the wind's average air speed and makes 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. [9]

Windbreak organizations

See also

Windbreaks in Lesja, Norway, also used to collect snow in a dry area. Lesja leplanting.JPG
Windbreaks in Lesja, Norway, also used to collect snow in a dry area.

Related Research Articles

<span class="mw-page-title-main">Soil erosion</span> Displacement of soil by water, wind, and lifeforms

Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and animals. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolian) erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes.

<span class="mw-page-title-main">Prairie</span> Ecosystems considered part of the temperate grasslands, savannas, and shrublands biome

Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type. Temperate grassland regions include the Pampas of Argentina, Brazil and Uruguay, and the steppe of Ukraine, Russia and Kazakhstan. Lands typically referred to as "prairie" tend to be in North America. The term encompasses the area referred to as the Interior Lowlands of Canada, the United States, and Mexico, which includes all of the Great Plains as well as the wetter, hillier land to the east.

<span class="mw-page-title-main">Hedge</span> Planted row of shrubs

A hedge or hedgerow is a line of closely spaced shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate a road from adjoining fields or one field from another, and are of sufficient age to incorporate larger trees, are known as hedgerows. Often they serve as windbreaks to improve conditions for the adjacent crops, as in bocage country. When clipped and maintained, hedges are also a simple form of topiary.

<span class="mw-page-title-main">Agroforestry</span> Land use management system

Agroforestry is a land use management system in which combinations of trees are grown around or among crops or pasture. Agroforestry combines agricultural and forestry technologies to create more diverse, productive, profitable, healthy, and sustainable land-use systems. Benefits include increasing farm profitability, reduced soil erosion, creating wildlife habitat, managing animal waste, increased biodiversity, improved soil structure, and carbon sequestration.

<span class="mw-page-title-main">Soil conservation</span> Preservation of soil nutrients

Soil conservation is the prevention of loss of the topmost layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination.

<span class="mw-page-title-main">Afforestation</span> Establishment of trees where there were none previously

Afforestation is the establishment of a forest or stand of trees (forestation) in an area where there was no recent tree cover. In comparison, reforestation means re-establishing forest that have either been cut down or lost due to natural causes, such as fire, storm, etc. There are three types of afforestation: Natural regeneration, agroforestry and commercial plantations. The intended benefits of afforestation are numerous. In the context of climate change, afforestation can be helpful for climate change mitigation through the route of carbon sequestration. Afforestation can also improve the local climate through increased rainfall and by being a barrier against high winds. The additional trees can also prevent or reduce topsoil erosion, floods and landslides. Finally, additional trees can be a habitat for wildlife, and provide employment and wood products.

<span class="mw-page-title-main">Riparian zone</span> Interface between land and a river or stream

A riparian zone or riparian area is the interface between land and a river or stream. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone,riparian corridor, and riparian strip are used to characterize a riparian zone. The word riparian is derived from Latin ripa, meaning "river bank".

<span class="mw-page-title-main">Silvopasture</span> Agricultural practice of grazing animals in woodland

Silvopasture is the practice of integrating trees, forage, and the grazing of domesticated animals in a mutually beneficial way. It utilizes the principles of managed grazing, and it is one of several distinct forms of agroforestry.

<span class="mw-page-title-main">Multipurpose tree</span> Trees grown and managed for more than one output

Multipurpose trees or multifunctional trees are trees that are deliberately grown and managed for more than one output. They may supply food in the form of fruit, nuts, or leaves that can be used as a vegetable; while at the same time supplying firewood, adding nitrogen to the soil, or supplying some other combination of multiple outputs. "Multipurpose tree" is a term common to agroforestry, particularly when speaking of tropical agroforestry where the tree owner is a subsistence farmer.

The Prairie Farm Rehabilitation Administration (PFRA) was a branch under Agriculture and Agri-Food Canada (AAFC), a department of the Federal Government of Canada.

<span class="mw-page-title-main">Erosion control</span> Practice of preventing soil erosion in agriculture and land development

Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development, coastal areas, river banks and construction. Effective erosion controls handle surface runoff and are important techniques in preventing water pollution, soil loss, wildlife habitat loss and human property loss.

<span class="mw-page-title-main">Conservation Reserve Program</span> U.S. federal aid program

The Conservation Reserve Program (CRP) is a cost-share and rental payment program of the United States Department of Agriculture (USDA). Under the program, the government pays farmers to take certain agriculturally used croplands out of production and convert them to vegetative cover, such as cultivated or native bunchgrasses and grasslands, wildlife and pollinators food and shelter plantings, windbreak and shade trees, filter and buffer strips, grassed waterways, and riparian buffers. The purpose of the program is to reduce land erosion, improve water quality and effect wildlife benefits.

<span class="mw-page-title-main">Social forestry in India</span>

Social forestry is the management and protection of forests and afforestation of barren and deforested lands with the purpose of helping environmental, social and rural development. The term social forestry was first used in 1976 by The National Commission on Agriculture, when the government of India aimed to reduce pressure on forests by planting trees on all unused and fallow lands. It was intended as a democratic approach to forest conservation and usage, maximizing land utilization for multiple purposes.

<span class="mw-page-title-main">Buffer strip</span>

A buffer strip is an area of land maintained in permanent vegetation that helps to control air quality, soil quality, and water quality, along with other environmental problems, dealing primarily on land that is used in agriculture. Buffer strips trap sediment, and enhance filtration of nutrients and pesticides by slowing down surface runoff that could enter the local surface waters. The root systems of the planted vegetation in these buffers hold soil particles together which alleviate the soil of wind erosion and stabilize stream banks providing protection against substantial erosion and landslides. Farmers can also use buffer strips to square up existing crop fields to provide safety for equipment while also farming more efficiently.

<span class="mw-page-title-main">Riparian buffer</span> Vegetated area near a stream, usually forested

A riparian buffer or stream buffer is a vegetated area near a stream, usually forested, which helps shade and partially protect the stream from the impact of adjacent land uses. It plays a key role in increasing water quality in associated streams, rivers, and lakes, thus providing environmental benefits. With the decline of many aquatic ecosystems due to agriculture, riparian buffers have become a very common conservation practice aimed at increasing water quality and reducing pollution.

<span class="mw-page-title-main">Sand fence</span>

A sand fence or sandbreak, similar to a snow fence, is a barrier used to force windblown, drifting sand to accumulate in a desired place. Sand fences are employed to control erosion, help sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas. Sand fences are also commonly employed following storm events in order to aid in the dune recovery process, particularly in developed areas where dunes are critical for protection of property.

<span class="mw-page-title-main">Great Plains Shelterbelt</span> Areas between Canada and West Texas afforested as part of the New Deal

The Great Plains Shelterbelt was a project to create windbreaks in the Great Plains states of the United States, that began in 1934. President Franklin D. Roosevelt initiated the project in response to the severe dust storms of the Dust Bowl, which resulted in significant soil erosion and drought. The United States Forest Service believed that planting trees on the perimeters of farms would reduce wind velocity and lessen evaporation of moisture from the soil. By 1942, 220 million trees had been planted, covering 18,600 square miles (48,000 km2) in a 100-mile-wide zone from Canada to the Brazos River. Even as of 2007, "the federal response to the Dust Bowl, including the Prairie States Forestry Project which planted the Great Plains Shelterbelt and creation of the Soil Erosion Service, represents the largest and most-focused effort of the [U.S.] government to address an environmental problem".

<span class="mw-page-title-main">Filter strip</span>

Filter strips, also referred to as buffer strips, are small, edge-of-field tracts of vegetated land that are used to reduce the contamination of surface water. They are primarily used in agriculture to control non-point source pollution, however, they may also be used to reduce sediment in storm water runoff from construction sites. There are several types of filter strips including vegetative filter strips, forested riparian buffers, and wind buffers. In agriculture, they are highly effective in reducing the concentration of nitrogen (N) and phosphorus (P) in runoff into surface water and are also effective in reducing sediment erosion and removing pesticides. This helps to prevent eutrophication and associated fishkills and loss of biodiversity. The use of filter strips is very common in developed countries and is required by law in some areas. The implementation and maintenance of filter strips is inexpensive and their use has been shown to be cost effective.

<span class="mw-page-title-main">Land restoration</span> Reinstatement of damaged landscape

Land restoration, which may include renaturalisation or rewilding, is the process of ecological restoration of a site to a natural landscape and habitat, safe for humans, wildlife, and plant communities. Ecological destruction, to which land restoration serves as an antidote, is usually the consequence of pollution, deforestation, salination or natural disasters. Land restoration is not the same as land reclamation, where existing ecosystems are altered or destroyed to give way for cultivation or construction. Land restoration can enhance the supply of valuable ecosystem services that benefit people.

<span class="mw-page-title-main">Desert greening</span> Process of man-made reclamation of deserts

Desert greening is the process of afforestation or revegetation of deserts for ecological restoration (biodiversity), sustainable farming and forestry, but also for reclamation of natural water systems and other ecological systems that support life. The term "desert greening" is intended to apply to both cold and hot arid and semi-arid deserts. It does not apply to ice capped or permafrost regions. It pertains to roughly 32 million square kilometres of land. Deserts span all seven continents of the Earth and make up nearly a fifth of the Earth's landmass, areas that recently have been increasing in size. As some of the deserts expand and global temperatures increase, the different methods of desert greening may provide a potential solution. Planting suitable flora in deserts has a range of environmental benefits from carbon sequestration to providing habitat for native desert fauna to generating employment opportunities to creation of habitable areas for local communities. The prevention of land desertification is one of 17 sustainable development objectives outlined by the United Nations, desert greening is a process that aims to not only combat desertification but to foster an environment where plants can create a sustainable environment for all forms of life while preserving its integrity.

References

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  2. "Role of trees in agriculture" . Retrieved 13 February 2018.
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  4. Withgott, Jay; Scott Brennan (2008). Environment: The Science Behind the Stories (3rd ed.). San Francisco, California: Pearson Benjamin Cummings. p. 249. ISBN   978-0131357051.
  5. Hetlzer, Robert (1972). Soil Survey of Walsh County, North Dakota. United States NRCS Soil Conservation Service. p. 75.
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  7. Ucar, Tamer; Hall, Franklin R. (2001). "Windbreaks as a pesticide drift mitigation strategy: A review". Pest Management Science. 57 (8): 663–675. doi:10.1002/ps.341.
  8. Wilson, John D. (1985). "Numerical studies of flow through a windbreak". Journal of Wind Engineering and Industrial Aerodynamics. 21 (2): 119–154. doi:10.1016/0167-6105(85)90001-7.
  9. Argete, J.C; Wilson, J.D (1989). "The microclimate in the centre of small square sheltered plots". Agricultural and Forest Meteorology. 48 (1–2): 185–199. Bibcode:1989AgFM...48..185A. doi:10.1016/0168-1923(89)90016-6.