Windbreaks

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Windbreaks

• An agroforestry practice

This presentation was developed by the USDA
National Agroforestry Center
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Presentation Objectives

• Define windbreaks
• Describe the benefits and types
• Recognize basic design considerations

Windbreaks
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What is Agroforestry?
the intentional combining of agriculture and
working trees to create sustainable farming
systems.
Riparian buffer
Forest farming
Alley cropping
Silvopasture
Windbreaks
Windbreaks
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What is a windbreak?

• Plantings of single or multiple rows of
  vegetation (trees, shrubs, grass) that are
  established for one or more environmental and
  economic purposes.

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What are the benefits?

• Reduce soil erosion
• Protect plants
• Enhance plant growth
• Manage snow
• Provide shelter
• Reduce energy needs
• Improve wildlife habitat
• Enhance aesthetics

• Moderate noise
• Screen views
• Reduce airborne chemical drift
• Improve irrigation efficiency
• Increase carbon storage
• Mitigate odors

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How does a windbreak work?

• Modify
• Air flow
• Sound waves
• Odor plumes
• Microclimate dynamics

• Trap/filter air borne
• Sediment
• Snow
• Nutrients
• Pesticides
• Pathogens
• VOCs

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What are the effects?

• Windbreaks
• lower wind velocity causing air-borne material
  to be deposited
• physically trap air-borne material
• adsorb some of the chemicals attached to
  air-borne material
• alter the microclimate on the downwind side of
  the windbreak

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How can air flow patterns be modified?

• Modification of the wind depends upon six key
  windbreak features
• Height
• Density
• Orientation
• Length
• Width
• Continuity

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Why is height important?

• H Effective height of the windbreak
• The height determines the distance of the
  downwind sheltered (protection) zone

H
10H to 15H
10H to 15H
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Why is density important?

• Dense maximum wind reduction but short wind
  shadow
• Moderately dense less wind reduction but longer
  wind shadow

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Why is orientation important?

• Location or layout
• Directly influences area protected
• Effects vary with critical weather periods and
  wind directions

Wind Rose
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Why is length important?

• For full protection, the windbreak needs to
  extend the entire length of the area needing
  protection to account for changing wind
  directions.
• Doubling the length of a windbreak will generally
  increase the area protected by 4 times

Windbreak
protected area
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Why is width important?

• Width influences
• Density
• Wildlife values
• Trapping capacity and efficiency

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Why is continuity important?

• Wind speed increases in a gap
• Gaps in the windbreak can result in damage or
  complications downwind

( of open wind speed)
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Types of windbreaks
Windbreaks
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Types of windbreaks field
Windbreaks
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Types of windbreaks farmstead
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Types of windbreaks livestock
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Types of windbreaks specialty
Living Snow Fence
Irrigation efficiency
Odor
Dust
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Multi-purpose windbreaks

• Bio-energy feedstock
• Food security
• Wildlife
• Income products

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Summary

• Windbreaks are an agroforestry practice
• Windbreaks provide multi-functional benefits
• Windbreaks can be designed to meet site needs and
  land owner objectives

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For Additional Information

• A number of web sites are available to provide
  more detailed information on windbreaks. Here
  are a few
• USDA National Agroforestry Center
  http//www.unl.edu/nac/windbreaks.htm
• The Center for Agroforestry http//www.centerforag
  roforestry.org/practices/wb.php
• Association for Temperate Agroforestry
  http//www.aftaweb.org/entserv1.php?page1
• USDA Natural Resources Conservation Service
  http//www.nrcs.usda.gov/wps/portal/nrcs/home

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Acknowledgements

• This presentation was developed by the USDA
  National Agroforestry Center (NAC), Lincoln NE.
• NAC is a USDA partnership between the U.S. Forest
  Service and the Natural Resources Conservation
  Service.

A partnership of
NationalAgroforestryCenter

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