- Plant a minimum of three rows; additional rows up to 8-11 rows will improve protection and increase benefits.
- Incorporate conifers as the major tree in the windbreak where soil conditions allow. Deciduous trees are only 5-20 percent as effective as conifers.
- Locate on the north and west site of the property; avoid surrounding the farmstead with a solid barrier of trees.
- Use several different species in the windbreak; plant within rows in blocks to minimize competition caused by different growth rates. For example, one half of the first row could be Norway spruce with the other half blue spruce.
- The distance between all rows should be at least 20 feet; the spacing between trees/shrubs within a row will vary from 4 to 20 feet depending on mature size of the species.
- For optimum wind lift, plant the tallest trees inside and the shortest shrubs on the upwind (north and west) side of the windbreak.
- The inside row of the windbreak should be 50 feet away from the protected site (to minimize snow accumulation) or with wider windbreaks 100 feet from the outside rows. The greatest wind protection will occur closest to the windbreak. Protection becomes minimal at 15 to 20 times the height of the windbreak.
- If snow accumulation is a serious problem, use a double row of shrubs on the outside of the windbreak spaced at least 30-40 feet apart.
- Where possible, take advantage of contours and locate the windbreak uphill from the protected site; height is relative for most wind protection.
The standard L-shaped, square corner windbreak can be modified. Trees can planted in groups instead of rows. Corners can be rounded or merged together. The key for optimum protection is providing wind protection on the NW quadrant.
Farmstead Windbreak
Much of Iowa’s land is relatively level to gently rolling with few trees to block the prevailing winter winds. Windbreaks — rows of trees and shrubs properly located — can slow, direct, and block these winter winds, resulting in many benefits to the landowner. A windbreak is a permanent part of farm landscape, so plan carefully before planting trees and shrubs.
A good farmstead windbreak adds thousands of dollars to property values and provides many benefits. Some benefits such as energy conservation and snow control are the result of wind speed reduction. Other benefits such as wildlife habitat and aesthetic value are the result of having trees and shrubs in the landscape.
Field Windbreak
Field windbreaks are linear plantings of trees/shrubs designed to reduce wind speed in open fields, preventing soil erosion and protecting adjacent crops from wind damage.
Field windbreaks are typically planted in multiple rows perpendicular to prevailing winds. On the downwind side of a well-established windbreak, wind is generally slowed for a distance of 10 times the height of the trees. Old field windbreaks may need renovation to function properly, including removal and replacement of selected trees/shrubs.
- Reduces soil erosion from wind.
- Protects water and air quality by providing a barrier against airborne soil, chemical drift, odors and dust.
- Provides wildlife food, cover and travel corridors.
- Diversifies agricultural landscapes.
- Sequesters carbon.
- Protects crops from wind damage.
- May increase crop yields by 10% or more, especially in dry years.
- May improve crop photosynthesis and water use efficiency due to micro-climate changes in temperature and humidity.
- Improves irrigation efficiency.
- Helps manage snow drifts and soil moisture by dispersing snow more evenly across cropland.
- Provides opportunities for additional income from salable tree/shrub products such as nuts, berries and decorative floral material.
- Adds scenic interest to fields and may increase property value.
Cost-Share Programs Available for Private Landowners in Iowa
Several programs are available for cost-share reimbursement to private landowners engaged in forestry-related conservation work. Practices such as tree planting, forested riparian buffer installation, forest stand improvement, site preparation for natural regeneration, wildlife habitat improvement, windbreaks, and fencing may be eligible for cost-sharing on private lands.
Please contact your district forester to determine which of the following program is best suited to your needs and goals.