Windbreaks benefit horticultural crops and improve economic returns
Economic loss caused by a reduction in crop quality and total yield can occur where windbreak protection is not provided around farm fields. Windbreaks will protect fruit and vegetable crops from damage caused by turbulent or strong wind. For example, windbreaks can prevent fruit drop in orchards as harvest approaches. Windbreaks can help reduce bruising and scarring on fruit and vegetables where the orchard trees and crop plants can otherwise be bumped around by wind.
Figure 1. A properly designed windbreak will allow adequate air circulation in the crop, while diverting strong damaging wind up and over the windbreak tree row. The protected area in the crop zone will extend downwind approximately ten to fifteen times the height of the windbreak trees.
A windbreak can be considered as either a horticultural project or a forestry project, where both industries offer technical support. Recommendations from forestry sources, such as Conservation Authorities may limit the choice of trees to native species, while horticultural projects may include native or non-native species of trees and shrubs, as long as the species selected for a windbreak will not spread as invasive or destructive plants into the environment.
White spruce, eastern white cedar and white pine are examples of native conifers. Non-native conifers, such as Norway spruce, Colorado blue spruce, Serbian spruce, Austrian pine and Scotch pine are effective windbreak trees.
Conifers are generally preferred for windbreaks around farm fields, although deciduous trees can also provide shelter. Conifers are narrow and occupy less ground space, while deciduous trees tend to have wider spreading canopies and can be aesthetically pleasing.
A single row of trees having some diversity of species will be relatively easy to manage. For example, three to five tree species, such as white cedar, spruce and pine can create a healthy diverse windbreak. Every season can vary from wet to dry and mild to hot. Some trees will perform better or stress more than others through the variety of weather conditions experienced over the years.
A single row of trees will be accessible on both sides by a mower or herbicide sprayer, which simplifies annual maintenance of weeds. Annual maintenance can maintain windbreak trees in good condition while preventing the establishment of invasive or nuisance species, such as buckthorn, wild grapes or alternate hosts of insect pests and diseases that can infest windbreaks.
Several tree and crop combinations should be avoided. Avoid planting trees of white pine near crops of red or black currant as both are co-hosts of white pine blister rust disease, lethal to white pine. Similarly, juniper and apples should not be combined to prevent cedar-apple rust disease. Walnut trees exude a natural herbicide called juglone, which will kill sensitive crops, such as apples and tomatoes where roots contact each other. Roots of poplar, soft maple and other wet-site species can plug underlying perforated drainage tiles.
Colorado blue spruce and Austrian pine have a natural thick coating of wax on their needles, making them drought tolerant and tolerant to winter road salt spray along highways, offering protection for salt-sensitive orchard trees, such as apples and peaches.
Windbreaks provide other useful functions:
- Moderate wind speed to improve the conditions for spray application, each window of opportunity for spraying may be extended.
- Catch and hold drifting spray material downwind of crops before leaving the field. Similarly, buffers of trees and shrubs intercept drifting spray to protect water courses.
- Provide shelter for honey bees and wild pollinating insects during crop flowering to improve fruit set. The necessity of insecticide applications on horticultural crops may limit a windbreak's ability to provide permanent habitat for wild pollinating insects. Alternatively, a wider multi-row shelterbelt consisting of diverse tree and shrub species and diverse ground cover would provide a suitable habitat for wild pollinating insects to survive near horticultural crops.
- Reduce complaints from sensitive neighbours or passing motorists, where conifers and deciduous trees create a visual barrier and block noise and dust from various farming practices, such as spray application, tillage, mowing or wind machines for frost control.
- Protect topsoil from wind erosion during periods where soil is exposed and vulnerable around planting time or post-harvest cleanup.
- Efficient use of irrigation water by reduced drying of soil and allowing normal evapotranspiration in healthy protected crop plants.
For additional information see the following links to recent provincial factsheets and educational videos on multifunctional windbreaks.
For more information:
Toll Free: 1-877-424-1300
|Author:||Todd Leuty, Agroforestry Specialist/OMAF and MRA|
|Creation Date:||04 June 2014|
|Last Reviewed:||04 June 2014|