The value of windbreaks
By Melanie Epp
Although the idea of windbreaks has been around for decades, the practice of planting value-added windbreaks is still relatively new. Todd Leuty, an agro-forestry specialist from the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) explains that windbreaks are perhaps one of the greatest tools a farmer can use to protect topsoil from the elements.
There are many factors that effect soil erosion, says Leuty, including wind, surface runoff, topography and the presence of vegetative cover. A well-designed windbreak, when properly maintained, not only offers protection for soil, but also for farm buildings, crops and livestock. Despite the fact that windbreaks require a small investment of time and money, the benefits are economically and environmentally significant.
The primary role of windbreaks is to reduce wind velocities, particularly near the soil’s surface. Although they’re most useful in the spring and early summer when newly planted crops are taking root in clean-cultivated soil, windbreaks provide valuable protection year-round, even in the winter months.
Well-established windbreaks can also help to conserve energy on farms. According to one estimate, good protection can reduce the heating and cooling costs of farm buildings by as much as 25 to 35 percent.
Driving winds, extreme cold and snow have all been known to affect livestock performance. A good windbreak can significantly minimize stress in cattle and reduce feed costs during cold months.
Esthetically speaking, windbreaks and shelterbelts can add to the attractiveness of the rural landscape, which can have the added effect of increasing tourism to the region.
Perhaps the most valuable benefit the farmer experiences, though, is an increase in crop yields, as well as improved overall crop quality. According to a windbreak publication by OMAFRA, field crop yields increase greatly when wind protection methods are applied.
“This increase has ranged all the way from a few percentage points to as much as a 50 percent increase or more,” says the report. Even higher yield increases were shown with some fruit and vegetable crops where appearance is important.
The report also states that yields were increased out about eight to 12 times the height of the barrier, as well as on the windward side of the barrier, where they are often increased out to three to five times the height of the windbreak. In some cases, windbreaks may also help to control weeds as well by reducing the spread of weed seeds.
“For field crops [in Ontario], yields can be 10 to 15 percent higher when they’re protected by windbreaks,” says Leuty.
“There are also situations where we see advanced stages of growth in the crop when it’s protected. In seed crops, for example, we see plants come into flower sooner when they’re protected from wind.”
The report also showed a rather significant yield increase in both corn and soybeans with good windbreak protection. In fact, “corn yields have been increased approximately 10 percent and soybeans about 20 percent out to a distance of 10 times the height of the windbreak.”
While the yield value of windbreaks cannot be understated, there are other benefits as well.
For example, a number of tree varieties can be planted for additional profit, including Christmas trees, hybrid poplars (or other biomass species) and sugar maples. But, there are logistical problems that farmers need to think about, says Leuty. “You don’t want to plant trees in the wrong spot, because if it’s in the wrong spot it’s a weed,” he says. “A big weed, and you have to manage it.”
Sugar maples can also be a good choice for extra profit, while simultaneously creating a windbreak.
“There’s a lot of interest in tapping maple windbreak trees for syrup. If you put sugar maples in a windbreak, they tend to get a nice big crown, and the sugar concentration is higher in that kind of tree than in a woodlot tree,” says Leuty.
Since the tree has more leaf surface, it produces more sugar – sometimes double the amount than those in traditional woodlots. If the farmer isn’t interested in producing maple syrup, he could rent the trees out for tapping or sell the sap.
Still, conifers are ideal Leuty notes. “They have uniform coverage from ground to top. The needles in conifers are perfect for breaking up the wind flow. They’re also ideal for building up a backpressure that forces damaging winds up and over. So a heavy component of conifer in a windbreak is best.”
Leuty cannot emphasize the importance of diversity in the windbreaks enough. “Diversity is key,” he says. “That way, if there’s a pest or disease of a specific conifer that comes through one year that heavily attacks one of those species, you’ll still have a windbreak.”
There is further value to be gained from windbreaks, including harvesting them for use as firewood and providing habitat for wild pollinators, which act as a natural support system to help pollinate fruit and vegetable crops.