By Madeleine Baerg
A 30-foot tall windbreak provides a zone of protection up to 360 feet in one direction and 150 feet in the other.
With the ever-increasing price of land, it can be very tempting to try to maximize production by cropping every possible inch of one’s acreage. While a row of tall trees along the edge of a field is a nice visual break, many producers question whether the trees’ agricultural benefits justify pulling multiple metres of viable cropland out of production. The short answer is a resounding yes. In fact, a well-designed and managed windbreak is the ultimate proof that less (land in production) really can be more (yield and soil health).
“A lot of producers will look at a windbreak and only see the small strip of land that is out of production, the limited area that adds root competition to the crop. They don’t see that the windbreak produces yield increases far out into the field,” John Enright, a forester with the Upper Thames River Conservation Authority, says. “You have to look at the big picture and the long term. In corn, we’re talking about a 10 per cent yield increase in the protected zone; in soybean the increase is 20 to 25 per cent. There’s no question the benefits far exceed the low cost of planting a windbreak and the small reduction in cropping space.”
A windbreak is a long, straight row of trees planted to limit the negative effects of harsh winds. By acting as a living wind fence that either allows, slows or forces horizontal wind currents upward, a windbreak’s crop yield benefits extend eight to 12 times the height of the trees on the leeward side and three to five times the height of the trees on the windward side. Therefore, a 30-foot tall windbreak will provide a zone of protection up to 360 feet in one direction and 150 feet in the other.
A windbreak’s crop yield benefits come from a combination of the improvements it makes to growing conditions. Wind protection means soil erosion decreases out as far as 15 times the height of the trees on the leeward side. Better snow distribution allows moisture to more evenly distribute and the land to warm earlier and more consistently in the spring, resulting in less runoff, better availability of water, earlier planting and a longer growing season. Decreased wind also allows better spray application and less drift. And, the trees that make up a windbreak suit beneficial wildlife: insect predation improves because the trees provide bird habitat, and pollination increases because lower wind speeds allow bees and other pollinating insects to work their magic.
A windbreak’s benefits are certainly not limited to the crop producer. A livestock producer will appreciate a windbreak’s improvements to noise, dust and odour control; their livestock’s decreased stress in extremely cold or windy conditions; and lower heating costs in barns and homes.
It can also improve road safety by reducing blowing snow, enhance wildlife habitat by serving as a travel corridor, enrich recreational opportunities like cross country skiing, snowmobiling and walking, and boost property values.
For those who might say “yes, but…,” the negative side of the windbreak equation is almost non-existent. Recognizing the multiple environmental benefits of windbreaks, conservation authorities in many regions are willing to do much of the work of planting and early maintenance of windbreaks on both public and private land. And grants that cover as much as 70 per cent of the cost of planting a windbreak exist in many areas.
“We recognize spring is a very busy time of year for agricultural producers, so we do our best to make it very easy for them,” Enright says. “In southern Ontario, for example, our conservation authority does the planting and then two applications of herbicide following planting to control vegetation. We ask that the producer mow adjacent to the windbreak for the first couple of years until the trees are well enough established to compete. It is not a big commitment on the part of the producer.”
For best success, Enright suggests planting a cover crop like spring barley or fall wheat under-seeded with white Dutch clover during a windbreak’s establishment period. Doing so helps to reduce weed pressure on the young seedlings, makes maintenance substantially easier and helps with tree growth rates due to the nitrogen fixing nature of the clover. Alternatively, producers seeking an even easier, herbicide-free system of weed management might opt for plastic mulch.
“At any of the sites where we’ve used plastic mulch, the success rates have been absolutely fantastic,” Enright says. “All things being equal, that’s the route I’d recommend.”
Establishing a healthy and effective windbreak does take some time and energy, however. Adequate planning, site preparation and early management are critical to success. Talking to your municipal planner and neighbours to get their approval in advance, then thinking through geographic factors like the location of drainage tiles and necessary spacing for equipment movement will save huge headaches in the long run. Finally, expect to have to look after your windbreak for some years before it starts to look after you: sign the establishing windbreak well so snowmobilers and equipment operators do not accidentally damage young trees, be prepared to water in drought conditions, and plan to mow and apply herbicide for at least three years to limit weed pressure and nutrient and water competition.
“[Is there] return on investment? There’s no question. But some people just don’t see it. There will always be those who pull out windbreaks because they don’t factor in all of the benefits. Part of that, certainly, is just a lack of understanding. If people understood how beneficial windbreaks are, we’d see a lot more of them going in,” Enright says.