By Andrea Watts
Windbreak benefits extend beyond reducing wind erosion. Research reveals windbreaks can also be customized to meet your farm management goals, whether it’s increasing wildlife habitat or benefiting visiting pollinators.
A “national menace” is what Congress called wind erosion during the Dust Bowl. This menace caused an estimated loss of 850,000,000 tons of topsoil and spurred President Roosevelt’s large-scale Shelterbelt Project of planting tree windbreaks across the Great Plains to reduce future wind erosion.
Research shows that reducing wind erosion isn’t the only benefit provided by these windbreaks, and they can be customized to meet your farm’s management goals, whether it’s increasing wildlife habitat or benefiting visiting pollinators.
In a field adjacent to a windbreak, there is an area where a crop yield of 110 percent isn’t uncommon; it’s the area which Charles Barden, professor of forestry with Kansas State University and principal investigator of the Great Plains Crop Yield Study, dubs the “sweet spot in the field.” In this sweet spot, usually found in an area about two times the height of the trees and extending out 12-15 times the height of the windbreak trees, research has found an increase in yield of 23 percent for winter wheat, 15 percent for soybeans and 12 percent for corn.
The reason for this increase is likely due to less evapotranspiration stress on the crops, explains Barden.
“When the wind blows on a hot, dry day, for people it feels good to have the wind blow when it’s hot, but plants don’t mind humidity. Humidity and calm air helps them use less water or use water more efficiently.”
This calm air also benefits specialty crops, such as melons and vegetables that are susceptible to wind damage. Bruce Wight, a former National Resources Conservation Service (NRCS) national forester and agroforester, says that growing these types of crops in the protection of a windbreak results in a “positive benefit to crop quality and crop yield in many cases.” This crop yield increase may also be a direct result of the increase in visiting pollinators which also prefer protected areas, as studies conducted on vegetable crops found an increase in pollination activity in protected areas with reduced wind speed.
In their role of reducing wind velocity, windbreaks can also serve as a buffer against the particulates being carried by the wind. Organic farms, which are adjacent to non-organic producers, are required to have a buffer in place, and windbreaks can function as a buffer to reduce the influx of pesticides.
“Windbreaks can help intercept spray drift and strain other air pollutants that may be coming off that non-organic farm toward the organic producers,” said Wight.
Even ranchers can benefit from the addition of windbreaks to their pastureland. During the summer, cattle want the cooling wind, just as we do. Yet during the winter they seek the shelter found in the windbreak, and this shelter translates into tangible savings in feed cost and calf survival.
Barden says that studies have shown, “windbreaks will reduce the amount of feed they have to consume just to get through the winter and increase their calving efficiency.”
Evolving Design, Value
Through the NRCS financial assistance programs and the Farm Service Agency’s Conservation Reserve Program, Wight estimates that over the past 10-12 years there was an average of 1,500-2,000 miles of windbreaks planted nationally each year, resulting in a total of 15,000-20,000 miles.
Yet those numbers reflect only what is being planted. Across the Great Plains states Barden sees a disconcerting overall trend of decreasing windbreak mileage: a combination of aging trees that aren’t being replaced and land conversion during times of high commodity prices. This prompts the question of, why would a landscape addition that can create a 110 percent yield and serve as habitat for pollinators, be removed?
“The reason why it can be so hard to see, to commit to the positive effects of the windbreaks is because the first few rows right next to the windbreaks are always very stunted, very pale. … and trees are drawing the moisture from the crop,” Barden explains, adding that farmers don’t necessarily connect the crop increase in the sweet spot of the field to the windbreaks. And there is no denying that the 1940s windbreaks consume acres of potential growing space, as they often contain 10-12 rows of trees.
Yet, there are ways to incorporate windbreaks onto a farm’s landscape so that overall productivity is not affected. Research has found that windbreaks can be narrower, needing only to be three to four trees deep, thereby increasing acreage available for cultivation. Recognizing that rows adjacent to the windbreak will be affected by the shade, it would be advantageous to plant a crop that is compatible with growing in shady conditions.
And windbreaks don’t necessarily have to be towering trees. Barden says that even an 8 to 10-foot-tall windbreak can provide protection for a small field. “The area being protected is in direct relationship with the height of the tree and the density in the windbreak,” said Wight. “Anywhere from 10-15 times the height of the windbreak is the area where you’ll see the most benefit, so if you’re growing in a small field, it won’t take a very large tree to protect it.”
In recognition of the increasing value of pollinators, windbreak designs are now incorporating pollinator-friendly shrubs. Edible plants, such as fruit-producing trees, are also being included, as they provide the “two-fold practice of providing both protecting value and product,” says Wight. With organic farmers striving to enhance the habitat value of their farm, he sees windbreaks as increasingly valued for their non-traditional benefits.
If you are considering enhancing or planting a brand-new tree windbreak, Wight recommends familiarizing yourself with the resources found on the USDA National Agroforestry center website as a starting point.
Having a sense of the prevailing winds and which times of the year your crops need protection is useful information to have in hand when visiting your local NRCS field office for assistance. Technical staff will work with you to design a windbreak to meet your management goals, whether it is growing edible plants for revenue or growing a windbreak that requires little upkeep.
The trees and shrubs selected will be those that are adapted to the soil types and grow well in the area, Wight explains. Though the composition of the tree and shrub species will vary depending upon the state and the purpose of the windbreak, the trees will generally be a mixture of deciduous trees, conifers and shrubs to protect the crops, livestock or buildings. Cost share programs are also available and the NRCS staff can assist you when applying for these programs.
On the Crosby Mint Farm in St. Johns, Michigan, fourth-generation mint farmer James Crosby was able to connect the sweet spot in the field to the adjacent windbreak. In the area of the field where the naturally occurring windbreak was being lost due to the county removing trees or development, during the spring the soil dried out, resulting not only in a crop loss but wind erosion too.
“It was one massive black cloud [300-400 feet tall and 1,000 feet across] created from the wind, and it would just travel through the valley … we would just sit and stare at it,” Crosby recalls. He knew they had to re-establish the tree line, but he also wanted the trees to provide protection immediately.
Working with Joan Benjamin, the farmer rancher grant program coordinator and associate regional coordinator with North Central Region-Sustainable Agriculture Research & Education, Crosby secured a grant through SARE in 2005. The grant process was self-explanatory and relatively easy, he says. He was awarded $6,000 through a cost-share grant, which covered the cost of purchasing trees, as he already had the heavy equipment needed to plant the trees.
He selected blue spruce, as they are fast-growing and require little maintenance.
A local Christmas tree farm gave him a discount on the 19-foot tall trees, and he planted 40 trees to reestablish the windbreak.
Now 10 years later following the planting Crosby says he has not seen a dust storm kick up, nor a decrease in crop yield. “In fact, there’s been a higher crop yield closer to the trees,” he says.
For farmers installing a windbreak adjacent to a road, Crosby recommends conducting a survey to identify the county and state easements before planting. And while there are other grant programs out there, he would recommend SARE.
“I’ve met people that are behind the organization, and they sold me on why they are top-notch. They set the benchmark for agriculture and helping local, small ranchers and farmers, so that’s why I’m so adamant and supportive of their programs.”
Red Fern Farm: Windbreak Benefits
A windbreak showcasing edible trees is what draws visitors to Red Fern Farm, an 86-acre farm in Wapello, Iowa. For nearly 30 years, husband and wife owners Tom Wahl and Kathy Dice have sold a variety of fruit and nut trees, such as pawpaw, chestnuts, persimmon and hazelnuts, across the United States.
These species feature prominently in the farm’s L-shaped 50-foot by 75-foot demonstration windbreak. Wahl is a proponent of incorporating edible trees into windbreaks as a revenue source; there is not one non-producing tree species that could not be swapped out with a crop-producing tree, he says.
In 1999 Wahl partnered with a number of local farmers to create the SARE-funded Farms Forever project to “promote and cost share crop-bearing windbreaks, shelterbreaks and riparian buffer strips as a more profitable and environmentally sustainable alternative to conventional agriculture.”
As a result of Wahl’s efforts to spread the word about the value of chestnuts, not only as a windbreak tree but also as a revenue source, many of the local farmers incorporated chestnuts into their windbreaks.
Over 10 years later and the trees having reached maturity, Iowa now has a commercial chestnut industry, with a growers’ cooperative of nearly 60 different farms. Under good management, chestnuts can generate a revenue of $8,000-$9,000 per acre per year, Wahl says, adding “you could have an entire windbreak of nothing but crop-producing trees, and on farms where the windbreak is taking up multiple acres, that could be a significant source of income that would considerably beat the row crops on an income-per- acre basis by a wide margin.”
Editor’s Note: This article appeared in the April 2015 issue of Acres U.S.A.