ROCKWELL CITY-Whether a windbreak is in need of renovation due to storm damage or old age, or it’s time to start a new windbreak, some basic tips can help extend the life of the new trees and enhance the windbreak’s effectiveness.
“A lot of Iowa’s windbreaks are 70 to 100 years old and are beyond their functional life spans,” said Jesse Randall, an Iowa State University Extension forester, who recommends planting a diverse mix of trees and shrubs to replace these aging trees.
Windbreaks along the north and west edges of a farm or acreage offer multiple benefits, including snow drift control, reduced fuel consumption, wildlife habitat, reduced livestock feed costs and property value enhancement. The sweet spot that maximizes the benefits of the windbreak is 50 to 100 feet from the protected area, whether that’s a house or a barn, Randall said.
A well-designed windbreak should include a minimum of three rows, including shrubs on the exterior row, followed by at least two rows of conifers and deciduous trees. An ideal windbreak would include two rows of shrubs, a row of hardwood trees, and rows of conifers, said Randall, who acknowledged that it’s becoming more difficult to find conifers that are suited to Iowa’s heavier, wetter soils.
Good conifer choices for Iowa windbreaks can include Norway spruce and white spruce, including the Black Hills spruce variety.
The Norway spruce is a fast-growing variety that requires a minimum of 20 feet between trees, said Randall, who noted that a 25-foot spacing is even better. The white spruce, which is smaller and narrower than other spruces, requires a 16- to 18-foot spacing and works fairly well on drier sites.
Concolor fir is a beautiful conifer that is a good choice for well-drained soils. Arborvitae, or white cedar, can handle wetter areas, although these trees can be susceptible to wind burn and winter burn, Randall said, who recommends the “Techny” cultivar, since it is less prone to these issues.
Eastern red cedar, which is native to Iowa, may not be the most attractive conifer, but it is well suited to a wide range of sites and provides excellent habitat for wildlife, Randall said.
While white pine is also native to Iowa, mainly in the northeast, it is a brittle tree that is susceptible to the wind and ice damage that can occur in western Iowa.
“It’s okay to plant white pine for species diversity in your windbreak, but don’t plant a lot of them,” Randall said.
While species diversity is one of the keys to a good windbreak, there are some conifers to avoid, Randall added. They include:
- Ponderosa pine: This tree is dying of needle blight and diplodia tip blight in Iowa.
- Blue spruce: These spruces are susceptible to rhizosphaera needle cast, a fungal disease that infects needles on the lower branches first and gradually progresses up the tree.
- Scotch pine: While Christmas tree growers used to plant this extensively, they no longer do, since the Scotch pine is susceptible to brown spot, pine wilt nematodes and bark beetles.
- Austrian pine: This pine is susceptible to diplodia tip blight and dothistroma needle blight, a devastating fungal disease. While there are products available to control these issues, “they are pricey,” Randall said. “You must spray each tree three times a year with a full-drench spray, meaning the tree is drenched from top to bottom. The cheapest I’ve heard per tree, per spray, is $100.”
Diseases aren’t the only threat facing conifers in Iowa. Mild winters can also be hard on these trees.
When temperatures soar higher than 40 degrees on multiple days, conifer trees’ needles become active and seek moisture to begin photosynthesis. As a result, the trees may dessicate themselves, Randall said. ISU forestry specialists are evaluating new conifer options for Iowa windbreaks, including the Serbian spruce.
Deciduous trees, shrubs
Deciduous trees can also be incorporated into a windbreak, Randall said, who noted that time to maturity is always a consideration. “Normally, it’s ‘live fast, die young’ with trees.”
While burr oaks, native to all of Iowa’s 99 counties, are slow-growing, they are long-lived, Randall said, adding that red oaks can also work well in the Iowa landscape and are a faster-growing oak.
More unusual trees like the Kentucky coffee tree, which can reach heights of 60 to 100 feet, can also work well in Iowa.
While the basswood or linden tree is suited to Iowa, it’s vulnerable to Japanese beetles. “These pests eat the lindens and everything in your garden,” Randall said.
Austrees, which are a hybrid willow, also present challenges.
“Since they are a perfect example of ‘grow fast, die young,’ they are not a long-term solution for a windbreak,” Randall said. “They can also grow into septic and tile lines.
“They can be okay, however, as a ‘screen’ for a hog confinement barn.”
Don’t forget to add shrubs to a windbreak, Randall said, recommending dogwood, highbush cranberry, ninebark, lilac, hazelnut, wild plum and Nanking cherry.
“Shrubs will knock your snow down and should be the first line of defense in your windbreak,” he said.
There are a number of cost-share programs available to help landowners who are installing a new windbreak or renovating an existing one. The Resource Enhancement and Protection program offers a 75 percent cost-share program, in which landowners are reimbursed for the cost of the trees, which must be planted according to specific guidelines.
Additional cost-share options may be available through the Conservation Reserve Program, the Environmental Quality Incentives Program and the Wildlife Habitat Incentive Program.
Contact a local Natural Resources Conservation Service for more details, Randall said.
You can contact Darcy Dougherty Maulsby by e-mail at firstname.lastname@example.org.
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