Native Conifers for Windbreaks?

Photos by Ryan Pankau, University of Illinois Extension.

Plant natives! That’s a cardinal rule, and excellent advice almost all of the time. However, to every axiom there are exceptions. Planting native conifers for windbreaks can become problematic in some situations.

When selecting windbreak trees, most homeowners pick conifers because of their wind-reducing effectiveness of year-round foliage with a bonus of green color in the dead of winter. However, conifers native to Illinois are few. Jack, shortleaf, red and white pines are all natives, with only white pines having a significant presence. Jack, shortleaf and red pines are found in just a handful of counties and are rare where they do occur: All are listed as state endangered. LaSalle County in north-central and a cluster of other counties in far northern Illinois have white pines in numbers. White pines are acclimated to the thin acid soils overlying eroding outcrops of St. Peter Sandstone, such as found at Starved Rock State Park in LaSalle County. White Pines Forest State Park in Ogle County contains the largest remaining tract of naturally occurring eastern white pines in the state—a relic from the last glacial period. White pines are widely planted statewide, but do best on light, well-drained forest soils. They often do not fare well on heavy, poorly drained prairie soils.

Another native conifer growing throughout Illinois on well-drained poor soil is the eastern redcedar. Many Illinoisans drive by these cedars every day, seeing them thrive along sloping highway rights-of-ways where they readily seed down. Why do they spread here? The berries are great winter food for a variety of birds that disperse the seeds. Plus, the sloping land and water rapidly spread the seeds. However, as a potential windbreak conifer, especially one in close contact with people, redcedars are not given a second thought because their needles are just that—needles.

Additionally, eastern redcedars grow slowly. However, as a row on the windward side of a windbreak, they have a place. There, contact with humans is reduced, lessening the chance of a brush-by encounter. Their tenacity is epitomized by their rugged, scraggly appearance—an appearance that is less apparent on the outside row from homeowners who have yet to develop an appreciation for what this cedar’s semblance represents, an ability to take the wind in stride.

As with small white pines, young eastern redcedars attract white-tailed buck deer in rut. Antler rubbing can literally destroy a young redcedar, even more so than a white pine. Several protective methods work to varying degrees. What works best for a particular planting may be found by trial and error. See Wildlife Illinois for information.

Of the non-native conifer species, what are the choices? A traditional favorite, Colorado blue spruce, has come on hard times, becoming subject to several fatal fungal diseases in recent years. Planting Colorado blue spruce is not recommended. A non-native conifer that seems to be a survivor and a favorite of farmers in central Illinois is the Norway spruce, widely planted on farm windbreaks and in Civilian Conservation Corps projects during the Depression Era of the 1930s. One negative: In rural areas, Norway spruces can be weakened in dry years by spider mite infestations from nearby soybean fields. Spider mites do not kill Norway spruces outright, but can weaken them, causing decline and susceptibility to other harm.

A non-native that shows promise is arborvitae. Many cultivars are available, so select one that is suitable for a windbreak. Although arborvitae do not grow rapidly, some cultivars reach 50 feet at maturity. They can form a solid wall of evergreen vegetation to block the wind. Arborvitae can be subject to severe bagworm infestations. See University of Illinois Extension for bagworm control information.

Planting a windbreak of a row or two of several conifer species in combination with a row or two of native hardwoods can be a prudent strategy. Several rows of trees with some suited native hardwoods as an interior row and a native shrub row on the leeward side makes a very attractive and effective windbreak. Such possibilities are often limited by space and can take substantial resources. Make your choices in concert with soil types, soil pH and drainage. Seek the advice of a person who has had experience in establishing and maintaining such a windbreak consisting of conifers, hardwoods and shrubs. The University of Illinois Extension has information on establishing windbreaks.

Eastern Redcedar—A Tough One

Eastern redcedars are rough and resilient. Nothing exemplifies tenacity more than a redcedar’s ability to withstand deer damage. Rutting white-tail buck deer take out their wrath, particularly on solitary standing redcedars. Why? Some say it is because deer like the smell of scraped and broken redcedar bark, branches and twigs exposing highly aromatic sap. Whether or not this is true, only the deer knows. However, a young tree survives as long as there is some continuous intact bark and cambium tissues left along one side of the tree. The same tree can suffer these deer-inflicted insults for several years and make it.

This tenacity and ruggedness make redcedars a good choice for planting on the windward side of a home or farmstead windbreak. Also, on the outside row, redcedars get a lot of sunlight, which they need because they are shade intolerant. Eastern redcedars are one of the native conifers that should be considered for windbreak plantings along with the non-natives that are customarily planted.

The eastern redcedar is not really a cedar at all, but is actually Juniperus virginiana, a juniper in the cypress family. Along with the southern redcedar, it is the only native juniper that normally grows in an upright and columnar form, reaching some 50 feet or more.

Eastern redcedars grow slowly, but to an old age: 100-year-old specimens are common, with 300-year-old trees not that unusual. Native to every county in Illinois, redcedar grows on dry, hardscrabble areas such as abandoned pasturelands, hillsides, rocky outcrops and barrens, explaining why they are commonly seen growing along the disturbed soil slopes of highways. It is very drought tolerant. Eastern redcedars grow fastest on well-drained alluvial sites where there is no competition from other tree species. Although redcedars are not thought of as a species of wet soils, it is sometimes found on the edges of swampy lands.

By fall, dark blue, fleshy, highly aromatic berrylike cones develop that are relished by birds and mammals. The berries are eaten by a variety of songbirds, including cedar and Bohemian waxwings and yellow-rumped warblers. Gamebirds such as bobwhites, pheasants, wild turkeys and ruffed grouse eat them. Mammals, including mice, rabbits, foxes, raccoons, coyotes, opossums and even skunks like the berrylike cones. Deer browse the foliage, particularly during severe winter weather. Eastern redcedar is also the food plant for the olive hairstreak butterfly. This tough tree provides more food for wildlife than is realized.

Eastern redcedar seeds are dispersed by birds, explaining in part why we see all sizes of young trees scattered, cascading down the slopes of interstate highways. If you choose to use redcedars next to a pollinator strip or a grassland adjacent to a windbreak, encroachment may occur. Be prepared to control the spread of eastern redcedar in these areas.

Even some of these highly “tamed” environments have wild natural history lessons to teach us. We just have to pay attention.

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Robert J. Reber is an emeritus faculty member in the Department of Food Science and Human Nutrition of the University of Illinois at Urbana–Champaign. He has been a lifelong student of many aspects of the Natural World, including archaeology. Bob has served as a managing editor and author for publications such as The Illinois Steward magazine and the Illinois Master Naturalist Curriculum Guide.