Tree Facts: Maintaining a shelterbelt

By Natalie Euler
Natural Resource Specialist, Northwest Area Conservation Districts

The method used to prepare for planting a new shelterbelt has a lot to do with future maintenance. Following are three common methods of shelterbelt site preparation. 1. Tilling – tearing up and fallowing the entire area where the trees are to be planted. Trees usually establish quicker with this method with no competition. 2. Chemical fallowing with herbicide the entire area the year before planting. Trees are scalp planted into the sod. Trees will establish but survivability varies. 3. Tilling a 10’ wide strip and fallow for each row. Trees are planted and weed control fabric laid. The vegetation between the rows remains helping to prevent weed invasion.

Planting shelterbelts with a variety of species helps decrease disease/ insect problems and extends shelterbelt life and function. Some shrubs to consider are silver buffaloberry, chokecherry, Russian almond, caragana, sand cherry, Nanking cherry, cotoneaster, golden currant, Hansen hedge rose, lilac and American plum. Some mid-size trees to consider include amur maple, apricot, crabapple, Arnold hawthorne, homestead hawthorne, Tartarian maple and Russian olive. Some tall trees to consider are honeylocust, hackberry, golden willow, cottonwood, Kentucky coffee tree, boxelder and bur oak. Some evergreen trees to consider are Meyers spruce, eastern red cedar, Rocky Mountain juniper, Austrian pine, Ponderosa pine, Scotch pine and Black Hills spruce.

Why do shelterbelts fail? Primarily due to moisture being at a premium in our sub-arid climate, heavy competition for that moisture is one of the main causes of shelterbelt decline. Smooth Brome Grass is the worst culprit but grasses in general are more efficient competitors for moisture than trees and shrubs. Weeds of various types if not controlled rob moisture from shelterbelts. Old age and death especially of short-lived tree species also occurs when trees reach the end of their expected lifespan.

The main shelterbelt maintenance methods are tilling, mowing, herbicides, weed control fabric and cover crops. Tilling eliminates weeds and grasses and allowing trees to establish. Mowers or Weed Badgers are often used by landowners or hired done. Chemicals are commonly used alone or in combination with other methods. Sprays like Treflan and Princep are used to maintain, or prevent competition from grasses and weeds within shelterbelts. Casoron is put around the holes in fabric to keep weeds from growing around trees and Roundup can be used for spot treatment weed control.

Generally weed control fabric has improved survival rates and increased growth rates of trees and shrubs in our area. The fabric needs to be cut in either an “X” or “half moon” pattern about a foot in size at planting. After 5 years the holes need to be enlarged to allow room for tree growth. As time goes on the holes will need to be enlarged again or the fabric removed.

Cover crops should be considered for use in shelterbelts. Two that work well are proso millet and wildflowers. Both reseed themselves providing dense cover that control weeds and grass competition. Over time viability of weed seeds decrease and trees grow large shading out weeds.

Finally, maintaining fences to keep livestock out of shelterbelts is also very important. Livestock can destroy shelterbelts over time by browsing leaves and twigs, rubbing bark off, breaking limbs, and compacting soil over tree roots.

My source for this news release was South Dakota Department of Agriculture, Division of Resource Conservation and Forestry. If you would like more information about “Maintaining a Shelterbelt,” contact Natalie Euler at the Conservation Office at 605-244-5222, Extension 4 or by e-mail at [email protected]