Agricultural Extension Service, South Dakota State College
Weeds affect young trees in the same way they affect other crops. Weeds rob trees of moisture, plant food and light. This often results in the death of most of the trees. Those that do manage to live are stunted. Planting a shelterbelt is a waste of time, money and land unless the planting is cultivated throughout its early life. Your young shelterbelt trees need the same care as any other row crop until they are big enough to shade out the weeds and grass. Results of an experiment carried out at South Dakota State College show how important clean cultivation is to tree growth. At the end of four growing seasons, clean cultivated trees averaged over three feet higher and one inch larger in diameter than trees cultivated only once each season. Clean cultivated trees also had many more low branches than those receiving one cultivation per seasort. The added growth · and low branching made it possible to stop cultivating a full year earlier.
Ferrell, E.K., "Shelterbelt Care" (1955). SDSU Extension Circulars. 686.