Competition can also be minimized by regularly cutting roots at a distance from the shelterbelt of approximately the height of the tree, to a depth of 60 cm. Ideally, shelterbelts should trap snow in wide, shallow drifts, reduce soil erosion and create a microclimate which increases crop yield. Unfortunately, very porous shelterbelts are required for even snow trapment while denser belts are necessary for effective reduction of erosion and for better microclimate. Therefore, the primary purpose of the shelterbelt must be determined when shelterbelts are being designed. Generally, tall, long lived trees planted in rows perpendicular to prevailing winds and combined with fields which are as narrow as is practical, can be expected to give the greatest yield increases.
Crops differ in their responsiveness to shelter.
Winter wheat, barley, rye, alfalfa and hay are highly responsive to protection, while spring wheat, oats and corn respond to a lesser degree. By combining proper tree species selection, good shelterbelt maintenance and responsive crops, shelterbelts can be expected to improve yields and increase profits. Prairie Farm Rehabilitation Administration.