Root Pruning of Siberian Elms

Field shelterbelts play an important role in protecting farmland from wind erosion. They also increase snow catch, moderate air temperatures, reduce evaporation and increase overall crop yield. Although generally beneficial, shelterbelts do compete with adjacent crops for moisture and nutrients. Siberian elm can rob moisture needed by crops due to its extensive lateral root system. Root pruning, the practise of severing lateral roots, can reduce the effects of Siberian elm root competition on nearby crops.

Root pruning can be done using a subsoiler. The subsoiler is pulled through the ground parallel to the shelterbelt, cutting the roots. To reduce stress on the trees, only one side of the shelterbelt should be pruned each year. This should be done during the spring or fall while the trees are dormant.

Root pruning should be done no closer than three-quarters of the height of the trees away from the shelterbelt, as illustrated below, to a depth of 60 cm. It should be repeated every two to three years to control new root growth. Pruning too close or too often could harm or kill the shelterbelt, especially if it is an older belt or under drought stress. During drought periods, root pruning should be discontinued completely.

While root pruning does not completely eliminate competition between field shelterbelts and crops, it reduces the competition and is one method which can be used by farmers to increase the effectiveness of their shelterbelts.

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