Pruning Forest Trees

Pruning trees is an excellent way to improve the value of a standing tree for a future harvest. It is most effective when done on trees that won't be harvested for 15 or more years to allow for adequate healing time. Also, due to its labor intensity, pruning should be done only on select trees with few or no defects that will produce the highest quality logs in the future. Concentrate pruning efforts on trees that are of a high-valued species (oak, cherry, hard maple, walnut, etc.), have straight, upright trunks, and have no splits, forks, other defects, or branches larger than 2 inches in diameter within the first 9 to 17 feet of trunk (larger limbs take too long to heal after they've been cut). It is not cost-effective to prune all or most trees in a woodlot; however, if you have a lot of spare time (which certainly most folks don't) it may be worth the effort.

Trees should be pruned to a height of 17 feet when possible. This will allow for the harvest of at least one 16 foot log from the lower portion of the tree. If this is not possible, prune at least enough to allow for one clean 8 foot log to be harvested.

Pruning can be done just about anytime, but is usually best in the dormant season. One reason for this is that most of the tree's nutrients and food reserves are stored in the roots at this time, not in the leaves and branches, so you won't be removing much of that material. Also, pruning wounds can be entry points for some diseases and insects, which typically are most prevalent in the summer and fall. Because of this, certain trees like oaks and elms, which are susceptible to oak wilt and Dutch elm disease, should never be pruned during the growing season.

Pruning DiagramPruning cuts should be made just outside the branch collar, not flush with the trunk. Flush cuts leave too much surface area resulting in higher chances of disease and much slower healing. A three cut technique works best as it eliminates the chance of bark being peeled from the trunk and allows the branch to be cut right at the collar without having the weight of the branch to deal with. The first cut should be made on the underside of the branch, a foot or so from the trunk, about one quarter of the way through the branch. (See diagram) The second cut should meet the first cut from the top of the branch. The third cut should be made just out side the branch collar (the slightly swollen area where the branch and trunk meet).

Monroe Conservation District
1137 South Telegraph Road, Monroe, MI 48161