Some landowners prefer the look of a pruned forest. Pruning improves access and visibility in a forest stand.
Removing branches when they are small can improve the quality of the future log by increasing the volume of clear (knot-free) wood produced. Whether this translates into an increase in log value depends on the species and local markets.
Pruning also is used to remove dead and diseased branches and to prevent disease infections in some cases. For example, in white pine stands, pruning can help prevent white pine blister rust infections by removing the most vulnerable infection sites.
Pruning can improve air circulation within a stand, which can help reduce fungal disease. On the other hand, pruning wounds can attract egg-laying insects or airborne fungal spores that then damage trees. For example, oak wilt is a serious disease in the upper Midwest. Pruning oaks in spring and early summer can greatly increase the risk of oak wilt infection. Before pruning, it is important to understand whether there are specific local forest health concerns that may be improved or made worse by pruning. Contact a local Extension forester in your area for advice.
Prune carefully to minimize tree damage. Pruning techniques vary for hardwoods and conifer trees. Figure 1 depicts proper pruning cuts. Many different tools are appropriate for pruning, including a hand saw, a pole saw, or clippers or loppers, depending on the size of the branch. Painting pruning cuts is not recommended.
To learn more about pruning, including technique, tools, and proper timing, refer to one of the Extension resources below.
Pruning Woodland Trees (pdf) (North Carolina State University)
Conifer Pruning Basics for Family Forest Landowners (pdf) (Washington State University)
Pruning Western White Pine: A Vital Tool for Species Restoration (pdf) (University of Idaho)
Managing Insects and Diseases of Oregon Conifers (pdf) (Oregon State University)
Amy Grotta, Oregon State University Extension Service