Expert’s Tip: Tree Pruning

Kimberly Miller, Winnebago Co. UW-Extension Horticulture Educator

As we move into November, we are definitely feeling the change of the seasons. To some this may seem like the end of the gardening season. However, this is the perfect time to start examining your trees to determine what pruning needs, if any, they need. Trees in the urban landscape endure stresses not found in forest conditions and often pruning is needed to remove dead branches, improve structure, enhance vigor, or maintain safety.

The best time to prune trees is during the late dormant season. Pruning at this time of year allows you to see the overall branch structure, it minimizes the risk of pest problems associated with wound entry, and it allows trees to take advantage of the full growing season to begin closing and compartmentalizing the wounds. It is especially critical to prune oak trees at this of year time (November to March) to limit the spread of oak wilt.

Trees should be pruned throughout their entire life. However, if young trees are “trained” or pruned to promote good structure they will remain in the landscape for more years than trees that were not. These trees also have a lower potential for structural failure at maturity and require less maintenance later on.

Before making any pruning cuts it is important to understand the biology of a tree and how it will respond in order to optimize the health and structure of your tree. Trees DO NOT HEAL, therefore each cut has the potential to change the growth of the tree and an improper cut can cause damage that remains for the life of the tree. No branch should be removed without a reason. Therefore, laying out your plan of action is important.

Tips for pruning your trees:

• Have objectives! This will dictate the type of pruning techniques to use. e.g. Crown thinning, raising, reduction, cleaning, restoration, etc.
• Each cut should be made carefully, at the correct location, leaving a smooth surface with no jagged edges or torn bark. Use the 3-point cut for larger limbs. By doing this, it will help the tree to optimize its “compartmentalization” process by which it limits the spread of disease through the wound site.
• Never remove more than 25% of the live branches of the tree.
• Wound dressing is not needed on pruning cuts, unless the prevention of certain diseases is needed (e.g. as oak wilt). If needed apply only a light coating of a non-phytotoxic material.
• Do not top your trees.
• Use the right tools for the job. Well-maintained and sharp tools will improve their performance.
• Do not prune near electrical and utility lines. Contact the utility company or hire a professional.
• Leave the pruning of large trees to the professionals (anything you cannot reach from the ground). For a list of certified arborists in your area go to http://www.treesaregood.com/findanarborist/arboristsearch.aspx

For more in-depth information on pruning techniques go to http://www.treesaregood.org/treeowner/pruningyourtrees.aspx

Posted by Vicki