Advantages of Winter Pruning
For many people, dating back to earliest history, trees represent everything from ashes to the zenith of life itself. Well-maintained, structurally sound trees are valuable assets to your landscape. They not only maintain and increase property values, but also help create and clean the oxygen we breathe, provide shade and moderate temperatures, and become living memories of special times in our lives. It is safe to say that a tree can often be thought of as an old friend.
In order to protect their long-term well-being, trees require and deserve occasional care. The majority of tree damage can be prevented by proper pruning. The best time to evaluate, care for (structural needs) and prune trees in Wisconsin is during the winter (usually November to April) when the tree is dormant.
Insect and disease activity
Most insects that live in trees and attack or transmit diseases are dormant during this time of the year. Timing to prune in winter is especially critical for reducing the likelihood of spreading oak wilt and other tree diseases like Dutch elm disease. Oak wilt, a common, devastating fungal disease that has been present in Wisconsin for a century or more, spreads from tree to tree through sap-feeding beetles that are attracted to freshly pruned or injured trees and root grafts between neighboring trees. Oak wilt causes the water and nutrient-conducting channels in the tree to plug up and fail. Once a tree is infected, water and stored nutrients can’t move upward from the root system, causing the tree’s leaves to wilt and fall. Red oaks, which include red, pin and black oak, are particularly vulnerable to this disease. Once infected, the tree faces quick death, often within one month. Prevention is the best defense against this disease. During winter, it is safer to prune trees like oaks and elms without having to worry about making them targets for these pests. In addition, tree wounds have a better chance of sealing in early spring before the majority of pests and diseases become active.
Dysfunctional limb identification
Each tree species has a unique form and structure that needs to be maintained. If damaged or dead limbs need to be removed, the overall structure of the tree must not be changed; doing so can weaken the physical strength of the tree. Without leaves on a tree, the structure can be assessed easily and corrected where necessary.
Obvious structural damage
Torn, crossed or stacked branches are all structurally dysfunctional and can cause health issues within a tree’s canopy. Without leaves, these problems are much easier for arborists to identify. For example, maples, lindens and hackberries are genetically inclined to develop “co-dominant branches,” which are poorly attached to the tree. It is easily identified and corrected when the trees are young, but if not corrected early, they become prone to breakage, which becomes a hazardous and more expensive situation for the tree owner later on. Pruning in the winter season enables a more complete health assessment and easy access to perform needed services. It may be difficult to see this structural disorder when leaves are on the tree, but it is obvious for the trained arborist in the winter season.
Less foliage, less weight
When we prune during the growing season, new leaf tissue and bark tissue are continually being added to the branches. A limb may weigh five times more in the summer months than during the dormant season. This extra weight is not present in the winter, lessening the potential of pruning cuts to rip or tear, which can minimize accidental damage.
Tree energy acquisition
During the summer, leaves are creating the food for the trees. When we prune limbs at that time, we are reducing the tree’s ability to generate energy and resources to survive. In the winter, the energy impact on the tree is significantly reduced.
Cold temperatures mean you can’t “smell the roses,” but the beauty and majesty of your trees are there for your enjoyment all year long. Now is the time to take simple steps to insure they will be there for years to come!