During the winter the physiological process of tree growth slows or stops entirely. This dormant period is the ideal time to prune trees for deadwood, improve vistas, or to improve branch structure. Tree growth occurs in cycles: During the spring, energy stored from the prior fall will be called upon to produce the first leaves of the year. Once the new leaves are formed, nutrients and new energy will be produced to promote further woody branch development throughout the summer. As the fall approaches winter, energy will be stored in the trees’ root tissues for the following spring flush of growth, and the cycle repeats. Pruning in the winter allows for the tree to have the maximum amount of energy storage in the fall, while supplying a smaller and healthier canopy the subsequent spring.
Insects and diseases that are active in the summer months do not pose a danger to trees in the winter months. Diseases such as Dutch elm disease and oak wilt are transmitted to living woody tissue by insects through a pruning wound. As a result, pruning of elms and oak trees should only be completed during the winter (as the potential for disease transmission is eliminated at this time).
In addition, an arborist will be able to clearly see the woody structure of a tree without the leaves being present during the winter. The buds – or the living tips of the branches – were formed in the fall. Arborists are easily able to distinguish between dead wood and living wood. If there are potential structural pruning needs, such as reduction or subordination cuts as needed to address potential future branch failure, the winter is an ideal time to have this type of pruning completed.
Having trees pruned in the winter may also reduce the impact on lawns and gardens. During the cold months of winter the ground will often be frozen. Frozen ground allows for mechanical equipment to be used in certain spaces without creating ruts or disrupting the turf. Gardens below trees will also be dormant so the impact of having tree work completed may reduce the potential for plant damage.
While you may want to spend the winter indoors by the fireplace with a cup of hot cocoa, it is an ideal time to have an arborist prune your trees.