With hurricane season just days away, officials at the Village of Wellington are urging area residents to take care of landscaping and pruning well in advance. The village’s landscape supervisor offers the following advice on the topic of tree trimming and pruning:
Many homeowners’ associations perform maintenance tree pruning on an annual basis. Most often, tree canopies are raised for clearance and sometimes thinned out to reduce wind load and increase light penetration. Typically, a sales person for the company bidding the work will look at the property to get a rough count and assessment of time required. Then, if awarded the job, the trimmers for the company will prune the trees based on general instructions.
An important component that is often omitted is an assessment of the need for structural pruning. Structural pruning is essential for young hardwood canopy trees to encourage strong form. While thinning is sometimes needed, structural pruning should take priority over thinning. Structural pruning can also allow light and wind to pass through, just as thinning does, but it does more for the actual strength of the tree by addressing the tree’s specific flaws.
In general terms, structural pruning improves the actual strength of a tree’s branches and makes it less susceptible to breaking in the event of a storm. There are three aspects to structural pruning: 1) elimination of crossing branches, 2) reduction or removal of branches with weak attachments to the trunk and 3) influencing overall canopy development.
It is important to eliminate any main branches that cross over one another, as their rubbing together over time can cause injury that forms decay. This creates a weak spot on the branch that is likely to break. One of the branches needs to be reduced to a lateral branch before the crossing point, or possibly removed all together to eliminate this problem.
Branches that have a narrow angle of attachment should be reduced in length or perhaps completely removed. A strong branch union on canopy trees is rather cup-shaped or u-shaped. When the branches emanate from the trunk at a sharp angle, or v-shape, often bark gets trapped between the branch and the trunk, which is called included bark. This is similar to driving a wedge between the branch and the trunk. When the branch gets large and heavy, and a storm comes along, it is much more likely to tear off from the trunk.
The final aspect of structural pruning is performing pruning cuts that affect the eventual mature form of a tree. Typically, a tree with a central main leader is stronger than one with codominant leaders (or main trunks of the same size). The centermost leader should be left to grow, and the codominant ones to the sides can be reduced in height by cutting the upright growing branches down to a lateral (or sideways growing) branch.
If a mature tree has developed with multiple main leaders and they all have good cup-shaped attachments, then making drastic cuts of more than 10 inches is not necessary. It is not advisable to make large diameter cuts on trees because these cuts are harder for the tree to heal or close, which might lead to decay inside the tree.
Always hire a professional tree service company with a certified arborist on staff who knows how to perform structural pruning. It is best to conduct major pruning in the winter season when the trees are more dormant.
Remember to only remove 25 percent of the canopy per year. Many trees will require structural pruning over several years to achieve desired results. However, structural pruning ultimately leaves a legacy for the community and is certainly worth the investment.