There are many reasons why tree thinning is beneficial to your home and property.

The primary reason is to allow more air movement and increased sunlight to your grass and landscaping, but proper thinning also reduces the splitting or breaking of limbs and trunks, inhibits fungal infections and promotes crown health and growth.

Whether you have new trees that need shaping and sucker branch removal or older trees with aged, brittle growth and dense canopies with little sunlight penetration, proper pruning techniques can help you maintain and preserve the health of both your trees and grass.

What should I know?

Before you begin pruning, it is important to remember that no more than one-fourth of the living branches should be removed per tree per growing season. With this in mind, examine the tree from the top down. Plan to keep branches with “U-shaped” attachments, as these are stronger than “V-shaped” attachments. Also, plan to remove sucker growth on lateral branches to re-direct the tree’s growing energy towards the tree’s crown. Finally, make sure to prune all branches that rub or cross each other.

Thinning trees should be done to evenly space lateral branches on the trunk and to select proper branch structure for maturing. Never remove a branch that is more than one-third the size of the stem. To maintain the proper structure and form of older trees, remember to prune out the “V-shaped” crotch branches. Be careful: over-thinning can unnecessarily stress trees and produce excessive sucker growth. If extensive pruning is needed it should be done over two or three growing seasons. Better tree health and appearance are achieved when thinning is properly performed.

When should I thin my trees?

The ideal time to thin hardwood trees is between August and January. Trees that flower should be pruned after they bloom, but be sure to check with a Certified Arborist to find out which varieties should not be pruned until they are dormant. Conifers are not often thinned, but can be pruned any time of the year.

Why prune?

Hardwoods are pruned primarily for selective branch and sucker removal and to improve light penetration. This promotes healthy growth of the grass and flowering plants below, which benefit from the increased light and produce more growth and flowers.

In many ornamentals with multiple stems or branches such as Bradford Pear, Riverbirch, and Maples thinning reduces the risk of splitting or breaking branches. The result is stronger trees and branches for extended tree life. Increasing air movement is beneficial in crowns of large trees. This will reduce the risk of uprooting trees, trunk failure or breaking branches. Air movement also helps reduce fungal problems for many trees, including Oaks, Maples, Birches, Ash, and ornamental flowering trees.

Always prune for the following reasons: first for safety, second to promote healthy growth, and third aesthetics. Never prune trees near or touching utility wires. If in doubt, consult a professional arborist.