Crown Thinning of Trees
Crown thinning is a type of tree pruning that removes 1 to 4 inches from the end of a limb, depending on the size of the tree. It is commonly done on mature trees to reduce crown density, which has several benefits. Thinning makes it easier for wind to pass through the crown area of the tree, which helps the tree to withstand storms or sunlight penetration. It also protects trees from various forms of stress including wind, ice, snow and gravity. Some property owners opt to trim trees because they prefer the appearance of a tree whose crown has been thinned.
Crown thinning is a practice that should be done by an expert arborist. Removing entire branches from the interior crown instead of removing portions from the end of the branch can have an adverse effect on the tree, leading to structural weakness. This incorrect approach is commonly referred to as lions-tailing, cleaning out, over thinning, stripping out the interior, or over lifting. If a crown has been properly thinned, there should be no change in the overall size of the tree.