A lush, green crown on your landscape trees is a beautiful thing, but there is such a problem as too lush of a tree. Overcrowded crowns require prompt pruning, as they can result in tree health concerns.
Crown Crowding Issues
Air circulation, or the lack thereof, is a major issue when the crown of your tree becomes too dense. Without air circulation, fungal and bacterial issues on leaves and stems can take over. Insect pests, like aphids, also spread more rapidly and may cause more extensive damage when the crown density is high. Further, if air can't circulate due to crowding, then it is likely more difficult for light and moisture to penetrate deeply into the crown.
Crowding can also lead to injuries in the tree. Crowded branches can rub and bang together, issues that lead to bark wounds and open the tree up to disease incursion. If a branch breaks in a crowded tree canopy, it is more likely to bring down multiple branches and cause more major injuries.
Signs of a Crowded Crown
Generally, when you stand beneath a tree on a bright, clear day, dappled sunlight should reach the ground. If it is heavily shaded beneath the tree, chances are that the crown needs to be thinned. Heavy shade can indicate an overly dense crown.
There are more obvious signs that it is time to trim. Branches that are rubbing or banging together or that show bark damage mean it's time to thin the crown. Lots of deadwood or sparsely leafed out inner branches in the canopy is another sign that thinning is overdue. Other symptoms of overdue thinning include an increase in fungal issues, branches growing at downward angles, and a lopsided crown form. The last happens when one side of the canopy grows denser than the other.
Crown trimming takes some care. First, all of the dead or badly damaged branches are removed. These are cut off at the base where they meet the trunk or the nearest main lateral branch. Then, your tree trimmer cuts out any branches that are rubbing together or that have poor growth form (such as those growing at a downward angle).
Once only healthy wood remains, any remaining thinning or balancing of the crown is completed. Usually no more than 1/4 to 1/3 of the existing wood is removed in order to open up the canopy. Your tree service prunes so there is a strong network of healthy lateral branches remaining.
Contact a tree trimming service in your area for more help with maintaining healthy crown growth in your landscape trees.