4 Common Tree Pruning Mistakes

Tree care is important to the health of your trees, the value of your property and ensuring you families safety from potentially hazardous trees. Below are some common tree pruning mistakes we see on trees throughout the area. As tempting as it maybe to take care of much needed tree pruning on your own to save some money. If you do not follow proper pruning, the process can permanently ruin the look of your valuable trees and often leave them susceptible to storm damage, disease and possibly decline and death.


This is usually one of the most obvious and ugly of tree pruning mistakes. It happens a lot of trees that were too large for the place they were planted. Topping involves cutting away a large section of the top of a tree’s crown, or all the leafing branches across the top half of the tree. What’s left with is a very unsightly specimen with severely weakened branch structure.

Bad Timing

There are good times to prune and bad times to prune your trees; it depends on the species and condition of the tree. In Ontario, for example, oak trees are most active from April to July and should be pruned in the fall or late winter (March). If a tree is already stressed, it should not be heavily pruned. You should always have your trees inspected by a certified arborist before you let anyone take a chainsaw to it unless you’re willing to lose the tree completely. Pruning west-facing branches isn’t a good idea in the heat of the summer; when you remove large limbs that shade the tree from the hot western sun, you can cause sun scald on red oaks, maples, and other susceptible species. Sun scald results in wounds and damage to the trunk bark that can severely damage your tree.

Improper Cuts

Another common tree trimming mistake happens when removing branches is to too close, or flush, to the main trunk. By doing this, you remove the branch collar; an area of tissue with specialized cells that help heal the wound. You’ll recognize it as a small swelling, or bump, right where the branch meets the trunk. The callous that the branch collar cells create will prevent disease from entering the trunk. When you cut that branch off flush to the trunk, you’re opening a wound that can allow in disease and pests, putting your tree on a path to an early demise. Bark tears can occur when the proper steps are not taken when removing large branches. If you make the wrong cut in the wrong order, you can end up with a large branch falling and tearing or splitting your main trunk.

Over Pruning

No more than about 15% to 20% of a mature tree’s foliage should ever be trimmed off at one time. In fact, 5%-10% is usually adequate. When you remove too much of the canopy, you’ll leave the tree unable to produce enough food, transfer nutrients and structurally support itself. People often over trim and thin their trees in hopes of getting the grass beneath to grow properly. If you have multiple trees in an area where you’d rather grow turn, often a better practice is to remove selected trees to let in more light and perform structural pruning on the remaining trees so that you can have both healthy trees and turf.