The best time to prune or trim trees is when they are dormant. This will help prevent the loss of water and also reduce the chances that fungi will colonize the wounds created. Dormancy typically occurs during the winter, but some trees also become dormant during hot, dry periods.
Nevertheless, trees can be pruned at any time of year if necessary. For example, safety concerns may dictate that you prune a tree as soon as possible, regardless of the season. The most important factor involved in pruning is the techniques used and the locations at which the cuts are made.
Every time you trim a tree branch, you wound the tree. These wounds can serve as sites into which fungi or bacteria can enter the branch and colonize the area. However, because trees have robust defense mechanisms, they can usually keep these fungal invaders at bay. However, the nature and location of the wound are important factors that can tilt the advantage in the direction of the tree or the fungus.
Trees Do Not Heal
Unlike animals, trees never truly heal, as they have no capacity to do so. Instead, trees simply seal up wounds through a process called compartmentalization. This prevents the spread of fungi (or other pathogens), but it can lead to weak spots in the wood. This means that tree wounds are, in effect, permanent. This demonstrates the importance of locating cuts correctly and making them in the appropriate manner.
Proper Pruning Cuts
To prune a tree correctly, you need a sharp, size-appropriate tool for the branch in question. Typically, this means shears or loppers for twigs and finger-thick branches, pruning saws for branches that are wrist-thick or smaller and chainsaws for anything larger. The cuts should always be placed about an inch outside the branch collar, rather than at the midpoint of a branch. This will give the tree the best chance of compartmentalizing the wound.
The Three-Cut Method
Anytime you prune large branches, you need to take steps to prevent the limb from stripping away the bark on the trunk as it falls. The three-cut method is the best way to do so:
1) Locate your first cut about 2 to 3 inches away from the branch collar. Starting from the bottom side of the tree, cut about halfway through the branch.
2) Your next cut should be located about 2 to 3 inches further from the trunk than the first cut. However, you’ll want to make this one from the top side of the branch. Cut all the way through the branch, allowing it to fall to the ground. Because the fibers on the underside of the branch have already been cut, the falling branch will not strip bark from the trunk.
3) Make the final cut about 1 inch away from the branch collar to remove the remaining stub.
If you need your trees pruned, reach out to your friends at Evergreen Arborist Consultants. While homeowners can certainly carry out minor pruning operations, it is not wise for amateurs to trim significant branches or work above ground level. Instead, give us a call and let one of our skilled and experienced professionals prune your trees in a safe and prudent manner.