Tree pruning

Tree trimming is likely a regular part of your yearly chores as a homeowner, but many people approach tree trimming without really knowing what they’re doing, and this can lead to irreparable damage. To help prevent this, we’ve come up with a list of some tips and proper trimming methods you can use when you go to prune your trees this year, and this will encourage healthy, long-living, and disease-free trees.

Only Use Clean Tools

Did you know that you can spread diseases from one tree to another the same way humans can spread some diseases? When you use a tool to trim a tree, you can pass viruses and fungi from that tree to others if you don’t disinfect your tools afterward. To prevent this, always disinfect cutting and pruning tools after each use. You can do this with one part bleach mixed into nine parts water, followed by a soap and water rinse.

Employ the One-Quarter Rule

When trimming a tree, you should never trim more than one-quarter, or 25 percent, of the foliage during a single growing season. Pruning is stressful for a tree, it increases the risk of disease, and it makes the tree vulnerable to insects, so you should never trim more than what’s necessary.

Use the One-Third Guides

There are a number of one-third rules to follow when pruning, and they include:

  • Don’t prune more than a third of a deciduous tree’s height
  • A third of the tree’s height should be from the trunk, and two-thirds should be the crown
  • The diameter of main branches should be a third smaller than the trunk

Make Sharp, Clean, Angled Cuts

Your tools should always be kept sharp to prevent damage when you’re trimming, and cuts should be quick and clean. When you’re shortening a branch, make the cut on a slight angle, and cut the branch a quarter-inch beyond a bud.

Choose the Right Time

Trees are best pruned when they’re dormant rather than during active growing phases, especially if your goal is to promote new growth, fruiting, or flowering. Late fall or late winter—after the coldest temperatures have passed—are ideal times to prune. The exception is that if you need to prune away dead, diseased, or hazardous branches, you should do so whenever you notice the problem branch. Pruning during dormancy will help prevent fungal infections, reduce sap loss, and minimize stress on the tree.

Only Trim Smaller, Younger Branches

To minimize stress on the tree and reduce the possibility of infection, only trim young branches that are smaller than 2 inches in diameter. If the branch is older or larger, avoid trimming unless you have a good reason, such as the branch is a hazard, is dead, or is diseased. You may also want to call a tree expert if you need to trim old or large branches.

Space Out Branches Evenly

When choosing branches to prune when you’re thinning the crown, select branches that will eliminate unevenness among the branch spacing. Especially with young trees, you want branches to be spaced out evenly throughout the tree. Similarly, you should also prune branches that are growing across or touching other branches.   

Avoid Injuring the Branch Collar and Ridge

The branch collar is the swollen section under the base of the branch where it connects to the trunk. The branch bark ridge is the upper section of the base where the branch connects to the tree. Take care not to cut through the collar or the ridge when you trim off branches: the cut should leave a small stump of branch so the collar and ridge are still intact.

Tree trimming is actually a bit of a scientific endeavor, and there are right and wrong ways to prune a tree. Proper trimming can be used to encourage growth, to make trees safer, and to increase the aesthetic appeal of trees. However, improper trimming can lead to fungal infections, virus transmission, stress, and damage to the tree, which is why it’s so important that you use the right techniques, the right methods, and prune the right branches at the right time.