How to Trim Trees

Trimming trees helps them grow strong while maintaining a neat and attractive shape. People trim trees to remove damaged branches, encourage new shoots, or shape the tree for a striking appearance. The key is to trim properly to avoid harming the tree. Continue reading to learn the basic steps.

Think about which branches you need to trim. Are you trimming for shade or height? Has the tree been trimmed recently? Before starting, consider what you want to achieve and set your goals.

• Your trimming goals will influence the timing of the task. Light trimming or removing dead branches can be done at any time, but for larger goals, you'll need to plan throughout the year.
• For instance, trimming in winter encourages vigorous new growth in spring. Summer trimming will slow the growth of the pruned branches, making it ideal if you're shaping the tree or want to limit the growth of branches you don't want to grow tall.

Examine the tree. Take a few minutes to assess the size and shape of the tree, envisioning its form once the trimming is complete.

Identify the main branches that form the "framework" of the tree." Avoid cutting these branches.

Remove any damaged branches first. Whether from a storm or other causes, broken branches should be cut away so that water and nutrients can be directed to the healthy branches instead of supporting the damaged ones.

Trim back excessive branches. Remove any branches growing in a tangled manner to allow air to circulate and light to reach every part of the tree. For healthy growth, air must flow freely around the branches. Branches growing too close together can create conditions for mold to thrive and attract insects.

• Remove branches growing inward toward the center of the tree. These branches make the tree look untidy and unhealthy.

Trim any obstructing branches. It's best to remove branches that cause obstruction, whether low-hanging branches blocking pathways or high branches threatening power lines, brushing against roofs, or hanging over the house. Other nuisance branches should also be trimmed away.

Trim branches to maintain the tree's shape. If you want the tree to have a more rounded or neat appearance, you can trim a few branches that grow at unusual angles. A small trim can make a big difference in the overall look.

Trim trees as little as possible. Every branch you cut reduces the tree's ability to protect itself, and the risk of fungal infections and insect infestations increases. Only trim when absolutely necessary, and never remove more than 25% of the tree’s branches.

• For most deciduous trees, make sure at least two-thirds of the branches remain, although this can vary by species. Keep in mind that a tree cannot survive if only a single bare trunk is left. A tree will experience severe stress if you cut off all its branches.
• Do not trim more than once in a season. Unless a branch breaks due to a storm, avoid trimming more than once each season as the tree needs time to recover.

Prepare pruning tools during the tree's dormant season. Trees experience less stress when pruned in late fall or early winter as sap loss is minimized. Pruning during this time is also better for the tree because the 'wounds' you create are less likely to be infected by fungi or insects, as these are less active during this season.

• The best time to prune is after the leaves fall, signaling that the tree will be dormant until early spring.
• If branches break due to a storm at any point during the year, it is better to prune them immediately rather than waiting until spring.

Make a cut on the underside of the branch. The first cut should not go all the way through the branch. This technique prevents the branch from breaking too close to the trunk as it falls.

• The cut should be made on the underside of the branch, also known as the branch's base, where it attaches to the trunk. Leave the branch base intact, so do not cut too close to the trunk.

Cut the branch several centimeters away from the trunk. The second cut should go all the way through the branch and be positioned outside the first cut (further from the trunk). Once the branch is separated, you will be left with a small piece of the cut branch.

Make a precise cut to leave a clean branch stub. Now, you can make a cut very close to the base of the branch. This will provide the best conditions for the tree to heal quickly.

• Remember not to cut into the base of the branch. This part should remain intact.

Clean your pruning tools. While you might not need to sterilize your tools unless you've cut into decayed or visibly infected branches, it's safer to disinfect your pruning tools with rubbing alcohol (or household disinfectants) after trimming each diseased branch. You should also wipe the tools with a disinfectant cloth after pruning a healthy tree and before moving on to other trees. Pathogens can sometimes spread through dirty pruning tools.