Tree trimming is not as easy as it may seem. If you just start lopping branches off and trying to mold the tree into your desired shape, you're going to end up with a weak tree — and maybe even a dead one a year or two from now! It's important to keep your tree's health in mind whenever you prune, and you can do that by adhering to the basic principles of tree trimming below.

Always remove the weakest or least healthy branch.

When faced with removing one of two branches, always remove the one that is weaker, smaller, or less healthy. For example, if two branches are rubbing together, remove the one that's smaller or that appears to already be damaged. Remember that your tree needs the leaves on its branches to harness the sun's energy and make its own food. If you remove its healthiest, most vibrant branches, you are going to be interfering with its ability to do that, and your tree will probably just grow weaker over time. 

Remove the whole branch.

Do not simply clip off the ends of the branches! This is not how you shape a tree, and it will cause more harm than good, as you are removing the part of the branch that is actively growing. If you determine a branch needs to be removed, then you need to remove that whole branch. Clip it about an inch from the spot where it meets the tree trunk. Leaving behind this one-inch nub helps keep your tree from leaking too much sap.

Use sharp, sanitized equipment.

Just as a doctor would sanitize their hands before performing surgery on a patient, you should sanitize your hands and equipment before trimming your tree. Trees are also prone to diseases, most of which are caused by fungi. Trimming can introduce those fungi straight into the tree's inner wood, which can lead to destructive disease. You can use alcohol or bleach to sanitize your pruning equipment.

You also need to make sure your shears are sharp, as cuts made with sharp shears heal more easily. Take the shears to your local landscaping supply store; most offer affordable sharpening service.

The basic principles of tree pruning listed above will go a long way towards ensuring your tree's health well into the future. If you are feeling intimidated by the prospect of trimming your own trees, reach out to a tree trimming company in your area.