Trimming a tree isn't just a task undertaken to control the size or shape of the canopy. It's also a necessary task to help keep the tree safe from disease organisms that have invaded a weakened branch or pests that are feeding on the deadwood of a dying branch. The following tips can help you recognize and remove dead and dying wood correctly.
Tip #1: Follow the fungus
Visible fungal growths, especially if present on a branch that is refusing to leaf out, are often signs of dead or dying wood. The one exception is some of the plant mildews, like powdery or downy mildew. These white, black, or gray powder-like fungal growths tend to coat the leaves on otherwise healthy branches. Otherwise, if you spot a lot of fungi and little to no growth, it's time to remove the branch.
Tip #2: Check for brittleness
Wood begins to dry out and become hollow after it dies. This, in part, is what makes it brittle. You may also notice a lot of insect activity on a dead branch or see small holes in the wood left behind by insects moving into the dead wood. The bark may even start to fall off. Prompt removal is necessary.
Tip #3: Sanitize for safety
Dead wood can harbor disease organisms or pests, which you can spread to healthy wood as you prune if you aren't careful. Prevent this issue simply by disinfecting your pruning shears or saw after each cut. To do this, the University of Florida recommends mixing a 25 percent bleach solution, which is one part household bleach combined with 3 parts water. Dip the tool into this solution after each cut. Just be careful not to spill the solution on any nearby plants, since bleach can kill grass and flowers.
Tip #4: Cut correctly
Knowing where and how to cut is also important. In most cases, make the cut at the collar of the dead branch, which is where the branch joins to the main trunk or to another branch. If only a small section of the branch is affected, you can also try cutting back to just in front of a healthy leaf bud on the healthy section of the branch. Use bypass shears to cut narrow branches, which are usually those smaller than the width of your thumb, and a pruning saw to cut through larger branches.
When you are done, dispose of all dead wood, since you don't want any diseased or pest-ridden wood to remain near the tree. Contact a tree trimming company (such as Treetime Inc) if you need more help.