About this time of year, I begin to experience what I call “garden itch”. I really want to get out and dig in the dirt and make something grow. Garden books tell us winter is the time to study garden catalogues, complete seed orders, and make plans for the next spring. While fun, these activities don’t seem to satisfy my itch.
However, all is not lost. There is one important gardening activity that is best completed in the winter. It involves conducting a thorough tree inspection. This is especially effective for deciduous trees because they no longer have leaves to hide their problems. So, on a sunny winter day, put on your hat and boots and take a close look at your trees.
What to look for:
Although winter may not be the time you want to solve tree problems, it is the time to identify them. Here is a list of things you may want to look for.
Structural Problems: look for situations that can be early signs of weakness that may later lead to branch or tree failure. Many of these can be solved later on through judicious pruning. Specifically, look for branches with a poor attachment angle. Where they join the trunk, branches should be directed slightly upward at an angle of 45 to 60 degrees. If they are too horizontal, or too upright, they will become weak. Plan to remove such problem branches, if it can be done without destroying the structure of the tree.
Also, look for cracks and splitting around branch junctions. If you find such damage on large trees, you may need to access some professional help to determine the best action. On small trees, you can reshape the tree to relieve the pressure that is causing the problem and help the tree heal itself. The last thing to look for is something called included bark. This is a situation where the tree does not make normal wood on the top of the branch junction and instead produces bark in the joint. It can be recognized by the soft, corky tissue (it may create an open crevice or be closed) that is present on top and down into the branch union. This makes the branch very weak. It is often associated with a steep branch angle. Plan to remove these weak branches if feasible.
Architecture and Appearance: When the tree is bare, you can step back and look at its overall growth habit. Determine whether or not it has good balance and overall appearance. Decide if the crown needs to be raised, lowered, or cleaned (but never topped). Record a pruning plan that can be implemented in the spring to improve the tree’s appearance and functionality.
Pests and Disease Problems: Although pests are typically not damaging during the winter, it is still a good time to look for problems that can be addressed during spring or summer. Some of the most destructive insect pests on trees are borers. Look for the small holes, the sawdust-like frass, or loosened bark that may indicate a problem is looming. Other types of insects such as aphids or beetles will overwinter as eggs on the trees and may become problematic next summer. Do some homework before the inspection and find out what to look for based on common problems for the tree species you are inspecting. Also, check for disease problems that appear as cankers on the bark. If you find such problems, study up on the solutions and prepare to deal with them when the season is right. That will give you one more scratch for the gardening itch.
A good winter tree inspection will identify problems you may not know you have. It will also give you time to come up with a good solution to one or more of the many issues that affect tree health. Winter may be a slow time for garden chores, but it does not need to be unproductive.
—Stephen Love, Consumer Horticulture Specialist