QUESTION: I have a 50-year-old maple tree with a large hole where a branch was cut many years ago. There are no signs of borers or sawdust. Should I be concerned? Is there anything I should do?
JENNIE, WESTLEIGH, NSW
ANSWER: The fact that this is an old wound on a mature Japanese maple, along with the absence of borers, is reassuring. However, my concern is that rain may enter the wound over time, potentially encouraging diseases and rot. That said, the inner cambium appears to have sealed the wound quite well.
While many people tend to ignore these holes, considering that a maple can live for over 200 years, I believe it’s worth taking a few extra steps to ensure its longevity.
Sunlight is one of the best protections. I recommend cleaning out any leaf litter and dirt using a gloved hand, then spraying the area with liquid copper to disinfect. I have previously inserted a 1cm diameter copper tube into the base of the hole to allow excess water to drain away.
To do this, measure the depth of the hole, then drill a 1cm hole upward into the base of the hole and insert the tube at an angle to facilitate drainage. Leave about 5mm of the tube outside the bark to allow water to drain off the trunk.
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