Large, old trees may appear to be strong and healthy, but hidden decay can undermine their strength and stability. Generally, maple trees decay from the top down and it becomes apparent that age is taking a toll on the health of the tree. Branches may fall from the canopy, and bark may begin to loosen and fall. The maple tree may begin to show fall color in the leaves well before healthier trees due to stress.
Oak trees begin to fail in a different pattern. They may appear to be fine, but deep inside the trunk, types of rot may develop and gradually decay the wood, until there is insufficient wood to support the tree against strong winds.
The problem occurred during the tropical storm and tornado that hit North Haven properties in the summer of 2020. When the fallen oak trees in the Elm Street cemetery and on the Town Green were examined after the storms, it was apparent that the trunks of these trees were hollow, like straws. When the interior rot was visible, it was not surprising that storm winds brought the trees down.
So how do you know if that beautiful black oak tree is rotting inside? Walt Brockett, licensed arborist, and a member of the Daytime Gardeners of North Haven, uses a method of coring to sample the interior wood to aid in determining its health.
With permission from Mike Maturo, head of the Public Works Department of North Haven, and North Haven Cemetery Commissioner Lynn Frederickson, Walt is starting to do some core sampling to identify if there are more trees that may be weakening and in danger of falling during a future storm. Property damage, such as broken cemetery monuments and fences, can be prevented when trees that are failing can be identified before falling,
Walt uses special bits on his power drill to drill a small hole into the tree trunk and remove core samples. This task should be done in the winter so the tree can heal over the little hole and avoid insect and disease damage that may occur in warm weather.
The drilling is done in a series of steps so Walt can examine the material at each step. Measurements are taken so he knows how deep into the tree his drill has gone. These measurements and samples will show the thickness of the good wood in the trunk.
Decisions about the health of the tree and risk of falling can then be based upon scientific measurements rather than just looking at the tree and trying to guess if it is still healthy.
The attached photos show sampling on a black oak in the Elm Street Cemetery. The diameter of the trunk is 46 inches and it appears to be healthy and strong. But there was another similar tree nearby before the tropical storm that blew down onto the Brockett family monument, causing damage. Monitoring the health of the two neighboring oaks will help identify if either need to be removed.
Core sampling also is planned for more trees on the Town Green.
Text and photos submitted by Sally Brockett.