TREES AND BAD WEATHER
changes in the dynamic movement of the forest. During the stormy season, when the canopy really starts to move, an oscillation of two trees connected with a cable can occur in a manner that causes a sudden heavy load when they move in opposite directions. Some ar- borists call this the “karate effect” when a support cable causes the same thing to happen. This is one of the reasons for removing cables during the stormy season, a practice that I recommend. Extreme heat. Another weather event that is becoming more common: heat waves. When abnormally hot tempera- tures persist, many things can happen to trees in a forest. For example, a phenomenon called “sudden limb drop,” which is still poorly understood, often occurs during hot weather.
temperatures were on average 30 degrees Fahrenheit hotter than nor- mal—and reached a peak of 60 degrees above normal for the time of year. The event caused quite a few unexpect- ed huge branch failures. Many in the science community think that the trees were so dry that a lack of water in the wood structure resulted in weakening of microscopic bonds in the wood, causing the breakage. This new phenomenon is something to consider during and after extreme heat events. Pay attention to noises in the woods because trees might make unusual sounds leading up to a failure. For example, one of our clients reported hearing a cracking and popping noise for a couple of days before a large branch tore out of one of their trees during the heat wave.
cern, it’s a good idea to have up-to-date measurements of their height, diameter of the main trunk, diameter of parts that might strike a target, and angle of lean if present. On a side note: There are two common- ly used ways of recording the angle of lean. One is to hang a plumb bob on the low side of the tree and use a piece of steel or a wooden stake to mark the plumb line. The second uses two aluminum nails set in the high side of the tree and a digital level is used to measure the angle. Regular monitoring of tree angles is easy to do and will ease any concerns or alert you to a problem, especially following a weather event. Photographic evidence. It’s also helpful to take photographs of areas that you’re monitoring. Set up spots where you take the same picture on a regular ba- sis. Photos should be taken at minimum in the dormant and active seasons, and each time your arborist assesses the course. You may need to take photos of certain trees more frequently, though, especially if there is a condition being monitored, such as a tree with a trunk wound—photos at frequent intervals will help to assess how well the tree is producing reaction wood or how quickly it is developing decay. Data and understanding. Create a file for each tree or area. If you have the means and know someone who can help you, the use of photogrammetric data (ob- taining information about physical ob- jects and the environment through the process of recording) can be extremely helpful. Having lots of information will help you and your arborist understand and assess risk over time and notice if anything has changed after heavy weather. Tracking your trees will help you and your arborist to identify symptoms that indicate a decline in health and struc- ture like yellowing or dying foliage, de- velopment of cracks in the stem, growth of fungal decay conks or other organ- isms that may affect the tree, changes in trunk anatomy that may indicate there are internal defects, and ground level
We saw this during the deadly 2021 heat dome event in Washington, when
Tracking Your Trees
Tracking the condition of your trees will help you to quickly recognize changes that may need to be addressed by a professional. Site map for trees. To facilitate post- event inspection, I recommend that you first create and maintain/update a map of your site with as much detail as possible regarding trees being utilized in and around operations. All those with fittings attached to them should be noted, as well as every tree within range of your course and associated facilities. Trees that are within a distance of 1 to 1.5 times their height to any facility should be considered in range. An arborist and your builder can help you gather these details during their initial inventory and subsequent inspec- tions. Generally, I recommend that an independent consulting arborist inspect the trees at least annually and should update the map during the inspections. Additionally, at least one employee should have extra training in visual tree assessment and be assigned to conduct regular inspections prior to daily course opening and after weather events.
A plumb bob and ground marker show how a leaning tree has shifted.
If you have trees that are already of con-
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