BY TIMOTHY SLAPE ISA Certified Arborist, ISA Tree Risk Assessment Qualified, ACCT Certified Challenge Course Inspector
ONE EYE ON THE TREES Monitor signs of stress to catch problems early.
Hasn’t 2020 been stressful? Your trees may also be a little stressed right now, just for different reasons, of course. Since trees can’t tell us what is bothering them, we need to look for the signals they offer. Sometimes these signals are obvious, but oftentimes trees give us only very subtle signals. So eye your trees carefully. Practicing good arboriculture will promote healthy and vigorous trees. Healthy trees are better suited to withstanding environmental or usage stressors. Remember, our adventure activities are new for trees, and are a source of stress.
Canopy tour and adventure park guides have a unique opportunity to observe trees very closely. They get to visit the trees in all conditions—early mornings when nature is uninterrupted by human activity, midday when the trees are crawling with guests, and in every type of weather Ma Nature can muster. While guides’ first responsibility is guest safety, keeping one eye on the trees whenever possible will benefit the entire operation. Here we outline some specific stress indicators guides—and other employees—can look for. However, sometimes simply noticing something has changed
from the last time we looked at a tree is more important than looking for or noticing a specific symptom. To start, staff should observe trees in three areas as they look for stress signals: the soil, the trunk, and the canopy (limbs, branches, and leaves). Each area shows stress differently. POTENTIAL STRESSORS, GENERALLY Have a good understanding of the kind of weather your trees are experiencing. Is your park having a single season drought or a multi-year drought? Has this year been exceptionally hot, cold, or wet? Was there a hard freeze after your trees flowered or budded? All are stressors.
The wilted leaves shown here show signs of scale insect damage. Upon investigation, the cambium layer of the affected branches was alive. This tree was treated with an insecticide and recovered.
In addition to weather, there are other general stressors to consider: Is there an invasive species moving through your region? Are there insects that your trees are a host to? Was a harmful herbicide spilled upstream from your park, or did a nearby farm fertilize its crops improperly, causing your trees to be over-fertilized? All these conditions are important because, like us, trees that have multiple stressors are more likely to struggle or succumb to disease. >>
55 Fall 2020
It’s a good idea to keep a daily weather journal for your park. Weather is very local—one valley can get a completely different amount of rain than the overall region or even the valley next door, for example. Looking back at your weather journal will help you understand if weather conditions are impacting your trees.