Guard Those Trees!
by Larry Hamilton, Charlotte Tree Warden

An all-too-common source of injury to trees is from lawn mowing. I continually see it. Damaged cells are killed, and although the surrounding tissue may grow over the wound, the dead tissue remains and will decay under the new bark. Breaking the protective bark layer exposes the living tissue to fungous spores that may result in subsequent major decay.
When homeowners and landscape-care contractors were using hand-push mowers, great care could be exercised when mowing close to trees. As mowers have become engine- or electric-powered, speed often reduces the margin of safety in mowing close to the stem/trunk. The riding lawnmower is even more of a hazard, particularly when operated by a contractor for whom time is money and rapid mowing is an objective. For a few good examples of such injury, look at some of the older tree plantings (about 16 years ago) around our Town Hall.
Young thin-barked trees are not immune to weed-whacker damage. Those fast whirling cords can quite easily break tender bark if one is not careful. This type of injury is very common.
One very good strategy for eliminating or reducing such damage is to place mulch around the base of the tree, at least ten to 12 inches in radius, depending on size of the tree. Wood chips or bark are commonly used, but stones can also do the trick for keeping mechanical equipment away. Various types of stem guards can be put in place in a circle around the tree, short flower border fencing, for example.
Newly planted trees are usually mulched for additional reasons. Mulch permits water to enter the soil, but simultaneously conserves what moisture is there. It gives some control of competing vegetation, prevents soil compaction from traffic and buffers the soil from extreme temperature change. This seems to have benefits for two or three years until the root systems develop extensively and can compete for moisture with other vegetation. After that, the main benefit is to keep equipment away from the tree and reduce compaction.
Mulch should be placed (usually) to a depth of three to four inches and replaced when needed. It is important not to have the mulch packed in against the stem; this would make a fine habitat for insects and fungi. Rather than have a mulch bed shaped like a volcano around the tree, it should be like a donut.
Another type of injury is worth a mention: dogs should not be tied to young trees, especially if using a chain. Mulching will not prevent damage in such cases.
During winter, another type of tree guard comes into its own. Many readers undoubtedly saw the blue plastic tubular tree protectors that the Rutter Tree Fund Committee installed on newly planted trees where it was deemed that mouse, vole or rabbit damage could occur. These reusable tubes will be put on each year until the trees are large enough in diameter to withstand some nibbling or gnawing by critters, possibly until four inches.
The newly initiated Charlotte “Tree Keepers” program will be concerned with these and many other elements of tree care and maintenance. It is not too late to enroll in this program if you hurry. Contact Annemie Curlin at annemie@accessvt.com or 425-3301.