By PAUL HETZLER
The heavy winds predicted for Thursday in St. Lawrence County could take their toll on your trees. Here are some tips on what what to look for when evaluating trees for potential damage.
When the wind blows, the cradle—presuming somebody left one in a tree—will rock, and the arborist will think about weak branch attachments and other tree defects. While some breakage is inevitable, a lot is actually preventable.
The dormant season is a good time to evaluate mature hardwoods for all kinds of defects, especially weak crotches, also known as unions, between branch and trunk and also between two (or more) major trunks. It’s fortunate that unions give us clues as to their soundness, starting with the angle of attachment. Whether it’s a branch-to-trunk union or trunk-to-trunk, unions close to ninety degrees are generally strongest, while narrower ones are weaker.
Let’s take a tree (with permission, of course) that has two (“codominant”) trunks with a narrow union. How dangerous is it? Well, are the trunks relatively upright or do they lean outward? The more they lean away from each other, the more vulnerable the tree is to splitting. The next step is to check for seams or cracks running down the trunk from the union. Two seams imply a far weaker situation than a seam on just one side. Decay is the next item to look for, though it’s not always obvious. Conks, loose bark, and woodpecker cavities indicate unsoundness, and it should go without saying that a “garden” of brambles and saplings growing in the fork means rot.
Maybe the clearest sign of weakness is a pair of ears on a union. Maybe I should clarify that. Trees are self-optimizing; that is, they respond to stress by adding tissue in ways appropriate to the problem. The weaker a union gets, the more a tree compensates by adding wood, in this case outward from the trunk in a sort of “ear” or “clamshell” shape.
Even the weakest unions can often be made safe by cable bracing two-thirds to three-quarters the way to the top from the union. However, an improperly installed cable is worse than no cable at all! Cabling should be only done by a professional who is familiar with the ANSI published standards for cable bracing. Because a mature shade tree is irreplaceable in one lifetime, and because it’s somewhat inconvenient to suddenly have a large portion of one appear in one’s living room, cabling is worth it.
Incidentally, the reason that cradle was in the tree? In many Native cultures such as the Iroquois, mothers would secure an infant’s cradleboard (the original baby backpack) to a tree while they tended the crops. The child thus got a nice, shady, adult’s-eye view of the world, and was always taken down if it got very windy.
For more information on trees (not so much cradles) call Cooperative Extension at 379-9192.
Paul Hetzler is a forester and a horticulture and natural resources educator for Cornell Cooperative Extension of St. Lawrence County.