As winter sets in, bringing wind and ice storms, we’ll see lots of broken trees. Wind and ice loads can snap limbs and break trees in half. It’s tragic to lose a mature tree that you depend on for shade, and falling limbs can damage your property. Often this damage is preventable. There are two ways to minimize dangerous and destructive splitting.
Most cases of tree splitting are caused by a defect called a “bark-included crotch”. This defect occurs when, instead of a healthy limb attached to the trunk, a tree forms a close crotch. As the tree grows, bark is “included” between the limb and trunk. The limb and trunk are not really attached, since the bark forms a seam down inside the tree. As the tree grows and the limb gets heavier, this hidden weakness becomes more dangerous. The tree may simply split in half by gravity, but usually it’s an ice storm or heavy wind that finally sends the limb crashing down.
The first way to prevent this is careful tree selection. Certain trees are very prone to weak crotches and should be avoided. The worst offenders are Silver Maple and Bradford Pear. When buying shade trees, try to find varieties with good habits. Deal with a professional who can help you steer clear of trees with defects.
We often see defective trees that began life as “volunteers”, simply sprouting and growing on their own. Volunteer trees need to be managed carefully and trained, or they can become dangerous. Pedigree is important with plants. The weakest softwood species tend to be the most eager “volunteers”, and they may not be desirable in your situation. Volunteer trees with defects should be cut down before they get big.
The other way to reduce risk is to carefully prune young trees, eliminating close crotches. The first few years of a tree’s life are the most important for training; quality nurseries routinely “limb up” young trees and correct defects. Older trees are harder and more expensive to fix. Tree surgeons can “cable” forked trees or bolt crotches together, but generally large close-crotched trees should be removed.
Winter is the best time to prune most trees. Once the sap rises and the buds start to swell, you could cause “bleeding” by cutting your shrubs and trees. Get it done now, while it’s easy to see the branches and spot where the problems are.
Pruning is done in three steps: First, remove all dead or diseased wood. You can tell this even in winter because healthy branches have a vitality that’s easy to spot, and dead or diseased limbs really stand out. Second, fix defects. Take out limbs that are rubbing or interfering with each other, cut off the lower limbs if they interfere with walking underneath, and get rid of crotches. Last, you need to cut off water sprouts or suckers (the long straight shoots that stick up or grow from the lower trunk). These should be cut cleanly right at the base or they’ll sprout two or three more.
A stitch in time saves nine, and timely pruning prevents dangerous tree problems by encouraging trees to grow straight, strong and healthy.
Steve Boehme is a landscape designer/installer specializing in landscape “makeovers”. “Let’s Grow” is published weekly; column archives are online at www.goodseedfarm.com. For more information call GoodSeed Farm Landscapes at (937) 587-7021.