Hazardous Trees

When I say that certain trees may be hazardous to your health, you may think I am about to give you a warning that trees cause illness, and, if so, I have good news for you. They don't. (Unlike seemingly everything else.) But, there may be trees out in your yard that could be hazardous, especially if you have older trees, and you need to take care of them before they cause property damage or worse yet, injury.

The first thing you need to know is how to recognize what we call a hazard tree, and when to call in professional help.

I recently attended a seminar that followed an intense windstorm, and in many of the arborists' opinions at that time, the only safe tree was a stump! Fortunately, this opinion lasted only a few days.

Loosely defined, a hazard tree is any tree with the potential to cause economic loss; specifically, damage to structures or power lines, and personal injury. This means that a tree is the woods usually isn't defined as a hazard tree, even if it fits my description simply because there is less chance of a target there and its unlikely to cause harm - it's just part of nature.

As a homeowner, you do have a legal responsibility to maintain you home in such a way that it won't harm people or neighboring structures. There is a body of law that exists that defines liability in cases where people were injured or property was damaged by such hazards, so realize that this can be a serious situation.

As another example, I have been told that when the President of the United States is visiting a new area - especially a park-like setting, forest or a tree congested town - even the trees are inspected.

One-way hazard trees can be avoided from the beginning is to buy strong-wooded varieties of trees and look for varieties with a large angle between the trunk and branches. The optimum angle is 90 degrees, and the closer to 90 degrees the branches get, the stronger and safer the branches tend to be.

In addition, in trees that are pruned properly with the tops being kept thinned out, well-spaced branches are less likely to become a hazard. You can even start with a weaker-wooded tree and make if safe through proper pruning.

The first thing to do to make sure the trees in your yard are not hazards is to look up. I don't mean that facetiously. Seriously, while you're mowing your lawn or enjoying your patio, look for broken branches high up in the tree just may be waiting to come down. These should be removed as soon as possible or the first strong wind may bring them down when you are not prepared.

Another danger sign that you should look for in older trees is what we can a conk, usually at or near the base. These are usually fungus lesions and they can appear to be quite pretty, in various shades of cream, clear through a rich mahogany. They are a manifestation of internal problems, usually indicating that the tree is rotting out from the inside. Many people don't realize that the problems are internal; thinking that the conk is simply an exterior growth. They appear on a trunk or branch as a smooth ray, usually parallel to the ground, growing over a period of weeks to years. Sometimes they even look like a mushroom growth. I've seen them as large as 12-15 inches wide on a big old oak tree. You should also check for splitting crotches in larger trees.

In all cases, you should call a competent arborist to examine the tree. The problem may only be the small area of growth you see or it may be an indication the entire center of the tree is rotting. The arborist may use a tool called an increment borer, which will be inserted into the tree to determine the amount and location of damage. A resistograph may also be used. If there is less than a certain thickness of firm tissue, (the arborist knows the standard), the tree may have to come down. Generally with conks, however, there is no "cure." It is essentially the beginning of the death process.

In addition to conks, and crotch splitting, there are other warning signs of tree problems. If the topmost branches don't seem to be expanding, root loss could be the culprit. If you can tell there is a root loss on a tree, that tree should be watched. One indicator is the slowing of the growth in stem length in the top portions of the tree.

Branch loss is much more obvious. If branches are breaking off or dying back from an old injury, they need to be removed. Tree tissue can't heal like skin. New tissue will close over the damage and the tree goes on, but any bark cuts, etc., should be watched.

Few trees become a hazard overnight, with the rare exception of damage from intense storms. Normal Ohio storms can be injurious to trees, but usually that damage is correctable and often, by proper care, preventable.

One way to prevent damage is to look for the "wind sail effect." This means that the branches are so dense that there is too much wind resistance and the tree could be toppled or badly split in a storm. One way to determine this is to stand under the tree. If, on a sunny day, there is absolutely no sunlight getting through, or if in a light rain shower, no rain touches the ground, you probably need the tree thinned by a professional.

The type of pruning they will be doing is called selective crown reduction. You SHOUD NOT have the tree "topped." Topping is only a "temporary fix" and is extremely damaging to the tree from that point on.

Other preventive methods for trees are cabling and bracing. Again, these should be handled by a professional. They are especially helpful for those narrow-angled branches and crotches I mentioned earlier. A cable can prevent the splitting of a tree whose trunk has bifurcated (split into two main portions.)

One more important preventive measure is something you can do without calling a professional: proper fertilization. In this case, I like to call it plant nutrient replacement.

The goal is simply to keep the plant growing well. We're not trying to start new vibrant growth in an old tree; we're merely maintaining the plant. An older tree can actually require more fertilizer than a new tree.

Remember, the best method for prevention of hazard trees and their damage is really to look up. Look for anything unusual about your tree - discoloration, slow growth, broken limbs and narrow branch crotches. As with most health issues, an ounce of prevention is worth a pound of cure. And, in this case, the branch you cut may save untold grief in the long run.