For Release September 11, 2001

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

I have been asked to examine quite a few trees the past couple of weeks. In every case, the homeowner indicated that they were afraid the tree was dead. In every case they were right, or at least partly so. The key clues have always been the same. The trees were all deciduous, there were several different species, they were relatively young trees (less than ten years in age, often less than five), they all died in a matter of a week or two, and in all cases the leaves simply wilted, turned brown and usually stayed on the tree.

One thing about serious and potentially fatal tree diseases is that they are almost always species, or at least tree family, specific. A disease that is going to kill a maple is not likely to also kill a peach tree or a redbud. Since the dead trees I was looking at were many different species, we can rule out a pathogenic organism.

If some sort of herbicide was involved, we’d usually see peripheral damage to other trees, shrubs or plants, or we would see a slower death, discoloration of leaves, deformation of leaves and the leaves seldom stay on the tree. None of that was evident here so we can pretty well rule out herbicide or chemical injury.

What we are left with is mechanical damage or environmental stress. The most common mechanical injury that would cause these symptoms is mower blight or weedeater wilt. In both cases, the bark at the base of the tree is completely removed or damaged by equipment. There was insufficient evidence of bark damage from mechanical sources.

Environmental stress is the failure of the tree to withstand whatever environmental extremes it is exposed to. It can be heat, cold, wet, dry, even different natural soil conditions or combinations of all the above or more. Trees that are just a few years old are more likely to be damaged by hot dry conditions because it takes a while for a root system to become well established. It may be a tree that is a recommended and adapted species. But if it doesn’t have an established root system, it can not access enough water to keep up with the demands that the weather is putting on the leaves.

Thin barked trees, like maples, can become sunburned. If a tree is turned 90 or 180 degrees from the orientation that it was planted in the nursery ,will have thin bark exposed to direct sun. This bark isn’t use to that extreme sun intensity, it sunburns and the bark dies. When this happens, the living bark surrounding this damaged area starts to develop callous tissue under the bark to repair the damage. But you now have less tissue to transport water throughout the plant.

Or sometimes it just gets too cold too quick and the water transport vessels are damaged. In all of these cases, the tree is stressed and more problems will develop. All of the trees that I have looked at were damaged and stressed by the weather of last summer, fall and winter. They were still alive this spring. But when the stress of late summer hit them, the water transport system couldn’t keep up with the demand, and the tree went into the plant version of cardiac arrest. Everything just shuts down. Death comes quickly.

Sometimes the roots of these plants will still be alive and will send up new shoots from below ground. Select the best shoot, cut everything else off and let it develop into a new tree. More often, though, all you can do is remove the tree, make sure that you are planting an adapted species, and try again.

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