Tree Decline Involves More Than Meets the Eye

Tree death – it’s an elusive and unfortunate occurrence. A person might perceive a tree as perfectly healthy up until the day that bark is falling off the trunk and branches are breaking on a windless afternoon. People point fingers at borer insects and other pests or diseases, but the truth of the matter is that these agents are often attracted to trees in distress. In addition, trees are often in a position of struggle long before secondary pests and diseases show up to finish them off.

One thing that you should know about tree health is that in Oklahoma, a perfectly healthy tree rarely dies from just one insect infestation or disease attack. Healthy trees are often capable of fending off these opponents, but once a tree becomes stressed by another adverse condition it becomes more susceptible to insects and disease. Most trees come under stress, usually from an environmental issue such as drought, extreme heat or cold (or a combination of those factors) or mechanical damage such as improper pruning, equipment or storm damage, and THEN the insect, fungus or nematode does him in. So, maybe it wasn’t borers that killed your tree. I mean maybe they were there and yes, they probably contributed to your tree’s demise… but did they kill your tree singlehandedly? Probably not. The root damaging trench that was dug two years ago within a few feet of the trunk along with last summer’s crazy heat and drought might have had something to do with it too.

Also, just because a tree has a canopy full of leaves that does not mean the tree is healthy. Sometimes trees produce excessive foliage to make up for a lack of energy stores caused by stress. If your tree has lots of sprouts growing directly out of the trunk or a branch, this might be an indication that your tree is stressed. Stressed trees also exhibit branch dieback, which means that twigs on the tips of the branches die while the inner part of the tree is full of leaves. The best thing that you can do to prevent secondary insect and disease agents from taking your tree from weak to dead is to keep it as healthy as you have the power to do.

If we have another hot and dry summer, give your tree a deep soaking with a garden hose once a week, in each quadrant under the drip line or canopy edge. Spread a 3-4” layer of mulch over the tree’s root zone out to the tips of the branches, if possible. Have an arborist conduct a soil test and fertilize your tree if any soil minerals are deficient. Find out more ways to grow a healthy tree under “Tree Resources”.

By keeping a watchful eye out for symptoms of tree stress, you can potentially prevent the unnecessary loss of valuable trees in your yard before it’s too late.

View more topics from the March 2013 Edmond Tree Mail message.