These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.
Early Tree Color Signals Stress
August 23, 2001
Each year about this time a few shade trees stand out in the landscape by showing early fall color. Trees turning color already in August most likely are stressed or in decline and call for a closer look to see what the problems may be.
Weather is one factor that contributes to stress in trees. This season, the hot and dry weather of much of mid-summer has certainly stressed trees. This is quite noticeable on trees located near pavement, such as streets and parking lots. Lots of leaf scorch typically shows on these trees, along with some early color.
Early fall color is often due to stress related to root or trunk problems.
Root zones are a key area. Root damage is a very common stress factor
that can lead to early fall color and decline. Examples include direct
injury from digging near the tree, injury from soil fill placed over the
root zone, chemicals in the soil, excess water, or too little water. In
addition, consider a girdling root to be a possibility, as roots growing
across others or cutting into the trunk can be a serious problem.
Take a good look at the very base of the trunk. There should be a natural root flare in this location. If the trunk goes straight into the ground like a telephone pole, problems are likely to occur. This situation may be due to soil fill, girdling roots, or perhaps planting the tree too deeply.
Examine trunks for wounds of various types, perhaps from equipment, storms, winter damage, or animals. Since the "lifeline" of trees (sending up water and nutrients) is just under the bark, damage to trunks can have significant impact and may be why a tree is stressed and declining. Applying pruning wound dressing to damaged trunk areas is not suggested.
The best overall suggestion for stressed trees is to avoid further stress. Water during drought periods, including fall. Perhaps fertilizing this fall or next spring may help. Also prune out dead wood, but avoid heavy pruning in late summer and early fall. Most of all prevent many of injury problems before they occur.