University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Consider Past Events When
Diagnosing Tree Problems

July 24, 1997

Decline and dieback may seem to have just occurred, but in reality many problems are the result of something that may have happened several seasons ago.

For example, construction injury is a common tree problem. What is often difficult to understand is the actual cause of the problem occurred well before the tree started to show symptoms. Digging and braking roots, putting soil fill over roots, changing drainage patterns, and soil compaction are all examples of construction injury. In all cases, root systems are impacted.

When root systems of trees are damaged, there is usually a delay in time before above-ground symptoms occur. Soil fill and compaction reduce available oxygen to roots, so they gradually die. Root rots may also slowly develop after injury. Thus it is not uncommon to build on a lot full of mature oaks, for example, and have the trees appear fine the first few years after moving in. Perhaps 3 or 4 years later (or more), significant dieback appears on the trees.

Likewise, past weather patterns may be contributing to tree problems appearing today. Drought, heavy rain flooding the soil, record cold in winter, and early or late record cold snaps all affect trees for some time to come. Not only direct injury, often damaging roots, but also by putting trees under stress. This stress then may make trees susceptible to insect borers, canker diseases, and root rot diseases.

White pines have been declining in Illinois in recent seasons, and much of this is attributed to weather patterns, such as exceptionally wet periods, causing decline of root systems. Pine bark beetle and bronze birch borer both have been widespread problems since droughts (such as 1988) because pines and white birches both have been under considerable stress.

About all that can be done for declining trees is to avoid further stress. Water during extended dry periods throughout the growing season, not just in the heat of summer. Prune out wood that is dead. Certainly avoid altering root zones of trees when building or doing major projects in the yard. Use caution when mowing or trimming around trees.

 

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