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