Severity of decay in roots, trunks, stems, and branches can be difficult to visually quantify using only decay indicators. In cases where decay has caused significant external cavities or where trees have partially failed, visual evaluation may be adequate to make an appropriate decision.
Decay indicators are useful in the basic assessment of trees for decay. The process of using decay indicators to initially evaluate decay in trees, followed by the use of advanced assessment techniques, can help establish a repeatable decay assessment process. These assessment tools provide tree services and arborists with a framework for systematically assessing and evaluating trees for decay better than the average municipality or homeowner. If in doubt about any of your trees, I recommend you contact your local tree service or arborist. If you are in the Chicagoland area please contact Trees "R" Us, Inc. for a professional evaluation of your trees by a certified arborist.