URBANA, Ill. – Now that summer is finally here and our summer road trips have begun, we can fully enjoy the trees and natural landscapes. During my travels, I have been noticing more and more diseased or dead trees in Illinois. When I notice those trees, the concern that comes to mind is safety.
A lot of residential and rural areas have been attacked by insects and diseases, like the emerald ash borer. These leave trees in varying health stages.
There are many signs of tree decline, where trees lose their vigor. One might notice pale green or yellowing leaves, early leaf drop, smaller leaves, poor overall growth, and dieback of branches or deadwood. Declines can be stress induced by environmental factors, improper care, insects, or disease over either short periods or years. Depending on the stressors, trees could recover or die out.
Deadwood is one of the common symptoms of hazardous trees. With a full leaf canopy, the deadwood can go unnoticed for long periods. Deadwood typically has no leaves, may have bark falling off in large pieces, and in some cases can be broken and hanging. Any branch larger than 4-feet or more or 2 inches in diameter are considered dangerous. Even small branches that fall can cause injury.
Ash trees that have been attacked by the emerald ash borer (Agrilus planipennis), or EAB, are at an increased risk of decline and having deadwood. The EAB larvae feed on the inner bark, disrupting the transport of water and nutrients within the tree. Due to this disruption, the leaf canopy of the tree begins to thin, the branches become deadwood, and soon the entire tree dies.
When trees die, they often become hazards to people, structures, and personal property. When people notice signs of decline, it is a good idea to discover the cause and contact a certified arborist. There are services available that can help to identify problems, like your local Extension office.
Bruce J. Black is a University of Illinois Extension educator, horticulture, 815-632-3611, firstname.lastname@example.org