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

Check Trunks and Roots of Problem Trees

May 31, 2001

Decline of shade trees can be due to a variety of problems. Disease and insects certainly are possible causes, as are various types of site factors. Regardless of the actual source, many problems originate from damage to the trunk and are roots.

When dead branches and thinning areas appear in the canopy of a tree, the first place to look for clues should be down at the base. Injury to root systems and trunks typically result in dieback of the upper portions of the tree. Examine trunks for wounds, such as from mowing equipment, vehicles, dog chains or clotheslines tied around the trunk and left too long, winter damage, or similar events. Woodrot fungi often appear in trunks after wounds have been made.

Mowing and trimming equipment damage leads the list of preventable damage to trees. Use care when mowing and trimming to avoid this problem. Consider eliminating grass adjacent to the trunks of trees, perhaps mulching around the base of trees and shrubs instead.

Failure to remove the twine or wire found at the top of the rootball after planting a tree or shrub is another cause of plant decline and death. Don't let this simple procedure kill a tree or shrub in your yard! Symptoms may not be apparent until plants suddenly die years after planting. Take a few minutes this weekend to check trees and shrubs planted in your yard.

Do some detective work in viewing the area around declining trees. Is there evidence of recent digging, soil movement, or change in drainage patterns? Most of the important roots of trees are only 12 to 18 inches deep, thus are sensitive to changes around them. Also keep in mind root systems extend out as far as the branches and beyond.

Also look closely at the base of the trunk. There should be a natural flare as the trunk enters the ground. If the trunk goes in straight like a telephone pole, it could be due to planting too deep, adding soil fill, or perhaps a girdling root below the soil surface.


Click here for the full article index