"What's wrong with my tree?"
I receive this question several times a month throughout the year. Many write, "The leaves on my tree are turning brown," or "Some of the branches are dying." So, what's a gardener to do? Answering a few simple questions may help.
Is your tree located on a recently developed home site?
Construction damage is a type of tree problem that can be difficult to diagnose. If the damage is not visible (a scar) or it does not kill the tree right away (dieback or dead tree), the tree can linger and have a slow death over several years. This slow death is often related to the amount of root damage that was incurred from the parking or operation of heavy equipment over the root system. This soil compaction causes root loss.
Has a grade change been made recently?
Changing the grade under a tree means adding or removing soil in the area of the root system. The removal of even a few inches of soil can damage feeder roots and cause shock to the tree. Most feeder roots are located within the upper 12 to 18 inches of the soil surface.
The injury produced by lowering the grade is often minor when compared with the damage done by raising the grade. An improperly applied soil fill of as little as one to two inches can also seriously affect some trees. Proper technique and precautions can sometimes limit the number of tree deaths.
How badly has drought affected your tree?
This often depends upon whether or not your tree is well established. Once a new tree is in the ground for two to three years, it is pretty well adapted to your site conditions and it can tolerate stress better. Trees growing in poor locations may have a hard time getting adequate water supplies even during normal rainfall.
Many times a tree can survive a single season of moisture stress, but a series of dry years can seriously reduce the vigor of the strongest trees: Once weakened, the trees are susceptible to damage by other pests such as: insects (borers, etc.) and fungi (decay fungi).
Does your tree have girdling roots?
When first planting a small tree, many people dig the hole too small to accommodate the full spread of the root system. Sometimes they even go so far as to wind the longer roots around the stem to make the tree fit into a smaller hole.
A few years later as the roots grow in diameter they begin to cut into the tree and choke it off. Such roots are called girdling roots, and they can cause untold damage.
The first symptom of a girdling root is the gradual decline of branch or perhaps the branches on one side of the crown. Every year more branches die, until finally one whole side of the tree is dead. Before this stage is reached, examine the tree trunk at the soil line for the presence of girdling roots. They can be located at or below soil level. If the crown is not too far gone, consider removing the troublesome root with a wood chisel during the dormant period.
Billy Skaggs is an agricultural agent and Hall County extension coordinator. Phone: 770-531-6988. Fax: 770-531-3994.