Question
Hi Dr. David
I live in a large wooded area in a neighborhood called Oakwood Hills. Needless to say I am surrounded by oak trees. I have 3 oak trees that are dying , a branch at a time. I assume that the problem is Oak wilt. Is there any practical way of saving these trees ? If not, what would you suggest re: removal of these trees ?
Thanks in advance for your help.
Sincerely
Bill Bollaert

Answer
It could be Oak Wil or it could be Oak Root Rot.  Unfortunately, there is no real paractical way of treating for these diseases.  The fungi that cause them live in the soil.  If you see mushrooms at some time during the year around the trees, I might think it is Oak Root Rot caused by Armillaria mellea, especially if the trees are close to one another.  The key is to prevent the fungi from moving from the affected trees to healthy trees.  The fungi do this thru root grafts, or roots of one tree touching another tree.  Some have suggested digging a trench around the affected trees (which is probably not practical), to cut the roots and prevent them from growing to a healthy tree.  The fingi cannot move from a dead tree stump to a healthy tree, the tree has to be alive to transmit the disease.  There are other causes of oak tree decline to include drought stress, old age and other stress factors such as construction work.  I would leave the trees in place and fertilize in the spring.  Also check the soil under the drip line see if the soil is compacted.  A piece of rebar will work for this.  Just go around the tree and try to push the metal bar into the ground,  If it is extremely difficult to do, the soil may be compacted enought to prevent new root growth, which would cause the tree to begin to die.  Some type of aeration tool to break up the soil will help greatly to increase water and air flow in and around the roots.  I would do the aeration and fertilization steps first and wait a year and see if there is improvement in the canopy growth.  If this works, you can do this for about three years in a row and the trees may begin to improve greatly.  I wish you good luck.  Contact me if you have more specific questions.