Question
Hello Dr. Vann,
I welcome your advice on the matter of a poplar tree that has diseased bark in the area of the trunk where there is a juncture connecting the main branches. A few years ago I noticed the problem and had a large part of the tree removed. I didn't realize that the disease continued slowly along the trunk and has killed yet another large limb. The affected bark is blackened and pock marked. Please help.
Carolyn

Answer
Hi Carolyn:

Unfortunately, once various microorganisms enter the tree (usually bacteria first, then a fungus usually follows)and decay begins, there is nothing to reverse this progress.  If the tree is growing vigorously, it can "wall off" the decay to some extent.  Ultimately, the tree usually become weakened physically to the point that the tree may fail especially during a wind storm or ice/snow accumulation on the branches. A tree can be decayed for many years and often we do not suspect decay until this failure occurs and we see that dark, spongy internal wood or the hollow tree.  Insects, like ants often move in on decayed trees. They are not the cause, but merely using the decay area as a home.

For these trees, prevention is best- no magic bullet.  Preventing wounds to the bark is important, of course this may be difficult especially for example during weather extremes that cause branch damage that creates a wound where these microorganisms can enter the tree and set up housekeeping.

Steve