Problem with birch tree

Asked June 8, 2019, 3:24 PM EDT

We have a mature birch tree. A large hole in the trunk has developed where a limb was cut off long ago.The hole appears to be about 4 inches wide at it opening and tapers downward deep into the truck for about 10 inches. It is dark, wet, and messy. The trunk is about 16 inches diameter and we would very much like to save the tree. Two pictures attached. Any suggestions? Thanks

Marion County Oregon

1 Response

Once you have wood decay fungi in the trunk of the tree, the main threat is tree failure due to main stem breaking after the rot weakens the wood. Wood rotting fungi usually are not pathogenic to the living part of the tree. The best way to prolong the life of the tree with trunk rot is to keep it healthy and vigorous so that it grows new wood faster than the old wood is rotting. Healthy trees can also "compartmentalize" wood rot by sending defensive chemicals to the zone where the fungus is growing in the wood. Make sure the tree has plenty of sunlight, moisture, and nutrients.

Perhaps the biggest threat to birch trees in our area is the bronze birch borer. If this insect gets in your birches, it can kill or weaken the trees. See references: