River birch not leafing out
Hello, I live just outside the city near Pittsburgh, PA and have noticed a problem with a river birch I planted in my front yard about 5 years ago. Small leaflets appeared a bit later than usual this year but have yet to fully open and the tree appears to be dying. Also, one of the three trunks has very little green growth. The tree has grown really well up until this year so I'm completely confused as to what would cause the condition. I have not had the soil tested but do know that there is a high amount of clay as is typical for the area. Any information would be greatly appreciated!
Allegheny County Pennsylvania
It appears there may be an issue in the root zone of this tree. It may be the result of physical disturbance of the roots from digging or excavation around the base of the tree. These symptoms also point to root decay from the root rot fungus Armillaria. While river birch generally tolerate occasional wet soil conditions, if the soil remains wet for too long, root rot fungus can take hold and thrive. Given that you mention clay soil, it is possible this area is not draining quickly enough, resulting in extended periods of wet soil conditions perfect for Armillaria fungus to thrive. Unfortunately, there are not many immediate outward signs of root rot. It is only after much damage has already occurred in the roots and base of the tree that we see outward symptoms like die back of branches and stunted and less foliage than normal. If this tree is indeed infected with Armillaria, there is not much that can be done beyond removing the tree.
Based on the photos and your brief description, it is hard to make a specific diagnosis. I would be happy to talk with you more about your tree and arrange for a site visit, if appropriate, to see if we can determine what might be the cause of the die back and lack of foliage on your tree. I can be reached at the Allegheny County Penn State Extension Office at (412) 263-1000.