Thanks for your question about your River Birch.

I have several growing in my yard so am reasonably familiar with them. They are notorious for releasing copious amounts of sap. There really is nothing to worry about nor can you do much to stop the flow. My River Birch are now doing exactly the same thing. I grant you that it is a mess to clean up but I guess that it is the price we have to pay to have such a beautiful tree in our yards. In past years when this happened with my trees, the sap flow declined during July. Hopefully this will also be your case. I don’t know whether this is weather/heat related or not. Possibly. I have found that a cloth dipped in mineral spirits normally cleans things up rather quickly.

Thanks for using this forum.