response from the Council
Dear tenmencount,
Thank you for your enquiry regarding the tree to the side of your property.
Unfortunately the land in question is not owned by Northumberland County Council. I am afraid i am not sure who does own the land. There is land in the area owned by ISOS Housing, so it may be possible that they could own the piece of land in question.
It may be worth while asking them. They can be reached on 0300 3001505.
Sincerely,