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I have been in touch by email with the local tree officer in the planning department to see if they can give me any information, initially it was relating to tree preservation orders, although i think it's unlikely.
When I hear from them, I can then go on to explain about the uncertainty (on my part) at least, as to who owns the piece of land. Currently, we are in this nest situation, and there is indeed a nest in this tree. How it manages to hold a wood pigeon, let alone a family of them I don't know as it's not that big. But nest it is, and birds there are in this tree, so cutting it back yet is not an option unfortunately.
Still, at least it gives me some time to try and find out whose tree it actually is. In fact, if it does turn out that the houses opposite own these trees, there may be others on this side of the boundary will want some action. At the very least my two next door neighbours are affected by them, they have grown very large, keep the sun from the bottom of the garden, and drop enormous amounts of leave which we have to clear up.
I love trees, and would hate to see them cut down, but they do need attention from time to time, especially where they are situated. We shall await events from the local authority, so will not be holding our breath.