Do you have a tree?
This is mine. My own personal sycamore.
OK, in the parallel human universe (see I'm still working on the multiverse hypothesis, Nobel Prize pending), Aberdeen City Council lay claim to the sycamore, which stands in the street directly outside my house.
But in the dog world, the tree belongs to me, no doubt about it. To make sure it stays that way, the first thing I do each morning after breakfast (Gail's and mine) is to rush out the front door and (how to put this delicately?) ensure the base of the trunk is liberally sprayed with all that I have saved up overnight.
There are other neighbours out there (you know who you are, flat-coated retriever Jake from no. 8, sleek greyhound Marcelle and fellow Westie Jock, both who live just up the road, next door's springer spaniel Molly, to name but a few) who will trespass on my property and leave their mark.
But I am a terrier, ever vigilant.