attaching a fence post to a tree?

[ohmygodwhathaveyoudone]

I have a problem at the moment with the placement of fenceposts?I have a 30' shared fence that is 3' high and is completely overgrown with ivy and the panels are as rotten as a pear so i decided to replace them with concrete posts and 150mm high gravel boards and slot in some panels,the problem i have is where the 3rd original wooden post is it has been bent over into my garden because the oak tree on the neighbours side has grown and pushed it at an angle (the tree is about 60' high)i was thinking of having the posts either side of the trunk but that would mean 2 panels of 3' long and trying to get a 3' long gravel board,it would also look silly aswell.Would there be a problem bolting the post to the tree (the neighbour said o.k.)or will it move slightly when the tree grew?all the other posts will be sunk 3' down and concreted in but as this post is touching the tree i think that i'm bound to hit a BIG root if i try to dig a hole.I could even use featheredge and position the posts either side of tree but my other 2 borders are larchlap panels.sorry for the long post.
any advice please.

 

[Deluks]

No don't fix the fence to the tree, of course it will move silly!

I say stop short of the tree, with a gap in the fence, leaving space for the tree to grow outwards. Then infill the gap with something flexible/decorative, a wire fence covered with a brush/reed screen for example.