john west wrote:

Would it help if i *tilted* the aerial *up* to point over the tree, or
do transmission signals not work like this?

It might help a bit (I think you should have a little nose-up anyway)
but the leaves are going to better at blocking signal than causing any
"lensing" of the signal at such a short range ... you're going to keep
having the problem as the tree grows year by year, getting the aerial up
higher would be a better solution.