mmm - this is a tricky one - as it's really down to personal taste - oddly enough my dad and i were chatting the other dad about what i should do with him "when he goes" and i said that i would like to have him "planted " up the woods and he said that he would like an oak tree planted with him - so assuming that we can get the right permissions - that is what i shall do
i'd actually like to plant a corkscrew hazel as a memorial tree - if my dad wants oak, that is what he shall get - and i'll plant a corkscrew hazel for one of my dogs (i actually lost one this year but she got a wych elm - so hazel it will be for the next one )