You need to get yourself down to Yandles keith. The Elm trunk slices they have in there (last time I went) were 4 foot across a single waney edge board. Absolutely stunning.
As to the wood, all I can attest to is that it's an interesting conundrum. I also echo that it's definitely not Yew and I would add it's not Oak either. It could be Elm and there is a very slim possibility for Olive Ash too but only if the photo was taken when the wood was absolutely soaking wet. I think Ash is much less likely. The grain looks extremely like wild cherry and yet the bark is nothing at all like Cherry and in fact rules that out. It's got a look of some wet chestnut I've seen before too but in terms of a definitive answer, I just couldn't say.