prefer the orignal but i think the b/w would look nice with loads of contrast and if you can get it to look right a red (i think) filter before you convert it to b/w
It is interesting to see how I had the very same thoughts as the other two before me: the black and white conversion clearly lacks in contrast, therefore much is the same grey (or a similar grey) and the photo looks flat.
The sepia covers all this well, but the inbuilt sepia in cameras, or a sepia filter in post processing software often gives photos too strong a tint.
So I, too, prefer the original here (and would like the sepia or toned b+w if the effect were weaker) because the bark is interesting.
Personally, I find this kind of photo is hard to take so the composition makes it something you would want to look at twice, and I have tried ... and can't say I am happy with any of my attempts.