Oak (solid), iroko (laminated), Any good hardwood, but some of them in big lumps, ie iroko, will shake and split, best to laminate it up, opposing the grain as you go.
Commonly oak is used as, because of it growth ring structure, "Ring Porous" it is very resilient to shock loadings as is ash, teak, chestnut, hickory and elm, but Oak lives longer than most and is cheaper than teak.