An almost impossible ask !
There are many species of oak, walnut and don't even get started with mahogany. Also which continent and latitude the tree grew on can create surprising variations from the same species of tree.
The wood in the picture seems to have had a previous purpose knowing that would help as well as planing it back to its natural self. Seeing the end grain might be more informative.
Density is also a good guide as many of the exotic hardwoods when seasoned actually sink in water.
Having said all that IT'S OAK without a shadow of a doubt !