not sure if there is one and only one 'preferred' wood - a close grain (ie does not soak up liquid) short fiber (i.e. not splinter prone) works.
I have a whole raft from cpbasils.com - it's black cherry. some are more than 15 years old and still in good condition.
for the cpbasil stuff, it's not so much the wood but his designs - the angles and sizes and bowls / curves / etc are seriously "correct" for their intended tasks making them easy, and enjoyable, to use.
not cheap, but top quality stuff that lasts forever. except if you have a Husky, a sausage flavored spatula has a very short half life when the puppy can reach it . . .