There is a good bit of overlap, probably d/t some role overlap between being a bit of a nature themed INT character vs a more intuitive WIS character. Neither should be a fish out of water in nature situations - so give an option to either character.
I like to focus heavily on role when it comes to differentiation. The walking field guide INT char shouldn't step on the toes of the WIS "I've been on the trail, just like my father's father, I have the knack, a field guide isn't going to learn you tracking".
The barb can forage, sees the mushrooms and sneers. If they can't find any better.. "well, crap, only cooky old squirrel Codger eats these, which one is red cap and which is deathcap?" Well Im going to find out the same ways my ancestors did