As I've had my little hobbit out wearing her feet off gathering ore for her little sister it suddenly occured to me that as much as I've been out (complete mastery) I should, given my vast experience, be able to track both wood and ore at the same time. I came looking for thoughts on this and found a post from 3 years ago about someone wanting this. The thought then was, that it would only affect one vocation. As a suggestion, I would leave the icons separate and make the ability to activate them individually. Maybe even make it a reward for reaching a certain level in both Forestry and Prospecting.
I know there will be bashing. Just please remember this is just a thought!