Alright, Moderate Fear then. You have to make a DL 20 Concentration Roll to overcome your Phobia in situations where it may apply (like you would have a harder time going into woods or, if you do find yourself with no other option but to go into them, would have to make a Concentration Roll or find yourself at a -2 to all Rolls while within it, essentially be constantly Intimidated while within the woods). 

So yea, just add must make a DL 20 Concentration Roll to overcome your fear in situations where it may apply.