Unsure on this card. It doesn't even seem to find a way into my Silvan decks when I play Thranduil and have resources. Perhaps Elrond is a better target?
1 resource for 1 defense can be okay, Dunedain warning is used all the time, but in a more rich sphere and not limited to one per character. I don't even really keep this on my sideboard since I'm not sure how many scenarios actually have forest locations. And even then you can't rely on it too heavily, what if you just draw enemies and now you have no forest location to travel to and extra attacks to defend with just 1 extra .
Sadly, I think staying true to the theme of the card makes it too weak to see much play, at least for me. It's a shame too, it's a pretty card that at least attempts to fill a distinct weakness in Silvan decks.