Land Aquired

Hello. We agreed to purchase a home on about 20 acres. 3/4 of it is forest. (Realtively flat, not marshy to my knowlesge) I guess I don't even know where to begin. How do I keep the forest healthy? If we are going to slowly harvest firewood for ourselves what is the best way to go about it. Are there under growth troubles or plants that could hurt my trees? Should I be on the look out certain trees that could be really valuable? I have not walked the land yet. Any could resources or advice would be greatly appreciated.