I just went back and looked at what was cut on my 8 acres and how much it was worth in January 2001.
Best White Pine (over 16' lengths) was $140
medium white pine (12'-16' lengths) was $95
average white pine (8'-12') lengths was $65
Red oak was $350
beech, hemlock was $75
ash, maple was $150
birch was $175
pallet wood was $50 and was mostly the bigger branches and smaller diameter trees
All prices are per 1000 board feet.
I had cut about 151,000 board feet of timber, with an average price of $138 per 1000 board feet, and left plenty of trees standing. The logger made a moderate mess but most of it was cleaned up and sent to an electric plant as pallet wood.
As others have suggested, get a professional logger or a professional forest person to evaluate and quote on what you have. Then get more than one opinion/estimate as they will vary considerably depending on who they sell the timber to and what their overhead is. My original estimate was only about 2/3 of what was actually cut.
One more thing, if you do have it cut make sure you get a bill of lading from the logger and the actual sawmill receipts to make sure you are not getting shorted. It happens. This is required by law in some states. Do not have your timber cut on a per tree basis. You will get screwed price wise.
Also some states require a permit to be issued to harvest timber. I do not know about PA but NH does. Since the state may get to tax your profits, receipts are really necessary. This will tend to keep the licensed loggers honest.
You might be surprised at how much you actually have. Good luck.