Greetings Fred:
It is impossible to provide appraisals over the internet; however, I can give you an idea of what black walnut logs are going for here in Illinois. Market prices have dipped over the last year and that dip is reflected in stumpage and FOB prices. I'm hearing walnut veneer stumpage prices in the range of $1.50-3.00/bf, with grade log prices in the range of $0.50-0.60/bf (Doyle scale). Delivered (FOB) prices, of course, would be higher. I don't deal at all with lumber pricing; however, lumber prices and stumpage prices are directly correlated!
There are plenty of mills out there still buying timber and logs. Even though the walnut and white oak market have veered off their highs of 2006-2007, you can still get a decent price for your trees and logs.
Just remember you've got a cut tree (i.e., log) on your hands -- so you can't be too picky regarding price. Had you marketed your tree first, and cut the tree after you had marketed it/sold it, you probably would have received more money.
Don't forget that you can always call your local Extension Forester and NYDEC forest products specialist for additional marketing assistance and local expertise -- nothing beats local professional expertise when it comes to marketing logs and timber!
Best of luck!
