Greetings Wanda:
Please contact a local professional consulting forester: Market your standing timber to as many prospective timber buyers as possible using the "lump sum, sealed-bid" method as this is absolutely the best way to sell your trees--which, by the way, is an investment you made when you purchased your woodland!
I would hate to see you sell these trees for $20K, only to know find out later other timber buyers "may" have been willing to purchase these trees for a lot more. You'll never know unless you MARKET your timber to multiple, licensed timber buyers!
Thank you for your question and please remember to contact a local consulting forester ASAP!