Hi Charles:
Thanks for your question! I would strongly encourage you to reach out to your local state or Extension forestry agency for a list of state foresters or professional consulting foresters. A professional forester will be able to assist you in the marking, marketing, and sale of your standing timber.
Cornell Extension Forestry:
https://blogs.cornell.edu/cceforestconnect/
NY DEC Forestry: https://www.dec.ny.gov/lands/4972.html
Best of luck!