Thanks for the question Vince!
First, it is always in the best interest of the landowner to seek professional forestry assistance prior to selling standing timber. Secondly, it is important to "market" your trees, rather than just selling them to Joe Logger who waves a couple thousand dollars in front of your nose!
Therefore, timber “marketing” involves maximizing economic return along with with practicing “good” forest management. If you want harvest timber the right way, along with maximizing financial returns…contact a professional forester today!
List of professional consulting foresters serving Illinois: http://dnr.state.il.us/conservation/forestry/CONSULTING_FORESTERS_06.pdf
Illinois Consulting Foresters, Inc.: http://www.illinoisconsultingforesters.org/
List of Illinois Dept. of Natural Resources District Foresters: http://dnr.state.il.us/conservation/forestry/DISTFRSTMAP.pdf
Association of Consulting Foresters: http://www.acf-foresters.org/AM/
Hope this puts you in the right direction!