Greetings Marsha. Thank you for your question.
What you are need is a certified forester (i.e., a trained professional with a four-year degree in forestry), not a tree broker. Missouri has many private consulting foresters and state government foresters (Missouri Dept. of Conservation) available to assist you with your forestry needs.
Rather than selling your timber directly to a logger, it would behoove you to "market" your timber with the services of a professional forester. Marketing your timber, rather than just selling it, will allow you to maximize the price you receive when selling your timber. Ask a local professional forester how this is done.
To contact a local professional forester who can service your needs in northern Missouri, please contact:
Missouri DOC Foresters: http://www.mdc.mo.gov/forest/contacts/
Missouri Consulting Foresters: http://www.missouriforesters.com/