TB -
Tim has hit the ferrous peg on the head.
Work with them, and work to understand their business. Know how much area mills are paying per thousand, and then expect and be willing to pay a slight premium, you are likely buying clear butts. (and a choice one at that if the stem is strait enough to do what you want) Learn to talk the talk - meaning, work to learn the techno-jargon of both the sawyer and the logger.
Understand that the mans bottom line is based on getting as many loads to the mill as possible in any given day, and that your maybe undersized load (and the extra work putting it together and perhaps the phone call precipitating it) might mean getting one less full load out in a day, be willing to accept yours after hours, make it a bonus and not a pain.
I've gotten calls about one lovely and lonely cruck on a cut, and arranged trucking myself (love ramp truck wreckers - winch it up, dump it off) because it's known a check will maybe appear in the mail for the cost of putting a stem aside at the landing, and making a phone call.
Talk to other area framers, then to foresters, work with both to create a market.
We are fortunate and in a relativly rare position in todays world, where we often work a commodity from it's raw source through to it's end use -
Like beef does not really come from supermarkets on little styrofoam trays, wood products do not really come palletized in big box stores - The consumer is too removed from most of what he uses and how it is made - So too, is the other end of the market from its end user - Like a cowboy rarly shares a smile and a glass of wine with the people who end up buying the finest cut from the beef he knew on the hoof - A logger rarely sees the end use of the tree he knew on the stump...
Invite the man and his people to the raising - make him interested in what you do - Build real working relationships.