I feel that forest landowners are forced to participate in some sort of forest certification only if they want more money for their trees or they feel there is some prestige in belonging and want that. Example; every once-in-awhile a landowner will come into my office and say "I'd like one of those Tree Farm signs to put up". When I explain that it's recgonition of belong to the Tree Farm System and not just handed out to everybody, some join and eventually do enough on their property to become a certified Tree Farmer, or they are just not interested in getting that involved.
If a landowner values being independent and is not looking for every cent he can get for his trees when he sells some, he doesn't have to join.