Congrats OTB, cool find!
My Grandfather belonged to a comparable organization, here in Virginia, known as the "Modern Woodmen". They were a fraternal organization of carpenters, cabinet makers, sawyers and perhaps loggers as well. They had regular local meetings and conventions to basically celebrate the craftsmanship of all things wood! I don't know this for sure but they probably offered insurance and other benefits to craftsmen who worked independently of the unions.
Best wishes and good luck!