Community-based forestry has received much recent attention as an effort to protect threatened Southern forests by linking conservation with sustainable livelihoods. Many researchers have emphasized the importance of effective organization for successful community-based forestry. While significant attention has been paid to community-level organizational design for collective action, less attention has been given to the role secondary-level grassroots associations play in supporting forest governance. The case of the Association of Forest Communities of Peten (ACOFOP) in Guatemala's Maya Biosphere Reserve is discussed, using a framework drawn from research on multipurpose agrarian federations. As it confronts ongoing problems of representation, equity and legitimacy, ACOFOP now encourages associated community forest concessions to diversify beyond commercial timber into collectively organized non-timber forest activities. Diversification, however, brings new governance issues with new participants, objectives and organizational logics that challenge ACOFOP to change while maintaining characteristics that support successful advocacy of its members' interests. ACOFOP and its members actively experiment with several organizational alternatives, each with diverse implications for the balancing of political and economic roles. To better understand and support community forestry initiatives, their associations and similar agrarian organizations should be viewed in dynamic rather than static terms, and the central role local participants play in adapting their own organizations recognized.