The document discusses transaction costs associated with smallholder farmers' participation in forest management schemes in Vietnam. It finds that transaction costs are higher for poorer households. This creates constraints on participation. The study examines transaction costs for different household wealth groups in a watershed in Hoa Binh province. It finds that searching, screening, negotiation and monitoring costs are highest for poorer households. To improve participation in payments for forest environmental services (PFES) schemes, the document recommends reducing transaction costs for poorer households and further research on community-based arrangements.