The Kulawi-Marena community is one of the communities with customary law units located in Sigi Regency, Central Sulawesi.They have inhabited the area around the forests of the Lore Lindu National Park (TNLL) long before Indonesia became a country. The Katuvua customary law system is a mechanism for effective natural resource management in preserving forests and ensuring social order, rather than the governance applied by national park managers. The writing of this article is based on research conducted by the author with the Indonesian Institute for Forest and Environment (RMI) with the support of FAO funds in 2018. Qualitative methods were used in the data collection process through Participatory Rural Appraisal (PRA), in-depth interviews, and Focus Group Discussions (FGD). This article describes the customary forest management practices by the Kulawi-Marena community based on the Katuvua customary law system. Furthermore, this article shows that this practice is a form of grassroots institutional innovation that reflects "sodality" according to the understanding that has been formulated by Prof. Tjondronegoro which in this case is for the context of people outside Java. This kind of grassroots innovation in forest management based on customary law can be used as a lesson for efforts to resolve agrarian conflicts around conservation areas.