In order to ensure its livelihoods, as many other all over the world, the population of Madagascar is increasing the pressure on resources, and in particular, on local biomass. This study examines how institutions are acting in the governance of biomass regarding to its potential impacts on global health. Thirty semi-structured interviews and twelve focus groups involving farmers and local institutional leaders were conducted in two disparate Communes near the capital Antananarivo. The purpose of these discussions was to gather information linking global health to the life of agrarian communities. As achievement of the methodological deployment, a mapping of institutions was set, showing the coexistence in the Malagasy highlands of traditional institutions: the household (ankohonana), the community (fokonolona) and the state (fanjakana), and new ones: the decentralised collectivity or Commune, religious communities and private enterprises or firms. Households, even though as mostly agrarian, are the most active in the production, consumption and transfer of biomass. However, their decision-making aptitude on biomass governance can be influenced by the authority of the state as a provider of public policies or by the holders of financial means as firms that favour certain productions over others. The activities of the interacting institutions maintain the power relations between them more than they preserve the regenerative capacity of biomass, the main source of well-being for agrarian societies.