This report, produced through a partnership between the business leaders’ initiative 3C (Combat Climate Change) and the Stockholm Environment Institute, gauges the availability of biomass for low-carbon energy and other uses in the context of sustainability and competing demands. Biomass is a promising source of renewable low-carbon energy, but it’s constrained by land and water availability, by soils’ ability to produce biomass, and by the need to return some biomass to the land to retain nutrients and soil moisture. There are also competing uses for biomass – for food, for animal feed, for materials, and to protect habitats and ecosystems – and the need to reduce emissions, in itself, also constrains land conversion and agricultural practices.