In this communication, we discuss some key ethical dimensions underlying the concept of biomass and its growing use in the environmental policy agenda on bioeconomy at national and European levels (National Strategic Plan on Forest-Wood, on Low carbon strategy, National strategy on biomass mobilization among others) in the context of limited non renewable and renewable natural resources and the crossings of planetary boundaries (Rockstrom et al. 2009; Steffen et al. 2015). Over the last decades, environmental ethics merged as an important field of research to advance in the recognition of the responsibility of human towards their environment. A further step and ontological shift is proposed by the emerging field of the ethics of non human living to discuss the concept of biomass and its role in bioeconomy policy agenda. Our analysis is organized along three questions. First, what dimensions of the ethics of living support the concept of biomass? Second, what ontological levelling down is operated when considering the ethics of non human living? Last, what are the consequences in terms of policy making and territorial development?

After reviewing the different meaning of the concept of biomass across scientific disciplines, we explore the different ethical theories at stake and the specific visions of the non-human living, as well as the ethical dilemma as stake when applied to the concept of biomass. We then highlight how this concept of biomass in its current used introduces a levelling down of the non-human living when considering the protection of biodiversity, as well as the sensibility and shared responsibility. Naming the non-human living and the specific ontological dimensions appears then as crucial dimensions contrasting with the abstract logic of quantification and measurement of the biomass, and its massification within the policy agenda. We illustrate our reasoning and the consequences of using the concept of biomass using few recent examples in the forest sector and the development of bioenergy. To conclude, we reaffirm the importance of naming and of ontologies when considering the ethics of non human living from an ecological bioeconomy perspective.