We compare sustainably managed with unmanaged forests in terms of their contribution to climate change mitigation based on published data. For sustainably managed forests, accounting of carbon (C) storage based on ecosystem biomass and products as required by the United Nations Framework Convention on Climate Change is not sufficient to quantify their contribution to climate change mitigation. The ultimate value of biomass is its use for biomaterials and bioenergy. Taking Germany as an example, we show that the average removals of wood from managed forests are higher than stated by official reports, ranging between 56 and 86 mill. m3 year−1 due to the unrecorded harvest of firewood. We find that removals from one hectare can substitute 0.87 m3 ha−1 year−1 of diesel, or 7.4 MWh ha−1 year−1, taking into account the unrecorded firewood, the use of fuel for harvesting and processing, and the efficiency of energy conversion. Energy substitution ranges between 1.9 and 2.2 t CO2 equiv. ha−1 year−1 depending on the type of fossil fuel production. Including bioenergy and carbon storage, the total mitigation effect of managed forest ranges between 3.2 and 3.5 t CO2 equiv. ha−1 year−1. This is more than previously reported because of the full accounting of bioenergy. Unmanaged nature conservation forests contribute via C storage only about 0.37 t CO2 equiv.  ha−1 year−1 to climate change mitigation. There is no fossil fuel substitution. Therefore, taking forests out of management reduces climate change mitigation benefits substantially. There should be a mitigation cost for taking forest out of management in Central Europe. Since the energy sector is rewarded for the climate benefits of bioenergy, and not the forest sector, we propose that a CO2 tax is used to award the contribution of forest management to fossil fuel substitution and climate change mitigation. This would stimulate the production of wood for products and energy substitution.

The increased use of biogenic resources is linked to expectations of “green” economic growth, innovation spurts through biotechnology, development options for rural areas, and an increasingly regenerative resource base that is also climate-neutral. However, for several years the signs for unintentional and unwanted side effects have been increasing. In 2015, the 2030 Agenda for Sustainable Development was published at the international level in order to address this problem and deliver a starting point for a comprehensive sustainability criteria evaluation catalogue. Impact indicators to quantify the environmental burden induced by national activities in foreign countries are especially lacking. In this article a comprehensive framework for the evaluation of the sustainability of the bioeconomy, considering key objectives and relevant criteria for environmental, economic, and social sustainability is developed. A special focus is set to the intersection area of the three pillars of sustainability, where the particularly important integrative key objectives and the indicators assigned to them (e.g., resource footprints) apply. This indicator set can be used as a basis for bio-economy monitoring, which uses and produces differently aggregated information on different levels of action, with a focus at the national level but also including global impacts of domestic production and consumption.

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This is a Response to the Letter by Welle et al., 13, 286–287.

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