Ecologically and economically sustainable level of timber harvesting in boreal forests - defining the safe operating space for forest use

Planetary-level analyses indicate that we are exceeding the ecological limits. However, we need approaches to implement global sustainability frameworks regionally, using natural resources at levels that allow for their regeneration. We present a framework to define limits beyond which ecosystems are threatened to collapse, to answer how much we can extract from ecosystems, and to manage natural resources for both human and ecosystem wellbeing. We exemplify this approach with the heath forest habitat types in Finland, which provide most of the national timber production. We use the IUCN Red List of Habitats to set favourable reference values for volume of deadwood, proportion of old-growth forest cover and proportion of deciduous trees. Through forest growth simulations and management optimization, we found that the proportion of old-growth forest is the most challenging criteria to be reached only by 2100. This would require not only a larger use of extensive forest management practices than hitherto but also to drastically reduce the maximum economic sustainable harvest level from the current 96% to 60%. By combining threat assessments with ecosystem modelling and management planning, this approach can support regional decision makers to make informed decisions to stay within safe limits of use of natural resources.