Building synergies among ground-based forest inventorying and monitoring networks to meet scientific, political and societal needs

Societal Impact Statement Ground-based Inventorying and Monitoring programs are crucial for documenting long-term forest responses to global change pressures, though there is limited coordination among them. We call for building synergies between different Inventorying and Monitoring programs, as well as community science and stakeholder engagement, to expand the temporal and spatial scale of forest monitoring and better integrate ground-based monitoring, remote sensing and modelling for timely detection of changes in forest conditions and functioning. This will be beneficial for the Proposal for a Monitoring Framework for Resilient European Forests and other not forestry-related European Union policies and strategies. Summary There are high expectations from policymakers and society about the role of forests in contributing to climate change mitigation and biodiversity conservation goals, while also supporting a sustainable forest-based bioeconomy. Yet, multiple global change drivers are undermining forest health and functioning, resulting in great uncertainties around the future of the ecological, economic and social benefits that humanity relies on from forests. Consequently, there is a pressing need to document the state of forests, which is traditionally accomplished through long-term ground-based inventorying and monitoring. There are several Inventorying and Monitoring networks in Europe, each with a specific scope, resulting in their independent development and limited interactions. There is now a growing need for a stronger integration across networks, both conceptually and operationally, to achieve an in-depth assessment of changes in forest status, underlying mechanisms and drivers, to support the development of pan-European Earth Observation products and the European Union strategies. Here we briefly summarize the forest ground-based Inventorying and Monitoring networks in Europe, identifying their role, strengths and areas for improvement. We suggest actions that can favour a transition towards a new, co-operative and effective era in forest monitoring, which can support research, policy and societal needs in a timely manner.