2021 Protecting old-growth forests in Europe A review of scientific evidence to inform policy implementation Lyla O’Brien, Andreas Schuck, Cecilia Fraccaroli, Elisabeth Pötzelsberger, Georg Winkel and Marcus Lindner Final report of a study carried out by the Resilience Programme of the European Forest Institute (EFI) with a study grant by the Ger- man Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). Recommended citation: O’Brien, L., Schuck, A., Fraccaroli, C., Pötzelsberger, E., Winkel, G. and Lindner, M., 2021: Protecting old-growth forests in Europe - a review of scientific evidence to inform policy implementation. Final report. European Forest Institute. DOI: https://doi.org/10.36333/rs1 European Forest Institute, Platz der Vereinten Nationen 7, 53113 Bonn, Germany www.efi.int Photo credits: Andreas Schuck (unless specified) Acknowledgements This study was carried out with funding from the German Federal Ministry of Environment, Nature Conservation and Nuclear Safety (BMU) between November 2020 and March 2021. Twenty external experts participated in a virtual workshop and provided feedback on preliminary study findings. We are grateful to Malgorzata Blicharska, Gherardo Chirici, Adam Felton, Georg Frank, Bogdan Jaroszewicz, William Keeton, Tobias Kuemmerle, Laurent Larrieu, Martin Mikoláš, Tom Nagel, Klaus Puettmann, Francesco Maria Sabatini, Johan Svensson, Miroslav Svoboda, and Kris Vandekerhove for their constructive comments and suggestions, which helped us to consolidate the study findings. We also appreciate the feedback received throughout the study by the German project steering group (Elke Steinmetz, Daniel Oberhauser, Jakob Poellath, and Moritz Stadler) as well as from EU Commission representatives (Cristina Brăilescu and Jose Barredo). This report reflects the opinions of the authors only, and not necessarily those of all the experts consulted, nor those of the donor or the EU Commission representatives. Table of Contents I. Executive Summary ..................................................................................................................................................6 1. Objectives and methodological approach .........................................................................................................13 2. Defining old-growth forests................................................................................................................................. 16 2.1 Introduction ..................................................................................................................................................................16 2.2 Old-growth forest and related terms .................................................................................................................16 2.2.1 Terms used to describe high conservation value forests ...........................................................16 2.2.2 Adapting the ‘primary forest’ definition for Europe ....................................................................18 2.3 Brief history of the old-growth definition .........................................................................................................24 2.4 Characteristics of old-growth forest definitions .............................................................................................26 2.4.1 Common criteria of old-growth definitions ....................................................................................26 2.4.2 Critiques of common elements and framing of definitions ......................................................28 2.4.3 Prospects of a future single definition ..............................................................................................33 2.5 Summarising the main findings on defining old-growth forests ............................................................34 3. Evidence of old and old-growth forests in Europe ..........................................................................................37 3.1 Introduction ..................................................................................................................................................................37 3.2 Evidence of primary and old-growth forests in Europe ..............................................................................37 3.2.1 Mapping primary and old-growth forests in Europe ..................................................................37 3.3 Inventory based data on European primary and old-growth forests ....................................................42 3.4 Knowledge on old-growth related tree attributes in European forests ................................................43 3.4.1 Variation of tree species´ lifespan .......................................................................................................43 3.4.2 Tree species´ lifespan depends on local site conditions .............................................................45 3.4.3 Characteristics that trees develop when they grow old .............................................................48 3.4.4 Information on age structure of European forests .......................................................................48 4. Approaches to protect old-growth forests and to maintain and develop old-growth forest attributes ............................................................................................................................................................51 4.1 Introduction ..................................................................................................................................................................51 4.2 Context: European forests differ in their provision of ecosystem services and protection status ................................................................................................................................................................51 4.3 Expanding the strictly protected forest area network ..................................................................................54 4.4 Integrative management approaches to maintain and develop old-growth forest attributes ..................................................................................................................................................................59 5. Associated benefits, consequences, and potential trade-offs of old-growth forest protection and development of old-growth forest attributes ...........................................................................65 5.1 Introduction ..................................................................................................................................................................65 5.2 Benefits, consequences, and potential trade-offs of expanding the strict protection network to support old-growth forest conservation ...................................................................65 5.3 Benefits, potential limitations and trade-offs of integrative management approaches ..........................................................................................................................................................................69 6. Policy implications ...................................................................................................................................................73 6.1 Introduction ..................................................................................................................................................................73 6.2 Definition of old-growth forests ...........................................................................................................................73 6.3 Evidence of old-growth forests and old-growth attributes .......................................................................75 6.4 Approaches to protect old-growth forests and to maintain and develop old-growth forest attributes ..........................................................................................................................................76 6.4.1 Expanding the strictly protected forest area network ................................................................76 6.4.2 Facilitating integrative forest management approaches to enhance biodiversity conservation ..................................................................................................................................82 6.5 Benefits and potential trade-offs of expanding the protected area network to improve old-growth forest protection and developing old-growth attributes in managed forests ................................................................................................................................................................84 6.6 Overall policy integration ........................................................................................................................................85 7. References ..................................................................................................................................................................89 5 I | Executive Summary es, and potential trade-offs of old-growth forest protection and management and development I. Executive Summary of old-growth forest attributes; and (v) Pol- icy implications. The study further incorpo- rates outcomes of a dedicated workshop held Introduction, objectives, and methods with twenty scientific experts; findings of this workshop can be found throughout the report. Primary and old-growth