Bark beetle outbreaks in forests: a pan-European view
19th Jul 2023
Extreme heat events and droughts have intensified due to climate change, and bark beetle outbreaks have reached unprecedented levels in conifer forests challenging traditional management approaches in production forests and leading to increasing public and political awareness. The need for coordinated international actions and a more comprehensive management framework also recognizing the social dimension of forest disturbances is growing.
Therefore, FOREST EUROPE recently organized a three-day workshop on “Managing biotic threats in forests – lessons learned from bark beetle calamities” (see programme here) in Breznice, Czech Republic, jointly with the Ministry of Agriculture of the Czech Republic, the Forest Management Institute (UHUL), and the Forestry and Game Management Research Institute of the Czech Republic (FGMRI). This event is part of FOREST EUROPE’S work toward the establishment of a pan-European Forest Risk Facility (FoRISK).
During the workshop, experts from 16 countries gathered to exchange good and bad experiences of bark beetle management in Europe, aiming to prevent and better prepare for future outbreaks of bark beetles and other biotic threats.
Different countries are facing different challenges:
In the first session, insights from the UK (Max Blake, Forest Research – Alice Holt Lodge UK) gave an idea on the ability of spruce bark beetles to spread over distances of 300-400 km, being blown over from outbreak areas in Belgium and France to the south-east of England. Spruce bark beetles are a non-native forest pest in the UK, and strict eradication protocols apply if an outbreak of this invasive species is detected. Gernot Hoch (BfW Austrian Research Centre for Forests) presented on the new and unexpected developments of spruce bark beetle outbreaks in natural spruce forests at higher elevations in Austria. Recently, higher temperatures have allowed for two beetle generation and population dynamics of unusual intensity also at higher elevations. The cooler climate in Finland and Norway has yet prevented the establishment of large-scale breeding populations of the spruce bark beetle, as presented by Tiina Ylioja (Luke – Natural Resources Institute Finland) and Paal Krokene (NiBio – Norwegian Institute of Bioeconomy Research). But also, these northern countries are preparing for more intense outbreak seasons due to increasing temperatures and are running national monitoring programs and setting-up preparedness plans. For some countries, the worst is likely still ahead, and we need more workshops connecting countries with different levels of experience and fostering cooperation.
Participants from Bulgaria (Petya Dimitrova-Mateva, Executive Forest Agency Bulgaria), Ukraine (Kateryna Davydenko, Ukrainian Research Institute of Forestry & Forest Melioration), and from the Czech Republic (Jan Lubojacký, Forestry, and Game Management Research Institute Czech Republic) also presented on bark beetle damages in pine forests. It is important for any management guideline to consider that different biotic and abiotic disturbance agents can also interact and result in further weakened tree stands. Bark beetle gaps in forest stands could create vulnerable edges that could also have cascading impacts, i.e., further facilitate the risk of increased wind disturbance.
Disturbances are interrelated and disturbance management has to consider the whole risk cycle:
The next session continued in this direction but also provided guidance for forest management in an uncertain future. Interrelations with other forest disturbances are possible at any time during a bark beetle outbreak – before (predisposition because of recent storm or drought events), during, or after (potentially flammable material of dead wood increasing the risk for fire). Eventually, one has to remember that after the disturbance is before the next disturbance, as Marcus Lindner (EFI Bonn) also reminded the participants during his presentation. He also highlighted that disturbance risk management should consider the full disaster risk management cycle with proactive and reactive management measures for prevention, preparedness, response, and recovery.
Marcus Lindner from the European Forest Institute.
The same rules apply for disturbances due to extreme climatic events, as participants learned in the presentation of Nenad Petrovic (University of Belgrade) on the severe damages of the Ice Break event in Serbia in 2014 and the regeneration process after almost ten years. Forest management strategies that ignore the uncertainties associated with climate change are unlikely to meet future expectations. Restoration of post-calamity areas was also the topic of Jan Leugner’s (Forestry and Game Management Research Institute Czech Republic) presentation. Large areas of bark beetle calamities often result in large areas of thickets (young forest stands) in the next decade from planting or natural regeneration of trees. Dissemination of new knowledge and experiences is of the utmost importance to avoid loss of species admixtures, loss of stability, and overall functionality of the ecosystems of the next forest generation.
Subsequently, the participants were introduced to the policy brief “Managing bark beetle outbreaks in the 21st Century” by the author Tomas Hlasny (Czech University of Life Sciences in Prague). This short and concise brief with recommendations for policymakers emphasizes that resilience thinking when adopted in policy and management frameworks, will help deal with increasing risks and enable us to see natural disturbances also as opportunities for creating new, resilient forests to adapt and recover from future shocks more efficiently. The policy brief also comes with a toolbox addressing the full disaster risk management cycle that can be directly implemented in national crisis plans. (Policy brief and a short summary video on the policy brief will be available soon).
In the afternoon of the second day, a field trip was organized for the participants in the southwestern Brdy Mountains with demonstrations of forest sites in the state and privately owned forests affected by spruce bark beetles at large-scale and measures taken to deal with the damage and for restoration explained. It was organized in cooperation with the Military Forests and Estates of the Czech Republic and the Forest Administration of the Archbishopric of Prague.
Risk management for forest disturbances: what is needed – towards FoRISK and international cooperation
During the last day, participants had a chance to learn about the activities of FAO on the management of bark beetle outbreaks from a global perspective by Shiroma Sathyapala (FAO), the initiative to establish a nationwide forest damage database in cooperation with the federal states in Germany at the new Institute for Forest Protection and the vision to extend it to pan-Europe by Henrik Hartmann ( Julius Kuehn-Institute for Cultivated Plants). Strengthening international cooperation for risk management is the idea behind the pan-European forest risk facility (FoRISK). FoRISK’s role will be to provide information about transboundary problems, get the leading countries involved, and enable local exchange. It should further be a platform for communication between science, policy, and practitioners. These were some of the results of a group work activity wherein the present experts were asked to provide feedback on the achievements of the FoRISK pilot so far and give guidance on further work before the Ministerial conference in Bonn 2024 makes a decision on the continuation of the FoRISK.
From FOREST EUROPE, we would like to thank all participants, co-organizers, and all involved speakers for their support and valuable insights provided, including also presentations on the experiences with spruce bark beetle from Germany (Ralf Petercord, Ministry of Agriculture and Consumer Protection, North Rhine-Westphalia), Czech Republic (Vit Sramek and Milos Knizek, Forestry and Game Management Research Institute), Poland (Kamil Szpakowski, General Directorate of State Forests Poland) and Lithuania (Glazko Zbignev, Ministry of Environment Lithuania). We hope to continue with this important work to safeguard the future of our forests.
