26-28 March 2025, Warsaw (Poland) and virtual
Warsaw University of Life Sciences (SGGW) Campus
Scientists from the COST Action “Joint effects of climate extremes and atmospheric deposition on European forests” (CLEANFOREST, CA21138) gathered at their third annual meeting at the Institute of Forest Sciences, Warsaw University of Life Sciences in Warsaw. Over the course of three days, from 26 to 28 of March, they discussed ongoing analyses aiming at improving our understanding on the effects of climate change and nitrogen deposition on health and functioning of European forests.
The plenary session on the first day opened with the keynote talk “Nearly a Century of Monitoring Stand Structural Diversity in Strictly Protected Forest Communities of the Białowieża Forest: Insights for Forest Management and Nature Conservation” by Dr Kamil Bielak (Institute of Forest Sciences, Warsaw University of Life Sciences).
‘Natural and strictly protected forests play a crucial role as reservoirs of biological and genetic diversity. They also serve as essential reference points for closer-to-nature forest management practice’ – stated Dr Bielak at the beginning of his talk. He shared data from long-term monitoring of tree species growth and dynamics running since 1936 in the Białowieża Primeval Forest, one of the largest and best preserved primary temperate lowland forests in Europe. Dr Bielak revealed impressive changes in forest structure and species composition across protected areas.
He emphasised that although overall forest structural attributes, e.g. measured using indicators such as carbon content, basal area and Shannon indices of species and size diversity, have remained relatively stable over time, the composition of tree species has changed significantly. Several species, including spruce, aspen, birch, pine, oak, ash, and maple, have shown notable declines in abundance. In contrast, late-successional species such as hornbeam and lime have increased in dominance across various forest communities. Nearly 600 monumental old trees in this area have been victims of the growing pressure of climate change, bark-beetle infestations and diseases.
The greatest structural and compositional stability was observed on eutrophic wet sites, while oligotrophic and mesotrophic dry sites exhibited lower temporal stability. The trend on nutrient-poor sites was largely shaped by the historically high abundance of spruce, a species that has seen a marked decline over the past few decades.
As Dr Bielak concluded, ‘natural forests can serve as valuable models for managed forest stands. However, in many cases, silvicultural interventions may be necessary, particularly when the goal is to maintain or restore a more balanced and diverse composition of tree species within a specific spatial and temporal framework.’
The core group and management committee met to review current progress and future needs within the CLEANFOREST COST Action. It was also an opportunity to discuss funding allocation, including the introduction of the new Young Researcher and Innovator (YRI) Conference Grants—an initiative launched by the COST Association to support early-career participation. Final details were also reviewed for the two upcoming training schools, the Training School on Global Change and Next Generation Manipulation Experiments, to be held at BIFoR-FACE, University of Birmingham from June 10 to 12, and the Interdisciplinary Summer School on Forest Ecosystems 2025, organized with the 3DForEcoTech, ARiF, and PANGEOS COST Actions and to be held in the University of Oxford & Wytham Woods in August 2025.
In productive, dedicated hybrid meetings in Warsaw, the four CLEANFOREST working groups presented the recent achievements, advanced ongoing meta-analyses and review papers, and planned next steps, both within their individual groups and through collaboration across the whole network. To know more about the activities of the CLEANFOREST working groups, visit our website: https://cleanforest.eu/structure/meet-our-working-groups/
In addition to ample networking opportunities during lunch and coffee breaks, a dedicated session was organized where participants were divided into small groups to give flash presentations. Each researcher briefly highlighted their work, creating a comfortable space to spark collaboration and exchange of ideas.
On the last day of the annual meeting we had the opportunity to enjoy a field trip to the KAMPINOS National park. This second largest national Park in Poland is located near its capital- Warsaw- and protects a remnant of primeval forest. It features a diverse landscape of dunes, swamps, meadows, and forests, hosting thousands of plant and animal species. Despite historical human impact, the area has been regenerating for over 60 years, becoming increasingly natural and supporting the return of species like elk, beavers, and lynx. In addition to its ecological value, the park preserves historical sites tied to Poland’s uprisings and wars, making it both a natural and cultural treasure.
We started our day at the visitors centre, where we were welcomed by Dr Eng. Adam Olszewski and his team, who provided an overview of the Park as well as main nature conservation and scientific activities. After the introduction, off to the forest, to discuss in the field main challenges related to forest management/conservation in relation to biotic and abiotic stressors. We had a chance to see the results of pine trees suffering from Ips acuminatus (bark beetle, sharp-dentated) infestation as well as mistletoe (Viscum album L.) that appears more and more frequently and in greater numbers.
The central point of the visit was the Kampinos Base Station for the Integrated Monitoring of the Natural Environment, located in the village of Granica on the edge of the Kampinos National Park, a part of the national environmental monitoring network vital for collecting comprehensive data on air, soil, water, and biodiversity.
The Kampinos measurement station is incorporated into Poland’s system for measuring and assessing atmospheric deposition, with a very wide range of compounds tested, including selected persistent organic compounds, inorganic compounds and heavy metals.
A big thank you to the local organizers, Klaudia Ziemblińska and Wojciech Kędziora, for the great and fruitful time in Warsaw. In particular, for their warm hospitality, smooth coordination, and dedication in making the meeting both productive and enjoyable for all participants.