We, the community of scientists, forest managers and national delegates that participate in, contribute to, and make use of, ICP Forests data and infrastructures met in Dresden 19-23 May, to celebrate 40 years of harmonized international forest monitoring in the UNECE region. We discussed the results obtained, the current situation and explored future directions and possible developments of forest monitoring.

Here we summarize into five key messages a science-based view on the importance of maintaining, supporting and further developing international forest monitoring in Europe.

Message 1. Long-term, internationally harmonized ground-based forest monitoring remains essential for science-based policy-making. 

Policy and decision makers should be aware that

• Monitoring helps with protecting European forests and their immense value, and inform forests and environmental policy. 

• When compared to the value of the resources it protects and the policy it informs, monitoring costs are negligible. 

Message 2. In its 40 years of activity, ICP Forests demonstrates that harmonized international forest monitoring is necessary and feasible. 

ICP Forests has been successful in

• Establishing a pan-European, quality-assured forest monitoring system capable of providing long-term data across regions, forest types, and environmental gradients.

• Developing internationally harmonized methodologies, a network of expertise and a governance structure that enables a participative decision-making process.

• Identifying changes in, and drivers of, forest health, growth and biodiversity, as well as status and changes in ecosystem chemistry (atmosphere, deposition, tree nutrition, soil and soil solution) and climate. 

• Demonstrating and documenting the success of clean air policy as well as the onset of new stress factors for European forests.

• Contributing to international policy processes (such as the Air Convention and Forest Europe) and research initiatives (Horizon Europe).

• Favouring national, international, regional and global research on key forest components, processes, dynamics, and ecosystem services.

Message 3. ICP Forests is an indispensable partner for any future pan-European forest monitoring system. 

ICP Forests provides a unique

• Ready-to-use pan-European monitoring system operated by the participating 42 Countries according to harmonized methodologies.

• Framework for key indicators and drivers of forest resilience, combining continental spatial coverage, tailored frequency of measurements for a large portfolio of attributes, and the long-term dimension. 

• Ground truthing infrastructure for calibrating and validating remotely sensed forest data, and for building, calibrating and validating models.

Message 4. Building on its success, ICP Forests is committed to continued evolution. 

It will evolve by

• Maintaining its relevance to policy, science and society.

• Fostering its collaborations (countries, organization, bodies) and broadening its geographical scope.

• Expanding its thematic scope (climate change, biodiversity), its data portfolio, its methods and its linkages with proximal and remote sensing products.

Message 5. Securing the future of ICP Forests is strategic for protecting European forests– action needed.

After the early successful co-operation with the European Commission, ICP Forests monitoring is now maintained by the participating countries. In front of its unique international added value, the benefits it generates and the need to ensure its continuation, with this declaration:

We urge all stakeholders from policy, science and society to 

• Actively recognize the value and the role of ICP Forests and the benefit derived from its unique long-term, large-scale data, information and harmonized methodologies.

• Ensure continued support for the maintenance and further development of ICP Forests monitoring activity. 

We therefore ask

• International organizations (such as the UNECE Air Convention, the European Commission): to develop mechanisms and agreements for supporting the ICP Forests monitoring activities in the participating countries and their co-ordination. 

• National organizations (such as ministries and research organizations): to secure support for the continuation and further development of the ICP Forests monitoring activity.

   

Prepared in Dresden, Germany, 19-23.05.2025