The international conference “Senie meži: politika un prakse” (Old-growth forests: policy and practice), organised by the Latvian State Forest Research Institute “Silava” in cooperation with the Latvian Academy of Agricultural and Forestry Sciences, has come to a close. The conference was opened by the chair of the old-growth forest working group of the International Union of Forest Research Organizations (IUFRO), and researchers from 10 countries presented papers.

In spring 2023 the European Commission published guidelines on the definition, identification, monitoring and protection of old-growth and primary forests. These acknowledge the significant differences between old-growth forests in different regions of the European Union, and each member state therefore has substantial work to do in developing locally appropriate approaches. The exchange of information and the debate on the methods used and the initial results between researchers from different countries, policymakers, forest owners and managers, and non-governmental organisations, such as took place during the conference, is essential for carrying out this task effectively.

The conference’s main conclusions

·       A landscape-level approach is crucial for maintaining and enhancing biological diversity, ensuring connectivity between protected areas of different categories with differing levels of protection and management regimes. Creating such a network and maintaining it dynamically and adaptively is the aim of ecological landscape planning. Old-growth forests under strict protection are an essential element of such planning.

·       The protection of old-growth forests is essential for safeguarding biological diversity. Their role — and hence their definition and delineation — does not depend on their ability to deliver other national or wider environmental objectives. For example, in the case of an environmental objective such as climate change mitigation, in some European regions old-growth forests of certain tree species can maintain a consistently high carbon stock in tree biomass over a long period, while in others (including hemiboreal forests) they cannot. This does not, however, alter the need to protect and study old-growth forests in order to gain insight into the values of biodiversity indicators and the dynamics of their change.

In delineating old-growth forests:

·       area matters — in order to ensure continuity in the presence of old trees and in the structural diversity of stands within a given territory, and thus a permanently available, suitable habitat for those species whose protection depends on conserving such old-growth forests. Given the variable natural disturbance regime and the influence of edge effects, determining their precise minimum area is problematic, but it should not be less than 50 ha;

·       age matters — when carrying out the initial identification and delineation of old-growth forest areas, they must consist of old stands, i.e. the dominant forest element must be old trees (150-180 years for conifers or hardwood broadleaves, or 100-120 years for other broadleaved species). Under the influence of natural disturbances, younger stands will in future also develop within the delineated old-growth forests; natural succession will take place and they will return to the old-stand stage, yet continuity in the presence of old trees will be maintained across the territory as a whole;

·       tree species matters — the aim is species of the late (climax) stage of succession, except in conditions where a pioneer species is more competitive and can form long-lasting stands, for example Scots pine in areas with oligotrophic sandy or peat soils.

·       quality matters — in order to identify all old-growth forest areas, account must be taken of the information obtained from the nature census and from other inventories concerned with characterising biological diversity. The most important indicators of old-growth forests are the heterogeneity of stands (especially vertical heterogeneity), the presence of standing dead dominant trees, and also a volume of deadwood of at least 50-60 m³/ha, made up primarily of large-dimension snags, standing dead trees and fallen trees. Forest drainage is to be regarded as an anthropogenic impact, but its presence is acceptable in a proportion lower than the overall share of drained forest in the region concerned. Once old-growth forests have been initially delineated in accordance with the defined criteria and the information in databases, they should be surveyed (inventoried) so that a final decision can be taken

The conclusions drawn at the conference will be used in further research, as well as in developing criteria for old-growth forests and identifying areas that meet those criteria, ensuring that the biodiversity elements associated with old-growth forests are maintained in the forest landscape.

The conference materials (for which the authors’ permission to publish will be obtained) will be available here: https://www.silava.lv/en/international-conference-old-growth-forests-policy-and-practice-on-october-10-2024