Trees outside forests are a key resource supporting Europe’s biodiversity

As the trees in man-made landscapes (trees along roads, waterways, in rural and urban landscapes) are an important factor in conserving Europe’s biodiversity, we propose to acknowledge and include their role, expressis verbis, in the 2020 Biodiversity Strategy.

The mid-term review of the 2020 Biodiversity Strategy indicated that „Overall, as compared with the EU 2010 biodiversity baseline, biodiversity loss and the degradation of ecosystem services in the EU have continued, as confirmed by the 2015 European environment — state and outlook report”. As IPCC indicates, climate change progresses at accelerating pace.

Trees outside forests are the key part of Europe’s green infrastructure in both urban and rural settings: they support preservation of biological diversity serving as both habitats and ecological corridors (1). Green infrastructure composed of trees, permeating man-made landscapes of Europe, not only connects biodiversity hotspots, it is the hotspot of biodiversity (2). In these environments, ancient trees rich in biodiversity have better chance to survive than in forests managed for timber. Additionally, trees are important for climate change mitigation and adaptation: trees in rural landscapes protect agricultural production and urban trees make life in cities possible.

Yet, the trees outside forests are among the least appreciated elements of the green infrastructure, not even mentioned in important EU strategy documents, and taken for granted by both the society and tree managers. The management of trees is often ineffective in European countries, with the result that the resource becomes impoverished (3). A special challenge is how to reconcile presence of trees with other types of infrastructure, such as roads (avenues), railways and canals. These, and other trees in rural landscapes, are particularly threatened by infrastructure development, agricultural technology, and improper maintenance. Using synergies between the green, grey and blue infrastructures maximises the benefits the trees offer for biodiversity conservation.

While opportunities to expand nature conservation areas are limited, green infrastructure offers practically unlimited opportunities to create habitats and, in addition, to contribute to climate resilience of European landscapes. EU Biodiversity Strategy 2020 targeted green infrastructure, however, it did not even mention structures made by trees, such as avenues and hedgerows. A greater weight in the new Biodiversity Strategy should be given to green infrastructure, particularly that composed of trees. This will help in protecting trees in man-made environments, that are threatened by infrastructure development and mismanagement. Support to conservation of trees outside forests will help to introduce standards and guidelines needed to assure their proper management for biodiversity, climate mitigation and adaptation, as well as quality of life. Loss of trees should be minimized and creation of new avenues and hedgerows should be required to compensate for those lost. The strategy should stand up for avenue trees that are particularly threatened by excessive traffic improvement concerns.

(1) Borek et al. 2018: Trees in rural areas – best practice and recommendations. http://drzewa.org.pl/en/publikacja/trees-in-rural-areas-best-practice-an…
(2) Kujawa K. 2006. Wpływ struktury zadrzewień oraz struktury krajobrazu rolniczego na zgrupowania ptaków lęgowych w zadrzewieniach. Akademia Rolnicza w Poznaniu,
(3) Pradines Ch. 2009. „Road Infrastructures: Tree Avenues in the Landscape”. CEP-CDPATEP (2009) 15E. Strasbourg.

Piotr Tyszko-Chmielowiec, Ph.D., Leader of LIFE Project: Trees for Europe’s Green Infrastructure, Foundation for Sustainable Development, tyszko@fer.org.pl