Researchers from the University of Copenhagen have uncovered a substantial layer of forest biomass lying outside traditional forest boundaries in Europe—roughly 15 million hectares. When translated into storage terms, this amounts to about 1 billion tons of biomass. The findings appear in a peer reviewed science publication focused on developments in forestry and environmental science.
To map this hidden green layer, the team employed advanced artificial intelligence tools alongside high-resolution satellite imagery. The combined approach enabled the detection of urban and rural trees that often go unnoticed in standard forest inventories. The AI-based methods achieved an accuracy score exceeding 92 percent, underscoring the reliability of this dual technology approach in capturing subtle, dispersed tree cover.
Among European nations, the Netherlands showed the largest share of non-forest trees, with about a quarter of its total tree cover located outside official forest areas. Within that external share, urban environments accounted for roughly 8 percent of the country’s total tree presence. The United Kingdom and Ireland followed, with external tree cover comprising about 22 percent and 20 percent respectively.
Brandt from the Department of Earth Sciences at the University of Copenhagen commented on these results, noting that outside-forest trees may have limited significance in large forested nations. In contrast, in countries where forest resources are more scarce, such as Denmark, the Netherlands, the United Kingdom, and Ireland, these trees contribute meaningfully to biodiversity, local climate regulation, habitat availability, landscape character, and the cycling of water through soils and ecosystems.
The broader takeaway is that European landscapes hold a mosaic of tree life that extends beyond the visible forested areas. By recognizing this dispersed arboreal presence, policymakers, land managers, and researchers can better understand and steward microclimates, watershed health, and species habitat networks—areas that are increasingly important in the face of urban expansion and climate variability.
In related regional efforts, large-scale reforestation initiatives in other parts of the world are making measurable progress in lowering industrial emissions, signaling a global trend toward nature-based climate solutions that complement traditional carbon management strategies. This European study contributes a fresh perspective on how dispersed trees, even when not located within formal forests, play a role in carbon storage, biodiversity, and ecosystem services across the continent.