“Primary forests can help the EU meet several of its objectives, including its targets under the EU Biodiversity Strategy 2030 and the EU Forest Strategy 2030. They would also help with key climate objectives by providing long-term carbon storage”, says expert Bart Nyssen.
Nyssen is a forest ecologist at the Department of Earth & Environmental Sciences at the Catholic University Leuven in Belgium. Together with his colleague Bart Muys, he authored the STOA study: ‘Tomorrow’s primary forests. The feasibility of realising novel primary forests in the western part of Europe’. They will present the study at the STOA Panel meeting in the European Parliament in Strasbourg on 12 March 2026.
You recently co-authored a study on recreating primary forests in the western part of Europe – what is meant by primary forests, and why are they important?
The key characteristics of primary forests are temporal and spatial continuity. Temporal continuity means that trees can get very old, hundreds or even a thousand years, which is something we don’t see in managed forests. Even more important is that the forest has existed on the same land for a long time; the rich biodiversity and complexity of these ancient forest ecosystems have been built over centuries.
Spatial continuity is important as well. Primary forests need to cover large areas to allow for natural disturbances such as storms, pests or fires, which are a normal part of forest development. Large scales of primary forest mean that these disturbances do not wipe out the entire forest and also provide habitats for large grazers and predators that need big territories to form viable populations. Primary forests are very resilient to climate change, as this high biodiversity buffers climate impacts.
We shouldn’t see primary forests as closed systems; natural disturbances create a dynamic mosaic of open and closed areas that shift over time. They are very important for Europe as they act as strongholds for biodiversity, play a major role in carbon storage, and enhance resilience to extreme weather by regulating water and cooling the climate.
What is the current condition of primary forests in Europe?
Bart Nyssen: Europe has roughly 4-4.5 million hectares of primary forest, mostly in Russia and Eastern Europe, while in the EU, primary forests are concentrated in Sweden, Finland, Bulgaria and Romania. Our study focused on the western part of Europe, specifically because there are only around 56,000 hectares of small, fragmented primary forest in the west, mainly in remote mountain areas like the Alps, Apennines, and Pyrenees.
The western part of Europe has been densely populated with high land pressure. There have been several major waves of deforestation and forest use, from the Roman period, the Middle Ages, and then most dramatically with industrialisation. Industrialisation also saw reforestation, because people began planting new forests, but these are of course not ancient forests.
The small remnants of ancient, old-growth forests are not always protected – we think that only around half of them have some form of protection. This is why restoration is important and why it is a long-term process: the characteristics that define primary forests – very old trees, decaying wood, complex soil structures, rich biodiversity – take centuries to develop. We need to give them time. Strict protection is essential, not just at the national level but also at the European level.
Protection also needs societal commitment. People need to see the value in primary forests and how they can benefit from them – low-impact management and ecotourism offer opportunities for people to appreciate these forests and give them a stake in their protection.
The study explores the potential, benefits and risks of recreating primary forests – can you tell us about some of the study’s findings?
Bart Nyssen: The study looks into the potential of recreating what we call “novel primary forests” – these ecosystems are fundamentally different from the primary forests from before, due to changes in soil and species configuration. So we’re not trying to recreate the past, but these novel primary forests will share the key characteristics of primary forests, like complexity, old-growth trees and rich biodiversity, but they will also reflect human influence and will therefore look a bit different.
When it comes to feasibility, the first thing to consider is whether a region still has pockets of ancient forest and whether there has been a long, continuous history of forest cover. This doesn’t guarantee success, but it gives us the best chance of restoring complex biodiversity. These remnants can act as starting points, allowing biodiversity to spread out again.
Rural depopulation is happening across large parts of Europe, with people leaving the countryside in places like the Iberian Peninsula, central Italy, central France and eastern Germany. This land use shift is creating huge opportunities for forest recovery.
We can also see the legacy of political and military history in Central Europe where large depopulation areas have been turned into uninhabited national parks, and these offer great potential for novel primary forests. In many ways, recreating primary forests isn’t just feasible, it is already happening, we just have to protect them.
Primary forests can help the EU meet several of its objectives, including its targets for protecting 10% of land under the EU Biodiversity Strategy 2030 and enhancing forest resilience under the EU Forest Strategy 2030. They would also help with key climate objectives by providing long-term carbon storage and adaptation benefits, as well as bringing socio-economic opportunities for nature tourism and rural development.
Where are some of the potential locations for novel primary forests?
Bart Nyssen: One location is the Gerês–Xurés UNESCO Biosphere reserve on the border between Portugal and Spain. The region was intensively grazed, but now with rural depopulation the remaining villages mostly rely on tourism and forests are naturally returning.
There are challenges, as many locals don’t like the change, but maintaining the old open landscape across tens of thousands of hectares isn’t practical. The solution is to allow the forest to develop in a large uninhabited core zone while keeping the traditional cultural landscape around the villages that lets people connect to their heritage.
There is still some livestock grazing in the core zone and the density is too high to let broadleaf trees like oak regenerate. This is a potential conflict, so we need to discuss with farmers, to offer them alternative grazing areas outside of protected core areas. There are also some active forestry plantations, so we’ll need to find other areas for timber production.
But overall, the trend is positive: we’re looking at a strict forest reserve of 17,000 hectares, surrounded by a 75,000-hectare buffer of managed land, all of which is embedded within a 250,000-hectare landscape, so it’s very well-integrated and balanced.
The best example we looked at was the Bayerischer Wald–Šumava in Germany and Czech Republic, which, along with adjacent forests extending into Austria, form a cross-border forest region. This has already been established as 21,000 hectares of strict forest reserve and is set to expand to 30,000 hectares in the next decade – that’s as large as we could dream of in Europe.
It then has a huge buffer zone of 90,000 hectares and a transition zone of more than 550,000 hectares that focuses on preserving the landscape and nature while carefully managing industrial and other human activities. This was truly the best example we found in the western part of Europe. National parks like these are ideal starting points because they already have strong legal protection and are sometimes managed with the explicit goal of becoming primary forests.
What kind of policies could enable the creation and restoration of primary forests?
Bart Nyssen: A coordinated policy mix is required, recognising that primary forests are essential for biodiversity, carbon storage and climate resilience. Legal certainty is needed, anchoring them in national restoration plans, while relocation or financial compensation mechanisms for private landowners can prevent or offset lost income from timber or agriculture.
Market-based instruments like carbon and biodiversity credits could act as enablers but must be robustly governed to avoid double-counting or greenwashing. Protecting existing remnants is urgent, but the good news is that novel primary forests already exist in practice, and their long-term success depends on protection, political commitment and cross-border coordination.