The dark primeval forest was never there
For twenty million years, Europe's landscapes were not the dark primeval forests of legend but luminous, shifting mosaics of grassland and open woodland, kept alive by the movement of elephants, rhinoceroses, and bison. A landmark study from Aarhus University now challenges the foundational assumptions of modern conservation, suggesting that current policies promoting dense afforestation are not a return to nature but a departure from it. The species that define European biodiversity — from wildflowers to skylarks — evolved not in shadow but in light, shaped by the restless presence of large animals that are now largely gone.
- A century of conservation policy rests on a myth: that Europe's natural baseline is dense, closed-canopy forest — and new evidence assembled across 23 million years directly contradicts it.
- Governments across Europe, including Denmark, are actively subsidizing the planting of uniform forests, accelerating a transformation that may be driving biodiversity in the wrong direction.
- The real architects of Europe's ancient ecosystems were megafauna — elephants, rhinos, aurochs — whose grazing kept landscapes open, flower-rich, and biologically diverse, and whose absence now quietly unravels what evolved in their presence.
- Researchers are calling for a fundamental reorientation: restoration should build woodland-grassland mosaics, not monocultures of trees, and must grapple seriously with returning large herbivores to the land.
- The study lands as both a scientific correction and a policy provocation — the 'closed-forest paradigm' is named, examined, and found wanting, leaving conservation institutions with an uncomfortable reckoning.
For most of the past twenty million years, Europe was not the dark, impenetrable forest of popular imagination. It was brighter, more varied, and fundamentally shaped by large animals moving through it. A new study from Aarhus University, published in Biological Conservation, has assembled the most comprehensive evidence yet to overturn a century of assumptions about what European landscapes actually looked like before industrial civilization.
The researchers drew on every available line of evidence — pollen trapped in sediment, fossilized insects and bones, isotope signatures in herbivore teeth, ancient DNA — spanning from the Miocene epoch to the pre-industrial period. The picture that emerged was consistent across millions of years: a dynamic mosaic of open grassland, scattered woodland, and flower-rich habitat. Not a closed canopy. Something far more open.
Large wild herbivores were the architects of this world. Elephants, rhinoceroses, aurochs, and bison kept vegetation open and prevented any single plant community from dominating. The species that evolved here — larks, jackdaws, wild poppies — did so in response to this grazing-driven openness. Many creatures now associated with traditional European farmland are, in fact, relics of this ancient system.
What makes the finding urgent is what has replaced it. The large herbivores are gone. Extensive grazing has largely vanished. And in their place, a new assumption has taken hold: that Europe's natural state is dense forest, and that restoration means planting trees. Senior author Jens-Christian Svenning calls this the 'closed-forest paradigm' — a framework that has shaped policy for decades and distorted what people believe nature even looks like.
The researchers conclude that restoration should instead prioritize mosaics of woodland and open habitat, and should seriously engage with returning large herbivores through rewilding or managed grazing. The sharp modern boundary between forest and open land, they argue, is a recent human invention — not a reflection of how Europe's ecosystems actually function. The dark primeval forest was never there. What was there was something more complex, more alive, and far more dependent on the presence of large animals than modern conservation has been prepared to admit.
For most of the past twenty million years, Europe was not the dark, impenetrable forest of popular imagination. It was something brighter, more varied, and fundamentally shaped by the presence of large animals moving through it. A new study from Aarhus University, published in Biological Conservation, has assembled the most comprehensive evidence yet to overturn a century of assumptions about what the European landscape actually looked like before industrial civilization arrived.
The researchers gathered every available clue about ancient vegetation: pollen trapped in sediment, charcoal from fires, fossilized insects and bones, isotope signatures in herbivore teeth, even fragments of ancient DNA. By combining these independent lines of evidence across the full span from the Miocene epoch—roughly twenty-three million years ago—to the pre-industrial period, they could see patterns that single-method studies could never reveal. The picture that emerged was consistent across millions of years and across climates both warmer and cooler than Europe's present day. The continent's typical landscape was a dynamic mosaic: patches of open grassland interspersed with woodlands of varying density, studded with flowers, alive with birds and butterflies. It was not a closed canopy forest. It was something far more open.
Large wild herbivores were the architects of this landscape. Elephants, rhinoceroses, aurochs, and bison grazed and browsed across the continent, their feeding and movement keeping vegetation partly open and preventing any single plant community from dominating. This grazing pressure was not incidental to the ecosystem—it was foundational. The species that evolved in this world, from larks to jackdaws to wild poppies, evolved in response to it. They became adapted to open, disturbed, flower-rich habitats. Many of the creatures and plants now considered typical of European cultural landscapes—the managed farmland and meadows of recent centuries—are actually relics of this ancient grazing-driven system.
What makes this finding urgent is what has happened in the last hundred years. The large wild herbivores are gone. The traditional extensive grazing that kept landscapes open has largely vanished from Europe. And in their place, a new vision has taken hold: the idea that Europe's natural state is dense forest, and that restoring nature means planting trees. Governments across the continent, including Denmark, now offer subsidies specifically for establishing closed-canopy forests. The assumption underlying this policy is that dense woodland represents the baseline, the true natural condition that humans disrupted. The study suggests this assumption is backwards.
Jens-Christian Svenning, the senior author, calls this the "closed-forest paradigm"—a framework that has shaped European nature management for decades and shaped what people think counts as natural at all. The problem is not merely academic. If the goal of restoration is to recreate ecosystems similar to those in which Europe's species evolved and to which they remain adapted, then planting uniform, dense forests works against that goal. It will reduce biodiversity. It will contradict millions of years of evolutionary history. It will replace the bright, flower-rich mosaics that shaped European life with something closer to a modern production forest.
The implications are direct and uncomfortable for current policy. Restoration efforts, the researchers conclude, should instead emphasize creating and maintaining mosaics of woodland and open habitat. This means not just protecting trees but also restoring the ecological role of large herbivores—whether through rewilding programs or through managed grazing. It means accepting that the sharp modern distinction between "forest" and "open habitat" is a recent human invention, not a reflection of how Europe's ecosystems actually work. The dark primeval forest, it turns out, was never there. What was there was something more complex, more alive, and more dependent on the presence of large animals than modern conservation has been willing to acknowledge.
Notable Quotes
Current reforestation practices are on the wrong track. This will not only be harmful for biodiversity; it will be in direct contradiction to the type of ecosystems that Europe's species have evolved in over millions of years.— Jens-Christian Svenning, Aarhus University
Restoration efforts should place greater emphasis on creating and maintaining mosaics of woodland and open habitats—not least through the restoration of natural-living large herbivores.— Jens-Christian Svenning
The Hearth Conversation Another angle on the story
So the study is saying Europe was never actually forested the way we think of it?
Right. For twenty million years, it was mostly open woodlands and grasslands mixed together—what they call a mosaic. Trees were present, but not dense enough to block out the sun across entire regions.
And what kept it that way? Why didn't it just become a solid forest?
Large herbivores. Elephants, rhinos, bison, aurochs. They grazed and browsed constantly, preventing any single plant community from taking over. Their presence was the main ecological force shaping the landscape.
So when those animals disappeared, the landscape changed?
Dramatically, especially in the last hundred years. Without the grazing pressure, the vegetation structure shifted. And then humans decided that dense forests were the natural state and started planting them as restoration.
But the study says that's backwards?
Exactly. The species that live in Europe—the birds, the wildflowers, the insects—they evolved in open, flower-rich habitats shaped by grazing. Dense forests are actually contrary to what they're adapted for.
So current afforestation policies are working against biodiversity?
According to this research, yes. If you want to restore ecosystems that support the species Europe has, you need open mosaics and large herbivores, not uniform tree cover.