Picture the wilderness of central Europe 100,000 years ago, or even a million years ago. You might instinctively imagine an endless expanse of towering trees, their thick canopies tightly interwoven and blocking sunlight from reaching the forest floor below. It is a classic, enduring image of a primeval continent untouched by human hands. But according to a major new scientific study, that familiar mental picture of Europe’s ancient forests is fundamentally misleading.
Instead of being blanketed by dense, dark woods, much of the ancient continent was a vibrant, sunlit landscape characterized by scattered trees, open woodlands, grassy clearings, and colorful wildflower meadows. In these dynamic habitats, birds and butterflies flourished under open skies, while enormous grazing animals constantly wandered the terrain, preventing trees and shrubs from taking over completely and maintaining a delicate ecological balance.
Researchers led by Aarhus University have discovered that this intricate mixture of habitats dominated Europe’s landscapes for more than 20 million years. Far from being the continent’s original and natural condition, the dense, shadowy forests that are common in many parts of Europe today appear to be a relatively recent development in the region’s long ecological history.
Published in the journal Biological Conservation, the findings challenge a longstanding assumption about what Europe’s wilderness looked like before widespread human intervention and landscape management. More importantly, they raise critical questions about modern reforestation programs, which frequently prioritize planting dense, uniform forests as a primary tool to combat climate change and protect local biodiversity.
"The study shows that current reforestation practices are on the wrong track—both here in Denmark, where subsidies are only granted for planting dense forests, and elsewhere in Europe," says Professor Jens-Christian Svenning from the Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) within the Department of Biology at Aarhus University, who served as the senior author of the study. "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."
Challenging the Myth of Europe’s Ancient Forests
For decades, conservation strategies across the continent have been heavily influenced by what scientists call the "closed-forest paradigm." This is the deeply ingrained belief that dense forests featuring nearly continuous tree canopies constituted Europe’s natural, default landscape before early human societies began clearing land for agriculture, livestock pastures, and permanent settlements.
Under this traditional view, the task of restoring nature often means stepping back and allowing trees to reclaim open areas, or actively planting dense forests in regions where they no longer exist.
The new research suggests that this widely accepted approach may overlook a crucial part of Europe’s ecological history. Rather than being uniformly covered by continuous canopy forests, the continent was characterized by shifting, dynamic combinations of grasslands, low shrubs, and open woodlands with varying densities of tree cover.
These diverse landscapes supported a rich variety of species that were uniquely adapted to thrive in both heavily wooded and open environments. Large plant-eating animals also played an indispensable role in maintaining this structural diversity by actively grazing, browsing, and physically disturbing the vegetation.
What 23 Million Years of Evidence Reveals
To reconstruct Europe’s ancient environments with unprecedented accuracy, the researchers examined an unusually extensive collection of paleoecological evidence spanning millions of years.
While previous studies have generally concentrated on more recent geological periods, this investigation extended much further into the past. It examined records stretching from the Miocene epoch—which began around 23 million years ago—through the pre-industrial era.
Paleoecology is the scientific study of ancient ecosystems using subtle clues preserved in fossils, sediment layers, and other natural archives. Because no single type of evidence can provide a complete and foolproof picture of the distant past, the research team combined several independent methods to cross-verify their findings.
These methods included analyzing fossilized pollen and larger plant remains, examining charcoal left behind by ancient wildfires, and testing chemical signatures preserved in the teeth and bones of ancient plant-eating animals. The team also evaluated fossil insects and mammals, alongside ancient environmental DNA recovered directly from preserved sediments.
Environmental DNA consists of microscopic genetic material left behind by living organisms in their surrounding environment. When successfully preserved in ancient deposits, this genetic trail allows scientists to accurately identify the specific plants and animals that inhabited a given region long ago.
Together, these diverse sources of evidence allowed the researchers to reconstruct not only what types of vegetation grew across the continent, but also how ecosystems changed over time and how large animals actively influenced their surroundings.
"Each type of proxy offers its own perspective, but together they let us see whether the landscapes were covered by dense forests, open grasslands, or a mix of the two," explains the study’s lead author, ECONOVO PhD student Szymon Czyzewski of Aarhus University. "By combining these datasets across time—from the Miocene to the pre-industrial era—we could trace long-term changes in vegetation and the role of large herbivores with much greater confidence than earlier studies that used only one method."
The accumulated evidence points to a remarkably consistent pattern. Across a span of more than 20 million years, Europe’s landscapes typically functioned as a shifting mosaic of trees, open spaces, and flowering plants, rather than continuous stretches of closed forest.
Significantly, these mixed landscapes were not restricted to one particular climate zone or weather pattern. They persisted under temperate conditions comparable to those found in much of Europe today, as well as during notably warmer and colder geological periods.
Elephants, Rhinos, and Bison Shaped Europe’s Wilderness
One of the most striking revelations of the study concerns the profound ecological influence wielded by large wild herbivores.
Ancient Europe was home to an impressive array of megafauna, including elephants, rhinoceroses, aurochs, and ancient bison. By constantly feeding on woody vegetation, stripping bark, and physically disturbing the ground as they roamed across the terrain, these massive animals helped keep significant portions of the landscape open and sunlit.
Their daily activities created vital opportunities for grasses, wildflowers, and other sun-loving plants that otherwise would have struggled to survive beneath a dense, light-blocking tree canopy.
This constant, dynamic interaction between large animals and vegetation helped sustain a richly diverse mixture of habitats, providing suitable conditions for a vast multitude of different species to coexist.
Modern Europe, however, is largely missing this critical ecological influence. Many of the large wild herbivores that once shaped its landscapes have long since disappeared, and traditional, extensive grazing practices have drastically declined over the past century.
"The ecosystems we see in Europe today lack the large wild herbivores that not only shaped landscapes but also sustained its biodiversity for millions of years," notes Czyzewski. "The most dramatic shift has largely taken place within the last hundred years, when traditional extensive grazing disappeared from large parts of the landscape."
This loss of natural grazing pressure has fundamentally altered how vegetation develops and spreads across much of the continent, helping to explain why present-day European ecosystems differ so dramatically from those of the distant past.
Europe’s Ancient Woodlands Were Full of Wildflowers
The research also offers an entirely new perspective on animal and plant species that are commonly associated with modern farmland and other human-managed environments.
Birds such as larks and jackdaws, along with mammals like the European hamster, are frequently regarded by modern observers as characteristic inhabitants of agricultural landscapes. Yet the researchers suggest that their deep evolutionary histories likely extend far back into the open woodland environments that existed long before the advent of modern agriculture.
Even familiar wildflowers share deep connections to these ancient ecosystems. Wild poppies, which are now frequently seen growing as weeds in modern agricultural fields, originally thrived in areas where large grazing animals disturbed the soil and vegetation within ancient woodlands.
These findings challenge the sharp, rigid distinction between "forest" and "open habitats" that so often guides modern conservation planning and land management.
In Europe’s ecological past, trees, meadows, shrubs, and grazing animals were not separate, competing components of nature. Instead, they frequently existed together, forming intricate, interconnected habitats that supported a wide and resilient range of wildlife.
Why Planting More Trees May Not Always Help Nature
These findings arrive at a critical juncture, as European countries continue to expand national forest cover in an effort to capture carbon dioxide, address the climate crisis, and halt the ongoing loss of biodiversity.
Although planting trees can provide important environmental and climatic benefits, the researchers argue that establishing large areas of uniformly dense woodland may not be the optimal strategy when the ultimate goal is to restore Europe’s native, historically authentic ecosystems.
Many native European species evolved in landscapes containing a mosaic mixture of trees, shrubs, and open areas. Converting these diverse habitats into continuous, closed-canopy forests can inadvertently reduce the variety of environments available to local wildlife, threatening the very biodiversity conservationists are trying to protect.
The study strongly suggests that future restoration efforts should place significantly greater emphasis on maintaining structurally diverse landscapes. This includes preserving open grasslands, scattered woodlands, and areas actively shaped by natural grazing dynamics.
"Instead, 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," Svenning concludes.
The findings add weight to a growing body of research from the same scientific group, suggesting that large animals played a far more decisive role in shaping Europe’s ecosystems than has previously been recognized. They reinforce the concept that Europe’s ancient landscapes were generally brighter, more open, and far more varied than the dense primeval forests so often depicted in popular imagination.
Rather than attempting to restore nature by simply planting more trees across every available acre, the researchers suggest that protecting true biodiversity will require recreating the complex, dynamic balance of woodlands, meadows, and grazing animals that shaped the continent for millions of years. The familiar image of Europe as a vast, dark, and unbroken forest may be deeply rooted in popular culture, but millions of years of multi-proxy scientific evidence are painting a very different, and much more vibrant, picture.