History: Ancient Wilderness Was a Sunlit Mosaic, Not a Dark Forest, Major Study Reveals**
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, with thick, interlocking canopies blocking sunlight from reaching the forest floor. Generations of art, literature, and even scientific conservation models have reinforced the idea of a primeval Europe dominated by gloomy, unbroken woodlands. But according to a major new study published in Biological Conservation, that familiar image of Europe’s ancient forests is fundamentally misleading.
Instead of a continent shrouded in shadow, much of ancient Europe was a vibrant, dynamic landscape of scattered trees, open woodlands, grassy clearings, and colorful wildflower meadows. Birds and butterflies flourished in these sunlit habitats, while enormous grazing animals constantly worked the land, preventing trees and shrubs from taking over and choking out the sun.
Researchers led by Aarhus University have found that this intricate mixture of habitats dominated Europe’s landscapes for more than 20 million years. Far from being the continent’s original natural condition, the dense, dark forests common in many parts of Europe today appear to be a relatively recent development in its ecological history.
The findings challenge a longstanding assumption about what Europe’s wilderness looked like before widespread human intervention and modification. More urgently, 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 dwindling 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) at the Department of Biology, Aarhus University, who serves 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 entrenched belief that dense forests with nearly continuous tree canopies constituted Europe’s natural, default landscape before humans began clearing land for agriculture, livestock, and permanent settlements.
Under this traditional view, restoring nature often means allowing trees to reclaim open areas naturally or actively planting dense forests where they no longer exist. Environmental managers have long assumed that more trees automatically equal a healthier, more authentic natural environment.
However, the new research suggests that this approach may overlook a crucial part of Europe’s ecological history. Rather than being uniformly covered by dense, sun-blocking forests, the continent was characterized by shifting, dynamic combinations of grasslands, shrubs, and woodlands with widely varying amounts of tree cover.
These ancient landscapes supported a rich variety of species that were uniquely adapted to thrive in both wooded and open environments simultaneously. Large plant-eating animals also played an indispensable role in maintaining this biodiversity by grazing, browsing, and physically disturbing the vegetation and soil, preventing any single plant type from monopolizing the landscape.
What 23 Million Years of Evidence Reveals
To reconstruct Europe’s ancient environments with unprecedented accuracy, the researchers examined an unusually extensive collection of evidence spanning millions of years.
While previous studies have generally concentrated on more recent geological periods, this investigation extended much further into the past. The team examined paleoecological records stretching from the Miocene epoch—which began around 23 million years ago—all the way through the pre-industrial era.
Paleoecology is the scientific study of ancient ecosystems using clues preserved in fossils, sediments, 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 long-extinct plant-eating animals. The researchers also analyzed fossilized insects and mammals, alongside ancient environmental DNA recovered directly from accumulated sediments.
Environmental DNA consists of microscopic genetic material left behind by organisms in their surrounding environment. When successfully preserved in ancient deposits, it allows scientists to identify specific plants and animals that lived in a region thousands or even millions of years ago, offering a remarkably detailed census of past life.
Together, these diverse sources of evidence allowed the researchers to reconstruct not only what types of vegetation existed across different epochs, 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 more than 20 million years, Europe’s landscapes were typically a shifting mosaic of trees, open spaces, and flowering plants rather than continuous stretches of closed forest.
Importantly, these mixed landscapes were not limited to one particular climate regime. They persisted under temperate conditions comparable to those found in much of Europe today, as well as during significantly warmer and colder periods throughout the geological timeline.
Elephants, Rhinos, and Bison Shaped Europe’s Wilderness
One of the most striking findings of the research concerns the profound ecological influence of large wild herbivores.
Ancient Europe was home to a charismatic and powerful megafauna, including ancient elephants, rhinoceroses, aurochs, and bison. By feeding on woody vegetation, breaking branches, trampling saplings, and disturbing the bare ground as they moved in herds, these animals helped keep large parts 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 and perished beneath a dense, overarching tree cover. This constant, dynamic interaction between large animals and vegetation helped sustain a richly diverse mixture of habitats, providing ideal conditions for a massive array 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 gone extinct, and traditional extensive grazing practices have drastically declined due to modern agricultural and land-use changes.
"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," Czyzewski notes. "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 widespread 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 a radically different perspective on species that are commonly associated with farmland and other human-managed environments today.
Birds such as larks and jackdaws, along with mammals like the European hamster, are frequently regarded as characteristic species of agricultural landscapes. Yet the researchers suggest that their evolutionary histories likely extend far back into the past, having developed within the open woodland and mosaic environments that existed long before modern farming was invented.
Even familiar wildflowers share deep connections to these ancient, animal-managed 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 often guides contemporary conservation planning and land management.
In Europe’s ecological past, trees, meadows, shrubs, and grazing animals were not separate, competing parts of nature. Instead, they frequently existed together in a balanced equilibrium, forming interconnected habitats that supported a wide range of wildlife.
Why Planting More Trees May Not Always Help Nature
The new findings arrive at a critical juncture, as European countries continue expanding forest cover to capture carbon dioxide, address the escalating climate crisis, and meet biodiversity protection targets.
Although forests can provide important environmental and climate benefits, the researchers argue that planting large areas of uniformly dense woodland may not be the most effective approach when the ultimate goal is to restore Europe’s native, resilient ecosystems.
Many European species evolved in complex landscapes containing a delicate mixture of trees and open areas. Converting diverse, open landscapes into continuous closed-canopy forests could therefore inadvertently reduce the variety of environments available to wildlife, harming the very species conservationists are trying to protect.
The study strongly suggests that future restoration efforts should place greater emphasis on maintaining structurally diverse landscapes, including open grasslands, scattered woodlands, and areas actively shaped by natural grazing processes.
"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 significant weight to a growing body of research from the same scientific group, suggesting that large animals played a far greater, more foundational role in shaping Europe’s ecosystems than previously recognized by mainstream ecology.
They also reinforce the reality 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 simply by planting as many trees as possible, the researchers suggest that protecting 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, unbroken forest may be deeply rooted in modern cultural assumptions about nature, but millions of years of physical and biological evidence are painting a very different picture.
