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 blocking sunlight from reaching the forest floor. Generations of art, literature, and even scientific conservation models have reinforced the idea of a dark, unbroken primeval forest blanketing the continent before the advent of widespread human civilization.
However, according to a major new study published in the journal Biological Conservation, that familiar image of Europe’s ancient forests is likely entirely misleading. Instead of being covered by dense, shadowy woods, much of the continent was historically a vibrant, dynamic landscape characterized by scattered trees, open woodlands, grassy clearings, and colorful wildflower meadows. In these sunlit habitats, birds and butterflies flourished, while enormous grazing animals constantly worked the land, preventing trees and shrubs from completely taking over and choking out other life forms.
A team of researchers led by Aarhus University has discovered that this rich mixture of habitats actually dominated Europe’s landscapes for more than 20 million years. Far from being the continent’s original natural condition, the dense, dark forests that are common in many parts of Europe today appear to be a relatively recent development in its long and complex ecological history.
The findings present a direct challenge to longstanding assumptions about what Europe’s wilderness looked like before widespread human intervention reshaped the globe. Crucially, they also raise urgent and important questions about modern reforestation programs. Across Europe, contemporary climate and conservation policies frequently prioritize planting dense, uniform forests as a primary mechanism to combat climate change and protect biodiversity.
Professor Jens-Christian Svenning from the Center for Ecological Dynamics in a Novel Biosphere (ECONOVO) at the Department of Biology at Aarhus University, who served as the senior author of the study, warns that current trajectories may be fundamentally flawed.
"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," Svenning notes. "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, European conservation strategies have been heavily influenced and constrained by what scientists call the "closed-forest paradigm." This widely accepted belief posits that dense forests with nearly continuous tree canopies constituted Europe’s true natural landscape before human beings began clearing land for agriculture, livestock, and permanent settlements. Under this conventional view, the standard blueprint for restoring nature often means allowing trees to aggressively reclaim open areas or actively planting forests where they no longer naturally exist.
The new research suggests that this approach may overlook a crucial part of Europe’s ecological history. Rather than being uniformly covered by dense, impenetrable forests, the continent was characterized by shifting, dynamic combinations of grasslands, low shrubs, and open woodlands that featured varying amounts of tree cover depending on the region and the era.
These heterogeneous landscapes supported a rich variety of species that were uniquely adapted to thrive in both wooded and open environments simultaneously. Large plant-eating animals played an indispensable role in maintaining this biodiversity by continuously grazing, browsing, and disturbing the vegetation, effectively acting as natural landscape architects.
What 23 Million Years of Evidence Reveals
To reconstruct Europe’s ancient environments with unprecedented accuracy, the researchers examined an unusually extensive collection of empirical evidence spanning millions of years. Previous scientific studies have generally concentrated on more recent geological periods, such as the post-glacial era. This new investigation, however, extended much further back into the past, carefully examining 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 specialized study of ancient ecosystems using physical clues preserved in fossils, sedimentary layers, and other natural archives. Because no single type of evidence can provide a complete or flawless picture of the distant past, the research team combined several independent scientific methods to cross-verify their findings.
These methods included analyzing fossilized pollen and larger plant macroremains, tracking microscopic charcoal left behind by ancient wildfires, and examining chemical signatures preserved in the teeth and bones of long-extinct plant-eating animals. Furthermore, the researchers studied fossilized insects and mammals, alongside ancient environmental DNA recovered directly from sediment cores.
Environmental DNA consists of minute traces of genetic material left behind by organisms in their immediate surroundings. When successfully preserved in ancient geological deposits, it allows scientists to identify the specific plants and animals that lived in a given region thousands or even millions of years ago. By combining these diverse datasets across deep geological time—from the Miocene epoch to the pre-industrial era—the researchers were able to trace long-term changes in vegetation and evaluate the exact role of large herbivores with much greater statistical confidence than earlier studies that relied on just a single methodological approach.
Szymon Czyzewski, an ECONOVO PhD student at Aarhus University and lead author of the study, explains the strength of this multidisciplinary approach. "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," Czyzewski notes.
The accumulated evidence points to a remarkably consistent pattern. Across a span of more than 20 million years, Europe’s landscapes typically formed a shifting mosaic of trees, open spaces, and flowering plants rather than continuous stretches of closed forest canopy. Importantly, these mixed landscapes were not restricted to a single climate regime. They persisted under temperate conditions comparable to those found in much of Europe today, as well as during significantly warmer and colder geological periods.
Elephants, Rhinos, and Bison Shaped Europe’s Wilderness
One of the most striking findings of the research concerns the profound ecological influence wielded by large wild herbivores. Ancient Europe was not a quiet, shaded woodland; it was home to magnificent megafauna, including ancient elephants, rhinoceroses, aurochs, and wild bison.
By feeding voraciously on woody vegetation and physically disturbing the ground as they roamed across the continent, these massive animals helped keep significant portions of the landscape open and sunlit. Their natural behaviors created critical ecological niches and opportunities for grasses, wildflowers, and other sun-loving plants that otherwise would have struggled and perished beneath a dense, overarching tree canopy.
This constant, dynamic interaction between large animals and evolving vegetation helped sustain a remarkably diverse mixture of habitats, providing ideal conditions for a vast array of wildlife. Modern Europe, however, is missing much of this critical ecological influence. Many of the large wild herbivores that once shaped its landscapes have been hunted to extinction or driven out, and traditional extensive grazing practices have drastically declined over recent centuries.
"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 points out. He notes that the most dramatic and rapid shift in these ecosystems has largely taken place within just the last hundred years, as traditional extensive livestock grazing and open-range management disappeared from large parts of the European countryside.
This severe loss of natural grazing pressure has fundamentally altered how vegetation develops and spreads across 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 new research also offers an entirely fresh perspective on 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 categorized by modern conservationists 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 dawn of modern farming.
Even familiar wildflowers share deep connections with these ancient, dynamic ecosystems. Wild poppies, which are now frequently seen blooming vividly in modern agricultural fields, also thrived historically in areas where large grazing animals disturbed the soil and vegetation within ancient woodlands.
These findings directly challenge the sharp, rigid distinction between "forest" and "open habitats" that so often guides contemporary conservation planning and land management. In Europe’s ecological past, trees, meadows, shrubs, and grazing animals were never truly separate parts of nature. Instead, they existed together in a continuous feedback loop, forming interconnected habitats that supported a wide range of specialized wildlife.
Why Planting More Trees May Not Always Help Nature
These revelations arrive at a critical juncture as European nations continue to expand state-backed forest coverage in an effort to capture carbon dioxide, address the escalating climate crisis, and meet biodiversity targets. While planting trees can undoubtedly provide important environmental benefits, the researchers argue that establishing large areas of uniformly dense woodland may be the wrong strategy when the ultimate goal is to genuinely restore Europe’s native, resilient ecosystems.
Because many native European species evolved specifically in landscapes containing a balanced mixture of trees and open areas, converting these historical habitats into continuous closed-canopy forests can inadvertently reduce the variety of environments available to wildlife. The study strongly suggests that future restoration efforts should place a much 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, all pointing to the conclusion that large animals played a far greater and more foundational role in shaping Europe’s ecosystems than previously recognized. They reinforce the reality that Europe’s ancient landscapes were generally brighter, more open, and vastly more varied than the dense primeval forests that populate the popular imagination.
Rather than attempting to heal nature by simply planting more trees everywhere, protecting biodiversity may instead require recreating the complex, dynamic balance of woodlands, meadows, and grazing animals that defined the continent for millions of years. The familiar image of Europe as a vast, dark, unbroken forest remains deeply rooted in modern cultural understanding, but millions of years of empirical evidence are painting a very different, and much brighter, picture.
