Europe Was Never a Giant Dark Forest, New 20-Million-Year Study Reveals

A comprehensive new study shows that Europe’s landscapes have been shaped by grasslands and open woodlands for more than 20 million years, suggesting that modern afforestation efforts go against this long-standing ecological pattern.

Imagine walking through untouched nature in central Europe 100,000 years ago, or even a million years ago. If you picture a dark, dense primeval forest where sunlight barely reaches the ground, you are likely imagining the wrong kind of past.

You have not gone far enough back in time. That picture is closer to a modern production forest than to much of Europe’s ancient landscape.

A more accurate image would be open patches of woodland mixed with colorful, flower-rich meadows, alive with many kinds of birds and butterflies.

From an ecological point of view, dense forests are a relatively recent development.

A new comprehensive study led by Aarhus University finds that, for more than 20 million years, Europe’s landscapes were usually mosaics made up of grasslands, scrub, and woodlands with varying tree cover. These were bright, flower-rich open woodlands shaped strongly by grazing animals as a major ecological force, rather than closed forests with dense canopies.

The study has just been published in Biological Conservation.

“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. 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,” says Professor Jens-Christian Svenning from the Center for Ecological Dynamics in a Novel Biosphere (ECONOVO), Department of Biology at Aarhus University, senior author of the study.

Svenning adds that the so-called “closed-forest paradigm” has shaped nature management for decades, along with ideas about what should count as natural. This view holds that dense, closed canopy forests were Europe’s baseline before major human influence.

All available palaeoecological evidence

The new study goes well beyond earlier work. While previous research has often looked mainly at more recent periods, the researchers brought together all available paleoecological evidence spanning the full interval from the Miocene epoch (which began around 23 million years ago) to the preindustrial period.

The study draws on a large synthesis of independent evidence. The researchers reviewed paleoecological studies covering the past 23 million years and combined several scientific “proxies” that can reveal past vegetation structure and ecological processes. These included pollen records, plant macrofossils, charcoal particles from ancient fires, stable isotope analyses of herbivore teeth and bones, fossil insects and mammals, and ancient environmental DNA preserved in sediments.

“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. 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,” explains the study’s lead author, ECONOVO PhD student Szymon Czyzewski of Aarhus University.

The conclusion is clear. Across this long span of time, Europe’s typical landscape was a dynamic mosaic rich in trees and flowers. Large wild herbivores such as elephants, rhinoceroses, aurochs, and bison helped keep vegetation partly open and diverse. This pattern appeared in temperate climates similar to those found in Europe today, as well as in warmer and cooler climates.

A continent without large grazers

Another major finding is that present-day Europe is highly unusual from an ecological perspective.

“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. The most dramatic shift has largely taken place within the last hundred years, when traditional extensive grazing disappeared from large parts of the landscape,” says Czyzewski.

The researchers also found that many species now seen as typical of cultural landscapes, including larks, jackdaws, and the European hamster, likely have evolutionary origins in the open woodland systems of the past. Wild poppies, now often associated with fields, once grew in disturbed areas within ancient woodlands where herbivores had shaped the ground.

This points to a key problem in modern conservation. The sharp separation between “forest” and “open habitats” is likely a recent human framework rather than a reflection of Europe’s long ecological history.

Implications for afforestation and restoration

The findings carry direct consequences for nature management and biodiversity across temperate Europe, especially at a time when tree planting is being promoted for climate mitigation and biodiversity goals.

If the aim is to restore ecosystems similar to those in which Europe’s species evolved and to which they remain adapted, the study indicates that uniform, dense forests are not the answer.

“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 study adds to growing evidence from the same research environment that Europe’s past was brighter, more varied, and more strongly shaped by large animals than long assumed.

One might say that the image of the dark, dense primeval forest will not disappear overnight, but it loses yet another supporting trunk.

Reference: “Revisiting Europe’s temperate forests: Palaeoecological evidence for an herbivory-driven woodland-grassland mosaic biome” by Szymon Czyżewski, Skjold Alsted Søndergaard, Ábel Péter Molnár, Matthew Roy Kerr, Jeppe Aagaard Kristensen, Joe Atkinson, Jonas Trepel, Maciej Sykut, Paweł Radzikowski, Signe Sangill Termansen, Karol Wałach, Elena A. Pearce, Sean E.H. Pang, Bartłomiej Zając, Juraj Bergman, Emil Sloth Thomassen, Ninad Mungi, Camilla Fløjgaard, Rasmus Ejrnæs, Robert Buitenwerf and Jens-Christian Svenning, 23 February 2026, Biological Conservation.
DOI: 10.1016/j.biocon.2026.111749

Funding: VILLUM FONDEN, Danish National Research Foundation, Independent Research Fund Denmark

Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.