A Biological Conservation study led by Aarhus University says Europe was shaped for over 20 million years by open woodlands, meadows and large grazers, challenging dense-forest reforestation strategies.
Researchers led by Aarhus University in Denmark report that much of Europe was not covered by endless dense forest for most of its deep history. Their study in Biological Conservation, titled "Revisiting Europe's temperate forests," concludes that for more than 20 million years, from the Miocene (beginning about 23 million years ago) to the pre-industrial era, the continent was typically a shifting mosaic of scattered trees, open woodland, grassy clearings and wildflower meadows. The authors say this challenges the "closed-forest paradigm," the assumption that a dense, near-continuous canopy was Europe's natural state before humans cleared land.
The team combined several independent kinds of evidence rather than one method: fossil pollen and plant remains, charcoal from ancient wildfires, chemical signatures in the teeth and bones of herbivores, fossil insects and mammals, and ancient environmental DNA from sediments. According to the researchers, the pattern held in temperate conditions like today's as well as in warmer and colder periods. They credit large herbivores such as elephants, rhinoceroses, aurochs and bison with keeping parts of the landscape open, and lead author Szymon Czyzewski says the most dramatic change came in roughly the last hundred years, when traditional extensive grazing disappeared from large areas.
The authors draw conclusions for conservation policy. Senior author Professor Jens-Christian Svenning argues that current reforestation practices are on the wrong track, including in Denmark, where subsidies are granted only for planting dense forests, and says this could harm biodiversity because Europe's species evolved in mixed ecosystems. These are the study authors' interpretations as reported on November 7, 2026; the findings concern landscape history rather than prescribing specific planting schemes, so their policy impact will depend on further scientific and public debate.
