Ancient DNA Reveals Early Forests in Doggerland

More than 16,000 years ago, forests were already taking root on the landmass that once linked Britain with mainland Europe and now lies beneath the sea.

The finding redefines the flooded plain between Britain and continental Europe as a welcoming refuge for vegetation, wildlife and perhaps early human groups during the last ice age.

Ancient forests in Doggerland

Sediments beneath the southern North Sea, between Britain and mainland Europe, have retained evidence from a lost river network and the landscape that once sustained early woodland.

Professor Robin Allaby of the University of Warwick analysed these deposits and identified genetic traces indicating that oak, elm and hazel grew there thousands of years sooner than anticipated.

The trees were present well before similar woodland evidence became widespread in British pollen archives.

This surprisingly early dating poses a fresh question: how did temperate forests become established so far north in the closing phases of the ice age?

Ancient DNA in mud

The cores contained sedimentary ancient DNA: genetic material left by plants and animals in ancient mud and sand.

Fine silt and fine sand produced the most reliable evidence, as slow-moving water allowed local DNA to settle close to the organisms that had lived there.

Coarser sand, in contrast, can introduce older material into younger deposits, an issue the researchers modelled before reaching their conclusions.

This validation was important, as it showed that 95 to 98 percent of DNA recovered from secure layers originated nearby.

Forests appeared very early

Oak, elm, hazel and alder were identified in southern Doggerland, the submerged territory between eastern Britain and mainland Europe, long before these trees became widespread in Britain.

Younger deposits also contained Tilia, or lime, a tree associated with warmer conditions that suggested the existence of locally mild areas during colder periods.

DNA from boar added weight to the argument that this was more than a few isolated young trees, since these animals required reliable food and cover.

Taken together, the evidence indicates a more varied habitat, providing water, shelter and forage long before the land was inundated.

A rare tree survived in Doggerland

A further unexpected discovery was Pterocarya, a relative of the walnut that has disappeared from north-western Europe but was clearly recorded in secure sediment layers.

The team excluded straightforward contamination because the DNA damage pattern matched that of other ancient tree DNA extracted from the same cores.

Earlier evidence suggested that this tree had disappeared from the area around 400,000 years ago, substantially earlier than the new indication.

Although this does not demonstrate uninterrupted survival across the entire region, it brings the species' local history much closer to the present.

Why timing matters

For years, ecologists have considered how temperate trees managed to move north so rapidly as the ice retreated.

One potential explanation has been microrefugia: small, protected locations in which species could withstand an otherwise hostile climate.

Doggerland supports that possibility, because mature woodland emerged too early to be explained by a gradual advance from the traditional southern refuges.

A refuge nearby would have enabled seeds, animals and, later, people to spread through northern Europe far more quickly.

Humans lived on Doggerland

The river system would have supplied abundant food and freshwater, making the wooded plain appealing long before encroaching seas transformed it.

This period predates the point at which the Mesolithic, the middle phase of the Stone Age, is firmly recorded in the area.

Subsequent evidence from the Maglemosian culture, an early northern European hunter-gatherer tradition, shows that hunter-gatherers were using northern wetlands by about 10,300 years ago.

The revised chronology therefore expands the period in which human communities may have travelled through, hunted and settled in Doggerland.

Doggerland flooded slowly

About 8,150 years ago, the Storegga tsunami was triggered by a huge submarine landslide off Norway's coast. The immense wave swept across the North Atlantic into the North Sea basin and struck the region.

Secure sediments laid down after the tsunami still contained terrestrial DNA, indicating that dry land remained close enough to supply local deposits.

“We unexpectedly found trees thousands of years earlier than anyone expected – and evidence that the North Sea fully formed later than previously thought,” said Professor Allaby.

Rather than occurring all at once, inundation appears to have progressed in stages, with some areas remaining above sea level until approximately 7,000 years ago.

DNA better than pollen

Earlier pollen research had suggested the presence of some early trees, but it could not reliably locate them within a small area.

DNA preserved in fine river deposits remained near its point of deposition, offering a record of what genuinely grew beside the river system that once crossed Doggerland.

This distinction is significant: pollen carried by air can travel great distances, whereas the heavier signals in sediment generally represent nearby vegetation.

A close examination of a single valley can expose refuges that broader regional records obscure.

Britain lost early history

Britain's limited early archaeological record now appears less an unexplained absence than the result of land being lost.

Rising seas submerged the routes, camps and coastlines that were once situated on Doggerland, rather than on the floor of today's North Sea.

This may account for why mainland Britain has preserved so little evidence of the earliest post-ice-age communities when compared with later eras.

Allaby said that the wooded terrain probably sustained early Mesolithic groups and could explain why so little material from that period remains in mainland Britain today.

Is Doggerland the mythical Atlantis?

Most people now regard Atlantis as simply an enduring myth: lost palaces, advanced technology and a city consumed by the sea. Yet Doggerland adds a real-world dimension to that familiar tale.

People hunted and lived in Doggerland before steadily rising seas drowned it, a fact that gives it an unsettling resemblance to Atlantis.

The comparison becomes more compelling when Plato's account is considered. He described a vast plain with mountains to its north. Doggerland was an extensive, fertile plain, with the Scottish and Scandinavian highlands lying to the north.

Some researchers also cite its scale. Estimates for Dogger Bank are unexpectedly close to Plato's stated dimensions for Atlantis.

There was also the catastrophe itself. Around 6200 BC, the Storegga Slide off Norway generated a tsunami roughly 4.9 metres high, which probably struck the remaining parts of Doggerland.

Plato wrote that Atlantis disappeared in a “single day and night of misfortune.” That phrase continues to sustain the theory.

However, Plato portrayed a mighty civilisation with bronze, chariots, temples and warfare. Doggerland has yielded only Mesolithic implements, bone harpoons and other hunter-gatherer remains: no vast city and no empire.

At present, considerable scope remains for debate on either side.

What comes next

This new evidence transforms Doggerland from a flooded connection marked on old maps into an ecological stronghold inhabited by living communities.

Further focused dredging and coring could investigate where people made camp, how long these refuges endured and which species lived alongside them.