The Black Death devastated medieval Europe, killing millions of people and transforming societies. But the pandemic also left a lasting mark on the natural environment. A new study of ancient oak trees in Italy reveals how forests began to recover following the population collapse of the fourteenth century, with evidence of those changes still visible nearly than 700 years later.
Published in Proceedings of the National Academy of Sciences (PNAS), the research uses radiocarbon dating to trace the history of ancient oak populations in two parts of Italy. The findings suggest that reduced human activity following the Black Death allowed forests to regenerate, creating an ecological legacy that has survived into the present day.
Dating Italy’s Ancient Oak Trees
The international research team examined two populations of exceptionally old oak trees: evergreen holm oaks (Quercus ilex) on Montecristo Island, off the coast of Tuscany, and deciduous sessile oaks (Quercus petraea) in the Aspromonte mountains of Calabria, southern Italy.
The two locations have very different environments. Montecristo’s oaks grow at elevations between 100 and 500 metres above sea level, in a relatively mild coastal climate. In Aspromonte, the trees occupy mountainous terrain between 1,100 and 1,800 metres, where colder temperatures and shorter growing seasons make forest regeneration more difficult.
Researchers collected wood samples from 26 oaks on Montecristo and 21 in Aspromonte. Using radiocarbon dating and statistical modelling, they reconstructed when the trees became established.
The two locations in Italy where researchers studied ancient oak trees: Montecristo Island, off the coast of Tuscany, and the Aspromonte mountains in Calabria. The figure includes photographs of the trees, local climate data and comparisons of trunk diameters. Image courtesy of Piovesan et al., PNAS (2026).
Their analysis revealed a concentration of tree establishment dates between approximately 1400 and 1650, coinciding with the centuries following the Black Death and its recurring outbreaks.
On Montecristo, the researchers identified a particularly pronounced period of oak establishment between 1407 and 1486, several decades after the Black Death reached Italy in 1347. In Aspromonte, evidence pointed to substantial human disturbance during the medieval period, followed by a slower and more prolonged recovery.
How the Black Death Helped Forests Recover
The Black Death, which swept across Europe between 1347 and 1350, caused enormous demographic and economic disruption. As populations declined, agricultural activity and other forms of human pressure on the landscape also diminished in many regions.
The researchers suggest that these changes created favourable conditions for trees to establish themselves in areas where human activity had previously restricted forest growth.
They write:
While factors such as fire and extreme weather events can strongly influence stand regeneration dynamics, the occurrence of a synchronized pulse of tree recruitment across environments as distant and contrasting as a remote northern Tyrrhenian island and the high mountains of southern Italy argues against natural disturbances being the primary drivers of the observed regeneration pulse. The Black Death pandemic is the most plausible release mechanism for a synchronized tree recruitment pulse across two distant, contrasting Italian oak stands, leaving a demographic legacy in the forest age structure that remains detectable after six centuries.
Climate also played a role in how quickly forests recovered. On Montecristo, relatively wet conditions appear to have helped the oak population regenerate, possibly producing a dense forest within approximately a century. This is consistent with historical descriptions of the island’s vegetation from the sixteenth century. In Aspromonte, recovery was slower because of the harsher mountain environment and the effects of earlier human disturbance. Nevertheless, the similarities between the two populations strengthen the argument that the Black Death and subsequent demographic changes played an important role in forest recovery.
The findings also support earlier research using fossil pollen records, which identified changes in European land use and forest cover associated with the pandemic.
Ancient Trees That Survived for Centuries
Radiocarbon dating of ancient oak trees from Montecristo and Aspromonte reveals periods of forest regeneration following the Black Death. The graphs show estimated tree establishment dates, historical plague outbreaks, climate conditions and the relationship between tree age and trunk diameter. Image courtesy of Piovesan et al., PNAS (2026).
Beyond revealing the environmental consequences of the Black Death, the study provides new evidence of the extraordinary longevity of Mediterranean oak trees.
On Montecristo, researchers identified holm oaks with estimated ages approaching 1,000 years. One specimen was estimated to be 950 ± 84 years old in 2025, extending previous estimates of the maximum lifespan of Mediterranean evergreen broadleaved trees by approximately 200 years.
The findings also demonstrate that the largest trees are not necessarily the oldest. Some exceptionally ancient oaks have relatively modest trunk diameters because they have grown slowly over centuries.
However, the survival of these ancient forests is not guaranteed. On Montecristo, grazing by feral goats has severely restricted the establishment of younger trees, leaving ageing oak populations with limited regeneration.
The researchers argue that protecting ancient forests is important not only for biodiversity but also for preserving living records of environmental history. More than six centuries after the Black Death transformed medieval Europe, its ecological consequences may still be visible in Italy’s ancient oak forests.
The article, “Ancient oaks reveal rewilding of Mediterranean forests after the Black Death,” by Gianluca Piovesan, Michele Baliva, Franco Biondi, Jordan Palli, Lucio Calcagnile, Alessandro Chiarucci, Raffaele Manicone, Gianluca Quarta, Giovanni Quilghini, Antonino Siclari and Charles H. Cannon, is published in Proceedings of the National Academy of Sciences. Click here to read it.
Top Image: An oak tree depicted in the Tacuinum Sanitatis, a late 14th-century Italian manuscript. Austrian National Library, Vienna, Cod. Ser. n. 2644, fol. 15r.
The Black Death devastated medieval Europe, killing millions of people and transforming societies. But the pandemic also left a lasting mark on the natural environment. A new study of ancient oak trees in Italy reveals how forests began to recover following the population collapse of the fourteenth century, with evidence of those changes still visible nearly than 700 years later.
Published in Proceedings of the National Academy of Sciences (PNAS), the research uses radiocarbon dating to trace the history of ancient oak populations in two parts of Italy. The findings suggest that reduced human activity following the Black Death allowed forests to regenerate, creating an ecological legacy that has survived into the present day.
Dating Italy’s Ancient Oak Trees
The international research team examined two populations of exceptionally old oak trees: evergreen holm oaks (Quercus ilex) on Montecristo Island, off the coast of Tuscany, and deciduous sessile oaks (Quercus petraea) in the Aspromonte mountains of Calabria, southern Italy.
The two locations have very different environments. Montecristo’s oaks grow at elevations between 100 and 500 metres above sea level, in a relatively mild coastal climate. In Aspromonte, the trees occupy mountainous terrain between 1,100 and 1,800 metres, where colder temperatures and shorter growing seasons make forest regeneration more difficult.
Researchers collected wood samples from 26 oaks on Montecristo and 21 in Aspromonte. Using radiocarbon dating and statistical modelling, they reconstructed when the trees became established.
Their analysis revealed a concentration of tree establishment dates between approximately 1400 and 1650, coinciding with the centuries following the Black Death and its recurring outbreaks.
On Montecristo, the researchers identified a particularly pronounced period of oak establishment between 1407 and 1486, several decades after the Black Death reached Italy in 1347. In Aspromonte, evidence pointed to substantial human disturbance during the medieval period, followed by a slower and more prolonged recovery.
How the Black Death Helped Forests Recover
The Black Death, which swept across Europe between 1347 and 1350, caused enormous demographic and economic disruption. As populations declined, agricultural activity and other forms of human pressure on the landscape also diminished in many regions.
The researchers suggest that these changes created favourable conditions for trees to establish themselves in areas where human activity had previously restricted forest growth.
They write:
While factors such as fire and extreme weather events can strongly influence stand regeneration dynamics, the occurrence of a synchronized pulse of tree recruitment across environments as distant and contrasting as a remote northern Tyrrhenian island and the high mountains of southern Italy argues against natural disturbances being the primary drivers of the observed regeneration pulse. The Black Death pandemic is the most plausible release mechanism for a synchronized tree recruitment pulse across two distant, contrasting Italian oak stands, leaving a demographic legacy in the forest age structure that remains detectable after six centuries.
Climate also played a role in how quickly forests recovered. On Montecristo, relatively wet conditions appear to have helped the oak population regenerate, possibly producing a dense forest within approximately a century. This is consistent with historical descriptions of the island’s vegetation from the sixteenth century. In Aspromonte, recovery was slower because of the harsher mountain environment and the effects of earlier human disturbance. Nevertheless, the similarities between the two populations strengthen the argument that the Black Death and subsequent demographic changes played an important role in forest recovery.
The findings also support earlier research using fossil pollen records, which identified changes in European land use and forest cover associated with the pandemic.
Ancient Trees That Survived for Centuries
Beyond revealing the environmental consequences of the Black Death, the study provides new evidence of the extraordinary longevity of Mediterranean oak trees.
On Montecristo, researchers identified holm oaks with estimated ages approaching 1,000 years. One specimen was estimated to be 950 ± 84 years old in 2025, extending previous estimates of the maximum lifespan of Mediterranean evergreen broadleaved trees by approximately 200 years.
The findings also demonstrate that the largest trees are not necessarily the oldest. Some exceptionally ancient oaks have relatively modest trunk diameters because they have grown slowly over centuries.
However, the survival of these ancient forests is not guaranteed. On Montecristo, grazing by feral goats has severely restricted the establishment of younger trees, leaving ageing oak populations with limited regeneration.
The researchers argue that protecting ancient forests is important not only for biodiversity but also for preserving living records of environmental history. More than six centuries after the Black Death transformed medieval Europe, its ecological consequences may still be visible in Italy’s ancient oak forests.
The article, “Ancient oaks reveal rewilding of Mediterranean forests after the Black Death,” by Gianluca Piovesan, Michele Baliva, Franco Biondi, Jordan Palli, Lucio Calcagnile, Alessandro Chiarucci, Raffaele Manicone, Gianluca Quarta, Giovanni Quilghini, Antonino Siclari and Charles H. Cannon, is published in Proceedings of the National Academy of Sciences. Click here to read it.
Top Image: An oak tree depicted in the Tacuinum Sanitatis, a late 14th-century Italian manuscript. Austrian National Library, Vienna, Cod. Ser. n. 2644, fol. 15r.
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