Most of us think of a century-old tree as a timeless piece of history.But in Portugal, that barely counts, because scattered across the country’s sun-baked south are hundreds of olive trees believed to be over 2,000 years old, with researchers now suggesting that one of them may have taken root nearly 3,700 years ago.Long before Portugal, or even Rome, existed, these ancient olive trees had already taken root. The discovery comes soon after a nearly 1,100-year-old tree was identified in Germany as possibly the oldest in the country, highlighting just how much older Portugal’s olive trees really are.The University of Trás-os-Montes and Alto Douro (UTAD) is the team behind these age estimates. Since tree rings are usually impossible to count in trunks that have hollowed out over centuries, UTAD’s researchers had to come up with another way to date these trees.What they have found is a whole network of ancient olive trees spread from the Alentejo down to the Algarve, many of which are still producing olives today, just as they were doing back in the Bronze Age. So how exactly are these olive trees dated? Where can you find them in Portugal, and what makes them so unusually good at surviving for this long?
The longest-living olive tree in Portugal is nearly 4000 years old
For a long time, the best-known contender for Portugal’s oldest tree was the “Oliveira do Mouchão,” standing in the parish of Mouriscas in the municipality of Abrantes. According to a statement by UTAD, the tree was already 3,350 years old at that point, making it, a contemporary of “the Phoenicians, Celtiberians and Romans.” Despite a trunk worn thin by time, in early 2022 it was “still producing olives as if in the flower of youth”. The tree even entered the running for the 2022 European Tree of the Year contest, finishing fifth in Portugal’s national round.But the Mouchão tree didn’t stay on top for long.Oliveiras Milenares later tracked down an even older tree, known as the “Oliveira do Peso,” growing on the Herdade do Peso estate in Vidigueira, in the Beja district of the Alentejo. According to the estate’s press release, it is aged at over 3,700 years, making it older than the Mouchão tree by several centuries. The estate calls it the most historically important tree on its land, and says it’s just one of a whole cluster of ancient olive trees there whose ages, added together, run into the thousands of years. The tree also made it to the finals of the 2024 Portuguese Tree of the Year contest, where it came in third.
How was the age of the trees determined?
The age of the Mouchão tree, and of many others like it, was found out using a patented mathematical model built by UTAD researchers. Rather than counting rings, the method estimates age from the trunk’s physical traits, like its diameter, height, and circumference. Using this approach, and working alongside the company Oliveiras Milenares since 2007, UTAD has gone on to certify dozens of other ancient olive trees around Portugal, including one in Santa Iria de Azóia, near Loures, thought to be around 2,850 years old.
There are several other old Olive trees in Portugal
Other notable ancient olive trees can be found in Monsaraz, in the Évora district, including one around 2,450 years old, as well as in Estremoz, Montemor-o-Novo, Lagoa, Beja, Vilamoura and Porto’s Serralves Park. UTAD’s dating method has also been used beyond Portugal’s borders, in Spain and France, including a tree in Menorca confirmed to be more than 2,300 years old.
So, what allows these trees to survive for millennia while most living things don’t stand a chance?
Researcher José Luís Louzada, who developed UTAD’s dating method, credits the olive tree’s ability to regenerate itself. According to the Euronews report, he said even an old section of trunk retains the capacity to sprout again, letting the tree keep producing fruit indefinitely.Louzada also credits the species’ adaptation to the Mediterranean climate, which suits Portugal’s south particularly well.
