Portugal's ancient olive trees may include a 3,700‑year‑old specimen — The Debate
Scientists say a Portuguese olive could be the continent's oldest living tree.
Portugal is home to hundreds of olive trees that are thought to be over two millennia old, and one may be as old as 3,700 years.
In Germany a tree recently identified may be about 1,100 years old, but in Portugal many olives are already estimated at more than two thousand years, according to the University of Trás‑os‑Montes and Alto Douro (UTAD).
The tree known locally as "Oliveira do Mouchão" in the municipality of Abrantes has long been considered a contender for the country's oldest. UTAD reported in October 2018 that it was then 3,350 years old.
It is an olive tree "a contemporary of the Phoenicians, Celtiberians and Romans" and, at the start of 2022, it was still producing olives despite a trunk worn by time.
The tree was a candidate in the 2022 European Tree of the Year contest, finishing fifth nationally and missing the chance to represent Portugal internationally.
The age estimate comes from a patented mathematical model created by UTAD researchers, applied with the help of Oliveiras Milenares. The model links a tree's age to trunk dimensions such as diameter, height and circumference, as described on the Florestas.pt portal, an initiative of The Navigator Company and Raiz, Forest and Paper Research Institute.
Other millennial olives have been certified across the country. In Santa Iria de Azóia, in the municipality of Loures, a tree was dated at around 2,850 years.
More recently, an olive on the Herdade do Peso estate in Vidigueira, Beja district, was assessed in 2021 as being over 3,700 years old. Known as "Oliveira do Peso", it placed third in the Portuguese Tree of the Year 2024 competition.
The estate highlights the heritage value of the "oldest millennial olive tree on the Herdade do Peso estate" and notes that a group of nearby trees together exceed 7,000 years in age.
Further ancient specimens are found in Monsaraz, Évora district, where one olive is estimated at about 2,450 years, and in locations such as Estremoz, Montemor‑o‑Novo, Lagoa, Beja, Vilamoura, Évora and Serralves Park in Porto.
UTAD has also been invited to date olives in Spain and France, including sites in Bordeaux, Girona, Málaga and on the island of Menorca, where a tree over 2,300 years old was certified.
The survival of these trees offers insight into the long‑term health of Mediterranean woodlands, a priority under the EU Biodiversity Strategy for 2030. Tourists drawn to such living monuments contribute to cross‑border cultural tourism, a sector supported by EU regional programmes. The dating technique pioneered by Portuguese researchers is now being used in neighbouring Spain and France, illustrating growing scientific cooperation across the continent.
According to José Luís Louzada, a researcher at UTAD who developed the dating method, the olive tree "without doubt is one of the living beings that best withstand the passage of time, thanks to its strong capacity for rejuvenation". He adds that a piece of trunk, no matter how old, can sprout again, allowing the tree to keep producing olives.
Louzada attributes the longevity to the species' excellent adaptation to the Mediterranean climate, which enables remarkable endurance. In Portugal these olives are especially common south of the Mondego and, in theory, could live indefinitely, outlasting many generations of people who walk the same land.