A 3,700-year-old olive tree in Portugal keeps producing olives as old trunk sections sprout again, revealing how one of nature’s longest-lived trees can repeatedly rejuvenate itself across thousands of years

Portugal is home to olive trees that may be more than 3,700 years old. These ancient trees have survived droughts, wars, changing landscapes and countless generations. One olive tree in Alentejo, Oliveira do Peso, was estimated at about 3,713 years old. But how can scientists know the age of a tree whose oldest wood may have disappeared? Researchers at Portugal’s UTAD use trunk measurements and mathematical modelling to solve this remarkable age mystery.