What is the oldest tree in Lausanne?
Lausanne's oldest mapped tree is the Napoleon Oak on the University of Lausanne's Dorigny campus, a pedunculate oak whose wood was dated by tree-ring and genomic analysis in 2017 to a germination around 1778, making it roughly 248 years old.
The dating is unusually solid for a city tree: researchers sequenced the oak's own wood in 2017 rather than relying on the local legend that Etienne-Francois-Louis de Loys planted it in 1800 to mark Napoleon Bonaparte's review of 40,000 troops nearby. The DNA analysis makes the tree roughly 22 years old at the time of that visit, so either it grew from seed on the spot a generation before Napoleon arrived, or it was transplanted as an already two-decade-old sapling, and both readings are printed on its page rather than one being chosen. It is not the only Lausanne tree near this age: the Cedar of Lebanon in Parc de Denantou is put at roughly 250 years by the same city register, and the Linden of Bon-Abri may be older still, at 260 by the register's own figure, though the tourist office's walking tour puts that same tree at only 160 and the two have never been reconciled. The oak's own dating method is the most rigorous of the three, which is why it holds the title here.
One of Lausanne's trees also appears in Autumn Worth the Trip, a themed collection spanning several cities.