What is the oldest tree in Zurich?

Platzspitz, the wedge of parkland where the Sihl and Limmat rivers meet, is Zurich's second-oldest public park, and its own gardeners have tagged its plane trees by planting year with a simple colour system: brown for 1780, blue for 1806, green for 1836, red for 1960, violet for 2005. The brown-tagged trees, planted in 1780, are the oldest documented specimens in the park and among the oldest confirmed trees in the city, already well established when Zurich was still a walled city-state and more than a decade before the French Revolution reshaped the continent around it. At least one of these plane trees is described by the city's own conservation survey as priceless, though the survey does not put a franc figure on it. Platzspitz's documented history as a public space runs back roughly 450 years, but almost nothing survives above ground from its earliest layouts; the 1780 planes represent the oldest generation that does survive, tagged and tracked rather than left to guesswork the way most historic city trees are.