What is the oldest tree in Porto?
Porto's oldest tree that anyone can walk up to is a Virginia tulip tree (Liriodendron tulipifera) beside Casa Tait in the Jardins do Palacio de Cristal, put at more than 250 years and one of the first individual trees Portugal placed under legal protection, in 1950. It stands in the free public gardens off Rua de D. Manuel II. The national register lists one older, a 300-year tulip tree in a school yard on Rua Joao de Deus, which is not open to visitors.
The tulip tree beside Casa Tait has the strongest documented age claim in Porto: it was already mature enough to warrant individual legal protection when Portugal formalised its tree of public interest classification in 1950, and both the city council's own parks department and independent garden historians place its age at over 250 years. That makes it older than the Palácio de Cristal gardens built around it, which German landscape architect Émile David laid out in the 1860s, and older than the original glass-and-iron exhibition palace itself, demolished in 1951 and replaced with the domed arena that stands there now. Casa Tait, the mansion beside the tree, took its name from a family of British port wine merchants whose 19th-century wealth shaped much of what grows in this corner of the garden, tulip trees, magnolias and camellias among them. A second, taller tulip tree grows nearby without the same formal protection status, and should not be confused with the older, classified specimen the question above refers to.
One of Porto's trees also appears in Autumn Worth the Trip, a themed collection spanning several cities.