What is the oldest tree in Dublin?
Dublin's oldest tree is very likely a yew in the private garden of the Old Glebe in Newcastle, on the city's western edge, estimated at between 500 and 700 years old depending on which measure you trust. It only opens to the public for a few weeks each year, in May, June and mid-August, under Ireland's Section 482 scheme for historic properties.
Ring counts are not possible without felling the tree, so estimates for the Old Glebe yew swing widely: a girth-based rule of thumb puts it past 500 years, while local tradition claims over 700. Either number makes it older than the house whose garden it now shares, built in 1710, and considerably older than the more famous ancient trees elsewhere in the city. Jonathan Swift, Dean of St Patrick's Cathedral, is said to have sat beneath it while composing verse, though the link between a supposedly ancient Dublin tree and a supposedly ancient Dublin writer is exactly the kind of story that attaches itself to old trees whether or not it happened, so treat it as folklore rather than settled fact. The nearest challenger for oldest is a good deal younger: a pair of yews in the National Botanic Gardens, possibly planted in the 1730s to commemorate the essayist Joseph Addison, though the garden's own historians cannot fully reconcile that story with the garden's 1795 founding date. Getting to the Old Glebe requires checking the calendar first. It is a private property that opens to the public for free under Ireland's Section 482 tax relief scheme, specifically in May, all of June, and nine days in mid-August, 10am to 2pm. Turn up outside those windows and the gate stays shut.
The yew, the oaks and their peers across other cities are collected in Europe's 10 Most Remarkable Ancient Trees.