What is the oldest tree in Edinburgh?

Yews resist dating more stubbornly than almost any other tree: their heartwood rots away as they age, so ring counts are useless and even careful girth-based estimates carry wide error bars. Historic Environment Scotland's cautious figure for the Craigmillar pair is at least 300 years, old enough on its own. The more dramatic local tradition, that they were planted to mark Mary, Queen of Scots' recuperation at the castle in 1566, would require them to be past 450, a gap of a century and a half that no one can close without harming the trees to find out. What is documented without dispute is the setting: a five-hundred-year-old ruined castle where Mary's own advisors met in 1566 to discuss removing her husband, Lord Darnley, a plot historians call the Craigmillar Bond. The nearest challenger for oldest is a good deal less certain still, an ash at Cammo Estate whose age rests entirely on the estate's 1710 founding rather than any measurement of the tree itself. Reaching Craigmillar Castle means a short bus journey from the city centre and a Historic Environment Scotland admission ticket; the yews are inside the entrance, free to see once you are through the gate.