¿Cuál es el árbol más antiguo de 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. That is why both answers here come with ranges rather than dates. The Great Yew of Ormiston is recorded by Scotland's Yew Tree Heritage Initiative as ancient and exceptional at over a thousand years, and by the Ancient Yew Group as one that could well be around a thousand; its branches have layered and rooted where they touched the ground, ringing a hollow centre, which is why it is also called the Cathedral Yew. It stands beside the old kirkyard in Ormiston, roughly 25 minutes from the city by car, and we list it here because it is within a day trip rather than because it is in Edinburgh. Inside the city boundary the oldest are the twin yews at Craigmillar Castle, where Historic Environment Scotland's cautious figure is at least 300 years. The more dramatic local tradition ties them to Mary, Queen of Scots in 1566, which would put them past 450, and no measurement settles it either way.