The Cranmer Square London Plane

In 2011 the earthquakes took the buildings around Cranmer Square and left the trees. Cranmer Courts, the former Normal School on the square's edge, was among the historic buildings destroyed or badly damaged. The square itself, and the ring of old trees around it, came through. This London Plane is the biggest of them. The city's register counts 24 large planes and ashes at this site, and this one has the thickest trunk, 506 centimetres round, under a crown about 19 metres high. The ground it stands on is as old as Christchurch. Cranmer Square was surveyed in 1849 and 1850 as one of the four original squares of the central city, and it has been ringed with deciduous trees for a very long time. How long this particular tree has been part of that ring is another matter. Nobody has published a planting date for it, and the register classes it as mature rather than veteran, which suggests decades rather than centuries. So the honest version is this: a big plane, on the oldest kind of ground the city has, on a square that outlasted its own skyline. If you know when it went in, tell us.