The Plane of Porta San Donato

Lucca's Renaissance walls are planted almost entirely as a single ring of trees, but the register singles out only three individuals along the whole circuit, and this plane, growing on the ramparts near Porta San Donato, is the thickest of the three: 4.88 metres round and 30 metres tall, the largest plane tree in the city by that measurement. Porta San Donato itself dates to 1629, one of the six gates built when Lucca reinforced its walls against a siege that never came; the fortifications outlasted every threat they were built for and became, instead, the tree-lined promenade that rings the old town today. Nobody has dated the tree specifically, only the gate beside it. The wall-top path, the Passeggiata delle Mura, is public, paved and open around the clock, wide enough for the joggers and cyclists who use it as Lucca's ring road for people rather than cars. This plane stands about a kilometre and a half west of the Orto Botanico cluster, an anchor for the far side of a wall walk rather than an extension of it. If you know when it was planted, tell us.