The Common Lime of Corongiu

Corongiu is three dams stacked up a valley above Sinnai, built between 1867 and 1922 to give Cagliari its first real water supply, and this lime tree has stood at the site for long enough that nobody now can say whether it predates the dams or came after them. At 2.6 metres round and 18 metres tall, it is the kind of specimen that only grows where a valley holds water and shelter both, which is exactly what an engineer would have looked for in 1867 too. The reservoirs still work, still supply Cagliari, and the paths around them are now a public walking trail through the hills, popular enough that Legambiente and the water utility Abbanoa run organised visits explaining the site's history. Sardinia's own monumental tree register lists the lime by its measurements alone, no age, no planting story, just the girth and the height and the place name. What that leaves unsettled is worth saying plainly: reach it on the open trail through the Corongiu valley, and whether that trail runs right up to the tree or past a fenced section of the works has not been confirmed. Anyone who has walked it can tell us, and settle the last honest gap in an otherwise well measured tree.