Shanwangping: the forest on the bare karst

Shanwangping stands at 1,300 metres in the hills of Nanchuan District, with more than 10,000 mu of forest, and it was the first national-level karst ecological park in China. The designation is precise: this is not a forest on deep soil but a forest on limestone, where soil has collected in pockets and cracks and the rock is never far below the surface. It was also rated one of the first forest oxygen bars, a phrase that means clean air and shade rather than anything scientific. The park is small next to Jinfo, whose scenic area covers 1,300 square kilometres, and it is the quieter of the two: fewer buses, more walking, and a road that ends in trees.

The forest opens. In the clearings the limestone comes through the grass in flat shelves and low ribs, and the grass grows in the hollows between them, which is what a karst meadow is: not a field but a surface where soil has held. The effect changes with the season, because thin soil dries and rewets faster than deep soil, and the green comes and goes in patches rather than all at once. This is the part of the park that people photograph, and it is also the part that shows how the place works. A tree on this ground is a tree that found a crack, and a meadow is a place where no crack was wide enough.

Nanchuan was a county from 637, a county-level city from 1994 and a district on 22 October 2006, and it holds 572,000 people, 60.97 per cent of them urban. The road up to Shanwangping leaves a district town whose speech is closer to the Chongqing urban area than its mountains suggest. The district's other advantage is water: its rice noodles are made with selenium-rich local rice and spring water from Jinfo that is rich in strontium, and the same hills supply the bamboo shoots and the visitors. The park is the upper end of that economy. What grows at 1,300 metres is a crop of air and shade, sold by the day.