Nature reserve in Guizhou continues to preserve its unique karst landscape and biodiversity, Yang Yang and Yang Jun report.

Over tens of thousands of years, rainwater and heat have combined in the subtropical weather in the south of today's Guizhou province, to allow fauna and flora to survive on rocky soil. But unlike many forests, much of the soil there has washed away because rainwater erodes the rocks of the karst landscape, allowing soil to seep through. Tree roots have to work hard to carry out their function of nurturing growth with such scarce offerings.

The indomitability of life that Zhang Yanquan, a worker with the Maolan National Nature Reserve in Libo county, Qiannan Bouyei and Miao autonomous prefecture, Guizhou, has observed in the forest, has provided him and other people with a new perspective to see the world and themselves.

Several years ago, Zhang showed a couple from Beijing around the forest. He pointed at the thick roots that snaked through the rocks and bared themselves on the surface, telling them that these sturdy trees had battled to survive. About one year later, he received a phone call from them.

"They called to thank me for saving her life," he said on a TV program.

When the couple visited the forest, the wife was seriously ill and depressed but she was inspired by the incredible scenery and eventually pulled through.

"This experience also changed my view of my work. I used to think it was hard work, but now I see the trees that we protect can not only benefit the entire human race, but also can give us some inspiration," Zhang said.

Located in the south of Guizhou, the reserve contains one of the few forests on 25 degrees north latitude on Earth. This is the Libo karst forest, dubbed "the emerald on the belt of the Earth".

The 21,285-hectare reserve shelters more than 2,670 vascular plants, 586 vertebrate animals and 1,589 insect species, including endangered species.

The Libo karst forest, the world's only existing forest of its kind, is part of the South China Karst, a UNESCO World Heritage Site recognized as a representative of karst landform development in the humid tropics and subtropics, with high aesthetic value.

The Libo forest displays the wonders of nature. On a clear day, one can see giant "alien" conical peaks carpeted with thick green trees standing sentinel. A ribbon of leaden cement, a trail for visitors, meanders almost lazily through.