Yaks and cattle graze on Potatso"s summer pastures, a living link to the region"s centuries-old herding traditions. [Photo provided to China Daily]

　　Summer arrives slowly at 3,500 meters above sea level in Potatso National Park.

　　The rich ecological landscape, marked by lush forests, grasslands and lakes, has a way of holding the heat back and unfolding it petal by petal, covering alpine meadows with a shifting tapestry of gold, white, deep blue and violet.

　　Step off the bus at the entrance of the national park in Shangri-La, Diqing Tibetan autonomous prefecture, Southwest China"s Yunnan province, and the first thing that hits you is the air — thin, cool and remarkably clean. The second is the silence. Not an empty silence, but a full one: wind moving through spruce needles, the distant clank of a cowbell, and the rustle of something small in the undergrowth.

　　Potatso is one of China"s earliest national park pilot areas. Its rhythms are slow — ecological change here is measured in decades, not tourist seasons.

　　Wang Guoxian knows this better than anyone. She has been guiding visitors through these forests for nearly two decades. As summer vacation arrives, she has been increasingly busy, taking at least three groups of guests each day across the park"s varied landscapes — a quick tour still takes four hours.

　　"We start at 7 am, and during peak season like now, we don"t finish until 7 pm. But being tired is good — it means visitors are here," she says. Her monthly salary increases by about 3,000 yuan ($444.6) during the peak summer season — enough to make a real difference in the mountainous region.

　　She makes a point of telling guests that the facilities and management have changed over the years.