Jiuzhaigou, the "Valley of the Nine Villages" (Sicadegu in Tibetan), earns its name from the Tibetan settlements that for centuries were the only significant human presence this once-remote region. The Tibetans long shared the valley with small groups of Qiang, one of the PRC's 56 officially recognized ethnic minorities, but little trace of the Qiang remains in Jiuzhaigou today.
The valley remained in isolation until the early 1970s, when its rich forests began to attract loggers. Fortunately for today's visitors, logging stopped in 1979. In 1982, the government declared the area a national park, and by 1984 planning was underway to develop it as a tourist destination. In 1992, UNESCO named Jiuzhaigou a World Heritage Site and, in 1997, a World Biosphere Reserve. Today, the park is carefully protected, with all major tourist infrastructure and development being relegated to Nuorilang, Zhangzha, Jiuzhaigou Town and other settlements outside the protected zone.
Today's indigenous inhabitants, the Tibetans of the original "Nine Villages," are forbidden to pursue agriculture or animal husbandry within the park and, as a result, make their livings in the tourist trade. You can view the remaining settlements of Heye, Shuzheng, Zechawa, Rexi and Heijiao, but you should remember that these are long-standing living communities, not simply tourist attractions featuring "exotic" Tibetans, and you should respect them as such. However, the locals are often more than indulgant of tourist wishes; Shuzheng is a particularly popular place to don Tibetan clothing and get pictures taken.
Jiuzhaigou has proven incredibly appealing to tourists, drawing over 7,000 visitors a day on average, and well over 10,000 a day during the high season. Along with nearby Huanglong Park, it has become one of China's top natural attractions.