In late June this dusty small town, an oasis in the Gobi Desert that sprang up hundreds of years ago as a stop on the Silk Road, drew more than 200 art conservation experts from around the world. They came to advance the cause of preserving and managing the Mogao Grottoes, 492 cave temples carved into a cliff face about 15 miles outside Dunhuang between the 4th and 14th centuries and covered with elaborate Buddhist wall paintings portraying visions of heaven and earth in ancient China.
With China's economy expanding and tourism growing even faster, insiders and outsiders worry that China will not take the time and trouble, or have the resources and expertise, to preserve its rich cultural heritage. Much has already been lost.
But success in Dunhuang would help lead the way for other Chinese sites. ''The tension between economic development and conservation is everywhere, and it's very serious,'' said Huang Kezhong, former deputy director of the China National Institute for Cultural Property. Fan Jinshi, director of the Dunhuang Academy, the guardian of Mogao, added, ''Most frequently, it's the cultural site that loses the battle.''
For Ms. Fan, a petite, feisty archaeologist said to rule the academy with an iron hand, the challenges come as much from the biting winds, sand, salt and water as from the growing ranks of tourists and the rapid development of this remote outpost. Still, with its comprehensive approach to managing the site -- including conservation labs, scientific and environmental research arms, fine arts and archaeology institutes, publications and exhibitions units -- ''it's a model for the whole of China,'' said Li Yang, deputy governor of Gansu province. The caves -- stretching in tiers for about a mile across the light gold face of Singing Sand Mountain -- had long been abandoned and were largely unknown until about 1900, when a Daoist monk discovered a huge trove of manuscripts in what is today known as the Library Cave. Locals paid little attention.
Once word about the honeycomb of caves filtered back to Europe, however, archaeologists and adventurers began to arrive. The caves were damaged; some had collapsed, in whole or in part. But inside, the explorers found a hidden world of Buddhist art: sculptures of Buddha, bodhisattvas and warriors as well as detailed murals depicting paradise and of daily life in rich shades of blue, green, brown, red and black.
Soon ''foreign devils'' were paying a pittance to haul away poems, prayer sheets, commercial records and even the wall paintings. (Most now reside in museums in London; Paris; St. Petersburg, Russia; New Delhi; and at Harvard in Cambridge, Mass. Repatriation is part of the Dunhuang Academy's long-term goal.)
By 1944 officials had recognized the caves' importance, establishing the academy. During the Cultural Revolution, Mogao was protected by no less than Zhou Enlai, said Richard A. Englehardt, regional adviser for culture in Asia and the Pacific for Unesco, which made it a world heritage site in 1987.
After China opened its doors to foreigners in 1978, conservation experts arrived from Japan, Britain, Australia, Italy and the United States. The Getty Conservation Institute, an arm of the Getty Trust in Los Angeles that was a co-sponsor of the recent conference with the Dunhuang Academy, started working here in 1988.
The task was huge. The Getty's work alone has several aspects. To stall sand erosion, it installed a mesh fence that reduces wind speed by 50 percent and helped arrange the planting of grids of straw and branches in the desert dunes. Then the Getty adopted Cave No. 85, where it has done extensive work analyzing water and salt damage to the murals. To save the wall paintings, the Getty has developed a process that removes some salt from the cave walls and readheres the mural plaster.
Even after years of work, only about 40 caves are accessible, on a rotating basis of 10 to 12 a day, to tourists whose numbers have grown to more than 300,000 a year from about 50,000 in 1980, the year after Mogao opened to the public. Most visitors crowd into the caves during summer, quickly increasing the temperature and humidity and adding to the mural damage.
''The scale of the site is so vast that there is conservation work for generations to come,'' said Neville Agnew, the Getty's top Mogao project specialist.
Nevertheless, the Dunhuang Academy's achievements have made its reputation around China. ''There is a tremendous demand on the Dunhuang Academy to help other areas on cultural protection,'' Mr. Huang said. Kuqa and Kizil, two cave sites on the Silk Road in Xinjiang Province, have asked for help, he said, as have three sites in Tibet that need expertise with the preservation of cave paintings and the Shaolin Monastery in Henan Province. The Dunhuang Academy has also set up an educational training course for northwest China.
''There is almost an endless line at their door asking for help,'' Mr. Huang said.
Preservation experts are hopeful about Dunhuang as a model for another reason too. It is one of the first two sites in China -- the other being Cheng De, the Qing dynasty summer resort north of Beijing -- to follow what are known as the China Principles. These heritage preservation guidelines were drawn up by China's State Administration for Cultural Heritage, along with the Getty Conservation Institute and the Australian Heritage Commission, and adopted in 2000.
The China Principles, which generally update existing international conventions, enshrine conservation principles and mandate an interdisciplinary management process. They require a master plan that, for example, researches and sets visitor capacity limits.
These guidelines have now largely been disseminated to the provinces, which are responsible for most heritage sites. But several experts at the conference said that many local officials appeared to be ignorant of them.
China has ''made great progress in training conservationists and establishing many legal systems in heritage conservation at different levels,'' said Tong Mingkang, a deputy director of the State Administration for Cultural Heritage. ''We now have a full, complete set of legal principles. The government has spent lots of money at different levels, and these achievements make us very proud.''
But he conceded, ''We need to adopt various measures to implement the China Principles.'' There is no enforcement mechanism for the standards.
Zhang Webin, a former director of China's heritage administration, was even harsher. ''We still lack a strategic plan,'' he said. ''Some don't understand the depth of conservation. We need to train professionals, particularly professionals with foreign experience. We need to have a complete law system.''
In the meantime experts are looking to the Dunhuang Academy, an appropriate view for perhaps more than one reason. Dunhuang means ''blazing beacon.''