Fan Jinshi
The grottoes in the Dunhuang area comprise the Mogao grottoes, the West Thousand Buddha (Xiqianfo) caves, and the Yulin grottoes near Anxi. Like a great many of the grottoes of China, these are Buddhist temples that were cut into cliffs along river banks. The Daquan River flows past the front of the grottoes.
The Dunhuang grottoes were carved into a conglomerate of the Quaternary Jiuquan system. Because the loose conglomerate rock was not suitable for fine carving, murals and clay-plastered polychrome statues were produced to depict the concepts of Buddhism. Each cave contains a combination of polychrome sculptures, murals, and architectural structures. These artworks were made over a thousand-year period from the fourth to the fourteenth century, when Dunhuang was a sacred center of Buddhism. Among the three grotto sites, 549 caves contain wall paintings and painted sculptures, and more than 250 caves contain other forms of art (Dunhuang Cultural Relics Research Institution; Li Yongning 1981, 1982). Altogether, these sites are of extraordinary artistic, historical, technological, and economic value. The Mogao grottoes in particular are one of the world's most famous large-scale cultural heritage sites. After fifteen centuries, some of the rock temples of the Dunhuang grottoes have undergone severe damage due to historical and natural causes. The cliff rock has fractured, sculptures have fallen over, and paintings have been damaged by flaking, peeling, and salt efflorescence (Fan 1993).
In January 1944, the Dunhuang National Art Research Institute was established by the Chinese government, initiating a new stage in the preservation of ancient relics. Since the 1950s, extensive emergency repairs have been carried out and scientific techniques of preservation applied.
The Pioneering Years (1943-50)
Fifty years ago, in the midst of China's war with Japan, some ten staff members of the Dunhuang National Art Research Institute began the work of preserving the grottoes under the leadership of Chang Shuhong, the institute's director at the time. Conditions were difficult due to limited financial support, lack of equipment, and the remote, windy, and sandy
Environment of China's northwestern frontier. Yet the team accomplished a tremendous amount of work. They constructed an enclosing fence 850 m long to control visitors, connected several caves with walkways, removed sand that had accumulated inside more than three hundred grottoes, removed the clay beds built by Russian refugees who had occupied the caves in 1921, made preliminary renovations, and installed wooden windows and doors in some of the rock temples to protect the artwork from human damage and erosion by blowing sand. In the course of this work, they also discovered six more caves and more than three hundred scrolls of sutras (Dunhuang Cultural Relics Research Institution 1977). For the purpose of site management, they supplemented and developed a new cave-numbering system based on an existing one, made an inventory of the grottoes' contents, produced a written description of the site, organized exhibitions, instituted guided tours, and arranged for security guards to be responsible for the safety of the grottoes. All of these efforts formed the initial framework for the present program of site protection, research, and presentation. All of the protection measures at that time were rudimentary to some degree. Nevertheless, they effectively prevented looting and vandalism of the caves. The eight years of hard work by these pioneers brought to light once more the importance of these cultural treasures to the heritage of the world.
Remedial Conservation Period (1950-80)
Although much work was accomplished during the previous period, deterioration due to either natural or human causes had yet to be addressed. Destabilization of the cliffs, salt efflorescence on the paintings and statues, and deterioration of the roofs of certain caves were advancing at an alarming rate.
In 1950, the Dunhuang National Art Research Institute was reorganized as the Dunhuang Cultural Relics Research Institution (now the Dunhuang Academy), and the first site-management department was founded. A series of comprehensive surveys was carried out to evaluate the impact of the natural environment on the grottoes, the deterioration of the caves and cliffs, features of the architecture, and the condition of existing wooden structures. On the basis of this survey, a comprehensive, full-scale renovation of the Mogao grottoes was begun in 1951.
At that time in China, traditional technology and craftsmanship were being revived. Earlier techniques were thus applied to the restoration of the damaged caves, the removal and replacement of components, the substitution of materials, and the restoration of fallen structures. Five Song dynasty wooden facades of Mogao caves 427, 431, 435, 437, and 444 were replaced and restored to their original shape (Zhao 1955). Rotten wood frames within some statues were replaced, and tilted statues were straightened. Clay was applied to the edges of wall paintings that had separated from the wall, and the paintings were secured with anchor pins and the application of grouting to effectively prevent further detachment. In 1965, experimental reinforcement work on the cliff face was carried out to reinforce a 200 m long middle section of the southern caves 232-260, using
Columns of rock construction and wooden planks. Stabilization of the precarious cliff face, made fragile over the centuries by extensive excavation of the caves in weak strata, was carried out from 1963 to 1966. Stone pillars were used to support overhanging rock at the top of the cliff face, and retaining walls were built to prevent block failure around the crevices. This project resulted in reinforcement of more than 570 m of the cliff face and 358 caves. At the same time, the walkways between caves of the same or different levels were connected, permitting access to several hard-to-reach caves while retaining the simplicity of their external appearance. With available technology, this million-yuan project resulted in the effective reinforcement of the southern portion of the Mogao grottoes to the greatest extent possible (Sun 1994).
Meanwhile, the most recent scientific technology began to be incorporated into the conservation work at Mogao. For example, testing of and experiments on the conglomerate using polymer materials (polyvinyl alcohol and polyvinyl acetate solutions) as adhesives led to the restoration of some of the previously untreatable flaking and salt efflorescence of the wall paintings (Li Yunhe 1993a). To prevent abrasion by windblown sand, experiments were conducted using grass barriers and windbreak fences (Ling 1993). Studies on the techniques of removing and transferring wall paintings were also conducted (Li Yunhe 1993b). The purposes of these studies were to expose the hidden wall paintings and to install paintings that had been removed from remote, endangered sites.
For the long-term protection of grottos from damage by natural processes and human factors while the caves were in use, we took the following remedial measures:
1. Following the ancient practice of building shelters outside and laying floor tiles inside the caves, doors and cement floors were installed in some caves to prevent abrasion from windblown sand and damage due to sunlight, dust, and visitors.
2. Sand and dust that had accumulated in front of and inside the caves were removed to prevent it from further entering the caves and damaging the wall paintings.
3. Weather stations were set up to monitor the environmental patterns around the Mogao grottoes (Sun 1993).
4. Descriptive pamphlets were published and explanatory plaques installed around the grotto site. Visitor regulations were drawn up and tour guides provided to explain the site to the visitors, monitor their conduct, and keep them from damaging the caves.
5. A system of regular grotto inspection was established to detect any damage caused by natural processes or human factors and to facilitate immediate emergency repairs to damaged caves.
Many national laws and regulations regarding the protection of cultural relics, including grotto sites, were formulated and promulgated before the 1960s. They included provisional management regulations and
Procedures, a list of major cultural sites, and temporary procedures for the repair and management of ancient buildings and cave temples. According to the Law and Regulations on Cultural Relics, the Dunhuang grottoes— including the Mogao grottoes, the West Thousand Buddha caves, and the Yulin grottoes—were listed as key national cultural protection sites. The establishment of these laws not only raised the prestige of the Dunhuang grottoes and resulted in society regarding them with greater importance but also put them under legal protection, which promoted and assisted in their conservation.
Renovation at this time consisted of a full-scale emergency repair to save and preserve those caves that were on the verge of collapse, as well as damaged wall paintings and statues. The data gathered during this first stage provided the foundation for identifying and achieving a preliminary understanding of the types of damage present. The conservation and management experience obtained during this period also helped those involved to develop a functional management plan. All these factors served to establish a good basis for entering the scientific stage of conservation work.
Scientific Conservation Period (1980 to Present)
In the previous stage, it was necessary to carry out emergency measures to mitigate against the severe damage threatening the safety of the grottoes and their cultural relics. It was realized that such renovation and reinforcement should be performed only on endangered areas, since unevaluated measures can sometimes lead to harmful side effects and cause further damage. The conservation measures that were undertaken were appropriate to the available scientific technology at the time, and the emergency repairs helped to stabilize seriously threatened grottoes.
Certainly, long-term management and safety of the Dunhuang grottoes cannot be limited to renovation and reinforcement measures; it should focus on scientific conservation with a primary emphasis on prevention. During this phase, therefore, the conservation team formulated a long-term scientific plan, trained conservation technicians, instituted protection measures, adopted advanced technologies, expanded international cooperation, and improved management to ensure greater development of conservation work than in the previous stage. The work carried out during this period emphasized (1) an interdisciplinary approach and the application of advanced technology, (2) scientific research on mechanisms of deterioration and techniques of restoration, and (3) development from microprotection at a local level to macroconservation of the entire site. During this period, the work focused primarily on environmental monitoring and visitor management.
World History
