Greater Angkor: the growth and demise of a giant low-density, agrarian city

Professor Roland Fletcher (University of Sydney) will talk about the recent LiDAR survey of Greater Angkor.

About the lecture

Urbanism in a tropical forest environment and the understanding of the growth and demise of the city of Angkor, in Southeast Asia, between the 7th and the 16th centuries CE,  have recently been redefined by introducing the concept of dispersed, low-density urbanism of agrarian-based societies. Methods ranging from high-altitude remote sensing such as AIRSAR (Airborne Synthetic Aperture Radar) and LiDAR (remote sensory technology), through ground surveys, excavations, dendrochronology, palynology and sedimentology have now been used to study the extent, spatial organisation, economic operation, development and demise of Angkor in its ecological context. 

The Greater Angkor Project, an international collaboration of the University of Sydney (Australia),  APSARA - the Cambodian agency that manages Angkor, and the EFEO (Ecole Française d'Extrême Orient), has demonstrated that the famous temples of Angkor were surrounded by vast suburbs integrated by a road and canal network within a vast low-density urban complex. This is Greater Angkor, covering about 1000 sq km and containing as many as 750,000 people at its peak in the 12th century.

The recent LiDAR survey has shown that the central urban area, with a road grid and numerous small domestic water tanks and house mounds , extends far beyond the walled enclosure of Angkor Thom, and is integrated with the sprawling outer suburbs and their network of road embankments and canals.

Angkor had been shown to have had a massive and elaborate water management network for dispersing water and for distributing it to the fields. This evidence ends more than twenty years of claims to the contrary. Huge masonry structures were built to control water and the canal system is extremely sophisticated. The landscape was re-engineered for agriculture with thousands of square kilometres of rice fields. The natural forest was replaced by an anthropogenic forest of economic trees and shrubs around the numerous timber houses on their occupation mounds, along embankments and within enclosures.

Angkor was seriously affected by severe climatic instability between the 14th and the 16th centuries, and interspersed mega-monsoons and mega-droughts had a massive impact. Huge deposits of sand filled the southern canals in the 14th century. Severe erosion is visible in the LiDAR images of central Angkor. The Siem Reap river is today eroded 5 to 8 m down into the Angkorian ground surface. The demise of Angkor is redefined and the study of this giant low-density city becomes very topical. The results transform the global implications of how large such low-density cities could become and brings together the evidence from the Maya cities of Central America, the Sinhalese cities of Northern Sri Lanka and the Khmer cities of SE Asia. Greater Angkor was an extensive, low- density city which cleared its landscape of natural vegetation, was dependent on an impressive and massive infrastructure, and was affected by severe climatic instability. These conditions have some resonance in the present day.

About the speaker

Roland Fletcher is Professor of Theoretical and World Archaeology at the University of Sydney. He grew up in London, England and attended St. John’s College at Cambridge University where he completed his undergraduate degree in 1970 and his PhD in 1975. He has worked at the University of Sydney since 1976 where he implemented a global, multi-scalar and interdisciplinary approach to Archaeology that integrates research, teaching and service to the community.  His global research has led to extensive cross-disciplinary collaboration both within the University and internationally, in particular on Angkor in Cambodia. The Greater Angkor Project, which has been funded by the Australian Research Council and UNESCO is an international collaboration with the French agency EFEO and with APSARA, the Cambodian government agency that manages Angkor. The project is part of the University’s Angkor Research Program of which he is Director. The program, manages a diverse range of research projects in Angkor and maintains a Research Centre in Siem Reap. As a result of his international collaborative research he has been an invited speaker and academic guest world-wide. In 2007 he was a Distinguished Fellow at Durham University’s Institute of Advanced Study and has recently been invited to the Institute of Advanced Study at the University of Minnesota. 

Major Accomplishments

Archaeological Theory and Philosophy: His work systematically defines the relationship between complementary but different scales of interpretation and explanation and specifies the fundamental role of the non-correspondence between materiality and social life in understanding the outcome of change and the processes of cultural evolution. The approach offers a new perspective on the materiality of human behaviour across a wide spectrum ranging from the evolution of hominid behaviour to industrialised warfare, and from the settlement patterns of hunter-gatherers to the limits of low-density urban growth in the agrarian and the industrial world. The key logical contribution is to reconcile long term, large scale, cross-cultural consistencies of behaviour with the contextually unique, short-term sociality of human communities. This approach has been applied in  a radical global approach to understanding the dynamic of settlement growth and decline in terms of the behavioural impact of material factors on community life and the dissonance with economy, ecology and global environmental processes.

Research on Angkor: The research derives from the predictions of the Interaction-Communication Stress model developed in The  Limits of Settlement Growth. The growth and decline of low-density pre-industrial urbanism is a critical test of the research value of the model which predicts that such settlements could reach vast sizes, far larger than their compact urban counterparts. The key contribution of the work has been to redefine the nature of Angkor as a low-density urban complex, covering about a 1000 sq km and vastly larger than had previously been envisaged. The result transforms the global implications of how large such cities could become, redefines their significance for the present day and integrates the demise of agrarian based low-density urbanism with extreme instability in climate change. This has led to an international collaboration on the Tropical Forest Urbanism Program that has brought Mesoamericanists to Angkor. A key result is the demonstration that Angkor had a massive and elaborate water management network, contrary to twenty years of opposition. In the words of Michael Coe in Science vol 311 (1367) this, “has pretty much laid the debate to rest”. One outcome of the Greater Angkor project has been the applied research of the Living with Heritage Project which has now led to development work on an integrated information management system for APSARA and the establishment of a major heritage consultancy,  the Angkor Management Framework, funded jointly by Cambodia and Australia and managed by the Australian heritage consultants Godden Mackay Logan.