Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [332]
A second benefit of Lake Tonle for nearby Angkor’s inhabitants was as a transport artery to the Mekong River and the sea. The remaining advantage was the lake’s high biological productivity, supporting per cubic yard the greatest concentration of freshwater fish in the world, thanks to the sediments carried into the lake each year with the Mekong River floods. An early French visitor to the lake wrote, “The fish in it are so incredibly abundant that when the water is high they are actually crushed under the boats, and the play of oars is frequently impeded by them.” The lake accounts for most of Cambodia’s fisheries today, supplies most of the dietary protein of Cambodians, and is responsible for their enjoying one of the world’s highest levels of fish consumption.
While rice was the food staple of the Khmer in the past as it is of modern Cambodians, much of the Cambodian plain rates as land of only medium to poor quality for growing rice. The soils are mostly sandy and low in nutrient content. Of the three main methods for growing rice in Cambodia, one, practiced especially in hilly uplands, is swidden, or slash-and-burn, agriculture, wholly dependent on rain falling on the fields for watering the crop. The second and most extensive method, but still not especially productive by Chinese and Japanese standards, is rice paddies on flat terrain flooded by rain. The most productive method, which yielded most of the rice consumed by the ancient Khmer, is termed flood-retreat farming: rice is planted in fields into which water stored in upstream impoundments is released.
Thus, Angkor’s environment offered some advantages—especially those associated with the lake, and with the large area of flat plain available in the Lower Mekong Basin. But it also posed problems. The Khmer solved those problems brilliantly for many centuries, thereby succeeding in establishing a great city and empire, but eventually became defeated by the problems.
Who are the Khmer, and how did their empire arise? Today the Khmer constitute 90% of Cambodia’s population, and they already dominated the area of Angkor at least 1,400 years ago, to judge from preserved Khmer inscriptions on stone. The Khmer language belongs to the Austroasiatic language family, consisting of about 150 languages spoken in scattered areas from India to North Vietnam and the Malay Peninsula and mostly surrounded by speakers of other language families (especially the Sino-Tibetan and Tai-Kadai families). That fragmented distribution suggests that the latter two families have been encroaching on Austroasiatic lands, and indeed we know that the Thais and Vietnamese have been expanding in historic times. The only other Austroasiatic language besides Khmer likely to be familiar to most readers of this book is the distantly related Vietnamese language, which has become much more heavily modified through contact with Chinese (e.g., in becoming a tonal language) than has the Khmer language.
Until as recently as 5,000 years ago, all peoples of tropical Southeast Asia were stone tool-using hunter-gatherers, as was formerly true of everybody everywhere in the world until the origins of agriculture. Rice farming reached Cambodia from southern China by 2000 B.C., and the subsequent arrival of efficient iron tools around 500 B.C. fueled increased food production and a population explosion. By around A.D. 200, archaeological excavations in Cambodia revealed the existence of modest-sized towns and small kingdoms. From A.D.