Using laser pulses, scientists shed new light on what must once have been a living city.
In recent decades, archaeological research has taught us much more about what scientists also call the “Greater Angkor region.” “An archaeological site near present-day Siem Reap, Cambodia,” says researcher Sarah Klassen. “This area is surrounded by famous temples, such as Angkor Wat, which is actually its center.” Excavations in today’s overgrown area have already provided more information about the Khmer Empire, which resided here between the ninth and fifteenth centuries AD. However, it remained unclear how many people lived in the area around Angkor Wat during the heyday of the empire.
A new study is now changing that. In a magazine Scientific advances Researchers estimate that 700,000 to 900,000 people lived on an area of about 3,000 square kilometers. “Our study covers the period between 800 and 1300,” says Klassen. “And 700,000 to 900,000 would live in this area by the end of this period.”
The new estimate largely depends on new lidar data. These data were obtained by firing laser pulses from the air in the jungle. These impulses move back and forth through the vegetation and then bounce off the surface. By calculating how long it takes for the laser pulses to reach the surface, an accurate map of this surface can be created. “In this way we can ‘see’ the hills on which the buildings once stood. The buildings themselves were made of wood and have long since crumbled.” But the hills are still there and can be visualized in an inimitable way with the lidar. ” “There’s something hidden in the landscape, but you can’t see it clearly,” said researcher Alison Carter.
Using lidar data, scientists have been able to identify thousands of people with altered or engineered surface elements claimed by the jungle over the centuries. “Lidar’s pictures were incredibly important,” Klassen points out. “With the lidar, we were able to map more than 20,000 previously undescribed archaeological sites.” And with that, the total number of sites described increased from 5,000 to 25,000. “
Researchers estimate that each household consisted of an average of about five people. And then they used lidar data to calculate the total population. Their number is between 700,000 and 900,000 people. It’s quite similar to what scientists used to suggest. In addition, based on lidar scans, scientists were also able to say more about how densely different parts of the area were. “I was surprised at how high the population density was on Wednesday,” says Klassen.
The contrast between such a busy city center, which, together with the surrounding area, was home to about 900,000 people, and today’s jungle-covered Angkor could not be greater. The turning point must have been somewhere in the fifteenth century. The area then emptied – for unknown reasons. Archaeologists have previously said that this happened very quickly, but more and more scientists are questioning it. So is Carter. “From our archaeological data, we see that in the sixteenth century, people were still in the landscape and that temples were being modified.” Our study is not designed to determine when people left the area, but it was probably much slower than previously thought. “
Although the research finally provides a little more information about how many people lived around Angkor Wat, scientists are not yet satisfied. “This study is (…) just the beginning,” says Klassen. “Now that we know how many people have lived in Angkor and how that has changed over time, we can begin to ask some very important follow-up questions.” For example: what was the load capacity of the landscape? “Some scientists, for example, suspect that the area has been abandoned because the drinking water supply was under pressure due to population growth. “What happens when so many people gather in one place?”
The answer to these questions is not only important if we want to learn more about the challenges facing the Khmer Empire. Research into these issues is also very relevant to us. “We can use these old cities to learn more about our current cities and shape the cities of the future.” Colleague Miriam Stark agrees; he also thinks that we can still learn from Angkor – certainly in view of the great challenge of our time: climate change. “Angkor was a tropical city that lasted for centuries.” More research on history and breaking point (cities, ed.) Can help urban planners face the challenges more and more cities face. “
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