LiDAR revolution: How a laser tech uncovered hidden archaeological wonders in Samoa

Archaeologists from the University of Auckland made a significant discovery in the Falefa Valley, which may provide insights into the origins of hierarchical societies in Samoa and the broader Polynesian region. Evidence of ancient rock walls, elevated mounds, and ditches has been uncovered within the dense jungle of the valley, offering critical clues regarding ancestral land and social structures in Polynesian culture, as outlined in a recent study.

Linking Population Growth and Social Stratification

This research, led by Associate Professor Ethan Cochrane of Waipapa Taumata Rau, University of Auckland, established links between a notable increase in the Samoan population, the presence of more fertile agricultural land, and the emergence of land demarcation practices alongside social stratification. Professor Cochrane expressed that the findings resonate deeply with local Samoans, who possess extensive knowledge of their land and are now able to compare ancient political and village boundaries identified through archaeological work with contemporary ones and those rooted in oral traditions.

LiDAR Technology: A Game-Changer in Archaeology

The fieldwork conducted in Samoa was facilitated by LiDAR (Light Detection and Ranging) technology, which employs pulsed laser light to gather precise distance measurements, thereby creating detailed topographical maps. This advanced technology is adept at penetrating dense foliage, thereby revealing hidden structures that would typically remain obscured by the forest canopy. Professor Cochrane noted that the use of LiDAR in Samoa is pioneering, allowing for the detailed visualisation of impressive rock walls and earthworks that date back between 600 and 900 years.

Surviving Harsh Conditions to Uncover Hidden Structures

The expedition proved to be quite challenging, characterised by harsh weather conditions and encounters with various environmental obstacles. Nonetheless, the structures uncovered represent remarkable architectural achievements. Some of the formations were identified as family dwellings constructed from stone and earth, akin to the contemporary dwellings observed in some Samoan villages, while others appear to have been civic or ceremonial in nature. Among the noteworthy structures were ‘star mounds’, standing up to two metres tall, which may have been used for hunting pigeons, a pursuit esteemed among the chiefly class.

Collective Action: A Response to Population Pressure

This study, conducted in collaboration with the National University of Samoa and with the consent of local villages, is the first to correlate the timing and motivations behind the construction of these ancient edifices with what Professor Cochrane describes as a ‘collective action problem’. The findings indicate that the establishment of extensive rock walls, which delineate land usage and incorporated irrigation systems for optimising agricultural output, was a direct response to the substantial population increase observed in Samoa approximately 900 years ago.

Land Fencing and the Rise of Resource Competition

The research posits that shared resources can diminish individual benefits, leading communities to seek strategies to secure access to vital resources. Following the population surge in the valley, groups began to fence off fertile areas to preserve exclusive access to these valuable lands, particularly in the western and northern regions, as substantiated by soil sample analyses.

Global Implications for Understanding Social Evolution

Professor Cochrane further suggests that the current chiefly system in Samoa, reflective of broader Polynesian social structures, may have been established on the basis of early land access disparities, a phenomenon that could also elucidate similar societal developments observed globally. The research raises compelling questions about the evolution of hierarchical societies over millennia, considering that around 20,000 years ago, human communities were largely egalitarian, with minimal distinctions in social status among hunter-gatherer societies. Today, societal structures depict a striking contrast, often characterised by significant discrepancies in power and status.