Ronald Towner – “The Forests and the Trees: Sourcing Construction Timbers at Aztec Ruins, New Mexico”

Obtaining materials from distant landscapes is a hallmark of the Chacoan world. For great houses in Chaco Canyon such as Pueblo Bonito and Chetro Ketl, flaked stone, ceramics, and other raw materials were unavailable locally. The movement of materials into Chacon Canyon, and around the Chacoan sphere, has fascinated archaeologists for decades. Large construction timbers, in particular, have been subject to intense research because so few trees grow in or near the canyon today. At the descendent Chacoan center of Aztec Ruins on the Animas in northwestern New Mexico, however, some wood resources, including pinyon pine and juniper were available locally. Other species that only grow at higher elevations, including ponderosa pine, Douglas-fir, and spruce, still must have been imported from mountain ranges at least 20 km distant. Previous studies have used a variety of techniques to source construction timbers to areas more than 50 km distant from Chaco Canyon itself, but the methods are typically time-consuming and expensive. Here I report our research on possible timber sources used in the Aztec great houses using tree-ring width-based sourcing methods. To date, we have sourced more than 300 beams, including archaeological materials sampled 100 years ago by Earl Morris, which were among the first to ever be analyzed at the Laboratory of Tree-Ring Research. We also now have comparable data for great houses both in and outside the canyon, and for different time periods. Our results document surprisingly distant timber sources and a dynamic pattern of shifting resource utilization between the 12^th and 13^th centuries at Aztec East and West Ruins.