Dynamics of the Thirteenth-century Depopulation of the Northern San Juan: The View from Cedar Mesa

Abstract

Tree-ring dates and ceramic seriations are used to refine the chronology of Pueblo depopulation of the Cedar Mesa-Natural Bridges area of southeastern Utah. The early to mid-1200s saw increased occupation in the canyons, but mesa settings continue to be inhabited throughout as well. Wood-cutting for construction tapers off in the 1250s and ends in the 1260s, well before the onset of 1276–1299 “great drought.” Factors contributing to the depopulation are reviewed, including regional evidence for shorter growing seasons. Widespread warfare may have motivated people to leave areas of low population density, such as Cedar Mesa, to join the more secure large settlements that continued to grow in southwestern Colorado, even as overall population in that area began to decline.

Fechas de anillos de crecimiento y seriaciones cerámicas son usadas para refinar la cronología del abandono poblacional Pueblo del área de Cedar Mesa-Natural Bridges del sureste de Utah. Durante principios y mediados de los años 1200s la región experimentó un incremento en la ocupación de los cañones, pero los altiplanos también continuaron siendo habitados durante este periodo. La tala de árboles para construcción disminuye gradualmente en los 1250s y termina en los 1260s, mucho antes del comienzo de la gran sequía de 1276–1299. Son revisados factores que contribuyeron al abandono poblacional, incluída evidencia de periodos de cultivo cortos. Guerras generalizadas pudieron haber motivado a la gente a abandonar áreas de baja densidad poblacional, como Cedar Mesa, para unirse a los más seguros grandes asentamientos que continuaron desarrollándose en el suroeste de Colorado, incluso cuando la población de esa área comenzó a declinar.

KEYWORDS:

• Pueblo III depopulation
• Ceramic seriation
• Tree-ring dates
• Multidimensional scaling
• Warfare
• Northern San Juan

Acknowledgments

Thanks to Mark Varien, Steve Nash, and Tom Windes for sharing tree-ring data, to Scott Ortman for help compiling the tree-ring data, and to Jamie Merewether for making available Hegmon's attribute analysis data that are curated at the Crow Canyon Archaeological Center. Two reviewers made comments which allowed us to improve this paper; we thank them. Curewitz' application of Hegmon's methods to CMP rim sherds and new tree-ring dates from the Sheiks Flats area of CM were supported by a grant to Matson from the Social Sciences and Humanities Research Council of Canada [410-2008-1677]. Figures 1–3 and 6–10 were drafted by Susan Matson, and Figure 5 by Kelsey Reese. Rodrigo de los Santos Alamilla prepared the Spanish version of the Abstract.

Notes

1 Also see reviews of the tree-ring evidence by Varien (2010) and Berry and Benson (2010).

2 The stem-and-leaf plots from Cedar Mesa include 22 dates recently obtained by Tom Windes from sites in the Slickhorn Canyon and Sheiks Flats area of Cedar Mesa (Windes 2014). Windes used field observations to evaluate the likelihood that the latest ring on each sample represented the death date of the tree. For this set of 22 samples, we used Windes' assessments, rather than the somewhat more conservative ones assigned by the Laboratory of Tree-Ring Research.

3 Only cutting or near-cutting dates (Laboratory of Tree-ring Research codes B, G, L, r, v, +B, +G, and +r—see Ahlstrom 1985) are included in Figure 5 histograms. Data are standardized so no site contributes more than 20 dates to this compilation (the Moon House complex is considered as a single site).

4 One of the wood samples from site NR C17-2 (42SA4564) yielded a non-cutting date of 1274vv, and two other samples had dates of 1379vv. The site notes describe these as small pieces of heavily weathered wood found together in a small pile in the sheltered portion of the site. They may be the result of someone bringing dead wood into the shelter with the intent of using it in a campfire. The latest archaeologically relevant date from the site is a cutting date of 1259B from an in situ construction beam.

5 Field numbers are used for sites throughout the paper. Tables correlating field numbers with Utah state (42SA) numbers can be found at <http://hdl.handle.net/2376/2775>.