Differentiating aspen and cottonwood in prehistoric wood from Chacoan great house ruins

Accurate taxonomic identification is an essential part of archaeological wood analysis. However, making identifications more precise than the genus level is usually not possible since species within the same genus typically possess very similar cellular morphology. This paper describes a method for distinguishing aspen (Populus tremuloides) from cottonwood (Populus fremontii, Populus angustifolia, Populus acuminata) in samples of wood collected from the San Juan Basin in northwestern New Mexico and southwestern Colorado. This method is then applied to archaeological wood samples from the Anasazi great house at Aztec Ruins National Monument in Aztec, New Mexico. The results of this study demonstrate that quantifiable differences do exist between aspen and cottonwood species and that the technique can be used to separate archaeological specimens of Populus wood.