The Curious Douglas-Fir (Pseudotsuga Menziesii) Trees in Schulman Grove, Mesa Verde National Park, Southwestern Colorado, USA

In 1954, archaeologists James Allen Lancaster and Don Watson and dendrochronologist Edmund Schulman asserted that a small grove of Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco var. glauca [Beissener] Franco) trees in Navajo Canyon on the west side of Chapin Mesa in Mesa Verde National Park contained evidence of stone-axe-cut tree limbs. In 1965, archaeologists Robert Nichols and David Smith published an article entitled “Evidence of Prehistoric Cultivation of Douglas-Fir Trees at Mesa Verde,” in which they supported the Lancaster/Watson/Schulman assertion with tree-ring dates from suspected stone-axe-cut limbs. If correct, Nichols and Smith (1965) document the only trees in the entire U.S. Southwest that contain ancient stone-axe-cut stubs and evidence of precolumbian forest management. Rather than accept their interpretations at face value, we attempt to replicate their dates through the (re)analysis of archived and recently collected tree-ring samples, and through a controlled analysis and comparison of archived and published records. We could not confirm their results, and we have no option but to reject their claim that Schulman Grove contains evidence of precolumbian tree manipulation by Ancestral Puebloan inhabitants of Mesa Verde.