Dendrochronology: The Scientific Discipline Created in Flagstaff

One of the most significant scientific disciplines was created right here in Flagstaff. Dendrochronology, the study of tree rings and their connection to environmental conditions, has been observed by humans for centuries, dating back to the ancient Greeks (Sheppard 2010). It wasn’t until Andrew Ellicott Douglass, who travelled to Flagstaff in 1901 to assist with the construction of an observatory founded by astronomer Percival Lowell, that dendrochronology became a significant scientific study. Douglass had many scientific interests interconnected with astronomy, a significant area of his research included the study of the earth’s climate and effects of sunspots (Dean 2012). In order to properly analyze climate, he was searching for a scientific discipline to create a weather record database stretching back long enough to reveal significant patterns. It was here, in the dry climate of the Southwest, biologically diverse with a landscape of ponderosa pine trees, that Douglas hypothesised that tree growth is directly correlated with climate, specifically rainfall. He researched the variation of tree-ring width and observed that these variations matched among trees from a large area, known as crossdating (Dean 2012). Thus, the potential of dendrochronology was realized and led to further scientific research through dendroclimatology and archeological dating. STEM City is proud to share our abundantly rich STEM community that has influenced advances in the study of climate change and archeological research.  

Written by Kelly Randazzo

Literature Cited
Dean, J. S. (2012). Trees, Time, and Environment. In C. E. Downum (Author), Hisat'sinom: Ancient peoples in a land without water (pp. 35-36). Santa Fe: School for Advanced Research Press.
Sheppard, P. R. (2010). Dendroclimatology: Extracting climate from trees. Wiley Interdisciplinary Reviews: Climate Change, 1(3), 343-352. doi:10.1002/wcc.42

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