This week, on July 5, we celebrate the birthday of A. E. Douglass who was born in 1867. Although an astronomer by training, Douglass is incredibly important to the field of arboriculture. He is known as the “Father of Dendrochronology,” a method of determining a tree’s age based on its rings. He observed a correlation between tree rings and the solar magnetic activity cycle and his research further went on to help detect climate changes from year to year within the tree, as rainier years often produced more growth, hence a wider ring. Dendrochronology has also been used to date archeological and sites and artifacts. Douglass started his astronomical research at the Lowell Observatory in Arizona and then went on to the University of Arizona, where the Laboratory of Tree-Ring Research (LTRR) continues his work.
For more information about dendrochronology at the LTRR, please visit: http://ltrr.arizona.edu/about/treerings