In MemoriamHarold Clark Fritts 1928–2019

Harold C. Fritts [known to many as “Hal”] passed away at his home in Tucson, Arizona, on January 10, 2019, at the age of 90. Hal was born December 17, 1928, in Rochester, New York, and was raised in the town of Pittsford where he developed a growing interest in nature. He attended Pittsford High School where he graduated as class salutatorian in 1947. Hal then enrolled at Oberlin College in Ohio where he earned his B.A. degree in 1951. Hal went on to graduate school at Ohio State University in Columbus, where he was awarded his M.Sc. in 1953 (Thesis:Radial Growth of Beech Trees in a Central Ohio Forest during 1952) and Ph.D. in 1956 (Dissertation: Relations of Radial Growth of Beech (Fagus grandifolia Ehrh.) to Some Environmental Factors in a Central Ohio Forest during 1954-55), both in botany. The primary instrument of his dissertation research was the “dendrograph” [named the Fritts-Dendrograph], developed with the help of his father, an engineer. One year before completing his Ph.D. Hal married his first wife Barbara June Smith. Hal took his first academic post as Assistant Professor at Eastern Illinois University in 1956. In 1960, he was appointed Assistant Professor of Dendrochronology at the University of Arizona, Laboratory of Tree-Ring Research (LTRR). His hire followed not long after the untimely death of LTRR Prof. Edmund Schulman in 1958. His early work examined intraand inter-annual treering growth of western conifers, aided by his dendrographs and cambial sampling. Moreover, he developed conceptual models of how various environmental factors could influence cell formation, maturation, and ring size, and eventually he began developing computer models of growth. This culminated in an advanced process model, TREERING, developed with Russian colleagues. These collective activities are tied to one of Hal’s enduring contributions to dendrochronology, namely that he injected scientific and computational rigor into the field and provided convincing quantitative validation to the underpinnings of dendrochronological principles. To this end, Hal also introduced