2023 140 ENV

Mass Measurements of Coast Redwood (Sequoia sempervirens) Cell Structure Inform Understanding of California Climate Variability

By: Triana Anderson

Department: Earth & Climate Science

Faculty Advisor: Dr. Alexander Stine

Increasing amounts of research indicate that measuring cell-anatomical geometry can improve our capacity for making inferences about past climate using records from trees (Gärtner et al., 2015; Crivellaro & Büntgen, 2020). Traditionally, dendroclimatology has consisted of measuring the width of individual tree rings and relating the variation in those widths to climate fluctuations. Width is an aggregate variable that can incorporate multiple growth responses to the surrounding climate and depends on an understanding of a tree's most limiting growth factor, which is often assumed to be constant in time. In contrast, the use of cell anatomical measurements has the advantage of allowing an investigation into discrete components of climate (for instance both temperature and precipitation) that have been tied to specific components of tree growth both theoretically and empirically (Castagneri et all 2017, Tyree and Zimmerman, 2002). The ability to take mass measurements of cell properties has required innovation in tree core preparation, imaging, and image processing methods, and training of an AI system to detect and make mass measurements of cells. This process has been used to take cellular measurements of coast redwood trees from Humboldt County, California. An investigation into Coast Redwood is of particular interest given that they depend on fog for a significant portion of their yearly water input. Because of this dependence on fog, variations in cell anatomy over time have been used to reconstruct a proxy record for past moisture variability. These records will inform our understanding of how California coastal climate may change as the planet warms.