Salinization of a Mid-Atlantic coastal forest: A comparison of tree-ring growth response to climatic variables in high and low elevation Juniperus virginiana chronologies at the St. Jones Reserve in Dover, Delaware

Keywords: Dendrochronology, sea level rise, coastal forest ecology
Session Type: Virtual Paper Abstract
Day: Monday
Session Start / End Time: 2/28/2022 09:40 AM (Eastern Time (US & Canada)) - 2/28/2022 11:00 AM (Eastern Time (US & Canada))
Room: Virtual 41

Abstract

Coastal forests in the Mid-Atlantic region are threatened by sea level rise through chronic and episodic salinization and hydrologic alterations, leading to inland marsh migration and the creation of ghost forests. This study uses dendrochronology to explore the growth impact of rising sea level on Juniperus virginiana (Eastern red cedar) at the St. Jones component of the Delaware National Estuarine Research Reserve in Dover, DE. High and low elevation chronologies were developed, and a difference chronology (high-low) was generated. The elevation-gradient boundary was selected based on cessation of tree regeneration and tree stress, determined through rapid field assessment. Soil tests confirmed higher soil moisture and salt content in the low elevation forest soil compared to high elevation. Ring width indices were compared to water level, precipitation, SPEI, and temperature with full and partial Pearson’s correlation analysis at various time lags. Trees growing at low elevation were more climate sensitive, presumably due to greater stress, responding favorably to cool, wet summers. Throughout the study period, correlations between growth and climate variables decreased while negative correlations with water level strengthened. Tree growth in the low elevation population became driven by water level decades earlier than those growing at high elevation. Given the widespread distribution of Eastern red cedar and its sensitivity to sea level, this species may be particularly useful as a sentinel of change in coastal landscapes as climates change and sea levels rise.