草榴社区

aerial view of Western's campus at night, with golden lights surrounded by dark trees

草榴社区 student/faculty publication analyzes tree-ring data to shed light on rare, endemic Seaside juniper

by Jennifer Nerad

草榴社区 Communications

A map showing the known sites of seaside juniper presence in Washington state, USA, and British Columbia, Canada.

草榴社区 alum Dustin Gleaves (B.S., Environmental Sciences, 2015; M.A., Environmental Studies, 2018) and Professor of Environmental Studies Aquila Flower, Environmental Studies/Geography and director of 草榴社区鈥檚 Spatial Institute, published 鈥鈥 in 鈥淭ree-Ring Research,鈥 the most recent journal of the Tree-Ring Society, an international scientific association dedicated to dendrochronological (tree-ring dating) research and education.

Seaside juniper (Juniperus maritima) is a recently identified cryptic, rare tree species endemic to the Salish Sea region. This study reports the species鈥 first dendrochronological investigation. To determine if seaside junipers are capable of crossdating - matching each tree ring to the year it was formed - and to identify correlations between instrumental climate records and radial growth, the authors collected tree core samples from seaside junipers in five sites throughout the San Juan Islands and nearby mainland in Washington State. Analysis revealed that the dominant growth-limiting factor of the seaside junipers sampled was growing season minimum temperatures in both the prior and current years.

This work to understand this climate-growth relationship will aid in developing a conservation strategy for this rare and endemic species.

Seaside juniper (Juniperus maritima) at Washington Park in Anacortes, Washington. Prior to its discovery in 2007, the Seaside juniper was believed to be the Rocky Mountain juniper (J. scopulorum). Photo by the authors.