Tracheid anatomy of Cryptomeria japonica grown in a humid temperate region: A proxy for short-term climate variability and a crossdating index

Abstract

The tree and site selection principle established for dendrochronology and its subfields has long been used as a standard reference for maximizing the climatic signal recorded in ring widths. However, this principle suffers from its stringent restrictions on available tree species and age, and a minimum number of ring widths. Additionally, a limitation of using ring widths is that it fails to capture the detailed responses to signals from short-term climatic variability preserved in wood chemistry and cellular anatomy. Recently, stable isotope and quantitative wood anatomy have shed light on these perspectives, enabling the extraction of climatic signals even from specimens that were previously considered unsuitable. This study aims to evaluate the potential of quantitative tracheid anatomy in Cryptomeria japonica trees of approximately 70 years of age from a humid-temperate region, Ashiu Forest Research Station, as a proxy for climate signals and a crossdating index, despite being suboptimal under conventional dendrochronological principles. Specifically, lumen radial diameter and cell wall thickness were analyzed for the period between 1965 and 2016. According to a correlation analysis, daily precipitation in July (rainy season) of the current year was highly correlated with the lumen radial diameter (r = 0.71). The lumen radial diameter was also useful for reliably crossdating (Student’s t-value = 7.34) C. japonica specimens from 1965–2016 that could not be crossdated by ring widths. The study findings suggest the possibility that tracheid anatomy of C. japonica may serve as a proxy for climatic variability and a crossdating index in humid-temperate regions.