Tree ring oxygen isotope dating of wood recovered from a canal in the ancient capital of Japan
Year: 2022
Type: article
Abstract: Trees growing in the lowlands of Japan are not climatically stressed; consequently, ring-width patterns are weakly correlated between different trees. Therefore, dendrochronological studies in Japan based on ring widths rely largely on climatically stressed conifers growing in mountainous regions and/or at higher latitudes. In contrast, oxygen isotope ratios (δ18O) are well-matched between trees, irrespective of climatic stress, indicating that the huge amounts of wood excavated in Japan could potentially be dated. Here, we tested oxygen isotope dating using unearthed stumps (Abies sp., Quercus sp., and Zelkova serrata) from Japan, which historical documents and archaeological evidence suggest date from 708 to 715 CE. A new 2470-year master chronology based on Japanese cypress samples (mainly Chamaecyparis obtusa) was developed, and our dating method was evaluated using modern samples collected from several species (Tsuga, Picea, Taxus, Pinus, and Quercus) across Japan and Korea. Our chronology was then used to date stumps recovered from the bank of a canal, which was constructed when Nara became the new capital city of Japan (Heijō-kyō in Japanese). Even though the samples had only 30–60 rings and comprised multiple species, including broad-leaf trees, their tree ring δ18O patterns were successfully cross-matched. The resulting site chronology was robustly dated against the master chronology, indicating that the felling dates of the stumps ranged from winter 697/8 to 709/10 CE. Overall, the dates are consistent with previous findings, but our study provides exact calendar dating related to the construction of the new capital, and demonstrates that oxygen isotope dendrochronology works well in Japan.
Authors: Masaki Sano, Zhen Li, Yumiko Murakami, Megumi Jinno, Yoko Ura, Akihiro Kaneda, Takeshi Nakatsuka
Language: English
Topic: Tree-ring climate responses
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,130
Awards: Interdisciplinary Approach to the "Crisis of the 14th Century", G6230054988, Intra-annual tree-ring analysis for precise dating and climate reconstruction, Reorganization of prehistorical structure of calendar age and evaluation of climate change effect in Japanese archipelago using tree ring oxygen isotope ratios, G7344925023, Advancement of the new dendrochronological method using oxygen isotope ratios, Quantification of the climate-productivity-population history in Japanese archipelago by refinement of oxygen isotope dendrochronology, Development of a new dendrochronological method using oxygen isotope ratios and its archaeological applications
OpenAlex ID: W4297755658