Tracing Ancient Solar Cycles with Tree Rings and Radiocarbon in the First Millennium BCE
First published: 2025
Brief summary
Annually resolved tree-ring radiocarbon record from the first millennium BCE reveals the 11-year solar cycle using Fourier transform and Lomb-Scargle periodogram analysis, plus a secondary 22-year Hale cycle signal.
Article
Tracing Ancient Solar Cycles with Tree Rings and Radiocarbon in the First Millennium BCE is a peer-reviewed journal article published by Nature Communications in 2025. It analyses an annually resolved tree-ring radiocarbon record from the first millennium BCE and reveals the 11-year solar cycle using Fourier transform and Lomb-Scargle periodogram analysis, plus a secondary 22-year Hale cycle signal.
The analysis focuses on 10.6 years (main peak), 10.3 years (secondary peak), ~22 years (Hale cycle). The data source is annually resolved tree-ring radiocarbon (delta-14C) record. It also considers FFT and Lomb-Scargle periodogram analysis with confidence thresholds shown. This gives the cycle claim a specific numerical and evidential setting rather than presenting periodicity only as a visual impression.
The authors observed a main significant peak at the period of 10.6 years accompanied by a smaller peak at 10.3 years when analysing the full record, along with several significant peaks around 22 years corresponding to the Hale cycle. The interpretation is strongest when species differences, site conditions, age effects and environmental covariates are controlled and the rhythm is reproduced independently.
For cycles researchers, the article brings together tree-ring radiocarbon, ancient solar cycles, schwabe cycle, hale cycle. It is relevant to botanical cycle research because plant growth and physiology can preserve or respond to environmental rhythms across daily, seasonal and multi-year time scales.
Because it is a peer-reviewed journal article, the article is a strong starting point for discussion in the Botany forum, although its conclusions should still be compared with later replications and updated datasets.
Source details and credits
- Source / publisher: Nature Communications
- Source type: Peer-reviewed journal article
- URL type: WWW
- Credits: Nature Communications
- URL: https://www.nature.com/articles/s41467-024-55757-y