Tree rings are crucial data for revealing tree growth responses to climate and reconstructing climate history. However, current research primarily focuses on coniferous species, with a lack of studies on broad-leaved trees, which dominate tropical and subtropical regions. This is mainly due to the unclear tree-ring boundaries and difficulties in dating broad-leaved species, limiting our understanding of the relationship between radial growth and climate response in subtropical broad-leaved trees. This study successfully established a Cinnamomum camphora tree-ring width chronology spanning 1785–2020 in Le'an, Jiangxi Province, making it the longest camphor tree-ring chronology currently available in China. The tree-ring width of Cinnamomum camphora showed a significant positive correlation with the lowest November temperature of the previous year, indicating that low winter temperatures are a limiting climatic factor for their growth. Our winter low-temperature reconstruction results show that extreme cold periods mainly occurred between 1860–1870 CE and 1890–1905 CE. Afterward, winter temperatures showed a fluctuating upward trend, with periods of decline between 1917–1935 CE and 1948–1963 CE. This temperature change pattern, compared with historical literature and temperature reconstructions from other coniferous species, revealed a high degree of consistency between Cinnamomum camphora and most other coniferous species in terms of climate response changes. This study expands the potential for tree-ring climate research on subtropical broadleaf species and provides important evidence for the dynamic evolution of future forest ecosystems in the region in the background of climate change.
Liu et al. (Sun,) studied this question.