In a recent study published in the journal "Contemporary Biology," Associate Researcher Zhang Yaling from the South China Botanical Garden of the Chinese Academy of Sciences, together with Professor Huang Jianguo, a distinguished professor from the School of Life Sciences at Zhejiang University, collaborated with 28 research institutions worldwide to reveal, for the first time, the response of forest woody phenology to temperature fluctuations on a hemispheric scale.
The journal also featured a commentary by Paolo Cherubini, the honorary editor-in-chief of the flagship journal Dendrochronologia, praising the study as "filling a gap in the feedback between tree growth and climate variability," offering "a new perspective for plant physiologists, forest ecologists, and climatologists." This recognition underscores the significant advancement this research brings to the respective disciplines.
Supported by funding from the National Natural Science Foundation of China and other international projects, this study engaged in international collaboration with 45 researchers globally. Utilizing dendrochronological methods, the researchers monitored woody phenology in 20 coniferous tree species across 75 study sites spanning the northern hemisphere (23-66°N) and encompassing boreal, temperate, subtropical, and Mediterranean regions. Further analysis revealed a convergence phenomenon in woody spring phenology with increasing temperature fluctuations. Specifically, wood cells tended to enlarge around June 5th, with cell wall thickening beginning around the summer solstice.
Notably, the traditional Chinese solar term "Grain Buds" typically begins around June 5th, coinciding with the onset of increased rainfall in most northern hemisphere regions. Enlargement of wood cells requires adequate moisture for turgor pressure. Meanwhile, cell wall thickening relies more on plant photosynthates, benefitting from the peak sunlight around the summer solstice, enhancing photosynthesis. Researchers suggest that under conditions of high temperature fluctuations, representing unpredictable environmental conditions, trees tend towards a relatively conservative growth strategy, favoring predetermined time points with sufficient water and light to initiate woody growth.
These findings suggest that under the backdrop of frequent extreme climatic events and increased temperature fluctuations globally, forest woody spring phenology may converge, initiating wood cell enlargement and thickening around June 5th and the summer solstice, respectively. This implies that forests may not respond to climate warming to the extent anticipated and that phenological convergence may increase competition among trees for resources such as water and nutrients, thereby affecting forest structure and productivity.
This groundbreaking research fills a crucial gap in understanding how temperature fluctuations in the northern hemisphere affect forest woody spring phenology, providing valuable insights for improving assessments and predictions of carbon balance at large spatial scales in forests.
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