Research of pine and larch tree-ring anatomy discovered patterns of its variability and climatic sensitivity

10.03.2018

Seasonal dynamics of the timing and rate in cell production and differentiation imprint climate signals into intra-ring variations of anatomical wood structure (e.g. intra-annual density fluctuations). Despite recent methodological advances in quantitative wood anatomy, our understanding of xylem response to climate at the finest scale of intra-ring resolution is incomplete. The goal of this study is to investigate intra-ring changes of tracheid dimensions (cell radial diameter and wall thickness) controlled by moisture stress. Anatomical wood parameters of Pinus sylvestris and Larix sibirica fr om two drought-susceptible locations in Khakassia, South Siberia, were analysed. We found that inter-annual variation of tracheid parameters regularly exceeds the variation between radial tracheid files. This suggests that the climatic signal is recording throughout the entire ring. However, each cell parameter has a specific zone in the ring wh ere its climatic response reaches the maximum. The climatic response of the radial cell diameter has a temporal shift across the ring, which is particularly apparent in pine rings. The climatic response of cell-wall thickness at the intra-ring scale has a more complex pattern. Our results facilitate investigation of the climate impact on tree rings at the finest intra-ring scale by quantifying the timing of climatic impact on ring structure and identifying specifically when climate impacts the formation of a particular cell.

Due to the current climatic change, rapid warming in Southern Siberia leads to increasing severity and frequency of droughts. Therefore, performed analysis of climatic impact on trees on the scale of cells and tissues is important for understanding and forecasting of tree growth and forest dynamics in the region.

Findings of this study are shown in the article “Pine and larch tracheids capture seasonal variations of climatic signal at moisture-limited sites”, which is accepted to publication in the international scientific journal “Trees: Structure and Function”. This journal occupies high positions in ratings of Scopus and Web of Science.