Contribution of Xylem Anatomy to Tree-Ring Width of Larch in Permafrost and Non-Permafrost Zone of Siberia

• Published in: Forests
• Main Authors: Margarita I. Popkova, Vladimir V. Shishov, Eugene A. Vaganov, Marina V. Fonti, Alexander V. Kirdyanov, Elena A. Babushkina, Jian-Guo Huang, Sergio Rossi
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2020
• Subjects: tree-ring structure; latewood; earlywood; number of cells; cell diameter; cell-wall thickness; Plant ecology; QK900-989; permafrost; Siberia
• Online Access: https://doi.org/10.3390/f11121343; https://doaj.org/article/a2e3f87ebb9f4c3db80386e91274151f

Due to adaptation plasticity to climate conditions, some tree species are widespread. How can mechanisms for adapting to contrasting environmental conditions change the patterns of tree rings formation? In this study, we explored differences in climatic conditions of permafrost and non-permafrost zones to estimate their influence on radial growth of Larix sibirica L. and Larix gmelinii Rupr (Rupr). We quantified the contribution of xylem cell anatomy to the tree-ring width variability. Comparison of the anatomical tree-ring parameters over the period 1963–2011 shows significant differences ( p < 10 −3 ) in the most characteristics of tree-ring structure between habitats based on non-parametric Mann-Whitney U test. Permafrost zone corresponds to lower cell production (30% difference in absolute average values between sites), smaller lumen diameter (10% difference) and thicker cell wall (50% difference). However, no difference was detected in cell-wall thickness of latewood ( p > 0.05). The generalized linear modeling shows the common dependence between tree-ring width (TRW) and the cell structure characteristics in contrasting environments, which can be defined as non-specific to external conditions. Thus, the relationship between the tree-ring width and the cell production in early- and latewood are assessed as linear, whereas the dependence between the radial cell size in early- and latewood and the tree-ring width becomes significantly non-linear for both habitats. Moreover, contribution of earlywood (EW) and latewood (LW) cells to the variation of TRW (in average 56.8% and 24.4%, respectively) was significantly higher with the effect of cell diameters (3.3% (EW) and 17.4% (LW)) for the environments. The results show that the larch trees in cold conditions form wood with high mechanical strength, while the larch in the south is characterized by xylem with increased efficiency to transport water. The work promotes better understanding the sensitivity of conifers to climate variability in contrasting ...