Wood Anatomical Traits Respond to Climate but More Individualistically as Compared to Radial Growth: Analyze Trees, Not Means

Abstract

Wood encodes environmental information that can be recovered through the study of tree-ring width and wood anatomical variables such as lumen area or cell-wall thickness. Anatomical variables often provide a stronger hydroclimate signal than tree-ring width, but they show a low tree-to-tree coherence. We investigate the sources of variation in tree-ring width, lumen area, and cell-wall thickness in three pine species inhabiting sites with contrasting climate conditions: Pinus lumholtzii in wet-summer northern Mexico, and Pinus halepensis and Pinus sylvestris in dry-summer north-eastern Spain. We quantified the amount of variance of these three variables explained by spring and summer water balance and how it varied among trees. Wood anatomical variables accounted for a larger inter-individual variability than tree-ring width data. Anatomical traits responded to hydroclimate more individualistically than tree-ring width. This individualistic response represents an important issue in long-term studies on wood anatomical characteristics. We emphasized the degree of variation among individuals of the same population, which has far-reaching implications for understanding tree species’ responses to climate change. Dendroclimatic and wood anatomical studies should focus on trees rather than on the mean population series.

New Methods in Digital Wood Anatomy: The Use of Pixel-Contrast Densitometry with Example of Angiosperm Shrubs in Southern Siberia

“…Comparison of growth rings in the same wood samples over several years demon- In diffuse-porous Alnus alnobetula and Prunus padus, the mean inter-series correlation coefficients (i.e., correlations between series for individual specimens, Table 2) for maximum, minimum, and average porosity in the ring were comparable or higher than those for the ring width series, which indicates the presence of a common signal to external factors affecting growth ring formation in these indicators. Of course, for such a short series, we cannot talk seriously about the level of significance, but even these preliminary results are already indicative, since they are at least comparable with the inter-series correlation coefficients observed for other anatomical parameters of the wood structure in both conifers and deciduous trees [39][40][41][42][43]. For the ring-porous Caragana arborescens, despite clearly visible differences in the structure of growth rings between years, the inter-series correlation coefficient is not close to zero only for the maximum porosity.…”