Changes in rainfall patterns enhance the interrelationships between climate and wood traits of eucalyptus

Abstract

The intensity of climate changes demands studies on the adaptability of the most planted eucalyptus genetic materials in the world, such as E. urophylla and E. grandis × E. camaldulensis which were evaluated in this study. The objective of this work was to evaluate wood traits and to relate it to the meteorological variables for each year of growth of the trees that grew in four sites with different climatic conditions and 33% rainfall exclusion. The wood traits evaluated were: wood density, vessel density, diameter and area, vessel wall thickness, total vessel wall thickness between adjacent cells, theoretical hydraulic conductivity, potential hydraulic conductivity, lumen conductivity area, vessel composition within space, vessel implosion resistance and vulnerability index to drought. Pearson’s correlations between the evaluated variables were estimated and the results expressed graphically through the correlation network. Multiple regression analysis with adjustment by the Exhaustive Search method was used to estimate the vessel wall thickness in order to isolate this characteristic and identify the explanation intensity of the meteorological variables. Pearson’s correlations between meteorological factors and wood traits show different interactions in the behavior of the clones and in the water availability conditions. Air temperature was present in all the vessel wall thickness estimation equations. The 33% rainfall exclusion provided the best equation adjustments with meteorological variables, explaining up to 84% of the variation in the vessel wall thickness. The rainfall exclusion intensified the effects of the interrelations between climate and hydraulic architecture in E. grandis × E. camaldulensis, with implosion resistance and vessel wall thickness having a strong relationship between climate and wood. The results of rain reduction in the dynamics between wood and climate have implications for indirect selection in breeding programs.