Wood hydraulic traits, tree-ring, and stable isotope analyses of Eschweilera coriacea in the Brazilian Amazon

Abstract

Climate change will affect global ecosystems; there is a pressing need for evaluation of its possible damaging effects on different trophic levels, especially for plant species. Analysis of the annual demarcation of tree rings on the secondary xylem allows us to examine environmental influence on the performance of trees over periods of time relevant in the past. Stable carbon isotopes enable us to make inferences on hydraulic stress suffered by trees over time, which can be used to reconstruct past climate variation. To better forecast responses of tree functioning under climatic change, we will quantify how the hydraulic strategies vary within species over large climatological and edaphic gradients. Among the tropical species Eschweilera coriacea (Lecythidaceae) produce annual tree rings, is a very interesting case study, as this species has an ample distribution throughout the Amazon, being one of the hyperdominant species. This high-longevity species produces annual tree rings with growth-ring boundaries characterised by alternating fiber and parenchyma bands. We will quantify these responses at sub-continental scale and evaluate the modifying role of soil fertility and rainfall on hydraulic traits, climatic drivers of tree growth and to assess tree responses to the rise in atmospheric CO2 levels of the last ~150 years. Our goals are to understand: (i) in what way tree growth and hydraulic drought resistance vary along climatic-edaphic gradients; (ii) whether ontogeny affects hydraulic drought resistance; and (iii) how these gradients modulate long-term responses of this tropical tree species to climatic change. Through sampling over environmental gradients, we anticipate contributing significantly toward improving understanding of environmental controls on tree functioning and growth in an important Brazilian biome. (AU)