Qualitative and Quantitative Variability of Tropical Tree Rings: Implications for Tropical Dendrochronology

Tropical tree species, like their temperate counterparts, show well defined rings, but the high diversity of tropical woody species is reflected in a high diversity of growth-zone structures, formed as a composition of different vessel, fiber and parenchyma characteristics.  Numerous examples show that even trees with generally distinct tree-ring boundaries are subject to high variability within a species and among individuals. In this talk, the anatomical background of the visibility of rings in tropical broadleaved species will be explained and an overview of the wood anatomy and the qualitative variability of tropical tree-ring structures will be given.For a deeper understanding of the influence of external growth factors on wood anatomical structures, samples of many tropical trees were analyzed across plant families and a wide climatic gradient. For all samples, a unique data set on climate, site and forest stand conditions is available. Various vessel variables as well as the relative cross-sectional area of vessel, parenchyma and fibre tissue were studied in individual tree rings of varying sizes. High variability of all features within and across species and sites can be observed. The differences within individuals show how trees can adapt or adjust to environmental variability and can provide information about the plasticity of a species under changing environmental conditions.The variable ‘vessel diameter’ showed the strongest and most significant correlations to other wood anatomical variables, but also to climate parameters and tree morphology. Tree size and crown exposure, on the other hand, had the strongest impact on vessel size and consequently on hydraulic stem architecture.Dr.  Esther Fichtler  recieved her BS in Forestry at the University of Göttingen, Germany in 1999, her MS in Tropical and International Forestry at the University of Göttingen, Germany, in 2001,  and her Ph. D. in Forestry from the University of Göttingen in 2011. Her dissertation entitled  “Ecological information of ring width, stable carbon isotope composition and wood anatomical variables in tropical tree rings - A contribution to dendrochronology in the tropics, ” was a major contribution to expanding dendrochronology into the tropics. Since 2011, she has had a post-doc  position at the University of Göttingen, Department of Crop Sciences, Crop production Systems in the Tropics – working on physiology and growth of tropical trees