, Volume 25, Issue 3, pp 345–354

Dendrochronology in the dry tropics: the Ethiopian case


    • Department of Geography, School of the Environment and SocietySwansea University
    • Department of Geography, Institute for Teacher TrainingRotterdam University of Applied Sciences
    • Department of Geography, Institute for Teacher TrainingFontys University of Applied Sciences
  • U. G. W. Sass-Klaassen
    • Forest Ecology and Forest Management Group, Centre of Ecosystem StudiesWageningen University
  • Z. Eshetu
    • Forestry Research CentreEthiopian Institute of Agricultural Research
  • A. Bräuning
    • Institute of GeographyFriedrich-Alexander University of Erlangen-Nürnberg
  • A. Gebrekirstos
    • International Centre for Research in Agroforestry (ICRAF), Global Headquarters
  • C. Couralet
    • Laboratory for Wood Biology and XylariumRoyal Museum for Central Africa (RMCA)
    • Laboratory for Wood TechnologyGhent University
  • I. Robertson
    • Department of Geography, School of the Environment and SocietySwansea University
  • R. Touchan
    • Laboratory of Tree-Ring ResearchUniversity of Arizona
  • M. Koprowski
    • Laboratory of Dendrochronology, Institute of Ecology and Environment Protection, Faculty of Biology and Earth ScienceNicolaus Copernicus University
  • D. Conway
    • School of International DevelopmentUniversity of East Anglia
  • K. R. Briffa
    • Climatic Research UnitUniversity of East Anglia
  • H. Beeckman
    • Laboratory for Wood Biology and XylariumRoyal Museum for Central Africa (RMCA)

DOI: 10.1007/s00468-010-0521-y

Cite this article as:
Wils, T.H.G., Sass-Klaassen, U.G.W., Eshetu, Z. et al. Trees (2011) 25: 345. doi:10.1007/s00468-010-0521-y


Dendrochronology is developing outside temperate and boreal regions. Over the past decade substantial progress has been made in Mediterranean and wet tropical regions. However, research in dry tropical regions, notably those of sub-Saharan Africa, has remained fragmentary. Here, we try to identify the unique challenges and opportunities of dendrochronology in the dry tropics. First, we briefly review the status of dendrochronology outside temperate and boreal regions with an emphasis on sub-Saharan Africa. Subsequently, we focus upon one of those areas where dendrochronology in the dry tropics is at the forefront of scientific advance: Ethiopia. A detailed review of tree ring studies in the lowlands and highlands highlights the complexity of ring formation and made us identify four major types of growth ring expression: anatomically not distinct rings, multiple rings per year, annual rings and multiple missing rings. This complex tree growth behaviour is associated with large-scale variations in precipitation regime (unimodal to multimodal) and relatively small-scale variations in tree sensitivity to water availability. Literature results are used to develop a scheme that can be used to predict differences in growth ring formation along gradients in these two factors. Because of the exceptional growth sensitivity of and the importance of local site conditions (topography, biological factors, etc.) for most trees sampled, those growing at the limits of their ecological amplitude are prone to possess multiple rings per year or multiple missing rings. In such circumstances, site selection should not always take place at the limits of the ecological amplitude of a species, but may sometimes have to be diverted to more mesic environments. Successful studies are now appearing, such as those reporting correlations between tree ring chronologies and Blue Nile river flows.


Acacia Juniperus procera Ring formation Tree rings Wood anatomy

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© Springer-Verlag 2010