Exploring climatic signals in stable isotopes of Sclerocarya birrea tree ring chronologies from the Sahel region in West Africa uri icon

abstract

  • The instrumental record of climate is just too short to understand how climate changes in Africa.Although a number of proxy data series have been developed from temperate and subtropical regions to trace the course of environmental and climatological fluctuations, precise palaeo-climate records from the tropics, notably from Africa,are still sorely lacking (Gebrekirstos 2009a). Therefore, it is central to identify potential climate proxies that could provide empirical data regarding past climatic events and its impact on important agroforestry species. Tree ring widths and stable isotopes in tree rings have been successfully used as climate proxies in temperate regions. Recently some progress has been reported with regard to the potential of tree rings as climate proxy in semi-arid Africa (Gebrekirstos et al. 2009b, Gebrekirstos et al. 2011, Trouet et al. 2006, Fichtler et al. 2004, Wils et al. 2010). Gebrekirstos et al (2009b) demonstrated the potential of d 13 C in tree rings of Acacia species to reflect physiological responses to environmental and climate changes as a tool for paleoclimatic reconstructions in Ethiopia. High correlations (up to r = -0.82) were found between the d 13 C chronologies and precipitation data, which demonstrates their potential to reconstruct precipitation in semi-arid tropics. Wills et al (2010) also demonstrated the use of d 13 C in Juniperus procera by reconstructing the flow of the Blue Nile River. In this context, we extend the study to West Africa in Burkina Faso (Sahel region) and East Africa in Tanzania (Miombo woodland). The overall purpose of the study is to establish large-scale correlation patterns between tree growth, precipitation and temperature that are affected by the Indian Summer Monsoon (ISM) and the West African Monsoon (WAM) in East and West Africa, respectively. This knowledge will help us to explore local and regional climate processes. In this paper we present preliminary pilot results that indicate the potential of stable oxygen and carbon isotopes in tree rings of Sclerocarya birrea from the Sahel region in Burkina Faso as a climate proxy

publication date

  • 2011