Tree-ring reconstruction of March-June precipitation from the Atlas cedar forest of Mount Takoucht, Béjaïa (northern Algeria)

Said Slimani,Emilia Gutiérrez,Dalila Kherchouche,Farid Bekdouche

doi:10.5424/fs/2021303-18111

Said Slimani, Emilia Gutiérrez + Show 2 more

Open Access

https://doi.org/10.5424/fs/2021303-18111

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Abstract

Aim of study: A March-June precipitation has been reconstructed for the period 1830-2015 using Atlas cedar (Cedrus atlantica Manetti) tree-ring records. Area of study: Atlas cedar forest of Mount Takoucht (Béjaïa, northern Algeria). Material and methods: Seasonal correlations were computed in order to identify the best period of the year for the climate reconstruction. The temporal stability of the tree-ring signal for precipitation was checked using the split-sample calibration-verification procedure. The reconstruction was performed using the transfer function method. Main results: The reconstructed data revealed high interannual to decadal variation in late winter to early summer precipitation. Wet conditions dominated during the 1830s and 1840s and were followed by sustained dry conditions during the mid-19th century, which registered two of the most severe droughts (1858 and 1869) over the period of reconstruction. Relatively moderate climate conditions marked the late 19th and early 20th centuries. A gradual return towards drier conditions was observed from the 1920s and reached high frequencies of drought around mid-20th century. After an exceptional prolonged wet period of 24 years (1966-1989), the reconstruction registered its highest frequency in extreme dry/wet events: the decade 1993-2002 recorded the highest drought frequency of the reconstruction, with the third most severe dry event (1999), while the last years were marked by a clear shift toward wet conditions. Research highlights: These findings provide relevant records on past climate variability in one of the rainiest areas in Algeria and constitute valuable knowledge for specific drought and wet periods monitoring in the region. Keywords: Dendrochronology; climate reconstruction; Cedrus atlantica; Algeria.

Highlights

Water scarcity has become a major constraint to socio-economic development and a threat to livelihood in increasing parts of the world (Liu et al, 2017)
The average correlation among all individual radii (0.29) and the explained variance in the first principal component of the series over the common interval (31%), which represent the strength of their common climatic signal (Touchan et al, 2014), is the lowest registered from all the sites used for climate reconstruction in Algeria so far (Touchan et al, 2008a, 2010, 2016, 2017; Kherchouche, 2012, 2013; Slimani, 2014)
This study presents the first long-term climate reconstruction using tree-ring data for the region of Béjaïa, which is one of the wettest areas in Algeria

Summary

Introduction

Water scarcity has become a major constraint to socio-economic development and a threat to livelihood in increasing parts of the world (Liu et al, 2017). The Mediterranean Basin has been referenced as a major climate change hotspot for the coming decades. Continuous high-quality instrumental data series in North Africa start in the early 1900s, but the majority cover only the latter half of the twentieth century. Tree-ring records, allow for the development of quantitative and validated paleoclimate drought reconstructions to help understand climate variability on time scales beyond that of the instrumental data (Touchan et al, 2008a). Tree-ring based climate reconstructions for the western Mediterranean highlighted a substantial increase in

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