Dendroclimatology and wheat production in Algeria

• Published in: Journal of arid environments 2016-01, Vol.124, p.102-110
• Main Authors: Touchan, Ramzi, Kherchouche, Dalila, Oudjehih, Bachir, Touchan, Hayat, Slimani, Said, Meko, David M.
• Format: Article
• Language: English
• Subjects: Agriculture; Algeria; Drought; Droughts; Drying; Mathematical analysis; Pinus halepensis; Precipitation; Reconstruction; Seascorr; Sensitivity analysis; Tree ring; Triticum aestivum; Wheat
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1016/j.jaridenv.2015.07.016

Drought is one of the main natural factors in declining tree-ring growth and the production of agricultural crops in Algeria. This paper addresses the variability of growing conditions for wheat in Algeria with climatic data and a tree-ring reconstruction of January–June precipitation from ten Pinus halepensis tree-ring chronologies. A regression-based reconstruction equation explains up to 74% of the variance of precipitation in the 1970–2011 calibration period and cross validates well. Classification of dry years by the 30% percentile of observed precipitation (131 mm) yields a maximum length of drought of five years (1877–1881) and increasing frequency of dry years in the late 20th and early 21st centuries. A correlation-based sensitivity analysis shows a similar pattern of dependence of tree-growth and wheat production on monthly and seasonal precipitation, but contrasting patterns of dependence on temperature. The patterns are interpreted by reference to phenology, growth phases, and – for wheat – agricultural practices. •Tree rings explain 74% of precipitation variance in regression.•In a 255-year reconstruction, the longest consecutive drought is five years.•Frequency of dry years is highest in the second part of the 20th century.•Tree-growth and wheat production respond differently to temperature.•This paper establishes a link between dendroclimatology and agriculture.