Dendrochronology in Jordan

Dendrochronology is a valuable tool for the study of past climate and increases our knowledge of climate variability beyond the short period covered by instrumental data. Two annual tree-ring width chronologies were developed for northern Jordan (Pinus halepensis and Quercus aegilops), one chronology for Carmel Mountain, Israel (Pinus halepensis), and one chronology for southern Jordan (Juniperus phoenicia). The results of our study show that the northern site chronologies are significantly correlated, but the northern and southern sites are not. A relatively high correlation was shown between October-April precipitation and a Pinus halepensis chronology, and between October-May precipitation and Quercus aegilops, both in the north. October-May precipitation was reconstructed for the time span AD 1600 to 1995 from the Juniperus phoenicia tree-ring chronology. The longest reconstructed drought, defined as consecutive years below a threshold of 80% of the 1946-1995 mean observed October-May precipitation, was 4 years, compared with 3 years for the 1946-95 instrumental data.