Cedar forests area in northeastern Algeria （Aures） is decreasing by the massive tree mortality. In some localities more than 95% of the trees have recently died （e.g. Boumerzoug in Belezma National Park）. Three re...Cedar forests area in northeastern Algeria （Aures） is decreasing by the massive tree mortality. In some localities more than 95% of the trees have recently died （e.g. Boumerzoug in Belezma National Park）. Three reported episodes of massive tree mortality in 1880, 1980, and 2000 were attributed to drought at least as the triggering factor. Our main objective was to reconstruct drought events that could be linked to Atlas cedar tree mortality using tree-ring series. We developed a Cedrus atlantica tree-ring width chronology in Chelia with a reliable period spanning from 1502 to 2008. Based on the relationship between chronology indices and instrumental precipitation data, we reconstructed total October-June precipitation. Dry events were identified using a threshold of 90% of the October-June mean instrumental precipitation. The unique drought event of 3-year period （1877-1879） could explain the tree mortality occurred in 1880. In terms of severity and frequency of droughts, the later half of the twentieth century seems to be the worst and may be responsible for the recent tree mortality.展开更多
文摘Cedar forests area in northeastern Algeria （Aures） is decreasing by the massive tree mortality. In some localities more than 95% of the trees have recently died （e.g. Boumerzoug in Belezma National Park）. Three reported episodes of massive tree mortality in 1880, 1980, and 2000 were attributed to drought at least as the triggering factor. Our main objective was to reconstruct drought events that could be linked to Atlas cedar tree mortality using tree-ring series. We developed a Cedrus atlantica tree-ring width chronology in Chelia with a reliable period spanning from 1502 to 2008. Based on the relationship between chronology indices and instrumental precipitation data, we reconstructed total October-June precipitation. Dry events were identified using a threshold of 90% of the October-June mean instrumental precipitation. The unique drought event of 3-year period （1877-1879） could explain the tree mortality occurred in 1880. In terms of severity and frequency of droughts, the later half of the twentieth century seems to be the worst and may be responsible for the recent tree mortality.
