Radial growth of aleppo pine (Pinus halepensis mill.) according to biotope parameters for the natural forests of Algeria’s Saharan Atlas

Abstract

This study was made in the forests of Senalba Gharbi, Senalba Chergui and Sehary Guebli, in the semi-arid zone of Djelfa (Algerian Saharan Atlas), which is characterized by rainfall of 300 to 400 mm/year. These are the last tree stands with Aleppo pine, Pinus halepen-sis, growing at the edge of the Sahara. To investigate the effects of altitude, exposure and topographic position on tree measurements (radial growth), 18 plots were selected for sampling over a period of 53 years. In each plot, two samples were taken from six of the dominant trees, using an increment borer, making 216 samples altogether. Analysis of the tree rings showed that exposure, altitude and topographic position have a significant effect on the width of the pine tree rings. Analysis of the dendrochronologi-cal series of tree-ring sizes then showed an overall decreasing trend of 10.5%. Radial growth data can thus be usefully analysed to identify trees with a high pro-bability of decline due to climate change.