DEMOGRAPHIC STRUCTURE OF QUERCUS CANARIENSIS FROM THE OULED BECHIH FOREST OF ALGERIA

Abstract

The main objective of this study is to analyze the demographic structure and spatial distribution of Quercus canariensis populations in the Ouled Bechih forest in northeastern Algeria. Knowledge of these parameters is an essential step in their sustainable management. Sample inventory plots measuring 30m x 30m (900m2) were identified by random sampling. Tree diameter at 1.30 m above the ground and total height of Q. canariensis were measured for each tree in four inventory plots. The demographic structures were established according to the classes of diameter and height and adjusted to the theoretical distribution of Weibull. The results show that the highest values of density (178 individuals/ha) and basal area (37.87 m2/ha) were respectively obtained in plots P2 and P1; while the highest values of Lorey's average height (18.56 m) and quadratic diameter (73.67 cm) were obtained in plot 1. The diameter and height structures show a concentration of adult individuals throughout the stands of this forest. The demographic analysis shows that the diameter structure of plots 1 and 3 present a left asymmetrical distribution, characteristic of monospecific stands with a predominance of old individuals with values of the coefficient c of 4.782 and 5.352 respectively. The values of c for plots 2 and 4 are less than 3.6; these values are of the order of 2.427 (P2) and 3.227 (P4). The distribution according to the diameter of these plots shows a right asymmetrical, characteristic of monospecific stands with a predominance of young individuals. Analysis of the height structure of these stands shows that plot 3 has a "c" value of less than 3.6 while the values of the other plots are greater than 3.6; this result attests to a predominance of tall individuals (10 to 15 m). In the perspective of rehabilitation and sustainable management of forest ecosystems, this study provides additional information on the current state of Quercus canariensis stands in the Ouled Bechih forest.