HEALTH STATUS OF A CORK OAK (QUERCUS SUBER L.) STANDS IN THE SERAÏDI (EDOUGH) STATE FOREST IN NORTHEASTERN ALGERIA

Abstract

The present paper presents the results of the investigation of the health status of the Seraïdi state forest where we chose the Berouaga stand and the Bouzizi stand. The field work, was carried out during the year 2016/2017, involved prospecting the forest, identifying the study area, and setting up the observation plots. The average number of trees per plot is 27, and there are a total of 10 plots (P1, P2, P3, P4, P5, P6 at the Berouaga site and P7, P8, P9, P10 at the Bouzizi site), each of which is spaced at least 100 meters apart from the others. The dendrometric characteristics (total height of the tree, diameters of the trunk at 1.30 m), exploitation (the height of debarking and the thickness of the cork), floristic, as well as the examination of the top (evaluation of defoliation and discoloration) and the trunk (presence of crevasses, holes of xylophagous insects, blackish ooze, lichenological flora and wounds) were recorded on 277 trees. The surveys revealed normal leaf coloring with slight defoliation at both study sites. Calculation of the decline index (DI) indicates that the Berouaga site (DI = 1.37 on average) and even Bouzizi (DI = 1.39 on average) are healthy. The trees have an average height of 7.50 m, a circumference of 143 cm and a bark height of 172 cm. Lichenological flora is ubiquitous at both study sites. A small percentage of trees in the study plots showed blackish oozing, deformations or wounds, while about 40 % of the sample trees showed crevasses and also wood-boring insect holes. The cork oak in the study plots is accompanied by an undergrowth rich in plants composed of several species belonging to different families such as: Erica arborea, Rubus ulmifolius Schott, Pteridium aquilinum, Cytisus triflorus, Cistus salviifolius, Asphodelus microcarpus, Daphne gnidium and Arbutus unedo. All the descriptors were subjected to statistical analysis using GLM to determine the weight of each factor in the variability recorded.