Structure, Tree Growth and Dynamics of &I&Cedrus atlantica&/I& Manetti Forests in Theniet El Had National Park (N-W Algeria)

摘要

In North Africa, Cedrus atlantica forests are in decline, following decades of anthropogenic pressure and repeated drought events. Mixed C . atlantica-Quercus ilex stands located in the Theniet El Had National Park (northwestern Algeria) were considered in the present study. Based on a stratified sampling, six temporary plots were established to describe structure (species composition, density, total height, diameter and basal area) and radial growth in relation to type of stand (pure and mixed), using a dendroecological approach. The diameter distribution of C . atlantica indicated the presence of few young individuals and a poor regeneration status in all the stands. The density and basal area of C . atlantica were significantly higher in pure stands, which necessitate silvicultural operations. In contrast, Q . ilex showed a progressive dynamic, at moderate altitude. Radial growth showed a significant decline from 1980 to the 2000s. The absence of an appropriate management plan and the increase in anthropogenic effects, without ruling out a role for the current climate conditions marked by drought, seem to be the causes of C . atlantica decline.