Climo-edaphic impact on the growth of Aleppo pine (Pinus halepensis Mill.) in the reforestation of the Naâma region (South-West Algeria)

Abstract

Pinus halepensis Mill. (Aleppo pine) is a forest species. Since the 1970s thisspecies has been used in the reforestation of Naâma region (South-WestAlgeria) for the restoration of supposedly degraded lands and to fight againstsilting. Our study focused on the growth of this taxon and some environmental descriptors. Climatic analyses classify the study area in the arid bioclimatic stage. A clear setback of the selected stations was observed on theEmberger diagrams, and this consequently allowed us to deduce the accentuation of the pejorative effects of climate on the dynamics of the vegetationcover in place, and that P. halepensis can develop in arid climates. The results of the physicochemical analyses of the studied soils revealed silt-sandyand sandy-loam textures, with a pH ranging from 7.1 to 8.08. The measurement of the electrical conductivity allowed deducing that the soils of thestudied stations were unsalted. The total carbonate content was high; thishigh grade was related to the nature of the bedrock, which is often limestone. The recorded values of the organic matter were low and ranged from0.3% to 1.7%. The average heights of the trees sampled in the reference stations were very contrasting; they generally oscillated between 2.3 and 16.4m. The CPA based statistical combinations highlighted the importance of thesoil depth and that of the texture on P. halepensis growth. Despite an aridclimate (low rainfall, high temperature) and poor and shallow soils, Pinushalepensis stands can develop in pre-steppe areas. This species has a remarkable ecological plasticity and is resistant to changes in the region ofNaâma (south-west Algeria).