The study aims to map, using very high spatial resolution satellite imagery, the argan tree formation located in the upper valley of Oued Grou. This stand corresponds to a disjunct population located about 400 km north of the main distribution range of the argan tree. It is considered a site of biological and ecological interest and has been identified as a priority for the implementation of conservation and enhancement measures.
The study area is characterized by a semi-arid bioclimate with mild winters, with annual precipitation estimated between 400 and 450 mm.
Overall, the argan grove appears as a degraded matorral resulting from the combined effects of wood cutting and overgrazing. It includes approximately 775 argan trees scattered over a 1,200 ha area with a silvo-pastoral vocation, located between 200 and 600 m above sea level.
Most of the argan trees grow on very steep slopes exposed to the south or southwest, on Paleozoic schist substrates characterized by poorly developed soils. In these areas, argan trees are mainly associated with five-leaved sumac (Rhus pentaphylla).
A few individuals are also observed on north-facing slopes. However, on these slopes, where soils are generally deeper and better developed, the dominant vegetation formation corresponds to woodlands of thuya (Tetraclinis articulata), wild olive (Olea europaea subsp. europaea), and mastic tree (Pistacia lentiscus).
To date, this site has never been subject to a management plan. This absence of management measures partly explains the degree of degradation observed, with nearly 68% of the area currently occupied by bare soils.
It should be recalled that the presence of the argan tree in the Oued Grou valley was first reported by Emberger in 1924. Furthermore, the study of the chloroplast genome of the argan tree has shown that these stands likely result from a relatively recent dispersal, probably of anthropogenic origin (El Mousadik & Petit, 1996).
Ref. Sahel Y., Dellahi Y. & Chahhou D., 2022 Mapping the Site of Biological and Ecological Interest of Rganat-Bouchkal (Tsili) Argan forest (Moroccan Central Plateau) using remote sensing. IOP Conf. Ser.: Earth Environ. Sci. 1090 012001
Posted by Jean-Paul Peltier.