Contribution à l'étude des groupements forestiers et pré-forestiers du Maroc oriental

Resumen

The authors study the forest and pre-steppic groupings of eastern Morocco. They are constituted by Quercus suber, Q. coccifera, Q. rotundifolia, Pinus halepensis et Juniperus phoenicea and take place into the upper units previously defined by Barbero, Quezel et Rivas-Martinez (1981). One Erico arboreae-Quercetum cocciferae of the Riffian littoral belonging to the Ericion arboreae Rivas-Martinez (1975) 1987, and one Cytiso arborei-Quercetum cocciferae almost present in the Béni Snassène, are specially described. Quercus rotundifolia constitutes four structures, two of which in the subhumide bioclimate: the Euphorbio briquetii-Quercetum rotundifoliae Tregubov 1963 on the Béni Snassène and the Festuco scaberrimae-Quercetum rotundifoliae specially on the Debdou monts and the nearest massifs; the latest structure individualizes, in the semiarid bioclimate, the sub-associations genistetosum durieui and pistacietosum atlanticae in the South of the El Ai'oun-Oudja trench. The Ampelodesmo-Chamaeropetum humilis constitutes a degradation stage of the green-oak forest, frequent in the North of Bou Iblane. Apart the matorral structures, Pinus halepensis individualizes pre-forest structures in Debdou: Coronillo valentinae-Pinetum halepensis and, on the J. Lakhdar: Bupleuro gibraltarici- Pinetum halepensis. Lastly, Juniperus turbinata appears with various structures in the upper valley of the Melloulou wadi and in the Ahermoumou region and constitutes various sub-associations into the Tetraclinido-Juniperetum turbinatae. The ecological and dynamic requirements of these groupings are specificied as well as, if possible, their geographic distribution.