Impact of ecological restoration techniques on the dynamics of degraded ecosystems of the mounts of Saida: Case of the forests of Doui Thabet (West Algeria)

The aim of the present study aims to establish the impact of different restoration techniques (soil and vegetation works) of five pioneer species of the Doui Thabet forest (Mounts of Saida, West of Algeria): Pinus halepensis, Pistacia lentiscus., Tetraclinis articulata, Juniperus oxycedru,. and Stipa capensis (= S. tenacissima L.) between 2018 and 2020. An experimental field device covering an area of 1 ha has been installed in the Doui Thabet forest in a Pinus halepensis massive more than 80 years old. The following work was carried out: mechanical grinding of the vegetation (chopping), turning (scarification of soil) to a depth of 10 cm, tillage (Deep ploughing) to a depth of 20 cm, controlled burning of branches, clearing of Stipa capensis, seedlings planted in different seasons for certain species (Stipa capensis = S. tenacissima L.), monitoring of stump rejections and natural sowing. The sowing result varies according to the species and restoration techniques, it is high for Pinus halepensis and Stipa capensis. It is low for Tetraclinis articulata and Juniperus oxycedrus and none for Pistacia lentiscus while for Stipa capensis it is quite high when planted in autumn compared to spring. Turning and burning have proven to be the most abundant treatments for regeneration and growth. Grinding has medium seedling density and growth, while deep tillage and natural sowing showed low seedling density and growth.