Monitoring the Spatiotemporal Evolution of the Green Dam in Djelfa Province, Algeria

Abstract

Green walls and green dams are increasingly being considered as part of many nation-al and international desertification initiatives. This paper studies the spatiotemporal evolution of the green dam in the Moudjbara region (Djelfa Province, Algeria) from 1972 to 2019 by using Landsat imagery, Land Change Modeler and Open Land package. The future evolution of pine plantations for the year 2029 was also forecasted, based on an anthropogenic scenario (i.e., an-thropogenic pressure is the main driver of the green dam destruction). Our findings revealed that the green dam project was successful for a few years, but after that, pine plantations deteri-orated significantly due to forest harvesting, livestock overgrazing, and the proliferation of the pine caterpillar processionary, which destroyed most of the reforestation. Land Change Modeler predicted a huge degradation of pine plantations for the year 2029, and if the deforestation con-tinues at the same rate, the green dam will disappear in the Moudjbara region during the next few decades. Aware of this threat, the Algerian authorities are now planning to reforest more than 1.2 million ha under the latest rural renewal policy by introducing new principles related to sustainable development, fighting desertification, and climate change adaptation

Assessing the evolution of the Aleppo Pine plantations by using field measurements and one-way Analysis of variance

“…As part of protecting this vast territory from the threat of desertification, Algeria undertook a largescale reforestation project just after independence. The project has a kind of vegetal wall called 'green dam', its first edition including the frustration of the advancing desert [14]. The field of intervention of the green dam is constituted by the pre-Saharan zone included between the isohyets 300 millimeters in the North and 200 millimeters in the south.…”

“…Initially, the green dam was meant to halt the desert's expansion into the country's north, with the goal of protecting natural resources, improving populations' living conditions, and preventing their exodus to metropolitan regions [14,[18][19][20]. Many authors have researched the evolution and current state of the Algerian green dam, and they have all stressed the green dam's inability to meet its intended goals, owing to a lack of planning, livestock overgrazing, and the project's lack of involvement of the local population [14,[18][19][20].…”