A GIS approach to identify the Cork Oak Decline in M’Sila Forest (North-West of Algeria)

The decline of cork oak trees in North-West of Algeria was supposed to be caused by a combination of primary or predisposing factors, and secondary or opportunistic factors. There is a broad consensus about the role of water scarcity and nutrients in the primary causes, given the similarity of symptoms of cork oak decline and of chronic water deficits. To identify and characterize the cork oak decline in M’sila forest, a cork oak mortality index was determined for each transience area using a GIS approach and a linear regression model formulated by analyzing the interactions between the attributes of station (competition of superior and inferior floor); and allowing a justification of cork oaks mortality. The mortality index is significantly high in the invasive shrub plots and where the Aleppo pine density is very high; in which competition for soil water between the trees and the inferior floor increases. The lowest mortality value characterized by a lower density of Aleppo pine and herbaceous inferior floor.