«P2-12 The forest pre-management method and its perspectives for Aleppo pine forests planning: Critical analysis of an Algerian method
1University of Tlemcen, Department of Agronomy and Forestry, PB 119, Tlemcen, 13000 Algeria,
The pre-management method is finalized in Algeria by Mr. GRIM.S and was applied essentially on the Aleppo-pine forests of the ‘Daia mounts’ and ‘Saida’ during the period 1976-1986. Itaffected some Aleppo pine zones in ‘Djelfa’ during 1968-1973 years. The main characteristic of the method is the 10 ha geometric parceling, resulting from orthogonal partition of a givenforest territory (primary network). Thissystem is constituted from 4 m large rides that aredistant in average 300 meters each-other, and opened in the North-south and East-west
directions. This preliminary carving is completed with a second one at the quadrangular polygon level and consists in a 25 m large tie ridge, representing in a way, a systematic thinning. Although it seems inopportune to pass judgment on the interest of the method (missing of reference information), one must remind the great controversy that followed (still itis) for the great sacrificed wooded areas and consequently for the physical and landscaped protection constraints engendered. However it presents some advantages such as thepossibility to access to different points of the forest, more objective descriptive and dendrometrical inventory, better supervision and protection and above all, an opportunity forthe inexperienced Algerian foresters to be familiarized with sylvicultural and forest planning
traditions, not counting significant quantity of extracted wood during the forest partition.
Certainly the great merit of the method is the highlighting (thanks to the primary networklines) the heterogeneity of Aleppo pine stands, described quite often as homogeneous, factthat probably contributed to the planning projects failure. Indeed, major part of Aleppo pineforests in Algeria is localized in semi arid zones and present most of the time great structural heterogeneity and are subject to unexpected changes. Both analytical and topographical parceling will always present limits and to be perfectly adapted to the two constraints,heterogeneity and changes, there is no way apart the geometric one. The forest premanagement
method (GRIM.S.1986) proposes such model but this way of systematic partition
may lead to accentuated heterogeneity of the polygon while this one must be homogenous.
One may reproach the method for the absence of flexibility while flexible parceling taking into account the stands heterogeneity and the risks of fast changes, and that moreover is geometric, seems to be adequate for semi-arid-pine forests. New approach could limit the existing disadvantages, through keeping the quadrangular geometric principle, but with not necessarily equal surface polygons (10 ha). In other words, lines of the primary network (vertical and horizontal as well) will be not necessarily North-south and East-west, notorthogonal or equidistant, but relatively spaced out according to the spatial organization of the affected territory. Another concept to be associated to this flexible geometric partition is the functional zoning, distinguishing wooded zones, multi-resources zones, recreation zones, etc.
Keywords: pre-management, geometric parcelling, flexible polygons, Aleppo pine»
* Depuis les années 1990, la méthode de préaménagement forestier s'intitule Méthode d'aménagement sur compartimentage préalable; cette approche comporte deux volets.
Le volet rectililigne - auquel fait référence Kada Benchérif - a été mis en application dans les Monts des Ouled Naïl en 1968 et 1969 puis dans les Monts de Daya et de Saïda entre 1973 et 1986.
Le volet non rectiligne a été concrétisé en 1993 et 1994 dans la série Sud de la forêt de Baïnem, près d'Alger.