Elaboration d'une base de données géographiques et catalogue des stations de la subéraie de la Maamora

Abstract

The cork oak regeneration is in the Maamora forest is capricious. Based on the hypothesis that some soils are unsuitable for cork oak development, thus leading to the replacement of a large portion of the forest with exotic species. However, soil is not the only factor to consider in landuse suitability. It is possible some areas might be unsuitable to the cork oak regeneration but their magnitude is unknown. The aim of this study is to highlight suitable sites for cork oak development.

To achieve this goal, firstly, the main known factors having an influence in the cork oak regeneration was identified and mapped. Secondly, due to the importance given to the thickness of the sand in the Maamora forest, its spatial dependence was studied by a geostatistical approach. Therefore, the factors were combined using a weighted linear combination with the weight of each criterion calculated by AHP (Analytic Hierarchy Process) resulting to a cork oak regeneration suitability index for the whole forest.

The mapping of these factors was made by inserting a fuzzy logic to avoid crisp classes. This permitted the integration of an uncertainty to the exact class boundaries

The main factors influencing the regeneration of the cork oak forest of Maamora are the continentality manifested by a decrease in precipitation from the west to east at the same time a rising temperature in the opposite direction, the bare soil slope less than 10% (gentle slope) and steep slope (> 15 %), the thickness of the sand, the slope of the clay floor, the flora and soil types.

Furthermore, a great variability in the thickness of the sand was observed. This variability is greater in the southwest northeast direction than in the opposite direction. Spatial dependence or spatial autocorrelation is less than 46.7 % with a sampling grid of 500 m X 500 m. From a systematic sampling of every 100 m gave a spatial autocorrelation of 87.7 %. Using a sampling grid of 500 m X 500 m, a large spatial variability was not observed. To take into account a greater portion of the spatial variability of the sand's thickness, a sampling grid of 300 to 350 m is advised.

Finally, four classes of regeneration suitability were obtained. These classes are good, medium, low and very low suitability and which represent 17.40 %, 40.18 %, 34.84 % and 4.28 % of the forest area respectively.

vi

ÕÎáã

åÐå ÉíãäÊá ÉÈÓÇäã ÑíÛ ÑÈÊÚÊ íÊáÇ ÉÈÑÊáÇ ÚÇæäÇ ÖÚÈá ÇÑÙä ÉÈáÞÊã ÉíáãÚ ÉÑæãÚãáÇ ÉÈÇÛ í íäíááÇ ØæáÈáÇ ÏíÏÌÊ .ÇåäíÈ Ç ãí áÎÇÏÊÊ ìÑÎÇ áãÇæÚ ßÇäå ÏÌæÊ äßá ÉÑÏÞáÇ ãííÞÊ í ÏíÍæáÇ áãÇÚáÇ íå ÊÓíá ÉÈÑÊáÇ ßáÐ Úãæ .ÑÇÌÔáÇÇ ÇåÞÇØä æå Çã äßáæ íäíááÇ ØæáÈáá ÉÍáÇÕ ÑíÛ ÞØÇäãáÇ ÖÚÈ ä äßããáÇ äã ÉÈÊÑãáÇ í íäíááÇ ØæáÈáÇ ÏíÏÌÊ ÉíáãÚ ìáÚ ÑËÄÊ íÊáÇ ÉíÓíÆÑáÇ áãÇæÚáÇ ÏíÏÍÊ ãÊ ÉíÇÏÈáÇ í áÇÄÓáÇ ÇÏå ìáÚ ÉÈÇÌáÅá åÐå ÌÒã ãÊ ÇÑíÎ .åÚÖæã ÑíÛÊ äÇßã ÏíÏÍÊ äã äßãÊ ÉíÌåäã ÏÇãÊÚÇ ãÊ áÇãÑáÇ ßãÓ ìáÚ ÒíßÑÊáÇ ÏÚÈ ÉíäÇËáÇ ØæáÈáÇ ÏíÏÌÊ ìáÚ ÉÑÏÞáÇ ÊÇÑÔÄã ÏíÏÍÊá ÉíáíáÍÊ ÉíãÑå ÉíáãÚ ãÇÏÎÊÓÇÈ áãÇÚ áß ÉíãåÇ ãííÞÊæ ÇåÖÚÈ Úã áãÇæÚáÇ .íäíááÇ ááÇÎ äã ßáÐ ìáÌÊíæ ÎÇäãáÇ :íå ÉÑæãÚãáÇ ÉÈÇÛ í íäíááÇ ØæáÈáÇ ÏíÏÌÊ ÉíáãÚ í ãßÍÊÊ íÊáÇ ÉíÓíÆÑáÇ áãÇæÚáÇ áãÇæÚ ìáÇ ÉÇÙÇ.ÓßÇÚãáÇ åÇÌÊáÇÇ í ÉÑÇÑÍáÇ ÊÇÌÑÏ ÚÇÊÑÇæ ÞÑÔáÇ ìáÅ ÈÑÛáÇ äã ÑÇØãáÇ áæØå í ÖÇÎäÇ .ÉÈÑÊáÇ ÚÇæäÇæ ÉíäíØáÇ ÉÞÈØáÇ áÇãÑáÇ ßãÓ ÉíÚíÈØáÇ ÊÇÑÏÍäãáÇß ìÑÎÇ .ÕáÇ ÏæÏÍ äíÈ ãÇÓÞäáÇÇ ÈäÌÊá íÈÇÈÖáÇ ÞØäãáÇ áÇÎÏÅ ÞíÑØ äÚ áãÇæÚáÇ åÐå äííÚÊ ãÊí

.ÓßÇÚãáÇ åÇÌÊáÇÇ ÓßÚ íÞÑÔáÇ áÇãÔáÇ åÇÌÊÇ í ÇÏÌ ÑíÈß áÇÊÎáÇÇ ÇÐå áÊÎã ÏÌ áÇãÑáÇ ßãÓ ßáÐ ìáÚ ÉæáÇÚæ ÑÊã 055 ìáÚ ÚÈÑã ÑÊã 055 ÉßÈÔ äã ÊÇäíÚáÇ ÐÎ Úã %7..4 áËãí íäÇßãáÇ íÊÇÐáÇ ØÇÈÊÑáÇÇ æ íäÇßãáÇ ÏÇãÊÚáÇÇ áÇ íÊáÇ ÉÑíÈßáÇ ÉíäÇßãáÇ ÊÇÑíÛÊáÇ ä æÏÈí ° % 74 æå íäÇßãáÇ íÊÇÐáÇ ØÇÈÊÑáÇÇ ÑÊã 055 áß ÉíÌåäã ÉäíÚ äã .ÚÈÑã ÉÖÎäã ÉØÓæÊã ÉÏíÌ :ÏÏÌÊáÇ ÉÑÏÞ äã ÊÇÆ ÚÈÑ ìáÚ áæÕÍáÇ ãÊ ÇÑíÎÇ .ã 055_í ÊÇäíÚáÇ ÐÎ Úã ÇåÖÑÚ ãÊí

.ÉÈÇÛáÇ ÉÍÇÓã äã % 7₇,7 æ % 47₇77 ₇% 75₇07 % 5 04₇7 ÚÈÇÊÊáÇÈ ÊÇÆáÇ åÐå áËãÊæ ÇÏÌ ÉÖÎäãæ

ÑííÇÚãáÇ ÏÏÚÊãáÇ ãííÞÊáÇ ÉÑæãÚãáÇ íäíááÇ ØæáÈáÇ :ÉíÓÇÓáÇÇ ÊÇãáßáÇ

vii

Table des matières

Résumé iv

Abstract v

ÕÎáã vi

Liste des figures x

Liste des tableaux xii

Liste des sigles et acronymes xiii

Introduction 1

Chapitre 1. Revue bibliographique 4

1.1. Principe de la typologie des stations forestières 4

1.1.1. Définition de la station 4

1.1.2. Principaux descripteurs des stations 5

1.1.2.1. Régime hydrique 5

1.1.2.2. Climat 5

1.1.2.3. Topographie 6

1.1.2.4. Fertilité du sol 6

1.1.2.5. Phytocénose 6

1.1.3. Utilisation pratique de la notion de la station 7

1.1.4. Notion de groupes de stations 7

1.1.5. Conclusion 8

1.2. Aperçu sur le chêne-liège 8

1.2.1. Aire de répartition du chêne-liège 8

1.2.2. Ecologie du chêne-liège 10

Chapitre 2. Matériels et méthodes 12

2.1. Présentation de la zone d'étude 12

2.1.1. Situation géographique, administrative et forestière 12

2.1.2. Caractéristiques du milieu 13

2.1.2.1. Cadre géologique 13

2.1.2.2. Cadre topographique 13

2.1.2.3. Cadre hydrographique 14

2.1.2.4. Cadre pédologique 14

2.1.2.5. Cadre climatique 15

2.1.2.6. Groupements et associations végétales de la Maâmora 20

viii

2.2. Approche méthodologique 21

2.2.1. Analyse des facteurs influençant la régénération du chêne-liège en

Maâmora 21

2.2.2. Outils de traitement 22

2.2.3. Facteurs considérés 22

2.2.3.1. Profondeur du plancher argileux (épaisseur du sable) 22

2.2.3.2. Pente du plancher argileux 24

2.2.3.3. Types de sol 25

2.2.3.4. Climat 25

2.2.3.5. Topographie 25

2.2.3.6. Groupements végétaux 26

2.2.4. Evaluation de l'aptitude 26

2.2.4.1. Identification de l'objectif 26

2.2.4.2. Détermination des critères et contraintes d'évaluation 26

2.2.4.3. Détermination des notes ou scores pour chacun des critères 27

2.2.4.4. Attribution de poids à chacun des facteurs 27

2.2.4.5. Description du processus d'AHP 28

2.2.4.6. Agrégation ou combinaison des poids et notes pour un résultat

synthétique 30

2.2.5. Base de données géographiques 30

Chapitre 3. Résultats et discussions 32

3.1. Analyse des facteurs influençant la régénération du chêne-liège en Maâmora 32

3.1.1. Epaisseur du sable et la pente du plancher argileux 32

3.1.2. Pédologie 33

3.1.3. Continentalité 34

3.1.4. Flore 34

3.1.5. Pente du terrain 35

3.2. Analyse de la variabibilité de l'épaisseur du sable 35

3.2.1. Analyse exploratoire des données 36