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Prunus avium is a component of the biodiversity in the forest ecosystems: its fruits are consumed by a large number of birds, its quality of the wood and its premature blooming confer it a big esthetic value. Multipurpose tree, it is present in the forest of Kroumirie in the Northwest of Tunisia. In this region, Prunus avium is a species exploited as a stock for cherry trees and ash wood for the cabinetmaking by the local populations. The natural populating, in constant decrease since a few decades, is threatened by diverse anthropogenic, getting more and more stronger pressures, reducing the capacities of natural regeneration of the species. The study of the ecological housing environment is essential to have a good knowledge of the ecology of such species to determine the conditions in which it develops and to set up appropriate rules of management. Indeed, Prunus avium prefers the lemon-clayey grounds, rich in nitrogen and with a relationship C/N lower than 10. The grounds which it prefers are of acid PH (4.3-6.7). According to the obtained results, such species resists well enough in lower temperatures (T min = 3°C) and is very sensitive to the summer drought (T max = 24°C). At the level of Kroumirie, the presence of Prunus avium is rare below 150 m of height, while it is regularly found in cliff- nesting situation, between 180 and 620 m, with a maximum near 550 m. The obtained results show that such species has an affinity for the lower slopes (0- 10 %). Our results allow formulating relative recommendations on the valuation of Prunus avium : practise plantations of this species at the level of the most preferable stations for the production of the wood and the stock for the culture of the cherry tree in the Northwest of Tunisia. Keywords: Tunisia, Prunus avium , central housing environment, marginal housing environment, environmental factors. Resume Prunus avium est une composante de la biodiversite dans les ecosystemes forestiers: ses fruits sont consommes par de nombreux oiseaux, sa qualite du bois et sa floraison precoce lui conferent une grande valeur esthetique. Arbre a usages multiples, il est present dans la foret de la Kroumirie au nord-ouest de la Tunisie. Dans cette region, Prunus avium est une espece exploitee comme porte-greffe pour le cerisier et comme bois pour l’ebenisterie par les populations locales. Les peuplements naturels, en constante diminution depuis quelques dizaines d’annees, sont menaces par diverses pressions anthropiques, de plus en plus fortes, reduisant les capacites de regeneration naturelle de l’espece. L’etude de l’habitat ecologique est indispensable pour disposer d’une bonne connaissance de l’autoecologie de cette espece afin de determiner les conditions dans lesquelles elle se developpe et de mettre en place des regles appropriees de gestion. En effet, Prunus avium prefere les sols limono-argileux, riches en azote et avec un rapport C/N inferieur a 10. Les sols qu’il prefere sont de pH acides (4,3 a 6,7). D’apres les resultats obtenus, cette espece resiste assez bien au froid (Tmin = 3°C) et est tres sensible a la secheresse estivale (Tmax = 24°C). Au niveau de la Kroumirie, la presence de Prunus avium est rare au-dessous de 150 m d’altitude, alors qu’on le trouve regulierement en situation ripicole, entre 180 et 620 m, avec un maximum aux alentours de 550 m. Les resultats obtenus montrent que cette espece a une affinite pour les pentes faibles (0-10%). Nos resultats permettent de formuler des recommandations relatives sur la valorisation de Prunus avium : pratiquer des plantations de cette espece au niveau des stations les plus favorables pour la production du bois et de porte-greffe pour la culture du cerisier au nord-ouest de la Tunisie. Mots cles : Tunisie, Prunus avium , habitat central, habitat marginal, facteurs environnementaux.

To study the impact of soil pollution on plant growth, our work focused on soil polluted by heavy metals. This soil was taken from the municipal landfill of Jendouba (North of Tunisia). We have undertaken to study the morphological behavior of a forest specie “Eucalyptus gomphocephala”. Two treatments are chosen (substrate containing 100% and 50% of soil taken from municipal solid waste of Jendouba) compared to a control (pilot soil). Morphological Parameters (stem height, root length, leaf area, the ratio of the stem/root and biomass) was measured. The plants grown on substrates based on an S1 (100% soil taken from municipal waste) and S2 (50%), exhibit morphological appreciable contribution to the control soil.

The mineralization of the organic matter is a very important phenomenon which leads to the release of nutriments used by plants. The rate of transformation of the organic matter depends on several factors and parameters such as climatic factors and biological and physicochemical properties of the soil and the litter. In this study, we investigate the effect of the addition of litter of various species as well as the effect of soil moisture on mineralization of organic matter and on mineral nitrogen release in three soils sampled in three cork oak stands during a period of 41 days under the same laboratory conditions. Carbon mineralization was determined using CO2 respiration method, whereas the mineral nitrogen content was measured at the last day of incubation both in soil samples with added plant leaf material, and in control soil samples without addition under two treatments of moisture (40% and 80% WHC—water holding capacity). Our results show that the addition of leaf litter causes an increase in the microbial activity. Soils without addition were significantly different from the plant leaf added soils in respect to carbon mineralization at the end of the incubation period. Moreover, it is noted that the mineralization of carbon is more marked with moisture at 80% than that of 40%, contrary to that of the nitrogen, which is not influenced by the variation of moisture.

Influence of climatic variables on the thickness of growth-rings in Tunisian cherry (Prunus avium). A dendroecological study conducted in northwestern of Tunisia has quantified the effect of monthly climatic variables (temperature and precipitation) on growth-ring width in five populations of the wild cherry (Prunus avium). Statistical analysis shows that the summer drought of the preceding year is the main factor (but not the only one) limiting the radial growth, followed by drought in the preceding fall and finally winter cold. Variability of the response depends more heavily on rainfall than temperatures, low rainfall leading to higher sensitivity to winter cold and summer and autumn drought. Growth of Prunus avium is generally positively influenced by the maximum temperatures (December) and precipitation (from August to January)., Une étude dendroécologique réalisée dans le nord-ouest de la Tunisie a permis de quantifier l’effet de variables climatiques mensuelles (températures et précipitations) sur la largeur des cernes de cinq populations de merisier (Prunus avium). L’analyse statistique montre que la sécheresse estivale de l’année précédente est le principal (mais non l’unique) facteur limitant la croissance radiale, suivie par la sécheresse de l’automne précédent et enfin le froid hivernal. La variabilité de la réponse dépend plus fortement des précipitations que des températures, une pluviométrie faible conduisant à une sensibilité plus forte au froid hivernal et aux sécheresses estivale et automnale. La croissance de Prunus avium est généralement influencée positivement par les températures maximales (décembre) et les précipitations (d’août à janvier)., Jdaidi Nouri,Zouwawi Ikbal,Hasnaoui Foued,Boussaidi Naceur,Abbès Chaabane,Torres Alvarez Enrique,Hasnaoui Brahim. Influence des variables climatiques sur la largeur des cernes de Merisier (Prunus avium) en Tunisie. In: Revue d'Écologie (La Terre et La Vie), tome 69, n°3-4, 2014. pp. 328-337.

The chemical composition and the biological activities of Mentha pulegium leaves extracts were evaluated. The main components of M. pulegium EO were menthone (41.7%), cis-isopulegone (31.71%) and isomenthone (15.03%). The methanol extract of M. pulegium was rich in phenols and flavonoids. The EO showed much better antioxidant activity than the methanol extract against the DPPH and ABTS radicals scavenging. The EO showed strong antibacterial and antifungal activities against 10 tested microorganisms (Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa, Aeromonas hydrophila, Listeria monocytogenes, Bacillus cereus, Aspergillus niger, Aspergillus flavus, Candida albicans) tested whereas the methanol extract almost remained inactive. The IZ diameters and minimal inhibitrice concentration values for tested microorganisms were in the range of 15–30 mm and 0.05–0.8% (v/v), respectively. Future studies should focus on to determine the usage ability of M. pulegium EO in foods as natural preservative in effective dose. Practical Applications The replacement of synthetic additives by natural active compounds fosters research on the screening of medicinal plants as sources of new antioxidants. Moreover, such compounds can be used for extension of product shelf life by inhibiting the growth of foodborne spoilage bacteria. This study focused on the evaluation of biological activities of M. pulegium EO because of its application in food industries as a reasonably safe agent. Thus, this species might be a good candidate for further investigation in developing new antioxidants, as well as preservatives in food against the well-known causal agents of foodborne diseases and food spoilage, particularly E. coli, S. typhimurium, L. monocytogenes, P. aeruginosa and S. aureus.