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Background: The cork oak is the major forest element of northern Tunisia, especially in Kroumirie. It is a species of greatecological, economic and social value, with a natural distribution limited to the western Mediterranean basin. Following serious biotic and abiotic problems, oak forests have been greatly affected and their natural regeneration has become very difficult, even almost absent these last years marked by last climatic changes. The association of cork oak with autochthonous plant species such as leguminous is an original research to resolve this problem. As part of this reflection, the association of the cork oak with Cytisusvillosus could positively influence its growth and productivity by providing the nutrients necessary for its survival in the face of climatic constraints. Methods: The study was conducted in two sites in the Kroumirie (Ain Draham and El Feija forests). In each site two populations of the same bioclimatic stage are chosen: a population of only cork oak and a cork oak population associated with Cytisusvillosus. Several parameters were measured on trees at each population: morphological (height, circumference, leaf area index LMA) ecophysiological (photosynthesis, stomatal conductance, transpiration) and cork quality (porosity, humidity, quality) parameters. Result: The oaks with legumes in both Ain Drahem and Feija sites showed highly significant differences compared to the other two populations without association; for morphological and ecophysiological parameters. In the same way, statistical analysis has shown that the cork oak trees in Feija population with Cytisus have better cork quality than other populations. We can conclude that the cork oak behaves better and have higher growth and better cork quality in the presence of legumimous species like Cytisusvillosus. Such results could encourage the reintroduction of this legume especially in degraded areas of cork oaks for their maintenance and preservation especially in the current climate conditions. [ABSTRACT FROM AUTHOR]

Background and Aims Oaks are the foundation and dominant tree species of most Mediterranean forests. As climate models predict dramatic changes in the Mediterranean basin, a better understanding of the ecophysiology of seed persistence and germination in oaks could help define their regeneration niches. Tunisian oaks occupy distinct geographical areas, which differ in their rainfall and temperature regimes, and are thus a valuable model to investigate relationships between seed traits and species ecological requirements. Methods Seed morphological traits, desiccation sensitivity level, lethal freezing temperature, embryonic axis and cotyledon sugar and lipid composition, and seed and acorn germination rates at various constant temperatures were measured in Quercus canariensis , Q. coccifera , Q. ilex and Q. suber , using seeds sampled in 22 Tunisian woodlands. Key Results Only faint differences were observed for desiccation sensitivity in the oak species studied. By contrast, the species differed significantly in sensitivity to freezing, germination rates at low temperature and base temperature. Quercus ilex and Q. canariensis , which occur at high elevations where frost events are frequent, showed the lowest freezing sensitivity. A significant correlation was found between hexose contents in the embryonic axis and freezing tolerance. Significant interspecific differences in the time for seeds to germinate and the time for the radicle to pierce the pericarp were observed. The ratio of pericarp mass to acorn mass differed significantly among the species and was negatively correlated with the acorn germination rate. Quercus coccifera , which is frequent in warm and arid environments, showed the highest acorn germination rate and synchrony. Conclusions Seed lethal temperature, seed germination time at low temperatures, the ratio of pericarp mass to acorn mass and the embryonic axis hexose content appeared to be key functional traits that may influence the geographical ranges and ecological requirements of Mediterranean oaks in Tunisia. [ABSTRACT FROM AUTHOR]

The early spring folivore green oak leaf roller moth, Tortrix viridana, is one of the most harmful pests of Palaearctic oaks. The young larvae develop inside flushing buds and therefore require moth egg-hatching and budburst of their host plant to be synchronized. The aim of this study was to understand which factors (geographical distances, oak species, oak leaf phenology and timing of moth egg-hatching) influence the genetic structure of the moth. We performed multilocus analyses (COI and COII mitochondrial genes and eight nuclear microsatellites) on 30 populations from key forest districts in Sardinia and other Mediterranean localities. Both mitochondrial and nuclear markers detected a genetic divergence among populations that were separated by long distances and/or wide sea straights (Sardinia–Corsica vs. Tunisia vs. Italian peninsula–Sicily). Mitochondrial variation was divided into two major haplogroups relating to early or late egg-hatching behaviour, which was dependent on adaptation to specific oak budburst phenologies. On a regional scale, AMOVA tests showed the highest fixation indexes when populations were grouped according to early or late egg-hatching, whereas oak leaf phenology [deciduous (pubescent oak) or evergreen (holm oak and cork oak)] was the main factor in structuring populations on a larger Mediterranean scale. Furthermore, we demonstrated evidence for non-random patterns of gene flow mediated by male-biased dispersal, with females as the philopatric sex. [ABSTRACT FROM AUTHOR]