Cytisus Legume Association Interests on Oak Growth and Cork Quality

Abstract

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.