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Le melange des essences est devenu un des enjeux majeurs de la gestion durable des forets en raison de l'importance des surfaces concernees et des nombreux avantages (prouves ou supposes) qu'il procure. Le melange constitue, pour le gestionnaire, un outil strategique car il permet, moyennant la prise en compte de quelques inconvenients, de repondre aux nombreux objectifs assignes a la foret : economiques, ecologiques et patrimoniaux. Mais les forestiers gerent les melanges le plus souvent de facon empirique, pragmatique et de nombreuses interrogations demeurent. C'est pourquoi les gestionnaires souhaitent que les chercheurs repondent a leurs interrogations techniques. La gestion de la lumiere, la synecologie des principales essences forestieres et les methodes de diagnostic restent des questions fondamentales pour les gestionnaires, sans oublier la prise en compte des aspects economiques.

This article deals with changes in silvicultural practices, in particular for pine and spruce. Silvicultural practices for production are the main topic of the article but other functions are dealt with as the multi-functional approach is predominant in France. For instance, uneven-aged silvicultural systems have gained considerable ground, particularly using deciduous species, in response to a demand from society (stability, landscapes), but which in the case of softwoods may be in contradiction with optimal, highly mechanised silvicultural practices. Another remarkable change is the wood industry’s demand for increasingly small diameters, which is also offers a means for adapting forests to climate change. But this trend is controversial. The revisiting of silvicultural methods that began in 1990 remains topical, with a view to establishing stands that are less capital-intensive and more mixed. However, the implementation of these methods has changed. Diversification of silvicultural practices might be further broadened by production models for medium-diameter trees with very little tapering.

Summary In the mediterranean region, the strong edaphic, climatic and economic constraints lead to the increase of the transplantation crisis of young trees. The use of controlled mycorrhizal infection is one of the means open to reduce the effects of this crisis by improving the quality of the forest trees grown in nursery, and the reforestation. To achieve this objective, a research/development programme was started and preliminary results are presented: screening of mycorrhizal isolates using physiological criteria; controlled mycorrhizal infection including the study of enzymic polymorphism in mycorrhizae as a tool for characterization of these organs; measurement of the effects of mycorrhizal infection on the nutrition of trees in nursery; ecophysiological study of experimental wood lots.

Patterns of habitat use by the wild boar Sus scrofa Linnaeus, 1758, in the agricultural ecosystem, were studied from late winter to early summer in southwestern France, by monitoring radio- collared individuals and collecting the animals activity signs.

Une synthese realisee sur 8 essais de reboisement effectues en region mediterraneenne par le CEMAGREF et l'Office national des Forets (STIR) permet de tirer les principales conclusions relatives a l'amelioration des techniques de reconstitution en especes feuillues en zone mediterraneenne. Parmi le materiel vegetal teste, ce sont les plants en godets de 000 cm 3 qui se revelent etre les plus performants pour un cout raisonnable. Ceux a section superieure ou egale a 50 cm 2 sont preferables. La technique du semis direct de glands s'est averee decevante pour l'installation des chenes. La reussite semble notamment trop aleatoire. L'utilisation d'un paillage ou la realisation d'un binage n'a aucun effet positif significatif sur la survie ou la croissance. L'abri-serre procure un gain significatif sur l'accroissement en hauteur des plants jusqu'a leur emergence de la protection. Ces techniques ne doivent pas faire oublier que les facteurs principaux de reussite sont le choix des stations appropriees et le soin apporte a la preparation du terrain ainsi qu'a la mise en place des plants.