tailieunhanh - Báo cáo lâm nghiệp: "Impact of drought and Hypoxylon mediterraneum on oak decline in the Mediterranean region"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài: "Impact of drought and Hypoxylon mediterraneum on oak decline in the Mediterranean region. | Ann Sci For 1996 53 753-760 Elsevier INRA 753 Original article Impact of drought and Hypoxylon mediterraneum on oak decline in the Mediterranean region A Vannini1 R Valentini 2 N Luisi 3 1 Department of Plant Protection 2 Department of Environmental and Forestry Sciences University of Tuscia Via s Camillo de Lellis 01100 Viterbo 3 Department of Plant Pathology University of Bari Bari Italy Received 24 October 1994 accepted 31 October 1995 Summary An association was evidenced in the last decade among changes in species composition changes in rainfall distribution and incidence of stress-induced pathogens such as Hypoxylon mediterraneum in old oak coppices in central and southern Italy. Quercus cerris and Q frainetto were more affected by decline than Q pubescens following periods of summer drought. The role of H mediterraneum on drought-susceptible species was relevant by increasing their mortality. According to our results changes in rainfall distribution and secondary biotic stress factors such as H mediter-raneum seem to act as factors of balance by restablishing the original forest composition existing before the selective pressure of coppice managment. oak I Hypoxylon mediterraneum drought I decline vegetation changes Resume Effets de la sécheresse et d une infection par Hypoxylon mediterraneum sur le dépérissement des chênes en zone méditerranéenne. Des modifications de la composition floris-tique de la pluviométrie et de la sensibilité à un pathogène induit par les contraintes comme Hypoxy-lon mediterraneum se sont produite de manière fortement interdépendante au cours de la dernière décennie dans des taillis anciens de chênes en Italie centrale et méridionale. Quercus cerris etQ frai-netto se sont révélés être plus sensibles au dépérissement resultant de périodes de sécheresse estl-vale que Q pubescens. L impact de H mediterraneum sur les espèces sensibles à la sécheresse s est traduit par une augmentation de leur mortalité. D apres nos résultats la .