tailieunhanh - Báo cáo khoa học: " Interactions between Scots pine, Ips acuminatus (Gyll.) and Ophiostoma brunneo-ciliatum (Math.): estimation of the critical thresholds of attack and inoculation densities and effects on hydraulic properties in the stem"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Interactions between Scots pine, Ips acuminatus (Gyll.) and Ophiostoma brunneo-ciliatum (Math.): estimation of the critical thresholds of attack and inoculation densities and effects on hydraulic properties in the stem. | 681 Ann. For. Sci. 57 2000 681-690 INRA EDP Sciences Original article Interactions between Scots pine Ips acuminatus Gyll. and Ophiostoma brunneo-ciliatum Math. estimation of the critical thresholds of attack and inoculation densities and effects on hydraulic properties in the stem Natacha Guérarda b Erwin Dreyerb and Franẹois Lieutiera c a Zoologie Forestiere INRA Orléans Avenue de la Pomme de Pin BP 20619 45166 Ardon Cedex France bUnité d Ecophysiologie Forestiere INRA Nancy 54280 Champenoux France cLaboratoire de Biologie des Ligneux Université d Orléans-la-Source BP 6759 45067 Orléans Cedex 2 France Received 28 April 2000 accepted 10 July 2000 Abstract - The aggressiveness towards Scots pine Pinus sylvestris L. of the association between a bark beetle Ips acuminatus Gyll and an Ophiostomatale fungus Ophiostoma brunneo-ciliatum Math. was investigated by estimating experimentally with young trees the critical threshold of attack or inoculation densities. Records of the relationship between natural attack densities by the beetles and survival of trees in a pine stand yielded a critical attack density threshold of about 900 m-2. Experimental mass inoculations of young pines with the fungus in a forest stand in Central France demonstrated a weak pathogenicity of this fungal species towards Scots pine. Inoculation densities varying from 200 to 1000 m-2 were used. Damage in the bark or in the sapwood recorded three months after the inoculations remained rather limited. The length of the induced reaction zones in the bark was small as compared to those obtained with more aggressive fungi and did not increase with inoculation density. Damage in the sapwood estimated either visually from the observed sapwood drying and from resinosis remained limited but increased significantly with the inoculation density. The impairment of hydraulic conductivity of inoculated trunk segments was rather large with at highest densities a loss of conductivity estimated to about 60 . .