Báo cáo lâm nghiệp: "Dendroécologie du pin laricio de Corse dans l’ouest de la France. Évolution du potentiel de croissance au cours des dernières décennies"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài: "Dendroécologie du pin laricio de Corse dans l’ouest de la France. Évolution du potentiel de croissance au cours des dernières décennies. | 931 Ann Sci For 1996 53 931-946 Elsevier INRA Article original Dendroécologie du pin laricio de Corse dans I ouest de la France. Evolution du potentiel de croissance au cours des dernières décennies F Lebourgeois M Becker Unite d ecophysiologie forestiere équipe phytoécologie Inra-Nancy 54280 Champenoux France Reẹu le 19 mai 1995 accepté le 7 septembre 1995 Summary - Dendroecological study of Corsican pine in western France. Growth potential evolution during the last decades. A total of 1 808 Corsican pines Pinus nigra Arnold ssp laricio Poiret var Corsicana were sampled in western France Pays-de-la Loire region . The evolution of the mean growth of each tree and the relationship between the radial growth and the present crown conditions were studied. For each ring earlywood and latewood widths were measured separately. The analysis of the mean radial growth in relation to the cambial age showed that the young rings 10 years were mainly made up of earlywood 70 to 80 . It was only from 40 years onwards that the percentages of each ring compartment become equal 50 . The radial growth mean curves from 1935 to 1991 showed i strong annual variations in relation to annual climatic conditions ii several crises of varying severity and length on the decade time scale during which growth declined because of sustained climatic stresses 1952 1962 and since 1981 III an increasing general trend of the growth indices 50 60 and 35 for respectively the total ring the earlywood and the latewood. These results confirm the long-term growth trends observed in several French regions for various species which may be interpreted as a result of global climatic changes as a consequence of the increase in atmospheric co2 atmospheric anthropogenic deposits especially of nitrogen compounds and improvement of silviculture selection of seedlings thinning density of plantation . By stratification of the whole sample according to crown condition divergent curves were obtained. The loss of vitality

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