tailieunhanh - Báo cáo lâm nghiệp: "Element analysis of tree rings in pedunculate oak heartwood: an indicator of historical trends in the soil chemistry, related to atmospheric deposition"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài: "Element analysis of tree rings in pedunculate oak heartwood: an indicator of historical trends in the soil chemistry, related to atmospheric deposition. | Ann Sci For 1996 53 685-696 Elsevier INRA 685 Original article Element analysis of tree rings in pedunculate oak heartwood an indicator of historical trends in the soil chemistry related to atmospheric deposition G Levy 0 Bréchet M Becker Unite d ecophysiologie forestiere Centre de Nancy Inra 54280 Champenoux France Received 1 September 1994 accepted 15 November 1995 Summary When investigating historical alterations of the soil chemistry it could be interesting to determine the mineral content of the successive annual tree rings. The study reported here aimed at verifying this assumption. Oak heartwood was selected in order to minimize the disturbance due to element translocations in the wood. This study was carried out in a forest included in a floristic and eda-phic survey performed earlier throughout northeast France. Xylem cores were extracted from the boles of five over 60-year-old pedunculate oaks in each of 68 plots. The analysis showed on average an increase in nitrogen and aluminum a decrease in phosphorus potassium and magnesium and no change for calcium in the rings corresponding to the last 30 years of the heartwood 1938-1967 . These results are consistent with those of the floristic and edaphic survey which had shown an increase in nitrogen and a trend towards acidification in most of the soils between 1970 and 1990 mainly due to atmospheric deposition Thimonier et al 1992 . Thus these changes in the soil chemistry had probably already affected the forest studied between 1938 and 1967. Finally tree-ring analysis of oak heartwood appeared to be an effective approach to reveal historical changes in forest soil chemistry. tree ring pedunculate oak I heartwood I soil chemistry atmospheric deposition Resume Analyse minérale des cernes annuels du bois de cceur de chêne pédonculé un outil de detection de changements intervenus dans les propriétés du sol en relation avec les depots atmosphériques. L etude porte sur 1 intérêt potential de analyse des cernes .