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Báo cáo khoa học: "Short-term variations and long-term changes in oak productivity in northeastern France. The role of climate and atmospheric CO 2"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Short-term variations and long-term changes in oak productivity in northeastern France. The role of climate and atmospheric CO 2. | 477 Ann Sci For 1994 51 477-492 Elsevier INRA Original article Short-term variations and long-term changes in oak productivity in northeastern France. The role of climate and atmospheric co2 M Becker1 TM Nieminen 2 F Gérémia 1 INRA Forest Research Center 54280 Champenoux France 2 Finnish Forest Research Institute PL 18 01301 Vantaa Finland Received 20 July 1993 accepted 24 January 1994 Summary A dendroecological study was carried out in 2 forests in northeastern France with the aim of identifying and quantifying possible long-term trends in the radial growth of sessile oak Quercus petraea Matt Liebl and pedunculate oak O roburL . A total of 150 sites were selected to represent the ecological diversity of these forests. An index Cd was used to correct annual ring width in order to compensate for the effect of different competition situations. The data were standardized with reference to the mean curve basal area increment vs cambial age . The growth index curves revealed a strong increase in sessile oak growth 64 during the period 1888 to 1987 as well as in that of pedunculate oak 40 . The growth increase in the young rings 60 years of sessile oak was 81 and that of young rings of pedunculate oak was 49 . The corresponding increase in the old rings 65 years was 48 and 15 respectively not significant for the latter . It would thus appear that pedunculate oak has benefited to a lesser extent than sessile oak from the progressive changes in its environment. Years showing a strong growth decrease are more common for pedunculate oak than for sessile oak. These results are consistent with a recent hypothesis about a slow but general retreat of pedunculate oak including severe episodic declines in favour of sessile oak in many regions of France. A model was created using a combination of meteorological data monthly precipitation and temperature starting in 1881 and increasing atmospheric co2 concentrations. The model explains 78.3 of the variance for sessile oak and 74.3 .