tailieunhanh - Báo cáo lâm nghiệp: "A model of with even-aged beech stands productivity process-based interpretations"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế, đề tài:"A model of with even-aged beech stands productivity process-based interpretations. | 1 Ann Sci For 1996 53 1 -20 Elsevier INRA Original article A model of even-aged beech stands productivity with process-based interpretations JF Dhôte Laboratolre de recherches en sciences forestieres ENGREF-INRA 14 rue Girardet 54042 Nancy France Received 18 July 1994 accepted 25 April 1995 Summary In order to describe the productivity of pure even-aged stands of common beech a system of three differential equations is proposed for dominant height basal area and total volume growth. The model was derived and fitted to 317 observation periods in 29 long-term experimental plots ranging from northwest to northeast France. It involves parameters at the forest and stand levels. Site index is the asymptote of the height-age curve. Model structure is such that for any given height some differences in total volume yield exist between stands of different productivities. This result is in contradiction with Eichhorn s rule. However in our model no parameter other than site index is necessary to characterize stand productivity. The possibility to generalize the model to a larger range of ecological conditions is discussed by a process-based interpretation. The site dependence of the parameters can be understood by reference to carbon-balance models. A linear relationship between basal area and height-growth rates is investigated by a separate model of sapwood geometry and dynamics. Fagus sylvatica L stand productivity Eichhorn s rule growth and yield models carbon-balance models sapwood Resume Un modèle de productivité des hêtraies régulières avec des interpretations éco-physiologiques. Afin de décrire la productive de peuplements purs et réguliers de hêtre on propose un systems de trois equations differentielles pour la hauteur dominante la surface terrière et le volume. Le modèle a été construit et aịusté à partir de 317 périodes d observations dans 29 anciennes placettes experimentales réparties entre le nord-ouest et le nord-est de la France. II comprend des paramètres .