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Báo cáo khoa học: "Linear and non-linear functions of volume index to estimate woody biomass in high density young poplar stands"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Linear and non-linear functions of volume index to estimate woody biomass in high density young poplar stands. | 335 Ann Sci For 1997 54 335-345 Elsevier Inra Original article Linear and non-linear functions of volume index to estimate woody biomass in high density young poplar stands JY Pontailler J R Ceulemans2 J Guittet F Mau 2 1 Laboratoire d ecophysiologie végétale CNRS Ura2l54 bailment 362 université Paris-XI 91405 Orsay cedex France 2 Department of Biology. University of Antwerpen UIA Universiteilsplein I B-26Ì0 Wilrijk. Belgium Received 3 April 1996 accepted 9 January 1997 Summary - Biomass estimations are very important in short rotation high density stands but usually require some destructive sampling. This paper discusses the potential use of allometric relationships based on volume index height X diameter squared for accurate and non-destructive estimations of stem biomass. When using this approach one implicitly assumes a constant conversion factor from stem volume index to real stem volume as well as a constant wood infradensity stem dry mass versus fresh volume both assumptions being questionable. Our results on five different poplar clones grown at two different sites Afsnee near Gent Belgium and Orsay near Paris France and under two different cultural management regimes underscore the following points i stem diameter measured at 22 cm aboveground and in two perpendicular directions is a relevant parameter to compute volume index in high density poplar stands ii power function regression equations fit the stem volume index versus stem dry mass relationship better than simple linear regressions iii attention should be paid to variation in wood infradensity which ranged from 0.35 to 0.44 kg dm-3 in our study. short rotation forestry high density plantations Populus I volume index allometric relationships Resume - Fonctions linéaires et non linéaires de rindice de volume pour I estimation de la biomasse sèche de jeunes plantations de peupliers. L estimation de la biomasse sur pied de parcelles denses cultivées en courtes rotations est généralement indispensable .