Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Genetic control of stiffness of standing Douglas fir; from the standing stem to the standardised wood sample, relationships between modulus of elasticity and wood density parameters. Part II. | 145 Ann. For. Sci. 56 1999 145-154 Inra Elsevier Paris Original article Genetic control of stiffness of standing Douglas fir from the standing stem to the standardised wood sample relationships between modulus of elasticity and wood density parameters. Part II Philippe Rozenberg Alain Franc Cecile Mamdy Jean Launay Nicolas Schermann Jean Charles Bastien Inra Orleans 45160 Ardon France Received 18 December 1997 accepted 1 October 1998 Abstract - Fairly strong positive relationships between stiffness and density have often been reported. No stronger relationships have been found when using parameters of density profiles based on an earlywood-latewood boundary. In this study we attempt to model the relationships among the stiffness of different samples and simple parameters derived from microdensity profiles not established according to an earlywood-latewood boundary. Furthermore we try to determine if there is a genetic variation for the relationship between stiffness and density. From the results we find that the strongest relationship between a single density parameter and stiffness is r2 whereas it is r2 when involving a classical within-ring density parameter. At clone level r2 ranges from to while it is for the bulked samples. The mathematical form of the models differ from one clone to another there is a genetic effect on the models. This could mean that different clones different build their stiffness in different ways. Inra Elsevier Paris. genetics modulus of elasticity wood density X-ray microdensitometry Douglas fir Resume - Moderation du module d elasticite à 1 aide de données microdensitométriques methodes et effets génétiques. 2e partie. On a souvent mis en evidence d assez fortes relations entre la rigidité et la densité du bois. Ces relations n etaient pas plus fortes quand on a essayé d expliquer la rigidité à 1 aide de paramètres microdensitométriques intra-cerne bases sur une limite bois ini-tial-bois final. Dans cette étude
