Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài:"A study on growth stresses, tension wood distribution and other related wood defects in poplar (Populus euramericana cv 1214): end splits, specific gravity and pulp yield. | Ann Sci For 1994 51 301-313 Elsevier INRA 301 Original article A study on growth stresses tension wood distribution and other related wood defects in poplar Populus euramericana cv 1214 end splits specific gravity and pulp yield p Castéra 1 G Nepveu 2 F Mahé 1 G Valentin 1 1 Laboratoire de Rhéologie du Bois de Bordeaux CNRS INRA Université de Bordeaux Domains de Hermitage BP 10 Pierroton 33610 Cestas 2INRA Station de Recherche sur la Qualité des Bois Centre de Recherches Forestieres Champenoux 54280 Seichamps France Received 25 January 1993 accepted 1st December 1993 Summary The development of radial shakes after felling the tree has been observed on transverse sections of 15 poplar logs. The importance of end splitting is related to the distribution of internal stresses in the stem growth stress the angular variations of wood structure specific gravity and pulp yield and the transverse mechanical resistance of wood. To investigate growth stresses longitudinal displacements after stress release were estimated at the periphery of the stem using the single hole method. At least 4 measurements were necessary to estimate the maximum displacement value and the circumferential heterogeneity of the stress field. The position of this maximum was generally found on the upperside of the trees. To examine end splitting the radial and longitudinal extension of splits were roughly estimated for all visible shakes occurring on cutting sections near stress measurements breast height . Shakes were also measured for comparison at the felling section of the logs. The dimensions of the longest shake were used as an indicator of the severity of end splitting. A complete map of wood basic specific gravity was made at the breast height level for all trees. This is associated with pulp yield measurements an increase in density and pulp yield being generally considered as an indicator of gelatinous fibres. Peak values of growth stresses in the stem were associated with a significant .
