Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Measurement of free shrinkage at the tissue level using an optical microscope with an immersion objective: results obtained for Douglas fir (Pseudotsuga menziesii) and spruce (Picea abies). | Ann. For. Sci. 64 2007 255-265 INRA EDP Sciences 2007 DOI forest 2007003 255 Original article Measurement of free shrinkage at the tissue level using an optical microscope with an immersion objective results obtained for Douglas fir Pseudotsuga menziesii and spruce Picea abies Patrick PERRÉ Frangoise HUBER LERMaB Integrated Research Unit of Wood Science UMR 1093 INRA ENGREF University H. Poincaré Nancy I ENGREF 14 rue Girardet 54042 Nancy France Received 17 May 2006 accepted 28 September 2006 Abstract - Shrinkage at the tissue level has been evaluated satisfactorily using relatively simple equipment comprising an optical microscope equipped with reflected light a standard objective a water immersion objective of same magnification and a digital camera connected to a computer. Shrinkage is calculated from pairs of images taken at the same magnification one collected during immersion in water and the other in air-dry state. A novel software program has been developed to determine shrinkage based on a closed chain of reference points chosen from the anatomical markers at the external part of the zone of interest. Measurements were performed on earlywood latewood and compression wood zones from two softwood species Douglas fir and spruce isolated from the rest of the annual ring with the aid of a diamond wire saw. As main results reference should be made to the low degree of shrinkage and high anisotropy factor of earlywood the marked and practically isotropic shrinkage in latewood and the low shrinkage with respect to cell wall thickness and inverse anisotropy ratio in compression wood. image analysis microscope shrinkage softwood tissue Résumé - Mesure du retrait libre à l échelle des tissus à l aide d un microscope optique muni d un objectif à immersion résultats obtenus chez le Douglas Pseudotsuga menziesii et l épicéa Picea abies . Le retrait a été évalué de fagon satisfaisante à l échelle tissulaire en utilisant un équipement relativement simple un .
