Investigation of potential sawlog quality indicators -: A case study with 32-year-old plantation Eucalyptus globulus Labill.

Thirty dominant or co-dominant, straight trees were selected from a 32-year-old thinned plantation of Eucalyptus globulus Labill. Growth strain at breast height was estimated using the longitudinal displacement which was measured with a CIRAD-foret method. One 12-mm diametrical increment core was collected from each tree at breast height and a SilviScan specimen prepared from each core. Density, cellulose microfibril angle (MFA), cellulose crystallite width (W-cryst) and Young's modulus along the grain (E-L) were determined using the SilviScan-2 technology. Weighted means and other characteristics of these four wood properties were determined and used as sawlog quality candidate indicators. Relationship between each sawlog quality candidate indicator and each of several arbitrarily defined sawlog quality descriptors were examined. Growth strain appeared to be the only useful indicator for log-end split severity and may also be a useful indicator for spring in dried boards. The radial variation of MFA (percentage of MFA values smaller than 12 degrees) appeared to be the most useful indicator of spring in dried boards. The radial variation of E-L (E-L slope) appeared to be more useful in predicting distortion in green slabs and possibly flitch during sawing. Density and cellulose crystallite width, either as tree means or in other expressions, showed no significant correlation with any sawlog quality descriptors.