Evaluation of the visual stress grading standard on French Spruce (Picea excelsa) and Douglas-fir (Pseudotsuga menziesii) sawn timber Guillaume Roblot, Damien Coudegnat, Laurent Bleron and Robert ColletAnn. For. Sci., 65 8 (2008) 812DOI: https://doi.org/10.1051/forest:2008071