In glued laminated timber (glulam) manufacture, the quality of wood used in the process is of utmost importance, for it dictates the quality of the finished product. The mechanical properties of wood are hard to determine, and can be accurately measured only by destruction of the measured samples. Mechanical properties can also be estimated with any of the several non-destructive methods, described in my thesis, that can assign a specific strength class to a piece of timber. I have also described the production line of glulam on the case of Slovenian company Hoja d.d., where I did the measurements used in my thesis. Based on mathematical model using my sample of 205 measurements and on the data collected by the previous studies, I have shown, that using properly graded timber, we could produce glulam of the highest quality using only Slovenian wood.