METHODOLOGY OF MICRODENSITOMETRIC MEASUREMENT FOR OAK WOOD (QUERCUS-ROBUR L AND QUERCUS-PETRAEA LIEBL) - PROPOSAL FOR A REPRESENTATIVE SAMPLING OF OAK WOOD DENSITY WITHIN RING

Microdensitometric analysis of oak wood has always caused problems; be cause of tangential anatomical variability within rings, it is difficu lt to obtain ring representative density components (latewood density or earlywood density). The microdensitometric slit passage distributio n in the ring as well as the slit height have a significant impact on density measurement repeatability. The study of two samples of sixteen rings showed that it is better to group the passages than to scatter them in the ring. In any case the small number of experiments generall y carried out for practical reasons is not sufficient to avoid the err atic influence of parenchyma rays on density measurements. A complemen tary solution could be to increase the microdensitometric slit height to integrate a greater tangential variability despite the small number of experiments. After considering fuzziness problems, which occur whe n microdensitometric slit height increases, it seems possible to combi ne a grouped passage distribution with a higher slit for a more repres entative evaluation of oak wood density.