The samples of wood with the trade name balsa obtained from a Slovenian trader were used to investigate the structure and to determine selected properties of wood. We wanted to find out if we are really buying the wood of balsa (Ochroma lagopus Sw.) On the selected samples, we made macroscopic and microscopic wood identification, and determined basic density, proportion of cell walls and volume shrinkage. To identify wood we made permanent slides, which were examined under a light microscope, and identified by using microscopic wood identification keys. We set the basic density, defined as the mass of oven dry wood per its maximal volume. Proportion of cell walls was measured on cross-sections observed under the light microscope using the programme NIS Elements BR 3.0. To determine the total volume shrinkage, we measured the volume of wood having moisture content above the fibre saturation point and oven dry wood. Identification has revealed that all the samples belonged to wood of balsa (Ochroma lagopus Sw.). The basic density varied from 62 kg/m3 to 328 kg/m3. The proportion of lumens was from 28 % to 52 %. The volume shrinkage was 7.4 % to 28.8 %, while 60 % of the samples collapsed during drying.
|
