Correlation between vessel features and hardwood drying properties; case study: beech (Fagus orientalis) and oak (Quercus castaneifolia)

In this research, the effects of vessel features, including vessel diameter, density and porosity on drying rate and casehardening of beech (Fagus Orientalis) and oak (Quercus castaneifolia) was investigated. For this purpose, flat-sawn boards with dimensions of 170×50×80 mm (L×T×R) were cut from the sapwood and were then dried in laboratory kiln at 50˚C and 50 % relative humidity to final moisture content of 8%. After drying, the severity of casehardening of dried boards was measured using prong test. For anatomical studies and measuring vessel features, white chalk and black marker method was used and scanned sections were analyzed using ImageJ. Pearson correlation was applied between vessel features and drying properties using SPSS software. Results showed that vessel proportion and porosity have more pronounced effect on the drying rate than vessel diameter and the latter feature can be ignored; as drying rate in the free-water domain was lower for oak having larger but fewer vessels than beech. Results also showed that correlation between casehardening and vessel diameter was significantly positive; however, a negative correlation was observed between porosity and casehardening.