Assessment on the sawing recovery and drying performance of salvaged solid timber through kiln drying process

For the past one decade, approximately 200 dead and fallen trees were extracted around FRIM Campus each year due to lightning strike and pest attack. These damaged standing trees are potentially dangerous and would pose risk to public safety if left unattended. Most of these trees are lesser known species and less in demand compared to commercially known timber species, and they had to be discarded due to serious decay if stored over long period. However, these logs harvested from lesser known species could still be salvaged if were processed by using proper processing techniques and treatment procedures. The properties and performance of the salvaged timber could be enhanced for the production of value-added products such as furniture and wooden crafts. The aim of this study was to evaluate the sawing recovery of selected salvaged logs and to determine its drying performance through kiln drying process. The study was conducted by using readily available log resources, obtained from dead or fallen tress extracted by FRIM’s Urban Forestry unit. Two species were selected which are Hopea odorata and Maesopsis eminii. These logs were converted into slabs of approximately 45 mm in thickness and 1.8 - 2.1 m in length. H. odorata and M. eminii slabs were tested for their physical properties before being dried at dry bulb temperature of 60°C in a 14 m3 capacity steam-heated drying system. The timber stacks were dried until a targeted moisture content of approximately 10%. The average sawing recovery of salvaged logs into slabs was evaluated based on their volume basis. The result shown that the average sawing recovery of H. odorata logs was 54.2% whereas M. eminii was 11.8%. The initial moisture content of H. odorata and M. eminii used in this study ranged from 34.9 - 36.84% and 79.3 - 105.21% respectively. The estimated basic density ranged from 671.84 - 698.15 kg/m3 for H. odorata and 415.53 - 453.61 kg/m3 for M. eminii. Meanwhile, the average volume shrinkage of H. odorata and M. eminii are 12.0% and 7.5% respectively. The drying time for H. odorata and M. eminii from fresh and partially air-dried condition to reach 8-10% moisture content was about 25 days. The result of the drying trial showed that both species were able to dry uniformly throughout the timber, although mixed species of different initial moisture content were dried in the same kiln charge.