Variability in Drying and Mechanical Properties for Blackbutt Timber in NSW

The impact of the variability in timber properties has been a challenge for companies involved in drying timber. The definition of quality considered in this study is to both minimize the dispersion of the final moisture contents in dried timber boards and to reduce cracking/checking. This work measured the amount of variability of timber properties by conducting drying experiments using timber boards taken from different locations within a single tree and between trees, for regrowth and plantation blackbutt timber (Eucalyptus pilularis Sm.). The quantified variabilities were then used to develop optimized timber drying schedules that are intended to dry regrowth and plantation blackbutt boards as quickly as possible without cracking in the presence of large biological variability. Previous work either developed optimized drying schedules to minimize the dispersion of the final moisture contents or reduced cracking/checking. No schedule has been developed to satisfy both aspects of quality. There is little information about the variability in timber properties with respect to drying and how strongly they are correlated. This work particularly addressed this aspect of the problem.