In this paper, dynamic MOE and static MOE of short-length radiata pine specimens produced for finger jointing were measured using non-destructive technique and correlated to each other. In order to obtain reliable static MOE data, 36 mm thickness shooks as well as the matched samples of reduced thickness (15mm) were tested, and the effect of annual growth rings on dynamic and static MOE is also addressed. Mathematical correlations were fitted between the dynamic MOE for the 36 mm thick shooks and the static MOE of the 15 mm thick samples. The coefficient of determination for dynamic MOE group 4,00-7,99 GPa was the strongest (R2= 0,82) and the correlation strength was further improved for sorted quarter sawn samples (R2= 0,92). Finally, the correlation between static modulus of rupture (MOR) and dynamic MOE is discussed.

A technique, useful for studying the formation of kiln brown stain in wood drying, has been developed to measure the surface colour change in a single board wood sample during drying. The wood sample is planed carefully in the green state to remove any surface wood that was damaged during cutting. The intact tracheids at the surface cause the evaporative front to remain at the surface during drying and therefore colour formation also occurs right at the surface. In this way, the colour can be measured using a spectrophotometer at various stages during drying without having to slice the sample. Experiments were carried out to measure the change in colour of wood from green to EMC corresponding to the drying schedule used. At the end of each schedule the boards were held at the EMC to determine how the colour changed below fibre saturation point. The results show that the colour of the wood continues to change below the fibre saturation point and the nature of the colour change indicates an increase in the complexity of the coloured compounds present. Further experiments were done to measure the rate of colour development at different temperatures using the technique developed. The results have shown a correlation between temperature and colour development over the range 50°C to 70°C with the rate increasing significantly above 60°C

Wood darkening and kiln brown stain (KBS) in kiln drying has caused significant economic loss to the wood processing industry which. Although extensive studies have been performed, feasible drying techniques have not yet been developed to economically produce bright, pale colour wood from commercial drying. The current work research has been conducted to dry radiata pine sapwood in hot air and in modified oxygen-free drying medium, namely, gases A, B and C. Four sets of matched samples were dried at three different temperatures of 50, 70 and 90°C, one set in a tunnel dryer simulating commercial hot air drying and three sets in a newly designed stainless steel cylinder, which was placed in an oven, for tests using the three oxygen-free drying media. The results show that no obvious KBS was detected near the surface of sample boards dried in all of the oxygen-free gases except for one run using gas B at 70°C. However, for hot air drying, the discolouration of wood could only be reduced by drying at the low temperature of 50°C. How kiln drying in air at or above 70°C induces surface darkening and KBS. These results indicate that using an alternative non-oxygen atmosphere to kiln dry wood could reduce surface discolouration and KBS

Experiments were undertaken to determine the effects of drying conditions (temperature and humidity) on the development of kiln brown stain in radiata pine during drying. Eight schedules were tested with temperatures ranging from 50°C to 120°C and relative humidity from 14% to 67%. The variables measured were moisture content, color expressed using the CIELab color space, and nitrogen content. The experiments have shown that the kiln brown stain is influenced by drying temperature and drying time. The recommendation is therefore that low-temperature and low-humidity schedules be developed for controlling color development.

A dynamic kiln-wide wood drying model was developed previously to solve the integral form of the unsteady-state mass, momentum and energy balance equations in the air side. For the wood side, an empirical model, characteristic drying curve, for the internal moisture movement is used, which was obtained for low and medium temperature drying of Pinus radiata, with a medium velocity of 1.4-4.1 m s-1. As part of the research programme to improve the design and control of dehumidifier wood drying kilns, the wood drying model has been assessed using the experimental data measured under drying conditions similar to those in dehumidifier kiln. It is noted that close agreement between the modelled results and the experimental data can be obtained for Pinus radiata drying processes with a medium air velocity (<; 5 m s-1). However, larger discrepancy between the modelled results and the measured data has been observed with a higher velocity (8 m s-1). To solve this problem a new characteristic drying curve, based on a two-zone diffusion model, has been used in the kiln-wide wood drying model and more accurate results have been obtained

Flatsawn and quartersawn Pinus radiata (radiata pine) sapwood boards were dried in a tunnel dryer in three runs using three drying schedules. These schedules represented low temperature (LT), accelerated conventional temperature (ACT) and high temperature (HT) drying. In each run, the boards were assembled in the dryer in two vertically matched layers with the flatsawn and the quartersawn boards being alternatively placed side by side. The samples were weighed at pre-set drying times. After drying, all of the samples were cut to two halves, one half for oven drying to determine the moisture content during drying and the remaining half for stress assessments. For LT and ACT drying, the quartersawn boards dried slower than the flatsawn boards, but for HT drying the difference between the quartersawn and the flatsawn boards was not statistically significant. The transverse residual drying stress in the quartersawn boards was, in general, lower than the flatsawn boards and the difference was most apparent for the LT drying