Radiata pine, the predominant species in New Zealand, has a relatively low stiffness corewood zone which can make the corewood of a log unsuitable for use as structural timber. This is associated with a significant value-loss. In a mill-scale trial it was assessed whether NIR could be used to assess green timber stiffness at an early stage in the sawmill. Thus the sawing patterns could potentially be adjusted to minimize downgrading of timber. An NIR spectrometer was used to record spectra from the areas of the future boards on the cant surface, after the first two opening cuts by a headrig saw to produce a cant. The material was then tracked through the sawmill and after kiln-drying and planing the cut boards were assessed for stiffness with a three-point bending test. The stiffness values were then regressed against the respective spectra from the area of the green, uncut cant from which the board was derived using PLS modelling. The resulting correlations of r~2 = 0.54 (big logs) and r~2 = 0.57 (small logs) based on full, random cross validation, were sufficient for an economic segregation of cants into different sawing patterns based on their corewood stiffness.
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