Evidence for associations between SilviScan-measured wood properties and intraring checking in a study of twenty-nine 6-year-old Pinus radiata

Wood anatomical characteristics of twenty-nine 6-year-old Pinus radiata D. Don trees, selected to represent the extremes of intraring checking, were assessed with SilviScan. Derived ring-level summary variables were calculated from the SilviScan pith-to-bark wood property traces, based on ring means, standard deviations, and quantiles. Incidence of checking was assessed on discs that had been oven dried using a standardized method, and evidence for associations between wood characteristics and checking was evaluated at the tree and ring level using Bayesian statistical methods. Bayes factors of 39.1, 14.9, and 7.8 were obtained at the tree level, representing moderate to good evidence for associations between ring medians of wood density, tracheid radial diameter, and cell wall thickness, respectively. Increasing wood density, decreasing tracheid radial diameter, and increasing cell wall thickness were associated with reduced incidence of checking. These are parameters expected a priori to contribute to tracheid cells' resistance to collapse under drying stresses. A generalized linear model with radial diameter and cell wall thickness as independent variables had a concordance of 83% for predicting the checking status of trees.