Effect of drying treatments on warping of 36-year-old white spruce seed sources tested in a provenance trial

Abstract

Wood from plantations will increasingly become a major source of supply for the lumber industry and this raw material is likely to have characteristics much different from those of the wood harvested in natural forests. This could require costly adjustments to manufacturing processes to maintain the quality of the end-use products. In Canada, white spruce (Picea glauca [Moench] Voss) is one of the main reforestation species and one of the most extensively used for lumber. In this study we investigated the genetic variation in warping in kiln drying of 25 white spruce provenances grown in a plantation and one from a second-growth forest stand. All of them were from the Great Lakes - St. Lawrence region. Two drying treatments were applied, i.e. conventional and high-temperature drying. For bow, crook and twist warp defects after drying, significant differences were not found among the provenances tested, nor between the drying treatments. However, significant differences were revealed between the mean of all provenances (plantation-grown) and wood from second-growth forests for crook and twist defects. The high proportion of tree to tree variation provides grounds for hope of rapid gains through mass selection.