Properties of UK-Grown Sitka Spruce: Extent and Sources of Variation.

Structural timber produced from Sitka spruce plantations in the UK typically achieves the requirements for the C16 strength class. However, very little is known about the variability of this plantation resource, or the factors that contribute to this variability. A study to benchmark the properties of the current resource found that there was a considerable amount of variation in wood properties between sites as well as between trees within a site. This benchmarking study has been complemented by studies which have investigated the impacts of genetics, precommercial thinning and rotation length on timber properties. In these studies, measurements of stress wave velocity have been made on standing trees, freshly-felled logs and sawn timber. Knowledge gained should assist in better utilisation of the current resource as well as identifyingmanagement practices that will lead to an improved future resource for structural applications