The objective of this study was to model the growth and development of the stem and wood properties of Scots pine (Pinus sylvestris L.) in order to investigate how silvicultural management affects the knots and other properties of wood. In the above context, an existing three-dimensional model for the structural growth, stem and wood properties (especially knots) of a Scots pine was further developed (Paper I) and used with a sawing simulator (Paper II) to study how management (initial spacing, thinning and artificial pruning of branches) affects the quantity and quality of the sawn timber (Paper III). In addition, empirical models were developed for the distribution of diameter growth along the stem (Paper IV) and prediction of early wood percentage, wood density and fibre length along the stem (Paper V). These empirical models were also integrated with a process-based growth and yield model simulations (Papers IV and V).
Based on simulations, it was found that in order to maximize the quality of sawn timber, trees should be grown at relatively narrow spacing (up to 5 000 stems ha-1) at the beginning of the rotation to reduce the growth of branches, whereas towards the end of rotation they should be grown at relatively sparse spacing (e.g. 500 stems ha-1) to accelerate the self-pruning of dead branches and occlusion of knots, and to increase the volume growth of the stem (Paper III). It was also found that the diameter growth and the properties of wood vary in individual trees significantly depending on the stand development phase, management and tree status in a stand and depending on which part of stem is considered (Papers IV and V). To conclude, the integrated models developed in this work provide possibilities to assess simultaneously the impacts of management on the growth and yield and the properties of wood.