Modelling pine and spruce wood mechanical properties in different initial stand density plantations in Lithuania

Two main parameters of wood quality in constructions are wood modulus of elasticity (MOE) and bending strength (MOR). To understand what kind of quality wood we are growing in our forests and how environment and forest management could affect wood quality parameters, we need to model these parameters by stand, tree, and sample results. This would help to predict MOE and MOR for the future stands.<br /> To determine the influence of stand density and thinning intensity on wood mechanical and physical properties of Scots pine and Norway spruce, the data was obtained from experimental trials plots, which were established in 1990 by Institute of Forestry. The experimental object was divided to a smaller trial plots with different initial stand density: 2 plots with 3000-4400 trees per hectare, 2 plots with 2000-2400 trees per hectare, 2 plots with 1000-1200 trees per hectare. In these trial plots different thinning programs were used 3; 2; 1 time. From each trial plot 6 model trees were chosen (38 Spruce and 76 Pine trees).<br /> Models were created by SAS statistical package. General linear regression models were chosen to create 4 models for prediction of: dynamic modulus of elasticity for log (MOElog); dynamic modulus of elasticity for samples (MOEdyn); global static modulus of elasticity (MOE) and bending strength (MOR) All parameters for creating models were chosen as random effects. Stand parameter was stand density (SD). Tree parameters were diameter at breast high (DBH), competition index (CI), average ring width (RD), average ring density (RD) and log high (LH). Sample parameters were knot at fracture point (K) and sample wood density (WD).<br /> Best result for MOE models was in pine stand R²=0,82 spruce stand R²=0,85. R²=0,57 was in pine stand for MOR and R²=0,65 in spruce stand. Keywords: Sustainable forest management, Research ID: 3484790