Influence of Planting Scheme on Some Physical Properties of Norway Spruce (Picea abies (L.) H. Karst) Wood

Abstract

This study analyses the influence of a planting scheme on physical properties of Norway spruce wood. The research material consisted of 326 Norway spruce trees (Picea abies (L.) H. Karst) selected from an experimental plot with four planting variants (2500, 3330, 5000, and 7510 trees·ha−1). The research aspects were: (1) wood density (measured by volumetric method and using microdrilling resistance as proxy), (2) microdrilling resistance, and (3) sound speed. There was a decrease in wood density values (from 0.3376 to 0.3367 g·cm−3) and in microdrilling resistance values (from 15.136% to 14.292%) as the number of trees·ha−1 used for plantation increased from 2500 to 5000. The planting variant with 7510 trees·ha−1 had the largest value (0.3445 g·cm−3 for wood density and 15.531% for microdrilling resistance). Sound speed decreased from 1032.8 to 989.8 m·s−1 as the number of trees·ha−1 increased from 2500 to 7510. These results show a relationship between DBH values and studied physical properties. This relationship is more evident for variants with low planting density (e.g., 2500, 3330 trees·ha−1) than that of dense planting variants (e.g., 7510 trees·ha−1). The explanation may be that the growth of trees in dense plantings is slower; in less dense planting variants, the increase in wood is greater, and as a result, wood volumetric density dependence on the DBH value is greater.