Planteringsförbandets inverkan på bildningen av kärnved hos tall (Pinus sylvestris L.) : en modellsimulering av planteringsförbandets inverkan?

Sammanfattning: The current state of knowledge indicates that there is more than one factor that initiates heartwood transition. This study supports its hypothesis on the theory that heartwood is formed by a fixed fraction of the annual growthring, 0,5 to 0,8 rings. To calculate heartwood volume modelings were carried out in four different pine stands with different spacings, 0,75, 1,25, 1,5 and three meters. The model indicates heartwood diameter (HWD) and is based on four explanatory variables, height (H), crown ratio (CR%), diameter breast height (DBH) and tree height (TH). The shifting plant spacing results in varying growth rate in the juvenile stage. This leads to rings with larger diameter in stands with wide planting spacing, which in theory, will lead to higher heartwood volume. This study demonstrated a higher mean volume of heartwood per tree with three meters plant spacing, 0,80 m3sk, compared to 0,75 meters width which gave a volume of 0,71 m3sk. The mean sapwood volume tended to demonstrate the same relationship when the sapwood increased with increased spacing. With three meter in spacing the volume amounted to 0,78 m3sk and the densest 0,61 m3sk. The ratio between heartwood and sapwood changed with spacings. Heartwood proportion increased with decreasing spacing, from 0,51to 0,54. The volume heartwood differed between 192 to 161 m3sk for respectively spacing and stand density. This indicates that stand density is an important factor. Several factors affect the width of the annual growthring. Planting spacing is one thus affecting the amount of heartwood in pine stands.