%0 Research article
%T Intra-tree models of juvenile wood in Norway spruce as an input to simulation software
%A Lindström, Håkan
%D 2002
%J Silva Fennica
%V 36
%N 2
%R doi:10.14214/sf.542
%U https://silvafennica.fi/article/542
%X Juvenile wood found in the first 5–25 growth rings of a conifer has a  structure and properties that differ from mature wood. Juvenile wood is  therefore said to influence processing and the end-use of sawn products.  Consequently, models describing the juvenile wood content, within and  between trees, could be useful in improving the utilisation and value of  wood as an industrial raw material. The objective of the present study  was to develop juvenile wood models, based on Norway spruce trees, which  could be used within a model system for conversion simulation studies.  Nineteen stands of Norway spruce (Picea abies [L.] Karst.) were selected  throughout Sweden. Based on DBH, two small, two medium, and two large  diameter timber trees were taken from each stand. DBH varied between  180–470 mm, tree height between 17–34 m, and total age between 51–152  years. Each selected tree was cross-cut into logs; discs were prepared  from the large end of each log and from the top end of the top log.  Image analysis was used to determine growth ring development on sampled  discs. Using tree and growth variables, the juvenile core radius and the  logarithmic value of juvenile wood percentage were modelled. The two  models had an R2Adj of 0.71 and 0.88 respectively.