%0 Research article
%T Intra-tree models of basic density in Norway spruce as an input to simulation software
%A Lindström, Håkan
%D 2000
%J Silva Fennica
%V 34
%N 4
%R doi:10.14214/sf.622
%U https://silvafennica.fi/article/622
%X Basic density is said to influence aspects of conversion, properties,  and end-use of forest products. Consequently, it is argued that accurate  models of basic density variation, within and between trees, could be  used to improve the utilisation of wood as an industrial raw material.  The objective of the present study was to develop basic density models  based on Norway spruce trees, that 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 moderate, and two large 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 butt end of each log and from  the top end of the top log. Computed tomography scanning and image  analysis were used to determine basic density and growth ring  development on sampled discs. Basic density development in 20-mm  segments from pith outwards was modelled in models based on ring width,  tree and growth condition data. The resulting models had an adjusted R2  of 0.37–0.51 and a RMSE of 37–41 kg/m3.