Modelling the inter-tree variation of Itnot properties for Pinus sylvestris in Sweden

Bjorklund, L. & Moberg, L. 1999. Modelling the inter-tree variation of knot properties for Pinus syluestris in Sweden. Studia Forestalia Suecica 207. 23 pp. ISSN 0039-3150. With the help of the Swedish Scots Pine Stem Bank, the variation of internal knot properties was studied between stems and stands in sections in which the vertical variation was small. By means of explanatory site, stand and tree variables, knot property models were developed to describe variation between and within stands. Much of the betweenstand variation, and the lesser part of the random tree variation, in knot size, knot length and knots per whorl, was accounted for. However, knot angle was difficult to predict. This probably largely depended both on genetic control of this property, and on the measurement error caused by the low longitudinal resolution of the computer tomography scanning technique employed. Individual tree measurements of variables stable over time, such as growth-ring width close to the pith and stem diameter at the height of the lowest dead branch, were highly significant, and were the most important explanatory variables. K e y words: knot angle, knot diameter, knot frequency, knot length, models, wood quality attributes, CT-scanning. Lars Bjorklund* & Lennart Moberg, Department of Forest Management and Products, Swedish University of Agricultural Sciences, P.O. Box 7060, S-750 07 Uppsala, Sweden. Torresponding author : e-mail address: [email protected] ISBN 91-576-5957-5.