1. Unit for Field-based Forest Research Swedish University of Agricultural Sciences Thomas Ulvcrona IUFRO Division 5 Conference 5.02.00 E Wood Composites and Wood Products

2. Unit for Field-based Forest Research Swedish University of Agricultural Sciences Thomas ULVCRONA* Shrinkage/ swelling coefficients in Norway spruce (Picea abies L. Karst) tissue types after impregnation with linseed oil Swedish University of Agricultural Sciences Faculty of Forestry Unit for Field-based Forest Research Svartbergets Fieldstation SE-922 91 Vindeln SWEDEN Here

3. Unit for Field-based Forest Research Swedish University of Agricultural Sciences The Unit for Field-based Forest Research was established in 2004 -Experimental forests -Field-based research stations -Long-term field trials that is owned by the Faculty of Forest Science

4. Unit for Field-based Forest Research Swedish University of Agricultural Sciences Connect forest production and wood science for future use within the frames of industrial supply chains Overall aim

5. Unit for Field-based Forest Research Swedish University of Agricultural Sciences Aim of work and methods The objectives of this study were to examine the principal characteristics of specific pre- treated, dried and green tissues from one Norway spruce tree, and to quantify the effects of impregnation on them. For this purpose, shrinkage/swelling coefficients (S) were monitored at each experimental stage. Ten samples of each of four types were taken, corresponding to four distinct tissue types: heartwood/mature wood, heartwood/juvenile wood, sapwood/mature wood and sapwood/juvenile wood. From each sample five specimens were prepared.

6. Unit for Field-based Forest Research Swedish University of Agricultural Sciences Characterized raw materials i.e. tissue types Oil uptake in the characterized tissue type Material property in the processed wood material

7. Unit for Field-based Forest Research Swedish University of Agricultural Sciences 1 2 3 4

8. Results Mean shrinkage/swelling coefficients (S-coefficients) following the impregnation process were between -12.1 and -13.7 % for pre-treated and green specimens, and +1.4 % for dried specimens. Values of S-coefficients after water procedure (subsequent to impregnation) in impregnated specimens varied between 13.6 and 9.8 % and in dried control specimens between 15.6 and 13.2 %. S-coefficients within tissue types were not significantly different in impregnated specimens; however S-coefficients in control specimens differed significantly between heartwood and sapwood tissue types.

9. Unit for Field-based Forest Research Swedish University of Agricultural Sciences Conclusions There appears to be scope to develop wood materials with tailored dimensional stability characteristics. If relevant material properties are assessed throughout the total production process.