Between-site and between-provenance differences in shrinkage properties of 10-year-old Eucalyptus globulus Labill

Summary Basic shrinkage properties of three provenances of 10-y-old plantation-grown Eucalyptus globulus Labill. from two sites in Mt Gambier region were determined. The properties included shrinkage and collapse in radial and tangential directions, and cross-sectional shrinkage after re-conditioning. Site had a highly significant effect on a number of shrinkage properties. There was no significant difference between provenances in any shrinkage property. Nevertheless, Jeeralang provenance consistently had the highest mean value for every shrinkage property in both radial and tangential directions (except for radial shrinkage), followed by King Island then South-eastern Tasmania provenances. Values for mean radial and tangential shrinkage, and mean radial collapse, in this study were well below the values of corresponding properties for 17-23-y-old E. globulus trees in Tasmania as reported by previous researchers. Internal checking was virtually absent in small specimens (20 mm × 20 mm × 90 mm) that were dried from green to 12% moisture content. The effect of growing conditions (stocking, pruning, water availability, soil conditions) on shrinkage properties and drying degrade requires detailed examination in future extensive studies. and variation in shrinkage levels, can also result in other forms of drying degrade such as case hardening. Collapse and all forms of checking are affected by wood permeability, extractive content, wood density and its variation, board thickness, drying practices and the presence of tension wood. Generally the severity of collapse checking increases with collapse. The amount of collapse is positively related to low permeability, high extractive content, low density and large variation of density, board thickness in the radial direction, severe