Provenance variation in New Zealand-grown Eucalyptus delegatensis. 2: internal checking and other wood properties.
A Eucalyptus delegatensis provenance trial was evaluated at age 8 years for growth rate, internal checking within growth rings, and other wood properties. Internal checking severely restricts the use of E. delegatensis for solid-wood products. Relations were investigated between internal checking variables and other wood properties (basic density, heartwood content, and moisture content) and stem diameter. Neither the size nor the frequency of internal checks showed any marked association with any of the other variables or combinations of variables. Internal checking features, however, differed strongly between two regional provenance groups, the Tasmanian provenances having less than half as many as the mainland Australian provenances. Heartwood was markedly less, and basic density averaged 9 kg/m3 higher, in the Tasmanian material. The Tasmanian provenances were also slightly superior in diameter growth. Accordingly, Tasmanian provenances are recommended over mainland ones for New Zealand plantations, even though tree form is not as good.