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The Wood From The Trees - Issue Five - Improving sawing and drying of plantation-grown shining gum

defect-free boards

Defect-free quarter-sawn boards from the Phase 2 study

A detailed analysis of the CRC’s first major processing study on pruned, plantation-grown shining gum (Eucalyptus nitens) was recently published in Volume 39 of the New Zealand Journal of Forest Science (downloadable from http://nzjfs.scionresearch.com). In this study we identified board surface checking as the most important grade-limiting defect, affecting the potential profitability of sawing plantation grown shining gum for appearance-grade products

The CRC’s second major processing study also used plantation-grown shining gum logs from the Forestry Tasmania silvicultural trial at Goulds Country, north-east Tasmania. A linear sawing system, the HewSaw R250, delivered improved sawing accuracy, and we evaluated a number of controlled drying schedules. There were marked reductions in board surface checking. Visible surface checks on back-sawn boards were reduced by more than 80%, from an average of 771 cm per square metre of board area in the Phase 1 study to 137 cm per square metre. Over 88% of boards in the Phase 2 study were free from surface checks.  Internal checking was also reduced in the Phase 2 study, with 54% of boards having no internal checking. 

quarter sawn boards

Quarter-sawn boards relatively free of internal checking, Phase 2 study

A detailed report on the Phase 2 study will be published as CRC Technical Report No. 200. These results will be very important to for growers and processors of the pruned shining gum plantation wood resources that are now reaching maturity.

A third processing study to be carried out later this year will examine product quality of rotary veneer and thin-section quarter-sawn boards, using pruned logs from the Lisle shining gum silvicultural trial in north-east Tasmania.  These trees have grown markedly faster than the Goulds Country, giving us further insights into the relationship between growth and wood quality.

Contact

Russell Washusen
03 9545 2173
Russell.Washusen@csiro.au