4 September 2006
An Ensis research project funded by the Forest and Wood Products Research and Development Corporation (FWPRDC) has surveyed the wood characteristics of the Tasmanian softwood plantation resource for the first time.
Conducted in cooperation with the main forest owners (Norske Skog, Rayonier and Private Forests Tasmania), this study used state-of-the-art data collection techniques to assess the wood quality of radiata pine stands and investigate environmental factors influencing major wood properties.
The study provides a benchmark for measuring the Tasmanian softwood resource in relation to its suitability for end-uses – mainly structural lumber and pulp and paper products.
Project leader Dr Dave Cown, a wood quality scientist from Ensis, says the predominant use for softwood timber is structural lumber, so the study concentrated on wood properties most closely associated with the stiffness and strength of end products.
Field sampling of mature stands (20 to 31 years old) involved the non-destructive assessment of wood density using acoustic technology to measure the sound time of flight in standing trees.
A high degree of variability was observed both within and between stands, as is normally the case with plantation softwoods.
“The ability to determine variability in standing trees using non-destructive tools is a major benefit to forest growers,” Dr Cown explains.
“The acoustic tools used gave good correlations with the actual stem and log stiffness, indicating that non-destructive sampling is a very practical approach to the assessment of standing forest crops.”
As in other regions, a wood density algorithm was customised for the Tasmanian resource so that the outerwood density of crops assessed at any age could be used to predict the average density of stems and logs at rotation age.
Dr Cown says that analysis using this algorithm showed that the wood density – and hence stiffness – was influenced by stand age and environmental variables such as altitude (negative) and site mean average temperature (positive).
“Wood density data has been used in planning by several Australasian companies to assess the suitability of stands for structural uses,” Dr Cown says.
“The inclusion of sonic tools in the Tasmanian survey has given us confidence that they will eventually replace wood density as an operational management tool in forest management and harvest planning to determine silvicultural regimes and the optimal harvest age of forest stands.
“Further work still needs to be done to develop algorithms to allow sonic values to be predicted into the future. Structural rotations could then be determined by target sonic values.”
The characteristics of the Tasmanian resource were found to compare favourably with other softwood regions in Australia and New Zealand.
Further Information:
Dr Glen Kile,
Executive Director FWPRDC
+61 3 9614 7544
Dr Simon Potter
Deputy General Manager, Wood Quality, Ensis
+61 3 9545 2150