Non destructive evaluation of Nothofagus fusca (red beech) wood properties within the North West Coast of the South Island, New Zealan

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Theses / Dissertations
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Thesis discipline
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Master of Forestry Science
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Silcock, Paul

This study is comprised of two major research objectives: 1) to quantify the incidence and proportion of defect in beech forests and explore the efficacy of applying defect detecting technology to natural forest management; and 2) to identify and assess those physical and mechanical wood properties of red beech that influence wood quality and forest operations from two sites (Howard valley and Wooly river) managed by Forever Beech Ltd. Overall there is a significant incidence of defect (56 %) in standing red beech and a low stem-to-timber conversion rate (40 %). An acoustic tomographic tool, Fakopp 2D, can be used to detect the presence of internal defect in standing trees, although the software used in this study was not able to consistently predict the location or volume of defect, it was a cumbersome instrument to use in the forest and data collection was a slow process. No case could be made for incorporating this technology in beech forest management practice. Four wood quality properties were used to assess beech forest in the NW Coast of New Zealand. Basic density and hardness are measures of wood quality and quantity on which many end-use and customer specifications are based. Green density is a measure of wood quantity which is used in forest operations to determine log bucking patterns for heli-lifting. The green dynamic modulus of elasticity (MOE) is another useful measure of wood quality, assessed using the TOF instrument - TreeTap. Measuring stress wave velocity (SWV) in standing red beech using time of flight (TOF) instruments provides a means to evaluate wood quality prior to harvesting. Forests of the North West (NW) Coast of the South Island were found to have low average basic density in comparison to average national values. Basic density and associated wood properties exhibited greater variation between trees than between sites. Trees sampled in the Wooly river site had higher basic density, green density, MOE and hardness values than those growing in the Howard valley. The trees of Wooly river also exhibited higher growth rates and a lower incidence of defect. All assessed wood properties of red beech decreased with altitude. MOE increased with increasing growth rate. These data provided for customer specifications and the operations and management of Forever Beech Ltd. The advantages of using MOE as a measure of timber quality are discussed.

Nothofagus fusca--Quality, Wood--Defects--New Zealand--West Coast, Nothofagus fusca--Ecology--New Zealand-West Coast, Forest management--New Zealand--West Coast
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