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Mr Juan Carlos Valencia

profile_valencia_thumbMr Juan Carlos Valencia
Masters student - COMPLETED

Topic: application of non-destructive evaluation techniques to the prediction of solid-wood suitability of Eucalyptus nitens plantation grown under a range of thinning strategies

Changing global market conditions for hardwood, associated with advances in silviculture and processing innovation, have favoured the idea of thinning and pruning eucalypt plantations to produce sawlogs suitable for high-value solid products.

From a producer's point of view, a successful value-chain based upon plantation-grown eucalypt timber would have to be technically, and profitably, able to produce:

a) suitable raw materials (industrial-sized logs with a very high proportion of clearwood and superior processing performance)

b) high-quality solid-wood products (with the appearance, strength, stiffness and dimensional stability attributes required by the market).

Each of these broad categories can be broken down into important solid wood quality traits such as growth stresses; wood density; wood shrinkage; tension wood; juvenile wood proportion; wood stiffness; log end split and sawn-board checking propensity. Each of these wood traits can be highly variable between and within species, provenances, stands and trees.

Most of these wood traits are strongly influenced by genetics and silviculture, so through genetic improvement, suitable silvicultural techniques and matching genotype to site-silviculture it was postulated that it would be possible to increase the value of plantation-grown eucalypt timber.

To achieve this, reliable and cost-effective wood quality sampling strategies to characterise each of the solid wood traits needed to be developed (such as those already developed for pulpwood improvement). Non-destructive evaluation (NDE) techniques had already been successful for screening standing trees, which assisted breeders to select those trees with the most favourable trait characteristics for their breeding programmes.

However, a successful NDE sampling strategy had not yet been developed for eucalypt plantation solid wood production and there is now a demand for its development.

The challenge was to develop reliable, robust, efficient and strong NDE-based predictors for crucial eucalypt wood quality traits such as growth stress. We also needed to advance knowledge about the relationship between these traits, the processing cost, and product quality and value.

My Masters in Science (MSc) project aimed to assess NDE techniques applied to standing trees and logs to estimate longitudinal growth stress and wood stiffness, to predict log processing performance, and ultimately to predict product value in a full rotation 22-year-old Eucalyptus nitens plantation.

The plantation is located at Gould's Country, inland from St Helens in north-eastern Tasmania. The existing plantation was established as a thinning trial by Forestry Tasmania in 1990 in order to understand the effect of thinning intensity and pruning on stand productivity; processing efficiency and product quality.

The NDE techniques to be evaluated by the MSc work were:

a) longitudinal growth strain of standing trees as an estimator of growth stress and its usefulness as a predictor of log end-split and log processing performance;

b) sound wave velocity measurements as estimators of sawn-board stiffness; and

c) assessing near-infrared technology as a predictor for wood shrinkage and collapse.

I am a Forest Engineer from Chile, where I have been a researcher with the Forest Institute of Chile (INFOR) for the past seven years.

My supervisors were Professor Brad Potts, Dr Chris Harwood (Ensis), Dr Peter Volker (Forestry Tasmania) and Dr Bruce Greaves (University of Tasmania).

My research contributeed to CRC for Forestry Research Program Two, 'High value wood resources', Project 2.4, incorporating wood quality into plantation estate management.

To browse other PhD projects available with the 'High value wood resources' research program, click here.