ORCID Profile
0000-0002-6282-3446
Current Organisation
University of Tasmania
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Publisher: Springer Science and Business Media LLC
Date: 22-03-2022
DOI: 10.1186/S13595-022-01122-2
Abstract: A method to segregate trees and logs of planted Eucalyptus nitens (H. Deane & Maiden) Maiden has been developed, showing that accounting for wood quality during the process of segregation and sorting of timber resources allows for the recovery of structural timber of the desired quality. Appropriate sorting of raw forest resources is necessary to allocate logs to different production streams, to ensure that the desired quality of timber is achieved. Acoustic wave velocity can be used to test the wood quality of trees and logs, and its use as a sorting tool needs to be investigated prior to the development of a segregation method to recover high-quality timber. This study aimed to develop a segregation methodology for plantation E. nitens trees and logs to obtain high-quality structural boards. Forty-nine logs of planted E. nitens were measured, assessed with acoustic wave velocity, and processed into 268 structural boards maintaining board, log, and tree identity. Board stiffness was determined via structural testing and boards were ranked in structural grades. Linear mixed effect models were used to predict board stiffness based on tree and log variables, and machine learning decision trees were used to create a segregation method for board grades. Different segregation options were compared through scenario simulation. The prediction of in idual board stiffness with tree or log variables yielded low coefficients of variation due to large intra-log variability ( R 2 = 0.22 for tree variables and R 2 = 0.28 for log variables). However, the decision tree identified acoustic wave velocity thresholds to segregate E. nitens trees and logs. When applied in scenario simulation, segregation based on log variables produced the best results, resulting in large shares of high-quality board grades, showing that a segregation method based on wood quality traits can yield larger higher recovery of higher quality timber, in respect to other scenarios. Acoustic wave velocity can be used to segregate trees and logs for structural boards from plantation E. nitens , and machine learning decision trees can support the development of a segregation method to determine operational thresholds to increase the recovery of high-quality timber.
Publisher: MDPI AG
Date: 15-03-2021
DOI: 10.3390/F12030343
Abstract: Stiffness is considered one of the most important structural properties for sawn timber used in buildings and laminated structures including mass timber elements. There is great potential to use plantation Eucalyptus timber for structural applications, and the successful development of a plantation timber supply chain for structural products will depend on the accurate selection and grading of the resource. In this study we aimed to investigate the suitability of non-destructive testing (NDT) to improve selection and grading of sawn boards sourced from a young E. nitens plantation. We studied 268 sawn boards traced from the tree through to final processing stages. We found high and positive correlations between stiffness (measured as dynamic modulus of elasticity) tested at each board processing stage through acoustic wave velocity (AWV) and the static board modulus of elasticity measured through mechanical testing on dressed boards. Position of the board in the stem and sawn board processing treatment significantly impacted board modulus of elasticity, indicating that early selection of logs would allow larger yield of stiffer boards. We investigated the grading of boards through the traditional Australian Standards using a visual-grading system and through AWV, finding a classification error of 82.5% and 45.2%, respectively. We developed a linear model which was used to re-classify the boards, obtaining a smaller classification error, including fewer boards being over-graded. Our results demonstrate that AWV can be used as an early selection method for structural boards and can also be employed to satisfactorily grade E. nitens plantation boards to be used in building structures and as elements of mass timber.
Publisher: MDPI AG
Date: 10-11-2020
DOI: 10.3390/F11111189
Abstract: Thermo-hydro mechanical (THM) treatments and thermo-treatments are used to improve the properties of wood species and enhance their uses without the application of chemicals. This work investigates and compares the effects of THM treatments on three timber species from Tasmania, Australia plantation fibre-grown shining gum (Eucalyptus nitens H. Deane and Maiden), plantation saw-log radiata pine (Pinus radiata D. Don) and native-grown saw-log timber of the common name Tasmanian oak (which can be any of E. regnans F. Muell, E. obliqua L’Hér and E. delegatensis L’Hér). Thin lamellae were compressed by means of THM treatment from 8 mm to a target final thickness of 5 mm to investigate the suitability for using THM-treated lamellas in engineered wood products. The springback, mass loss, set-recovery after soaking, dimensional changes, mechanical properties, and Brinell hardness were used to evaluate the effects of the treatment on the properties of the species. The results show a marked increase in density for all three species, with the largest increase presented by E. nitens (+53%) and the smallest by Tasmanian oak (+41%). E. nitens displayed improvements both in stiffness and strength, while stiffness decreased in P. radiata s les and strength in Tasmanian oak s les. E. nitens also displayed the largest improvement in hardness (+94%) with respect to untreated s les. P. radiata presented the largest springback whilst having the least mass loss. E. nitens and Tasmanian oak showed similar dimensional changes, whilst P. radiata timber had the largest thickness swelling and set-recovery due to the high water absorption (99%). This study reported the effects of THM treatments in less-known and commercially important timber species, demonstrating that the wood properties of a fibre-grown timber can be improved through the treatments, potentially increasing the utilisation of E. nitens for structural and higher quality timber applications.
Publisher: Springer Science and Business Media LLC
Date: 15-02-2022
DOI: 10.1007/S00107-022-01790-X
Abstract: Plantations of Eucalyptus species are planted and grown worldwide for short rotations and with limited silvicultural treatments mostly to produce pulplogs for the pulp and paper industry. These resources could be used as raw material for construction timber, to support the increasing need of renewable resources from the building sector. To use fast-grown Eucalyptus logs as a source of sawn timber log grading standards are needed, which can be developed accounting for log characteristics impacting sawn timber recovery. This study aims to examine the quality of fast-grown Eucalyptus logs and relate relevant log quality traits to sawn timber characteristics. Wood quality and log characteristics of forty-nine fast-grown Eucalyptus logs and the characteristics and structural properties of 268 sawn boards milled from those logs were investigated. Significant differences were found in wood quality characteristics from logs sourced from different positions in the stem. However, sawn boards did not differ in their wood quality traits according to log position, which influenced only the amount and type of knots on the board surface and some structural properties. Moreover, log characteristics including volume, taper, log end splits and stiffness significantly impacted important board recovery traits. The results of this study show that log characteristics such as volume, taper, log end splits and stiffness should be accounted for in log grading standards seeking to grade fast-grown Eucalyptus resources for different product classes.
Publisher: Routledge
Date: 02-11-2022
Location: Sweden
No related grants have been discovered for Michelle Balasso.