Gunns Ltd

Launceston, Australia

Gunns Ltd

Launceston, Australia
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Joyce K.,Gunns Ltd | Potts B.M.,CSIRO
New Zealand Journal of Forestry Science | Year: 2010

Silvicultural treatments that are aimed at increasing plantation growth rate may also impact directly or indirectly on wood properties. We examined this impact in a fertiliser × clone trial in northwestern Tasmania, Australia. Nitrogen (N) and phosphorus (P) fertilisers were applied at planting to three Eucalyptus nitens (Deane et Maiden) Maiden clones and one F1 hybrid clone of E. nitens and E. globulus Labill. in a factorial design with each clone exposed to two levels of nitrogen (0 and 23 kg N/ha) and two levels of phosphorus (0 and 21 kg P/ha) spot-applied close to each seedling. The trial comprised four replicates per treatment with 5 × 5 tree clonal plots. Height was measured at ages one and two years, and diameter at breast height over bark at age 11 years. Increment cores at breast height were obtained from one fastand one slow-growing ramet within each clonal plot to determine corewood basic density, near infrared-predicted kraft pulp yield, cellulose content, and extractives content. No significant interactions among main treatments were detected for any of the growth- or wood-property traits. Nitrogen application increased cellulose content (p < 0.05). Phosphorus application significantly increased diameter (p < 0.01), but resulted in lower wood density (p < 0.001). Within clonal plots, large trees had lower wood density (p < 0.001) and a higher extractives content (p = 0.004) than the corresponding small trees. Pulpwood production per hectare (calculated from plot volume, mean whole-tree adjusted density and mean plot kraft pulp yield) indicated that: (i) the choice of germplasm had a much larger effect on plantation profitability than did the starter fertiliser application; and (ii) that failure to account for adverse changes in wood properties in calculating pulp fibre production would result in over-estimation of the gain in pulp production due to starter phosphorus application by up to 0.6 t/ha or 20% per 12 year rotation.

Kookana R.,CSIRO | Holz G.,Gunns Ltd. | Barnes C.,Gunns Ltd. | Bubb K.,Forestry Plantations Queensland | And 2 more authors.
Journal of Environmental Management | Year: 2010

We studied the leaching and dissipation of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-s-triazine) and its two principal metabolites (desethylatrazine and desisopropylatrazine) for more than two years through soil profiles at five forestry sites across Australia (representing subtropical, temperate and Mediterranean climatic conditions with rainfall ranging from 780 to 1536 mm yr-1). Following atrazine applications at local label rates, soil cores were collected at regular intervals (up to depths of 90-150 cm), and the residues of the three compounds in soil were analysed in composite samples using liquid chromatography. Bromide was applied simultaneously with atrazine to follow the movement of the soil water. While bromide ion rapidly leached through the entire profile, in most cases the bulk of atrazine, desethylatrazine and desisopropylatrazine remained in the top 45 cm of the soil profile. However, a small fraction of residue moved deeper into the soil profile and at a subtropical site (Toolara) trace levels (ng L-1) of atrazine and one of its metabolites (DEA) were detected in perched groundwater located at a depth of 1.8 m. Data on the total residues of atrazine in soil profiles from all sites except the Tasmanian site fitted a first-order decay model. The half-life of atrazine in surface soils at the subtropical sites (Toolara and Imbil) ranged from 11 to 21 days. Four separate applications of atrazine at Toolara resulted in a narrow range of half-lives (16 ± 3.6 days), confirming relatively rapid dissipation of atrazine under subtropical conditions (Queensland). In contrast, a prominent biphasic pattern of initial rapid loss followed by very slow phase of degradation of atrazine was observed under the colder temperate climate of Highclere (Tasmania). The data showed that while its 50% (DT50) loss occurred relatively rapidly (36 days), more than 10% of herbicide residue was still detectable in the profile even a year after application (DT90 = 375 days). The rate of dissipation of atrazine at warm subtropical Queensland sites (Imbil and Toolara) was 2-3 times faster than sites located in colder climate of Tasmania. The marked contrast in DT50 values between subtropical and temperate sites suggest that climatic conditions (soil temperature) is one of the key factors affecting atrazine dissipation. At the Tasmanian site, the combination of leaching of the herbicide in subsoil and slower microbial activity at cooler temperatures would have caused a longer persistence of atrazine. © 2010.

Hamilton M.G.,University of Tasmania | Dutkowski G.W.,University of Tasmania | Joyce K.R.,Gunns Ltd | Potts B.M.,University of Tasmania
New Zealand Journal of Forestry Science | Year: 2011

Eucalyptus nitens (Deane & Maiden) Maiden is widely planted in temperate regions of the southern hemisphere, principally for pulpwood production. Eucalyptus denticulata I.O. Cook & P.Y. Ladiges was previously recognised as an informal variant of E. nitens and, accordingly, was included in many 'E. nitens' field trials. We reviewed data from 85 E. nitens/E. denticulata field trials, located in Australia, Chile, China, Italy, Lesotho, New Zealand, South Africa and Zimbabwe and ranging in age from less than one year to 14 years, to investigate racial (among population groups) genetic variation in growth, wood-property, tree-architecture, fitness and morphological/developmental traits. Meta-analyses were undertaken on these data to gauge the significance of differences among races across trials. Race × rainfall zone interaction was also investigated by categorising field trials as summer-rainfall, winter-rainfall or nursery-based. Race × rainfall zone interaction was significant for growth traits only. In general, Central Victorian E. nitens populations outperformed New South Wales E. nitens populations in winter-rainfall zones, but this ranking was reversed in summer-rainfall zones. On average, E. denticulata grew less rapidly than the best-performing E. nitens races, particularly in winter-rainfall zones. Differences among races were detected in basic density, a commercially important trait, but these differences were small in magnitude. Significant differences among races were also evident in branch size and stem form (straightness). Eucalyptus denticulata races had significantly thinner branches than all E. nitens races except Southern Central Victorian, and Central Victorian E. nitens races generally had the straightest stems. The small number of trials represented for most traits limited the power of meta-analyses but significant differences among races detected in our study are likely to represent consistent and robust differences across a broad range of environments. © 2011 New Zealand Forest Research Institute Limited, trading as Scion.

Blackburn D.,University of Tasmania | Harwood C.,CSIRO | Innes T.,Gunns Ltd | Williams D.,Forestry Tasmania
Forest Products Journal | Year: 2010

We successfully tracked the identities of more than 550 selected 13-year-old trees from a Eucalyptus nitens (Deane & Maiden) progeny trial through tree felling, harvesting of butt logs, and sawmill processing to finished sawn boards using a two-stage approach. To track log identity from the standing tree to the log yard, we used a numbered under-bark wooden identification plug, glued into a hole drilled in the trunk prior to harvesting. To track tree identity for individual sawn boards, log-end templates with corresponding tree identification numbers were glued to the log ends before milling. Materials and methods used withstood harvesting and debarking, log transportation, milling, air and kiln drying, steam reconditioning, and final machining. A second study confirmed the success of the under-bark plug method to successfully track 548 selected standing trees through harvesting and transportation to the mill. © Forest Products Society 2010.

Blackburn D.P.,University of Tasmania | Blackburn D.P.,Cooperative Research Center for Greenhouse Gas Technologies | Hamilton M.G.,University of Tasmania | Hamilton M.G.,Cooperative Research Center for Greenhouse Gas Technologies | And 8 more authors.
Annals of Forest Science | Year: 2011

• Introduction : There is increasing interest in managing Eucalyptus nitens plantations for sawn timber production. • Aims : This study aimed to determine the potential for genetic improvement of traits affecting green sawn board recovery in plantation-grown E. nitens. • Methods : The study was undertaken on an E. nitens progeny trial. All trees were measured for diameter at breast height (DBH) and stem straightness, and 560 trees were selected for timber processing. Assessment was made of survival, log and green sawn board volume, log taper, and both upper and lower log end splitting. Genetic variation in and between these traits was estimated. • Results : Genetic differences among races were significant for DBH at years 9 and 14, stem straightness, log taper and green sawn board volume. Within-race, narrow-sense heritabilities were significant for DBH, stem straightness, log volume, and both upper and lower log end splitting. Positive and significant additive genetic correlations were observed between DBH at all ages and survival, stem straightness and log volume. Significant adverse genetic correlations were shown between upper log end splitting and DBH at years 9 and 14. • Conclusion : These findings showed that harvest-age stem straightness and log volume objective traits in E. nitens are amenable to genetic improvement and that selection for early-age DBH in breeding programmes should improve harvest-age survival, stem diameter and straightness, as well as log and green sawn board volume. However, these improvements are likely to be countered to some extent by increased end splitting of logs from larger trees. © 2011 INRA and Springer Science+Business Media B.V.

Southerton S.G.,CSIRO | MacMillan C.P.,CSIRO | Bell J.C.,CSIRO | Bhuiyan N.,CSIRO | And 5 more authors.
Australian Forestry | Year: 2010

We used association studies to identify allelic variation in genes that influence wood fibre development in Eucalyptus nitens (Deane & Maiden). Genes selected for analysis were differentially expressed in wood with contrasting properties such as cellulose and lignin content, pulp yield and microfibril angle (MFA). Single nucleotide polymorphisms (SNPs) were identified by sequencing the candidate genes in a number of unrelated individuals. Selected SNPs were genotyped across 420 unrelated E. nitens trees from central Victorian populations and growing in a provenance trial at Meunna in north-western Tasmania. Significantly associated SNPs were genotyped across two other populations in northern Tasmania in order to validate associated SNPs. We have compiled a database of phenotypic information relating particularly to wood fibre properties for each individual in the association and validation populations. Associations between SNPs and wood properties were identified by comparing trait means in different SNP genotype classes. Several significantly associated SNPs identified in the Meunna population were validated in the other populations. The direction of the allele effect was reversed for two SNPs that were associated with kraft pulp yield. DNA markers identified in this research may be used to complement existing selection methods in breeding programs.

Downes G.M.,Cooperative Research Center for Greenhouse Gas Technologies | Meder R.,Cooperative Research Center for Greenhouse Gas Technologies | Ebdon N.,Cooperative Research Center for Greenhouse Gas Technologies | Bond H.,Cooperative Research Center for Greenhouse Gas Technologies | And 4 more authors.
Journal of Near Infrared Spectroscopy | Year: 2010

To date, near infrared (NIR) spectroscopy calibrations to predict Kraft pulp yield (KPY) and cellulose content (CC) have been developed using woodmeal samples. Our study, building upon such calibrations for KPY and CC, used NIR spectra collected at 5 mm intervals from the radial longitudinal surface of pith-to-bark breast height strips in 12 Eucalyptus nitens trees to develop calibrations for KPY and CC prediction from wood surface spectra. Both laboratory and portable NIR spectrometer instruments were effective in predicting radial variation, with standard errors of prediction in the vicinity of 1%. Both cellulose and KPY increased from pith to bark, showing a range of 5-8% within individual cores. The range was greater when the radial sampling interval was reduced to 1 mm, allowing the sub-annual variation to be better resolved. Commercially useful calibrations can now be developed quickly from air-dry increment cores and more cheaply than has been previously possible. © IM Publications LLP 2010. All rights reserved.

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