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Liu Q.,Hunan Academy of Forestry | Chen S.X.,China Eucalypt Research Center | Li Z.H.,Central South University of forestry and Technology | Arnold R.J.,China Eucalypt Research Center
Journal of Tropical Forest Science | Year: 2012

A field trial to examine growth and wound healing of pruned Corymbia torelliana was established in a 40-month-old plantation in western Guangdong, China. It included: (1) pruning all branches up to stem diameters of 5, 6, 7 or 8 cm, (2) wound protection with wax or paint and (3) a control with no pruning. Measurements of growth and wound occlusion taken at various intervals up to 12 months after pruning showed that pruning generally impeded height growth, promoted diameter at breast height (dbh) growth and slightly increased taper. The optimal pruning intensity for tree growth was pruning up to stem diameter of 8 cm. Lower wound occlusion rates occurred in heavier pruning intensities. The optimal intensity for rapid wound occlusion was pruning up to stem diameter of 7 or 8 cm. Paint resulted in better occlusion than wax. The fastest wound occlusion occurred in stem section of height 2.51 to 5.35 m above the ground. Rate of wound occlusion up to 12 months showed correlations with dbh increment, initial wound size and pruning intensity. © Forest Research Institute Malaysia. Source

Li B.,Science and Technology Extension Station | Li B.,Central South University of forestry and Technology | Arnold R.,China Eucalypt Research Center | Luo J.,China Eucalypt Research Center | Li Z.,Central South University of forestry and Technology
Australian Forestry | Year: 2012

Eighty-four open-pollinated families of Eucalyptus dunnii representing 14 natural stand seed sources and one seed orchard source from Australia were established at two sites in central and southern Hunan province in 2004. These were assessed at ages 2.5-3.5 y (around half the average rotation length of eucalypt plantations in China) for tree growth and stem straightness at both sites and cold tolerance at age 3.5 y at the central site. At the southern site, all trees were cut back to stumps at about age 3.5 y, following ice storms that led to stem breakage of almost all trees. Subsequently, the coppicing traits of number of sprouts per stump and DBH and height of the largest sprout per stump were assessed at 12 months after felling. Significant differences were observed among seed sources for almost all traits. At each site, average individual tree volume of the best seed source was more than 60% above that of the poorest. The magnitude of variation among families within seed sources was generally greater and more often significant than the variation among seed sources-especially for average tree volume. The magnitude of the variations observed in stem form, though significant statistically, were small. Significant seed source differences were found also for cold tolerance at the central site and for all three coppice traits at the southern site. Estimates of within-seed-source individual-tree heritability for individual-tree volume in 2007 at the southern site and in 2006 at the central Hunan site were 0.11 ± 0.07 and 0.17 ± 0.15 respectively and that for stem straightness at the southern site was 0.17 ± 0.07. Heritabilities for coppice traits, assessed only at the southern site, ranged from 0.14 ± 0.11 for number of sprouts per stump and up to 0.42 ± 0.17 for DBH of the largest coppice on each stump. Heritability for cold tolerance at the central Hunan site was 0.11 ± 0.10. These heritabilities and favourable phenotypic and genetic correlations indicate selection would be effective to improve both volume and growth of subsequent coppice development. These results indicate emphasis should be placed on selecting the best candidate trees of E. dunnii regardless of their seed source for inclusion in future breeding and propagation populations of this species in Hunan. Together, the results presented support the value of investing in E. dunnii's genetic improvement; significant gains could be delivered to commercial growers and investors including enhanced financial prospects and decreased risks for commercial plantations of this species. Source

Luo J.,China Eucalypt Research Center | Zhou G.,Dongmen Forest Farm | Wu B.,Dongmen Forest Farm | Chen D.,Dongmen Forest Farm | And 3 more authors.
Australian Forestry | Year: 2010

Five seed source - family trials of Eucalyptus grandis were planted at Dongmen Forest Farm in southern Guangxi, China, between 1987 and 2001. Growth was assessed up to age 5 y on an annual basis for three trials and in 4 out of 5 y for two trials. In 2008 growth was assessed again, along with pilodyn penetration, at trial ages ranging from 7 to 21 y. These trials initially contained 386 families representing 49 seed sources, including a total of 97 families from four different improvement programmes. Two trials included small numbers of Dongmen second-generation families. Thinning was applied variously in all trials. Large significant differences between both seed sources and families within seed sources were observed at each assessment. At age 5 y, which approximates an average rotation for fibre plantations in southern China, the best seed sources included Ravenshoe, Windsor Tableland, Copperlode and Paluma areas of northern Queensland; Bellthorpe in southern Queensland; Aracruz, Brazil; and Florida, USA. Some families from local selections at Dongmen also performed very well. Sources from the Coffs Harbour region in New South Wales were markedly inferior for growth, as was a South African seed orchard source. Superiority of seed sources for growth at age 5 y was generally maintained through to the 2008 assessment. At the later-age assessments in 2008 (trial ages 7, 18 and 21 y), sources notable for combining superior volume growth with higher wood density (i.e. lower pilodyn penetration) included Ravenshoe, Queensland; Aracruz, Brazil; Florida, USA; and some from Dongmen, China. However, the 2008 growth results may have been biased by heavy selective thinning regimes. Within-seed-source heritabilities at single sites for height at age 1 y and then volume at ages 2,3,4 and 5 y ranged from 0.03 ±0.02 up to 0.45 ±0.10 and generally peaked at age 3-4 y in each trial. Genetic correlations between growth at early ages (height at 1 y, volume at ages 2, 3 and 4 y) with growth at rotation age (age 5 y volume) were moderate to very strong. Optimum selection efficiency for volume was generally reached at age 2 to 3 y but did not decline markedly between ages 3 and 5 y. Source

Arnold R.J.,China Eucalypt Research Center | Xie Y.J.,China Eucalypt Research Center | Midgley S.J.,Salwood Asia Pacific Pty Ltd | Luo J.Z.,China Eucalypt Research Center | Chen X.F.,China Eucalypt Research Center
International Forestry Review | Year: 2013

China's plywood production grew rapidly over the past 15 years from around 9 Mm3 yr-1 in the mid 1990s to over 55 M m3 yr-1 by 2011. Associated with this has been a proliferation of small-scale eucalypt veneer mills processing young (≤ 5 yrs) small diameter logs (mostly ≤ 12 cm small end diameter); by 2011 there were over 5000 such mills in China with a collective capacity to process well over 15.0 M m 3 yr-1 of logs. We review key characteristics of this eucalypt veneer industry with special focus on three key regions for eucalypt veneer production in China. Factors that have spurred and facilitated the rapid growth of this industry are reviewed along with future challenges likely to emerge for China's eucalypt veneer industry. Source

Luo J.Z.,Nanjing Forestry University | Luo J.Z.,China Eucalypt Research Center | Arnold R.J.,China Eucalypt Research Center | Arnold R.J.,University of Melbourne | And 5 more authors.
Journal of Tropical Forest Science | Year: 2012

Variation in pulp wood traits between eucalypt clones across sites and implications for deployment strategies. A total of 20 hybrid eucalypt clones at age 5 1/2 years across four sites in coastal south-west China were assessed for volume and a subset of these for wood basic density and wood mass production. Six of these clones were also assessed for kraft pulp yield. Across the four sites the average tree volume, wood basic density, tree wood mass and pulp yield were 0.119 m 3 tree -1, 474 kg m -3, 0.063 tonne tree -1 and 49.0% respectively. There were significant differences between both sites and clones for all the key traits studied. The best site for wood mass productivity had average plot wood mass of 0.239 tonne while the poorest site, only 0.128 tonne. Significant clone ×site interactions were found for survival, volume tree-1, plot volume and plot wood mass. Clone and/or clone ×site effects accounted for the major portion of variation for almost all the traits. However, site effects accounted for more variation on plot wood mass, indicating the importance of site selection. On account of the clone ×site interactions, adopting a site-specific selection and deployment strategy was estimated to provide 15% greater wood mass yield across the region compared with a generalised selection and deployment strategy. © Forest Research Institute Malaysia. Source

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