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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.

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.

Arnold R.,China Eucalypt Research Center | Arnold R.,University of Melbourne | Li B.,Hunan Forest Botanic Garden | Luo J.,China Eucalypt Research Center | And 3 more authors.
Australian Forestry | Year: 2015

Inland humid subtropical regions of Chinas southern provinces have substantial areas of land potentially available for forest plantation development. Such development would help address a substantial deficit in domestic production compared with demand for timber and fibre raw materials. However, the tropical and subtropical eucalypt varieties that are the basis of highly productive and commercially successful plantations in Chinas warmer coastal regions have proved poorly adapted to inland regions which are characterised by hot humid summers and frequent winter frosts and cold events with temperatures down to -8°C or lower.To evaluate a range of Eucalyptus species and provenances for plantation development in this subtropical environment, three species-provenance trials were established in southern and central Hunan province from 2001 to 2004. Included in these trials were 64 provenance seedlots representing 22 species and a locally selected Eucalyptus camaldulensis clone. Five of these seedlots represented somewhat improved sources from South Africa, whilst the others were unimproved natural stand provenances. Species that demonstrated the best growth and survival at age 6 years were E. amplifolia var. amplifolia, E. benthamii, E. dunnii and E. dorrigoensis. Species which showed reasonable performance in at least one trial and warrant further investigation include E. saligna × E. botryoides and E. deanei. Whilst E. macarthurii had the best cold tolerance, it had relatively poor performance for growth and survival. Provenances from imported improved sources (from South Africa) in most cases proved inferior to, or no better than, the best natural-stand provenances of the same species, providing salutary guidance for prospective growers. © 2015 Institute of Foresters of Australia (IFA).

Zhou Q.-Y.,China Eucalypt Research Center | Chen S.-X.,China Eucalypt Research Center | Han F.-Y.,China Eucalypt Research Center | Chen W.-P.,China National Petroleum Corporation | Wu Z.-H.,China Eucalypt Research Center
Chinese Journal of Applied Ecology | Year: 2010

An investigation was made on the biomass- and energy allocation in 1-4-year-old Eucalyptus urophylla x Eucalyptus tereticornis plantations at Beipo Forest Farm of Suixi County in Guangdong Province. Stand age had significant effects on the retained biomass of the plantations (P< 0.01). The biomass was in the range of 10.61-147.28t • hm-2. Both the total biomass and the biomass of above- and belowground components increased with increasing stand age. The proportions of leaf-, branch- and bark biomass to total biomass decreased with year, while that of stem biomass was in reverse. The biomass allocation of the components in 1- and 2-year-old plantations decreased in order of stem > branch > bark > root > leaf, and that in 3- and 4 -year-old plantations was in order of stem > root > branch >bark > leaf. The mean ash content (AC) of the five components at different stand ages ranged from 0.47% to 5.91% , being the highest in bark and the lowest in stem. Tlie mean gross caloric value (GCV) and ash free caloric value (AFCV) of different components ranged from 17.33 to 20.60 kj • g-1 and from 18.42 to 21.59 kj • g-1 respectively. Of all the components, leaf had the highest GVC and AFCV, while bark had the lowest ones. Stand age had significant effects on the GVC of branch, stem, and bark, and on the AFCV of leaf, stem, and bark (P <0.05) , but the effects on the GVC of leaf and root, the AFCV of branch and root, and the GVC and AFCV of individual trees were not significant (P>0.05 ). The retained energy of 1 4-year-old plantations ranged from 199.98 to 2837. 20 GJ • hm-2, with significant differences among the stand ages ( P<0.01 ). The retained energy of various components and plantations increased with stand age, and the energy allocation of various components had the same trend as biomass allocation.

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.

Chen S.,Central South University of forestry and Technology | Chen S.,China Eucalypt Research Center | Arnold R.,China Eucalypt Research Center | Li Z.,Central South University of forestry and Technology | And 4 more authors.
New Forests | Year: 2011

A large initial stocking × fertilizer factorial field trial established in 1993 with a Eucalyptus urophylla × grandis hybrid clone in southern Guangxi province, China, included 6 initial stocking treatments ranging from 667 to 2,222 trees ha-1 and 6 fertilizer treatments. Growth data was collected at various intervals up to age 192 months and also data on outer-wood pilodyn penetration (as an indicator of wood density) and acoustic velocity through the outer-wood (as an indicator of modulus of elasticity) at the last assessment. This report examines the results for the main effect of initial stocking treatments and stocking × fertilizer interactions across ages. There were significant differences between initial stockings for both average individual tree volume and standing volume ha-1 at all ages up to 144 months, but just average individual tree volume at 192 months. At ages up to 75 months total standing volume decreased as initial stocking decreased-maximum volume being obtained at 2,222 trees ha-1. From 88 to 110 months the highest standing volume was obtained at 1,667 trees ha-1 and then at ages 144 and 192 months, 833 trees ha-1 provided the highest standing volume. Average individual tree volume at all ages generally increased as initial stocking decreased-the largest trees were obtained at 667 trees ha-1. As age increased the proportional differences between tree volumes at higher and lower stockings increased-at age 27 months average individual tree volume at 667 trees ha-1 was 72% greater than that at 2,222 trees ha-1 and differences increased steadily with age up to 190% at 192 months. There were no significant differences between initial stockings for the properties of the outer-wood assessed by pilodyn penetration and acoustic velocity. Also, no significant interactions were found between initial stocking and fertilizer treatments for any traits at any ages implying that effects of initial stocking and fertilizer are additive for the traits assessed. © 2010 Springer Science+Business Media B.V.

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.

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.

Luo J.,China Eucalypt Research Center | Arnold R.,China Eucalypt Research Center | Lu W.,China Eucalypt Research Center | Lin Y.,China Eucalypt Research Center
Euphytica | Year: 2014

The gall wasp Leptocybe invasa is a major insect pest on plantation Eucalyptus in many countries. Since appearing in China in 2007 it has had major impacts on commercial plantations-some commonly planted Eucalyptus varieties have proven particularly susceptible, including hybrids involving Eucalyptus camaldulensis and E. tereticornis parent species. Intra-specific variation within each species for L. invasa susceptibility was examined in two seed source and family trials in southwest of Guangdong. The E. camaldulensis trial included 101 seedlots representing five natural stand and six seed orchard sources which also represented three sub-specific taxa. The E. tereticornis trial included 143 seedlots representing 11 natural stand and four seed orchard sources, including breeding seed orchards in China. Both trials were assessed for susceptibility to L. invasa along with height at age 9 months. Sub-specific taxa within E. camaldulensis differed significantly (P < 0.01) in L. invasa susceptibility but not height or survival; subsp. acuta had the lowest average susceptibility and subsp. simulata and obtusa were of intermediate susceptibility whilst material of uncertain sub-specific taxa from India had the highest average susceptibility. In E. tereticornis regions of origin and seed sources within regions differed significantly (P < 0.01) for both L. invasa susceptibility and height; the region China (all somewhat improved sources) had both the best average height growth and lowest susceptibility whilst the region Australia (all natural stand sources) proved inferior to China for both average susceptibility and height. A strong significant correlation was found between seed source average L. invasa susceptibility and annual rainfall at seed source geographic origin in E. tereticornis (r = -0.873; P < 0.01), implying that seedlots from higher rainfall environments are markedly less susceptible to L. invasa. The equivalent parameter in E. camaldulensis was also strong (r = -0.730) though not significant, perhaps due to having only five data points available. Differences between families within seed sources for both L. invasa susceptibility and height growth were also highly significant (P < 0.01) with the former trait proving moderately to strongly heritable (hi 2 = 0.54 ± 0.40 in E. camaldulensis; 0.52 ± 0.50 in E. tereticornis). Height had low to moderate heritability in both species (hi 2 = 0.11 ± 0.15 and 0.26 ± 0.08 respectively). Tree height and L. invasa susceptibility showed a moderate negative (favourable) genetic correlation in E. camaldulensis (-0.33 ± 0.64) and a moderate to strong negative (favourable) genetic correlation in E. tereticornis (-0.47 ± 0.31). Corresponding phenotypic correlations, though significant, were somewhat weaker (-0.16 and -0.29 respectively), indicating a trend for taller trees to have lower levels of L. invasa susceptibility. © 2013 Springer Science+Business Media Dordrecht.

Luo J.,China Eucalypt Research Center | Arnold R.,China Eucalypt Research Center | Ren S.,Guangxi Forest Research Institute | Jiang Y.,Guangxi Forest Research Institute | And 3 more authors.
Annals of Forest Science | Year: 2013

Context: Processing young, small eucalypt logs into veneer is a burgeoning industry across southern China. However, plantations supplying these logs were mostly established for pulpwood; little information is available on variation and selection among commercial eucalypt clones/varieties in regards to suitability for veneer production. Methods: Tree growth and log form were assessed on 11 eucalypt clones from a 5-year-old trial in southern China. Logs from these were rotary peeled for veneer; recovery percentages plus a range of quality and value traits were assessed on the outturn. Results: Tree volumes, green veneer recovery ratios (%), veneer quality grades, log value, and value m-3 varied significantly among both clones and log positions up the stem. The clone with the best veneer recovery ratio (50.5 %) provided nearly twice that of the poorest clone (28.4 %). Average veneer value log-1 by clone ranged from RMB 6.7 (US1) up to RMB 15.1 (US2) and average value m -3 by clone ranged from 589 RMB m-3 (US88) up to 925 RMB m-3 (US139). Overall, sweep was the key factor influencing veneer recovery ratio and value. Knots, especially dead knots, holes and splitting were major factors influencing veneer quality grade. Middle and upper logs had significantly higher veneer recoveries, grades, and values m-3 than the lower logs. Conclusions: Excellent potential exists for selecting among eucalypt clones, and even among log positions within trees, for optimizing veneer production. © 2013 INRA and Springer-Verlag France.

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