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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.


Wang J.-Z.,Guangxi Dongmen Forest Farm | Xiong T.,Guangxi Dongmen Forest Farm | Zhang L.,Guangxi Dongmen Forest Farm | Li Q.-W.,Guangxi Dongmen Forest Farm | And 4 more authors.
Forest Research | Year: 2016

Objective: A 25-year-old Eucalyptus cloeziana provenance trial was conducted in Guangxi Dongmen Forest Farm to analyze the genetic variation of the growth and stem form quality traits in order to select the superior provenances and individuals for further study in medium and large diameter of wood and seed breeding. Method: The genetic variation of growth and stem form quality traits of 11 E. cloeziana provenances were analyzed and selected by variance analysis and comprehensive analysis of the building of the equation based on the trait selection index. Result: The results showed highly significant differences in diameter at breast height (DBH), tree height (H), individual tree volume (V), stem straightness (ST) and stem fullness (SF) among 11 Eucalyptus cloeziana provenances. The heritabilities(H2)of five main traits was 0.634~0.895, and individual heritabilities(h2)was 0.136~0.342, selection index equations of provenances and individuals were built based on DBH, H, V, ST and SF. According to this standard, 4 superior provenances and 13 superior individuals were selected, and the genetic gain of volume reached 11.2% and 29.7% respectively. Conclusion: These results indicate that the genetic variation of the five main traits is under a strong genetic control at provenance level and a lower genetic control at individual tree level. In consideration of rapid growth and fine wood property, the provenances D47, S14127, B47 and S12195 are superior materials for further study in medium and large diameter of wood breeding. © 2016, Chinese Academy of Forestry. All right reserved.


Zhang K.,CAS Research Center for Eco Environmental Sciences | Zheng H.,CAS Research Center for Eco Environmental Sciences | Chen F.L.,CAS Research Center for Eco Environmental Sciences | Ouyang Z.Y.,CAS Research Center for Eco Environmental Sciences | And 5 more authors.
Solid Earth | Year: 2015

Vegetation plays a key role in maintaining soil quality, but long-term changes in soil quality due to plant species change and successive planting are rarely reported. Using the space-for-time substitution method, adjacent plantations of Pinus and first, second, third and fourth generations of Eucalyptus in Guangxi, China were used to study changes in soil quality caused by converting Pinus to Eucalyptus and successive Eucalyptus planting. Soil chemical and biological properties were measured and a soil quality index was calculated using principal component analysis. Soil organic carbon, total nitrogen, alkaline hydrolytic nitrogen, microbial biomass carbon, microbial biomass nitrogen, cellobiosidase, phenol oxidase, peroxidase and acid phosphatase activities were significantly lower in the first and second generations of Eucalyptus plantations compared with Pinus plantation, but they were significantly higher in the third and fourth generations than in the first and second generations and significantly lower than in Pinus plantation. Soil total and available potassium were significantly lower in Eucalyptus plantations (1.8-2.5 g kg-1 and 26-66 mg kg-1) compared to the Pinus plantation (14.3 g kg-1 and 92 mg kg-1), but total phosphorus was significantly higher in Eucalyptus plantations (0.9-1.1 g kg-1) compared to the Pinus plantation (0.4 g kg-1). As an integrated indicator, soil quality index was highest in the Pinus plantation (0.92) and lowest in the first and second generations of Eucalyptus plantations (0.24 and 0.13). Soil quality index in the third and fourth generations (0.36 and 0.38) was between that in Pinus plantation and in first and second generations of Eucalyptus plantations. Changing tree species, reclamation and fertilization may have contributed to the change observed in soil quality during conversion of Pinus to Eucalyptus and successive Eucalyptus planting. Litter retention, keeping understorey coverage, and reducing soil disturbance during logging and subsequent establishment of the next rotation should be considered to help improving soil quality. © 2015 Author(s).


Yang J.,Beijing Forestry University | Yao P.,Beijing Forestry University | Li Y.,Beijing Forestry University | Mo J.,Guangxi Dongmen Forest Farm | And 2 more authors.
Euphytica | Year: 2016

Artificially inducing 2n gametes through chromosome doubling is an effective way to obtain polyploids. In this study, Eucalyptus urophylla microsporogenesis and flower development were investigated to guide 2n pollen induction. We also investigated suitable conditions for colchicine treatment. Our results showed that E. urophylla 2n pollen was spherical and had a large volume (mean diameter 28.57 ± 0.46 μm), while normal untreated pollen (mean diameter 19.68 ± 0.11 μm) was tetrahedron. The highest rate of 2n pollen production was 28.71 % when the flower buds, which ranged in size from 3.5 to 4.0 mm, underwent treatment with 0.5 % colchicine solution for 6 h. Further studies suggested that diplotene to diakinesis and metaphase I to telophase I were suitable meiotic stages for chromosomes doubling, due to asynchronous development of microsporogenesis between the anthers in a single flower bud. These data help to illuminate research in other areas, such as triploid eucalyptus production by chromosome doubling of female gametes. © 2016 Springer Science+Business Media Dordrecht


Yang J.,Beijing Forestry University | Lan J.,Guangxi Dongmen Forest Farm | Yao P.,Beijing Forestry University | Huang Z.,Beijing Forestry University | Kang X.,Beijing Forestry University
Journal of Forestry Research | Year: 2016

Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis were examined using chromosome tableting to provide a method to predict the meiotic stages in this species. Although microsporogenesis was normal, cytokinesis during meiosis of pollen mother cells occurred simultaneously, with strong asynchronism observed in the two different lengths of stamens in a flower bud. In a single flower, the developmental period of microsporogenesis in anthers on the longer stamens was always ahead of those on the shorter stamens. Flower development was also asynchronous at different locations on a branch. Flower buds on the upper side of the branch were larger in diameter than those on the lower side. In addition, a correlation was observed between microsporogenesis development and flower bud diameter growth. The pachytene stage was first observed when the diameter of the flower buds increased to 3.0 mm, and the majority of the meiotic stages were observed when bud diameters ranged from 3.5 to 5.0 mm. This study showed that the developmental stages of microsporogenesis in Eucalyptus urophylla × E. grandis could be distinguished readily, which may be applicable to future breeding studies. © 2015, Northeast Forestry University and Springer-Verlag Berlin Heidelberg.

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