Time filter

Source Type

Yu B.,State Academy of Forestry Administration | Zhang Q.-L.,Inner Mongolia Agricultural University
Forest Research | Year: 2015

The Larix gmelinii overcutting forest formed by final cutting in the 1980s at Chaocha Forest Farm, Genhe Forestry Bureau of Inner Mongolia was investigated. Based on the tree's location data of 8 sample plots in the L. gmelinii forest, the impacts of forest stand pattern and quadrat (5 m×5 m) stem-number on the amount of dead standing trees were analyzed, the relationship between the location of big trees and the regeneration saplings and the location of dead standing trees was discussed, and the forming mechanism of distribution pattern of dead standing trees was clarified. The results are as follows. 1. The ratio of dead standing trees increased with the increase of tree species. The dead standing trees were formed mainly in the stage of regeneration saplings, with the diameter class distribution mainly being below the fourth diameter class, and the average ratio of trees accounting for 82.2% of the total. In the regeneration saplings (including dead standing trees), an average ratio of production of dead standing trees is 8.8%. 2. The distribution of dead standing trees followed a aggregated pattern. The forest stand pattern, the quadrat stem-number and the amount of regeneration trees were in a significant correlation with the amount of dead standing trees. The forest stand pattern had not a significant effect on the pattern of dead standing trees. If the degree of aggregation of the forest is greater, the probability of the formation of dead standing trees will be greater, and the amount will be greater. 3. The location of dead standing trees had a significant correlation with the location of regeneration saplings and regeneration big trees. The main performance was the mutual relation between larch and white birch. The location of dead standing trees was mainly at the aggregation area of the big trees and regeneration saplings. Compared to the regeneration saplings, the big trees had greater impact on the dead standing trees, and specifically, the impact from larch was greater than that from the white birch. The white birch's regeneration saplings had not a significant impact on the formation of larch's dead standing trees. The dead standing trees affected were mainly the species with a higher ratio or greater amount of dead standing trees upon the species of trees. The forest that had an impact on dead standing trees depended mainly on the position of the sample trees and the stem-number. ©, 2015, Chinese Academy of Forestry. All right reserved.

Yu B.,Beijing Forestry University | Yu B.,State Academy of Forestry Administration | Wu J.-S.-G.-L.,Beijing Forestry University | Wang B.-T.,Beijing Forestry University | Da B.-X.-L.-T.,Inner Mongolia Alukeerqin Banner Forestry Bureau
Forest Research | Year: 2010

The distribution pattern characteristics of different stand structures in herbage-Lariz forest and Ledum-Larix forest were analyzed by sample plots surveying. The study indicated : (1) In the 36 - 65 years old herbageLarix forest and 54 - 63 years old Ledum-Larix forest distribution pattern, the proportions of even distribution, random distribution and clustered distribution were 6. 3% , 50% and 43. 8%. (2) From a view of forest types, in herbage-Lam; forest distribution pattern, both the clustered distribution and regular distribution were 11.1%, the random distribution was 77. 8% , while Ledum-Larix forest distribution pattern was all followed regular distribution. (3)In herbage-Larix forest and Ledum-Larix forest with composition of 6 Larix and 4 broadleaf species to 10 Larix and no broadleaf species, the distribution pattern was mostly clustered distribution and random distribution. Cluster distribution was mainly concentrated in the composition of Larix(70%)and broadleaf species(30%) to Larix(90%) and broadleaf species(10%).

Yin Y.,Chinese Academy of Forestry | Bian M.,Chinese Academy of Forestry | Bian M.,State Academy of Forestry Administration | Song K.,Chinese Academy of Forestry | And 2 more authors.
IAWA Journal | Year: 2011

Radial variations in microfibril angle (MFA) and their effect on the mechanical properties of plantation-grown Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) were investigated with the aim of achieving an effective utilization of the wood. Correlations between MFA and mechanical properties, including longitudinal modulus of elasticity (MOEL), static bending strength (MOR) and compression strength parallel-to-the-grain (CS), were analyzed for predicting the quality of timber. The results indicated that MFA had a greater variation in juvenile wood than in mature wood. The biggest change occurred close to the pith in Chinese fir. The outer-rings (rings 9-30 from the pith) have a relatively low MFA, together with high mechanical properties and high density, when compared with the inner-rings (rings 1-8 from the pith). The MFA had significant negative curvilinear correlations with all the mechanical properties (MOEL, MOR and CS) of Chinese fir, with the value of r 2being 0.88,0.69 and 0.74 respectively.The correlation between the MFA and basic density (BD) was strong in certain consecutive rings (rings 5-30 from the pith), but this did not apply across the whole billet, i.e. from the pith to the bark.

Zeng X.-W.,Chinese Society of Forestry | Yu B.,State Academy of Forestry Administration | Wu J.-S.-G.-L.,Beijing Zhonglin Tianhe Forest Certification Center | Hong Y.,Academy of Forest Inventory and Planning | And 2 more authors.
Forest Research | Year: 2014

In order to propose new design ideas of recovering mixed stand which mainly composed by Pinus koraiensis, some issues about stand structure were discussed and analyzed, such as diameter, spatial pattern, stand volume growth, regeneration and plant diversity, based on three types of overcutting spruce-fir forest on Changbai Mountains. The most difference among the forests was the ratio of conifer trees to broad-leaved trees, with stepped-rates of 9:1, 8:2 and 7:3. The results showed that: P. koraiensis forest became cutting object because of unreasonable and non-operating cutting in the past. The amount of P. koraiensis trees greatly changed among different diameter intervals, and loss happened when diameter greater than 18 cm, which led to the decline of parent tree, seed and provenance, contrary to positive evolution. The spatial pattern of mixed stand was not exactly the same as that of the main tree species, and showed difference among different trees in the same stand. The three forests with different needle/broadleaf ratios followed a random, aggregation and uniform distribution. P. koraiensis assumed aggregation distribution. So the following should be done to recover mixed stand which mainly composed of P. koraiensis. 1. Taking P. koraiensis and precious broadleaf species as the goal, adopting the target tree cultivation method, removing the trees affecting the renewal and growth of target trees, taking spruce fir and broad-leaved tree as accompanying species, weakening the dominance of spruce and fir, and eventually restored the stand gradually to the P. koraiensis and broad-leaved mixed stand; 2. For the stand with conifer tree and broadleaved tree mixed in the ratio of 8:2 and 7:3, changing aggregation distribution into uniform distribution through repair planting, intermediate cutting and combined with natural regeneration; 3. Adopting artificial supplementary interventions to help the natural regeneration ofP. koraiensis, such as repair planting, litter cleaning and so on.

Yu B.,State Academy of Forestry Administration | Yu B.,Beijing Forestry University | Wang B.-T.,Beijing Forestry University
Forest Research | Year: 2011

This research analyzed the data of forest stand, sample trees and meteorological condition for plantation of Robinia pseudoacacia and Pinus tabulaeformis in Fangshan County and Ji County of Shanxi Province, to investigate the water-consumption. The results showed: (1) The water-consuming quantity of plantation increases with increasing forest age. The water-consumption will exceed the precipitation when the stand reaches a certain age. It is 15 years for the plantation of sunny slope Robinia pseudoacacia in Fangshan County; 5 years for the half-sunny slope Robinia pseudoacacia plantation and 23 years for the plantation of half-sunny slope Pinus tabulaeformis in Ji County. (2) Under the current precipitation condition, the water-consumption can't reach its required level, there is insufficient water stress. The order of water-consumption quantity in growing season from high to low is Jul, Jun, Aug, May, Sep and Oct. The precipitation condition limits the plantation's demand on water and its rational distribution during growing season. Therefore, it is necessary to control or regulate the stand density in different growth stages with a consideration of the management objectives and the precipitation input.

Zhang J.,Beijing Forestry University | Zhang J.,CAS Institute of Chemistry | Zhao S.,Beijing Forestry University | Zhao S.,State Academy of Forestry Administration | And 7 more authors.
Molecules | Year: 2014

Polyphenol extracts from the burs of Castanea mollissima Blume (CMPE) exhibited potential antioxidant and hypoglycemic activities. The α-glucosidase inhibitory activities of CMPE were assessed as a means of elucidating the mechanism behind its hypoglycemic activities. In vitro studies showed that CMPE significantly inhibited both yeast α-glucosidase, through a noncompetitive mode with an IC50 of 0.33 μg/mL, and rat intestinal α-glucosidase. In vivo studies revealed that oral administration of CMPE at doses of 600 mg/kg significantly reduced postprandial blood glucose levels by 27.2% in normal rats following sucrose challenges. Gel permeation chromatography revealed that CMPE exhibited typical characteristics of high-molecular-mass polymers with mean (Mn) and weight (Mw) average molecular weights of 35.4 and 50.7 kDa, respectively, and a polydispersity (Mw/Mn) of 1.432. Acid hydrolysis analysis indicated the presence of ellagitannins. These data suggest that CMPE, enriched with ellagitannins, would be an efficacious dietary supplement for diabetes management through the inhibition of alpha-glucosidase. © 2014 by the authors.

Gong W.,South China Agricultural University | Chen S.,Fujian Agriculture and forestry University | Liu W.-Z.,South China Agricultural University | Deng X.-F.,State Academy of Forestry Administration | Tu T.-Y.,CAS South China Botanical Garden
Chinese Traditional and Herbal Drugs | Year: 2015

This study aims at developing fast and accurate species identification methods for the plants of Mussaenda L. In the present study, DNA barcoding analysis was carried out on 89 individuals representing 20 species of Mussaenda in order to evaluate the performance of the four candidate barcoding loci (matK, rbcL, trnH-psbA, and ITS) and ITS2 region. Based on sequence similarity and Neighbor-joining (NJ) tree reconstruction, we detected inter-and intra-specific genetic distances using Kimura 2-parameter (K2P). Inter-specific genetic distance of species in Mussaenda was significantly higher than intra-specific genetic distance. The region of ITS2 showed the highest discrimination power among the independent sequences. Comparably high species discrimination power was also revealed by the matK and ITS data set. The candidate barcode of rbcL displayed the lowest identification rate among the others. However, each individual candidate barcode demonstrated significantly lower discrimination power than the barcode of combined data set. Comparable discrimination power was revealed between the two barcodes of combined sequences matK + rbcL + ITS and matK + rbcL + trnH-psbA + ITS, which showed the values around 77% and 75% based on sequence similarity and NJ tree method. Totally 15 species were identified based on NJ analysis of matK + rbcL + ITS. Consequently, the combined sequence of matK + rbcL + ITS provides an effective and fast tool for the identification and authentication of medicinal plant species in the genus Mussaenda L. ©, 2015, Chinese Traditional and Herbal Drugs. All right reserved.

Wu X.-Q.,CAS South China Botanical Garden | Li P.-X.,CAS South China Botanical Garden | Li P.-X.,University of Chinese Academy of Sciences | Deng X.-F.,CAS South China Botanical Garden | And 2 more authors.
Journal of Systematics and Evolution | Year: 2015

Typical distylous species display both reciprocal herkogamy and heteromorphic incompatibility, which exclude self-and intramorph pollination and accordingly promote intermorph pollination. Here we explore an unusual distylous flower associated with self-and intramorph compatibility in Mussaenda macrophylla Wall. The species did not exhibit a precise reciprocal herkogamy, and the populations studied had a slight bias in favor of the short-styled morph (S-morph). In addition, pollen tube growth in intermorph pollination was faster than either in intramorph or self-pollination, indicating that cryptic heteromorphic self-incompatibility occurred in M. macrophylla. Specifically, pollen tube growth rates after legitimate and illegitimate pollination were much more highly differentiated in long-styled morph (L-morph) than in S-morph, which might be attributed to the increased deesterified pectin in the tip of L-morph pollen tube wall in comparison with S-morph. Transmission electron microscopic observation revealed illegitimate self-pollinated pollen tubes of two morphs were seriously degraded with the large autolysosome-like vacuoles in cytoplasm of L-morph pollen tube but accumulating small vacuoles in that of S-morph pollen tube, suggesting that incompatible pollen tubes might undergo autophagic programmed cell death except self-incompatible S-morph pollen tubes. Our results indicate that M. macrophylla is morphologically distylous with a cryptic heteromorphic self-incompatibility breeding system, which functions differently in S-morph with self-pollination compared with other illegitimate pollination. © 2015 Institute of Botany, Chinese Academy of Sciences.

Zhong S.-S.,Harbin Institute of Technology | Fu X.-Y.,Harbin Institute of Technology | Hu S.-R.,State Academy of Forestry Administration
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | Year: 2011

To improve prediction accuracy of aviation equipment cost under small sample size, a prediction model named information diffusion support vector machine is proposed after combining the information diffusion method and support vector machine. The topology and modeling process of the model are also described. The model parameters include both continuous parameters and discrete parameters, so that a different update strategy is adopted to each component of the particle position when solving the problem of model parameter selection using the particle swarm optimization. Finally, the information diffusion support vector machine is applied to the production cost prediction of military aircraft avionics equipment. The average absolute relative error of the result is 3.3%, which can satisfy actual requirement.

Liu T.,Harbin Institute of Technology | Hu S.-R.,State Academy of Forestry Administration | Luo N.-N.,Harbin Institute of Technology | Jiang J.-H.,Harbin Institute of Technology
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | Year: 2011

To improve the fuel economy of hydrostatics hybrid vehicle(HHV), a HHV dynamic simulation model is built up for performance analysis in MATLAB/Simulink. The optimal tuning of these threshold logic control strategy parameters is formulated as a constrained nonlinear programming problem with an objective function minimizing fuel consumption. The engine active pressurized torque difference and the active pressurized pressure limit are the objects of optimization. A multi-objective genetic algorithm(GA) optimization method is applied to get the optima of work modes and energy distribution in different drive cycles, which gives the compatible control strategy parameters. Simulation results demonstrate that the optimized control strategy parameters allow the engine working in more fuel economy area, improve the fuel economy of HHV. This method can be used for off-line parametric optimization and to shorten the time of controller calibration in the real vehicle.

Loading State Academy of Forestry Administration collaborators
Loading State Academy of Forestry Administration collaborators