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Kinetics analysis and strategy of compensation control study for feeding platform of curve saw for wood
Meng Zhaoxin, Cao Jiajia, Zhu Li, Ma Jingyao, Shi Jinsong
Corrected proof  doi: 10.12171/j.1000-1522.20190234
[Abstract](652) [FullText HTML](271) [PDF 1404KB](17)
Abstract:
ObjectiveFeeding platform is a mechanism designed by imitating manual feeding when sawing wood board. The posture of platform end is the key to ensure sawing quality. A compensation control strategy was proposed in this paper to enhance the accuracy of end posture as the error of platform cannot be simply and efficiently compensated just through hardware.MethodFirstly, Lagrange method was used to establish the dynamic transfer function of the platform. Through dynamic analysis, the motion characteristics of the key components of the platform were analyzed. By simulation and other methods, according to mathematical solution, the error and its characteristics of the end posture were studied, thus a simple error model was established. Secondly, based on the traditional PID control and the parameter optimization function of RBF neural network, a single neuron PID controller suitable for the feeding platform was designed to compensate the driving displacement relation of each branch chain and to carry out real-time compensation control on the mechanism. Finally, the compensation control strategy was verified and analyzed by the joint method of Matlab and Adams, and the algorithm was transplanted to the controller of the feeding platform successively.ResultAfter compensation by the single neuron PID algorithm, the offset error of the end trajectory curve of the feeding platform in X and Y directions was reduced from 3 mm to less than 1.5 mm, and the angle error was reduced from 3.5° to 1.5°, and in most curve segments, the end trajectory curve of the platform completely coincides with the command curve.ConclusionThe SN-PID proposed by this paper can effectively improve the accuracy of the end posture of the woodworking saw feeding platform, and the feeding platform after compensation control can realize the precise cutting task of the wood plate.
Optimization of induction conditions for embryogenic callus of somatic embryogenesis in Cunninghamia lanceolata
Wu Xialei, Han Chao, Sun Yuhan, Cao Sen, Hu Ruiyang, Xu Jinliang, Zheng Huiquan, Li Yun
Corrected proof  doi: 10.12171/j.1000-1522.20190196
[Abstract](736) [FullText HTML](147) [PDF 955KB](21)
Abstract:
ObjectiveThis paper aims to optimize the induction culture of embryogenic callus in the somatic embryogenesis process of Cunninghamia lanceolate and explore the effects of basic medium, maternal genotype and exogenous additives on the induction of Cunninghamia lanceolate somatic embryo.MethodFemale gametophyte (the immature zygotic embryo is in the multi-embryo stage) of three parental genotypes (Z1, Z2, Z3) were used as explants, and used six basic media, different concentrations of exogenous additives of TDZ and MeJA, cytological observation during the induction culture.ResultWith DCR as the basic medium, the induction culture was best, the callus induction rate was 70.74%, and the induction rate of embryogenic callus was 17.36%, which was the best choice for the induction of immature embryo culture of Cunninghamia lanceolate; the maternal genotype had a greater impact on embryogenic callus induction, and the female gametophyte of the Z1 genotype tree was most suitable for inducing embryogenic callus; with DCR as the basic medium, adding sucrose 30 g/L, activated carbon 1 g/L, plant gel 5 g/L and adding plant growth regulator 2,4-D 1.5 mg/L, KT 0.4 mg/L, MeJA 1.2 μmol/L and TDZ 0.004 mg/L, for the embryogenic callus of Cunninghamia lanceolate, the induction rate was the highest, reaching 19.83%; embryogenic callus can be induced in only 4 days, and the structure and polarity characteristics of the proembryogenic masses in different stages were significantly different.ConclusionThe basic medium, maternal genotype and exogenous additives all significantly affected the induction culture of Cunninghamia lanceolate somatic embryos. Female gametophyte with Z1 donor parental genotype as explants, DCR as the basic medium and adding MeJA and TDZ in combination can significantly improve the somatic embryos induction rate of Cunninghamia lanceolate.
Relationship between leaf functional trait variation of Cotinus coggygria ​​​​​and location geographical-climatic factors under drought stress
Li Jinhang, Zhu Jiyou, Catherine Mhae B. Jandug, Zhao Kai, Xu Chengyang
Corrected proof  doi: 10.12171/j.1000-1522.20190079
[Abstract](278) [FullText HTML](180) [PDF 861KB](25)
Abstract:
ObjectiveThis study aims to identify leaf functional trait variation patterns and differences of Cotinus coggygria seedlings from different locations and to analyse the influences of different geographic-climatic factors on leaf functional trait variations under continuous drought environment.MethodA standard continuous drought stress experiment was carried out using one-year-old C. coggygria seedlings from five different locations within China. Three levels of water regimes were set: control (CK, 75% ~ 80% of soil field capacity), moderate stress (MS, 55% ~ 65% of soil field capacity) and severe stress (SS, 35% ~ 45% of soil field capacity). ANOVA was used to identify the effects of drought, location and their interaction on leaf functional traits. On the other hand, the principal component analysis (PCA) and the redundancy analysis (RDA) were used to measure the relationship between location distribution of the species and the geographical-climatic factors and the influences of geographical-climatic conditions on leaf functional trait variation degree (TVD), respectively.Result(1) Drought stress had significant effects on all the leaf functional traits. Seedlings under SS had lower leaf function traits in terms of leaf chlorophyll content (LChl, 17.61%, P < 0.001), relative water content (RWC, 3.71%, P < 0.001), specific leaf area (SLA, 10.89%, P = 0.002), and leaf area ratio (LAR, 17.22%, P = 0.001) compared to the seedlings under CK. However, seedlings under SS had higher leaf dry matter content (LDMC) and leaf density (LD) than control by 9.04% (P < 0.001) and 14.52% (P = 0.009), respectively. (2) Correlations among leaf functional traits became stronger in drought environment, which showed that SLA had significantly (P < 0.01) negative links with LDMC and LD, LDMC and LD had a significant (P < 0.01) and positive relation, and RWC had significantly positive correlations with LChl (P < 0.01), SLA (P < 0.01) and LAR (P < 0.05). (3) The leaf functional traits showed significant differences among C. coggygria locations under drought treatments. SLA (P = 0.002), LChl (P = 0.025) and LD (P = 0.026) were significantly different under MS treatment, and LChl (P < 0.001), LAR (P < 0.001) and RWC (P = 0.005) were significantly different under SS treatment. (4) Among the five different locations, C. coggygria seedlings from Yanqing County in Beijing had the highest average trait variation degree (the mean values of all trait variation degrees) of 17.57%, while the lowest was from Jiang County of Yuncheng City in Shanxi Province of 6.97%. (5) After the screening of RDA, precipitation of the driest month (DMP, P = 0.002), growing season mean monthly precipitation difference (GSPD, P = 0.008), Max. temperature of the warmest month (WMT, P = 0.016) and average annual precipitation (ANP, P = 0.036) had significant effects on leaf functional trait variation degree. Particularly, DMP had negative relationships with all trait variation degree, but had more significantly negative correlations with the variation degree of LDMC and LD. GSPD and ANP had significantly negative correlationss with the variation degree of SLA and LAR. WMT was closer to the variation degree of LChl.ConclusionSignificant differences were found for leaf functional traits of C. coggygria among different drought treatments and different locations. The local climate (especially DMP, GSPD, WMT and ANP) was the main cause of leaf functional trait variation of C. coggygria from different locations under drought stress. Among seedlings from the five locations explored in our study, seedlings from Jiang County of Yuncheng City in Shanxi Province were more suitable to be introduced to the arid areas in northern China, as a result of a relatively high DMP, a proper GSPD and ANP, a relatively low WMT, and a low average leaf functional trait variation degree under drought stress.
Soil enzyme activities and physicochemical properties of typical woodlands in karst faulted basins
Sun Yonglei, Lu Zeyang, Zhou Jinxing, Pang Danbo, Liu Yuguo, Guan Yinghui
Corrected proof  doi: 10.12171/j.1000-1522.20180328
[Abstract](249) [FullText HTML](160) [PDF 801KB](26)
Abstract:
ObjectiveSoil enzymes are involved in all soil biochemical processes and are closely related to soil physicochemical properties. In this paper, three typical woodlands in karst faulted basins were studied, and the relationships between soil enzyme activities and physicochemical properties of forest lands were explored, which provided a reference for vegetation ecological restoration in this area. MethodIn this study, the Pinus yunnanensis, Eucalyptus maideni and natural secondary forest in the karst faulted basin were used as research objects. The relationship between soil enzyme activities and physicochemical properties was studied using the methods of redundancy analysis.Result(1) The soil pH values of the three forest lands ranged from 5.47 to 6.03, and the soil bulk densities of the 10−20 cm and 20−30 cm soil layers in the Pinus yunnanensis forest were significantly higher than those of the Eucalyptus maideni forest and the secondary forest (P < 0.05). The contents of total nitrogen (TN) in 0−10 cm and 10−20 cm layers of Eucalyptus maideni forest were significantly higher than those in Pinus yunnanensis forest and secondary forest (P < 0.05). The available phosphorus (AP) content in 0−10 cm soil layer of secondary forest was significantly higher than that in Pinus yunnanensis forest and Eucalyptus maideni forest (P < 0.05). The contents of soil orgenic carbon (SOC) and ammonium nitrogen (AN) showed the law of secondary forest > Pinus yunnanensis forest > Eucalyptus maideni forest. (2) The activity of acid phosphatase and urease in the 0−10 cm soil layer of three woodlands was in the order of secondary forest > Eucalyptus maideni forest > Pinus yunnanensis forest, while the 10−20 cm soil layer showed the opposite law. The highest activities of amylase, cellulase and invertase in 0−10 cm and 10−20 cm soil layers were obtained from secondary forest, followed by Pinus yunnanensis forest and the lowest in Eucalyptus maideni forest. In addition, the soil enzyme activities in the soil layers of the forests were significantly different (P < 0.05), and the soil enzyme activities showed a trend of decreasing with the increase of soil depth. (3) Through the redundancy analysis of soil physicochemical properties and enzyme activities in the three forest lands, the results showed that SOC, AN, AP and pH all had a significant positive correlation with invertase activity. However, TN was significantly negatively correlated with invertase activity. Soil bulk density was negatively correlated with urease and acid phosphatase activities. (4) the Monte Carlo test showed that the order of importance of soil physicochemical properties on soil enzyme activities was: SOC (41.4%) > AN (32.9%) > AP (24.3%) > soil bulk density (12.6%) > TN (7.9%) > pH (5.5%).ConclusionComprehensive analysis showed that SOC and AN were the main indicators affecting the changes of soil enzyme activity in the study area. The secondary forest is the best in the restoration of soil fertility and enzyme activity in karst faulted basins, while the advantage of Pinus yunnanensis forest is higher than that of Eucalyptus maideni forest.
Pyrolysis kinetics of major landscape tree species in Hohhot of northern China based on thermogravimetric analysis
Wang Lei, Xu Jiachen, Zhen Yaxing, Zhang Heng
Corrected proof  doi: 10.12171/j.1000-1522.20190280
[Abstract](265) [FullText HTML](127) [PDF 1255KB](28)
Abstract:
ObjectiveTrees are the material basis for forest or landscape fires, and also the inevitable factor for fires. Reasonable selection and allocation of landscape plants is the basic work of constructing biological fire-resistant forest belts. At present, the researches on pyrolysis and flammability are mostly about forest fuels, but there are few studies on pyrolysis kinetics of landscape tree species. In this paper, the pyrolysis kinetics of 21 landscape tree species in Hohhot of northern China were studied and the fire-resistant landscape tree species were chosen to provide a theoretical basis for urban ecological security and tree planting in fire-resistant green space.MethodThermogravimetric analysis was used to study the thermogravimetric behavior of landscape tree species under the conditions of high purity oxygen as carrier gas, air as ventilation atmosphere, gas flow rate of 10 mL/min and heating rate of 60 ℃/min. The TG-DTG curve was used to analyze the pyrolysis process and pyrolysis parameters of landscape tree species.ResultThe pyrolysis of 21 landscape tree species in air atmosphere experienced dehydration, rapid pyrolysis and carbonization stages. The corresponding parameters of the sample in the rapid pyrolysis stage were obtained by the Coats-Redfem integration method of the first-order reaction kinetic model.ConclusionThe order of thermal stability of leaf parts of each tree species from low to high was: Sambucus williamsii, Berberis xinganensis, Amygdalus triloba, Buxus sinica, Viburnum mongolicum, Sabina vulgaris, Rosa xanthina, Buddleja alternifolia, Tamarix chinensis, Amygdalus davidiana, Spiraea pubescens, Morus mongolica, Amygdalus persica, Syringa reticulata, Sorbaria kirilowii, Flueggea suffruticosa, Acer stenolobum, Weigela florida, Cotoneaster acutifolius, Elaeagnus angustifolia, Lycium chinense. The P-value of the pyrolysis characteristics index of leaf part of each tree species from large to small was: Lycium chinense, Cotoneaster acutifolius, Syringa reticulata, Weigela florida, Rosa xanthina, Elaeagnus angustifolia, Sorbaria kirilowii, Morus mongolica, Amygdalus davidiana, Amygdalus persica, Acer stenolobum, Tamarix chinensis, Buddleja alternifolia, Sabina vulgaris, Buxus sinica, Berberis xinganensis, Flueggea suffruticosa, Amygdalus triloba, Spiraea pubescens, Viburnum mongolicum, Sambucus williamsii. Based on the comprehensive analysis of thermal stability, ignition temperature and pyrolysis characteristics index,Flueggea suffruticosa, Acer stenolobum, Elaeagnus angustifolia, Lycium chinense and Weigela florida are strong fire-resistant landscape tree species. The results can provide a theoretical basis for the prevention and control of urban forest fires by landscape tree species.
The quantitative characteristics of natural protected areas in Northeast China
Zhang Fangling, Pu Zhen, Liang Xiaoyu, Gu Yuanyang, Xing Shaohua
Corrected proof  doi: 10.12171/j.1000-1522.20190139
[Abstract](1259) [FullText HTML](354) [PDF 633KB](35)
Abstract:
ObjectiveAn in-depth analysis of the quantitative characteristics of national natural protected areas in large geographical units of China is crucial for reforming the protected area system and establishing an effective national park system.MethodBased on the data collected from 594 national natural protected areas in Northeast China, this paper examines their quantitative characteristics on the basis of three aspects: construction categories, construction periods and natural ecosystem, We also identified and calculated national natural protected areas that have overlapping boundaries.ResultThe results show that the establishment of national natural protected areas in Northeast China experienced three stages, namely the stage of stagnation, the initial develop stage and the stage of rapid development, suggesting the overall upward trend from 1956 to 2016. Affected by natural environmental and social factors, the distribution of national natural protected areas in the study area is uneven and patchy. There are as many as 108 national natural protected areas with overlapping scope, especially nature reserves and forest parks. According to ecosystems in the research area, it can be roughly classified into six categories, among which forest ecosystems and inland wetland ecosystems dominate in terms of quantity and area, grasslands and meadows, desert, ocean and coasts was overlooked, some parts of areas were not protected.ConclusionWe suggest that the future development of natural protected area in Northeast China can take into account both diversification and systematization. In regard to the planning and establishment of natural protected areas, we should focus on the spatial distribution of natural ecosystems and pay more attention to the consistency of natural protected area catigories with ecosystem types, in order to provide the convenient for construction and management. Optimize and integrate hot spots that natural protected areas gathered according to main natural ecosystem by construct national park, merge natural protected areas that spatial proximity, protected objects has association. This research will provide scientific data support for the establishment and management of national parks and natural protected areas in Northeast China.
Experimental research on mechanical performance of damaged bracket set joints
Chen Jiuzhang, Chen Xueyao, Dai Lu
Corrected proof  doi: 10.12171/j.1000-1522.20190278
[Abstract](2378) [FullText HTML](211) [PDF 1265KB](29)
Abstract:
ObjectiveThe bracket set is an important component of the wooden structure in Chinese ancient architecture system, which plays a vital role in maintaining the mechanical properties of the whole structure reliable. There are different degrees of damage of bracket set joints in existing ancient structures. While at present, most of the researches on the mechanical properties of bracket set joints are based on intact bracket sets, and little consideration is given to the mechanical properties and deformation rule of damaged bracket sets, especially under the condition of decaying and volume loss caused by worm moths. Therefore, it is of great practical significance to study the effect of damage on the mechanical properties of bracket set joints or even the whole structure, which can also help provide scientific basis for the repair and protection of ancient timber structures.MethodThis research took a typical second-story bucket arch on columns in supporting platform of Yingxian Wooden Tower, Shanxi Province of the northern China as the object, and made four groups of bracket set models with the 1/3.5 scale. One group of model kept in perfect condition, while the remaining three groups were drilled with holes in different positions artificially to weaken the stress-bearing section of components of the bracket set joints, so as to simulate the real damage to them. By adopting the vertical loading test, the load-displacement curves of four groups of bracket set joints were obtained, and the mechanical characteristics and deformation performances of bracket set joints were clarified combining the test result.ResultThe test result and data analysis showed that under certain vertical loads, the failure of bracket joints was mainly reflected in the fracture, bending deformation of the second-story Hua-Gong and cracks on the connection block. The failure mode of damaged bracket set joints was similar to that of the intact one. While pre-drilled groups sufferred from worse damage as their ultimate load and stiffness decreased, and the negative effect caused by the former damage was more obvious on the stiffness of bracket set joints.ConclusionWhen the damage type is the same and the overall damage condition of the structure is similar, the damage on the first story of a bracket set joint would exert greater influence on stiffness, which means it is easier to deform when bearing vertical loads.
Improvement of insulin resistant HepG2 cells glycometabolism effect by polyphenol from the fruit of Viburnum sargentii
Fu Qun, Wang Mengli, Gui Bin, Guo Qingqi
Corrected proof  doi: 10.12171/j.1000-1522.20190243
[Abstract](170) [FullText HTML](70) [PDF 1053KB](8)
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ObjectiveThis study investigated the improvement of the polyphenol from the fruit of Viburnum sargentii (PVSK) on insulin resistance (IR) model of HepG2 cells, and to evaluate its hypoglycemic activity.MethodHigh concentration insulin was used to induce in vitro IR model, and the stability (cell activity method) and reliability (Z factor method) of the model were evaluated. Blank group, IR model group, positive control group (metformin) and PVSK group were set up. Cell viability was detected by MTT assay, glucose content in culture medium was detected by Glucose oxidase method and the consumption of glucose was clculated; glycogen content was determined by anthrone method; the activity of hexokinase (HK) and pyruvate kinase (PK) were determined by colorimetric method. Enzyme-linked immunosorbent assay (ELISA) was used to detect the activity of phosphoenolpyruvate kinase (PEPCK) and glucose hexaphosphatase (G6PC).ResultInsulin induction treatment of HepG2 cells at 10− 6 mol/L for 24 hours was the best condition for the production of insulin resistance model, and the IR model had high stability and reliability within 12 ~ 36 hours. 0.10 ~ 1.00 mg/mL PVSK polyphenol group had significantly higher glucose consumption than model group (P < 0.05). The highest glucose consumption was (3.49 ± 0.11) mmol/L in 24 h and 0.50 mg/mL groups, with a consumption rate of 88.81% (P < 0.01). Comparedwith model group, PVSK polyphenols could increase glycogen content by 33.65% (P < 0.01), HK and PK activity by 43.36% (P < 0.05) and 48.41% (P < 0.01), respectively. The inhibition rates of G6PC and PEPCK activity were 22.86% (P < 0.01) and 17.33% (P < 0.05), respectively.ConclusionPVSK could increase HK and PK activities of IR-HepG2 cells, accelerate glycolysis and increase glycogen content. Inhibiting the activity of G6PC and PEPCK can reduce the production of endogenous glucose. Therefore, the polyphenols of PVSK have a certain effect on the treatment of insulin resistance cells.
Effects of climate and phylogeny on the relationship between specific leaf area and leaf element concentration of trees and shrubs in Changbai Mountain of northeastern China
Gao Linhao, Sun Han, Bai Xueqia, Dai Shuang, Fan Yanwen, Liu Chao, Wang Xiangping, Yin Weilun
Corrected proof  doi: 10.12171/j.1000-1522.20190320
[Abstract](147) [FullText HTML](80) [PDF 888KB](13)
Abstract:
ObjectiveSpecific leaf area (SLA) is a key functional trait of plants. It is affected by climate and phylogeny, and is closely associated with leaf element concentration. Therefore, the relationships between SLA and the abiotic and biotic factors are useful for understanding the strategies of plants in adaptation to environment and resource utilization. Meanwhile, trees and shrubs belong to different life forms, so we need to examine whether they differ in adaptation strategies related to SLA.MethodThis study was based on the comparison of dominant tree and understory shrub species in sample plots along the altitudinal gradient of Changbai Mountain, northeastern China. We established a phylogenetic tree using DNA barcode sequences, and analyzed the relationships of SLA with leaf element concentrations, climatic factors and phylogeny. We examined whether the relationships between SLA and leaf element concentrations, and the influence of climate and phylogeny, were different between trees and shrubs.Result(1) The SLA of trees and shrubs was negatively correlated with mean annual precipitation and positively correlated with thermal conditions (mean temperature of the coldest month and potential evapotranspiration). However, different from shrubs, the SLA of trees was more affected by phylogeny. (2) For both trees and shrubs, SLA was positively correlated with leaf total nitrogen (TN) and total phosphorus (TP) concentrations, but negatively correlated with total carbon (TC) concentration. Trees and shrubs differed significantly in the regression slopes of SLA with TN and TP, but did not differ in the slope of SLA with TC. (3) Climatic factors significantly affected the slope of the relationship between SLA and TC, while phylogeny affected the slope of SLA with TN and TC for both trees and shrubs. Climatic factors and phylogeny together affected the slope between SLA and TP for shrubs, but not for trees.ConclusionThe adaptation of SLA to environment and the resource utilization strategy were similar for trees and shrubs, but there were also differences in the modulators of the relationship between SLA and TP for trees and shrubs. Compared with trees, the understory shrubs have a tendency to convergent evolution, generally with high-SLA leaves and more sensitive to climate, and may store more phosphorus in the leaves to meet the needs of survival.
Construction method of ventilation corridor woodland in urban fringe area of Beijing: taking the Heizhuanghu District as an example
Xu Yiding, Yang Zilei, Li Yunyuan
Corrected proof  doi: 10.12171/j.1000-1522.20190002
[Abstract](4990) [FullText HTML](113) [PDF 2267KB](20)
Abstract:
ObjectiveIn recent years, Beijing’s air quality is increasingly threatened, urban forest construction can improve the air quality to some extent. Limited by the existing basic conditions such as superior planning, climate, river and farmland distribution, the construction of urban forest in urban fringe is a difficult point in the construction of forest city, especially the construction of ventilation corridor urban forest facing many practical problems and technical difficulties.This paper takes the ventilation corridor urban forest construction in Heizhuanghu District of Beijing as an example, introduces the specific construction strategy and scheme in detail and verifies the effectiveness, providing a case basis for the development of forest city construction in such areas.MethodThrough macro-planning of urban forest structure layout, medium-view optimization of urban forest structure characteristics and micro-construction of urban forest plant communities, Ecotect and Winair were used to establish and compare two 3D models before and after urban forest construction in different recurrence periods (5, 10, 15 m/s).Result(1) Together with the present situation of Heizhuanghu District condition and principle of ventilated corridor function, we built urban forest system mainly by macro planning and forest structure, increasing the forest land area, the rules keeping ecological cold source, clearing forest corridor mainly being northwest - southeast direction, the width was greater than 150 m, the micro construction of grassland, and shrub structure mainly combined with the present situation of the plant community of terrain type ventilation corridor. (2) Under the conditions of 5, 10 and 15 m/s of the northwest wind, the average air velocity of the sample zone parallel to the ventilation corridor of the urban forest increased by 0.042, 0.033 and 0.101 m/s compared with that before the modification; the average air velocity in the vertical sample zone increased by 0.023, 0.0593 and 0.0753 m/s. After the modification, the air velocity in the simulated area increased, and the air velocity increased with the wind force increased. Air flows faster inside the forest corridor than outside.ConclusionThe air velocity of the ventilation corridor type urban forest reconstructed with the combination of multi-dimensional strategy is greatly increased compared with the area of the region, which fully shows that the construction of the ventilation corridor type urban forest in the urban fringe can effectively accelerate the wind speed and achieve the comprehensive objectives of ventilation, cooling and sewage discharge.
Phenotypic diversity analysis of blueberry germplasm resources
Li Wei, Wang Pan, Qiqige, Zhang Qichang, Huang Bingjun, Xiao Zejun
Corrected proof  doi: 10.12171/j.1000-1522.20190279
[Abstract](3458) [FullText HTML](111) [PDF 665KB](24)
Abstract:
ObjectiveThe genetic diversity of phenotypic traits of blueberry germplasm resources was studied in Shandong and Jilin provinces to provide theoretical basis for the conservation and genetic improvement of the germplasm resources.MethodThe phenotypic traits of 47 blueberry varieties were measured, and the phenotypic diversity among blueberry varieties was discussed by principal component analysis, correlation analysis and cluster analysis.ResultPrincipal component analysis showed that the first four principal component characteristic root values greater than 0.5 contained 25 traits, with a cumulative contribution rate of 53.477%, accounting for 67.57% of the survey indicators. 62 pairs were significantly correlated with the number of phenotypic traits, 40 pairs were significantly correlated. Blueberry varieties, phenotypic trait variation of rich germplasm resources, quality traits and aromatic wiener diversity index distribution of quantitative traits ranged in 0.32 - 1.36 (average 0.87) and 0.22 - 2.06 (average 1.8), the quality characters of 15, contained 52 mutation types. There were 22 quantitative traits, and the coefficient of variation ranged from 11.39% to 46.98%. This indicated that the quantitative traits of blueberry phenotype showed more extensive variation than the qualitative traits.When the Euclidean distance was 17, 47 blueberry varieties were divided into 5 groups. Each group had a certain correlation with the cultivated habitat and cultivated group.ConclusionIn this study, we identified 40 blueberry varieties of Jilin Province and Shandong Province both phenotypic diversity and genetic relationship, the choice in cultivating blueberry new varieties, parents should focus on canopy, shrub height, canopy length to diameter, thickness of fruit powder, fruit sepals by posture, fruit hardness, fruit sepals length-width ratio, looks like the fruit sepals type, such as index, the results can provide reference for excellent germplasm resource evaluation and selection.
Effects of P fertilization methods on growth and nutrient uptake of Vaccinium spp. seedlings
Wang Aibin, Zhang Liuyang, Song Huifang, Zhang Ming, Miao Yahui, Guo Yuxiao, Zhang Lingyun
Corrected proof  doi: 10.12171/j.1000-1522.20190235
[Abstract](283) [FullText HTML](184) [PDF 846KB](30)
Abstract:
ObjectiveBy exploring the effects of phosphate fertilization methods on growth and nutrient uptake of Vaccinium spp., this study found out the suitable fertilization method for blueberry seedling cultivation, and provided theoretical and practical basis for scientific fertilization of Vaccinium spp.MethodTwo-year-old‘Misty’ was taken as test object. By means of completely randomized design, we set up four fertilization methods, including single fertilization (DF), linear fertilization (LF), average fertilization (AF) and exponential fertilization (EF), whereas no fertilization provided as control (CK). Employing principal component analysis, the best P fertilization method was comprehensively evaluated on the basis of morphological indexes, physiological indexes of leaves and soil physicochemical properties compared with the control.ResultThe results showed that the length growth of basal branches, dry mass of 100 leaves, leaf areas, the number of basal branches and crown width could be enhanced remarkably under all the fertilization methods; the content of P, K, soluble sugar, soluble protein, phenols and chlorophyll in leaves were also increased. The total nitrogen, total potassium, nitrate nitrogen, ammonium nitrogen, available potassium and pH were lower than CK in the soil, whereas the total phosphorus, available phosphorus, organic matters and EC were higher than CK. The effects of exponential fertilization were the most obvious on the length of Vaccinium spp. basal branches, diameter of basal branches, dry mass of 100 leaves, leaf areas, number of basal branches, crown width, leaf K content, soluble protein content, phenols content, chlorophyll content of leaves, and available potassium, organic matters and pH in the soil. Straight fertilization was proved to be the best method for N content in the leaves than other treatments. Meanwhile, the leaf phosphorus contents of exponential fertilization and average fertilization were more stable than other treatments.ConclusionAltogether, the effects of different P fertilization methods on the growth of Vaccinium spp. are as follows: EF > AF > DF > LF > CK. These data indicate that the fertilization treatments can promote the growth of Vaccinium spp. and the most effective fertilization method is exponential fertilization.
Extraction, antioxidant and antibacterial activities of essential oils from Magnolia wufengensis
Cheng Jiali, Ma Jiang, Xiao Aihua, Zhu Zhonglong, Sang Ziyang, Ma Lüyi
Corrected proof  doi: 10.12171/j.1000-1522.20190249
[Abstract](3514) [FullText HTML](82) [PDF 724KB](14)
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ObjectiveThe aim of this study is to establish a set of reliable process system for the extraction of essential oils from Magnolia wufengensis buds and provide technical support as well as theoretical reference for its subsequent development and application. The extraction process of essential oils from M. wufengensis buds was studied, and chemical compositions, antioxidant and antibacterial activities were identified and evaluated.MethodBased on single-factor experiment, the supercritical CO2 fluid extraction conditions of essential oils from air-dried buds of M. wufengensis ‘Jiaohong No.1’ were optimized by response surface methodology. Components of essential oils were qualitatively and quantitatively analyzed by automated mass spectral deconvolution and identification system combined with retention index. DPPH free radical scavenging method and reducing power method were used to analyze the antioxidant activity of essential oils. Disk diffusion method and broth microdilution method were used to measure the antibacterial activities.ResultUnder the air-dried pretreatment condition, the optimum processing conditions for extracting essential oils from M. wufengensis were as follows: extraction temperature 47 ℃, extraction pressure 40.7 MPa, dynamic extraction time 102 min. The extraction yield of essential oils under this condition was (1.217 ± 0.014)%. A total of 30 components were identified, accounting for 70.65% of the total components. DPPH free radical scavenging method showed that the IC50 value of essential oils was 12.82 mg/mL, and the AEAC value was 198.64 mg. The essential oils had certain antioxidant activity, and the reducing power method showed the same results. The inhibitory effect of essential oils on the four tested bacteria was in order of Staphylococcus aureus > Bacillus subtilis > Escherichia coli > Salmonella typhimurium.ConclusionA feasible supercritical CO2 extraction process of the essential oils from the air-dried buds of M. wufengensis was established for the first time. Furthermore, the main components of the essential oils were identified and its antioxidant and antibacterial activities were verified.
Site index model for Larix olgensis plantation based on generalized algebraic difference approach derivation
Niu Yilong, Dong Lihu, Li Fengri
Corrected proof  doi: 10.12171/j.1000-1522.20190036
[Abstract](165) [FullText HTML](116) [PDF 1174KB](26)
Abstract:
Objective Forest site quality assessment is fundamental to forest management and important for estimating forest growth and yields, evaluating forest potential productivity, and making suitable silviculture practices. In this study, the generalized algebraic difference approach (GADA) method was used to develop the more flexible polymorphic site index model based on 60 stem analysis data of dominant and co-dominant trees. The model will provide basic reference for evaluation of the site quality for Larix olgensis plantation in Heilongjiang Province of northeastern China. Method By selecting the growth equations of modification of the Weibull equation, Korf equation and Richards function, 6 difference site index models were developed by GADA method based on the stem analysis data collected from 1994 to 2017 in Heilongjiang Province. The parameters of model were fitted with nonlinear least square method. Combined with fitting data and validation data set, the model was preliminarily selected by four indexes, i.e. R2, root mean square error (RMSE), modelling efficiency, and average absolute error. The optimal models were further screened by residual plots and site index curve clusters. The optimal model and the model developed from ADA method by the same basic equation were compared and evaluated through site index curve cluster and parameters, ages when annual growth reaching the maximum value (inflection) and the values. Result The difference model based on the Richards equation \begin{document}$h = a{\left( {1 - {{\rm{e}}^{ - bt}}} \right)^c}$\end{document} with free parameters \begin{document}$ a = {{\rm{e}}^{{X_0}}}, c = {c_2}/{X_0},$\end{document} \begin{document}${X_0} = \dfrac{1}{2}\left[ {\ln {h_1} + \sqrt {\ln {h_1}^2 - 4{c_2}\ln \left( {1 - {{\rm{e}}^{ - b{t_1}}}} \right)} } \right]$\end{document} was selected as the optimal model. The results of its parameter estimations were b = 0.046 8 and c2 = 4.675 4, respectively. The goodness of fit and validation indicators of model were as follows: R2 was 0.987 4, RMSE was 0.749 1, MAE was 0.904 0, and EF was 97.04%. Compared with the model developed by ADA method, the optimal model derived by GADA method can better predict the growth process of dominant trees. Conclusion In the derivation of the status index model, according to the GADA method, the difference model derived from specifying multiple parameters as free parameters has not only good fitting effect, but also can conform to the properties of multiple asymptotic lines and curve polymorphism at the same time, while the ADA method can only satisfy one of them at the same time. According to the fitting results of the optimal model, the asymptotic value of the high growth curve for the dominant tree increases gradually with the increase of the site index, and the time of inflection position occurs earlier. This shows that the Larix olgensis plantation with better site conditions, the growth rate and maximum value of the dominant tree height increase, and the maximum value of height growth rate occurs earlier.
Screening study of fire resistant tree species in Jianshui County, Yunnan Province of southwestern China
Gu Wangming, Lu Zeyang, Huang Chunliang, Li Yifan, Guan Yinghui
Corrected proof  doi: 10.12171/j.1000-1522.20180378
[Abstract](1364) [FullText HTML](574) [PDF 768KB](24)
Abstract:
Objective According to the characteristics of forest fires and afforestation species in Jianshui County, Yunnan Province of southwestern China, 18 major afforestation species were selected as research objects, aiming to screen out fire resistant tree species suitable for forestry development in Jianshui County, and in order to provide a certain theoretical basis for forest fire prevention in this area. Method Using 16 indicators (the physicochemical properties and combustion properties of tree species such as water content, crude fat and ash, the biological and ecological characteristics of tree species such as thick and thin canopy, leaf thickness and bark thickness, and the natural regeneration ability of tree species, seedling source and afforestation) as evaluation factors, and the fire performance of 18 species was comprehensively evaluated by typical sampling, point selection survey, experimental measurement and analytic hierarchy analysis. Result According to the assessment results, the tree species were divided into four categories, category I (optimal fire- resistance trees): Michelia macclurei, Pistacia chinensis, Camellia oleifera, Pittosporum brevicalyx are the preferred species for fire-resistant forest belts; category II (secondary fire resistant trees): Ternstroemia gymnanthera, Photinia serrulata, Ligustrum lucidum, Cyclobalanopsis glauca, Symplocos sumuntia, which can be used as a fire-resistant tree species to create a biological fire-fighting forest belt; category III (ordinary fire resistant trees): Quercus acutissima, Quercus variabilis, Pistacia weinmannifolia, Sapium discolor, which are difficult to plant as a fire tree species, but can be used for forest fire prevention; Category IV (non fire resistant trees): Pinus yunnanensis, Fraxinus malacophylla, Eucalyptus globulus, Pinus massoniana, Platycladus orientalis, have poor fire performance and should not be used as fire tree species and should be protected. Conclusion In view of the current characteristics of forest stand structure with single forest structure and large forest area in Jianshui County, it is suggested that category I and category II fire tree species can be built as the main bio-fire forest belt in the future to achieve the purpose of blocking the spread of forest fires; the fire performance of the category III tree species is general, and the field can be planted in combination with category I and category II fire tree species according to site conditions and regional characteristics.
Modeling stem taper profile for Pinus sylvestris plantations using nonlinear quantile regression
Xin Shidong, Jiang Lichun
Corrected proof  doi: 10.12171/j.1000-1522.20190014
[Abstract](3390) [FullText HTML](136) [PDF 1446KB](33)
Abstract:
ObjectiveThe aim of this study was to develop stem taper equation for Pinus sylvestris based on quantile regression, and the prediction accuracy of the nine quantiles (τ = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9) and the traditional nonlinear regression stem taper equations was compared and analyzed.MethodThe stem taper data of 154 Pinus sylvestris plantations in Jinsha Forest Farm of Qitaihe Forestry Bureau was taken as the research object. The single, segmented and variable form taper equations were selected, and the nonlinear quantile regression method was used to construct the stem taper equations of Pinus sylvestris. The performance of all constructed stem taper equations was compared and analyzed by these evaluation statistics: coefficient of determination (R2), mean absolute bias (MAB), root mean square error (RMSE), mean percentage of bias (MPB).Result(1) The results showed that the stem taper equations could converge at 9 quantiles (τ = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9), respectively. Quantile regression method can flexibly predict changes in taper curve of each quantile. (2) Compared with the nonlinear regression, the stem taper equations based on the median (τ = 0.5) perform best during the fitting process. The best performance was obtained for the variable exponential equation. (3) The validation results also showed that compared with the nonlinear regression equations, the MAB and MPB of the single taper equation based on the median (τ = 0.5) both decreased by 26.7% and the RMSE decreased by 19.9%. The segmented equation and the variable form equation based on the median (τ = 0.5) showed the better prediction ability. (4) The prediction equations of the median regression are better than the corresponding nonlinear equations for the most stem sections.ConclusionQuantile regression method is a robust modeling method, the variable exponential equation based on the median (τ = 0.5) shows more prediction precision. It is suitable for the prediction of stem taper for Pinus sylvestris in this region.
Effects of slope position on soil microbial biomass carbon and nitrogen in natural Pinus sylvestris var. mongolia forest in the cold temperature zone
Xiao Ruihan, Man Xiuling, Ding Lingzhi
Corrected proof  doi: 10.12171/j.1000-1522.20190309
[Abstract](133) [FullText HTML](87) [PDF 662KB](23)
Abstract:
ObjectiveIn order to study the characteristics of soil microbial biomass carbon and nitrogen in natural Pinus sylvestris var. mongolia forest in the cold temperature zone, the dynamic variation rule of soil microbial biomass carbon and nitrogen and those influencing factors were analyzed to provide a theoretical basis for soil nutrient transport and flow characteristics in the natural Pinus sylvestris var. mongolia forest.MethodMeasurements were taken every month from May to September in 2017 at three sites, including the top, the middle, the lower regions of slope in the Pinus sylvestris var. mongolia forest. The microbial biomass carbon and nitrogen in the 0 - 10 cm and 10 - 20 cm were determined by chloroform fumigation and extraction method, with their seasonal dynamics and the relationships with soil physicochemical properties in three sites.ResultThe results showed that the soil microbial biomass carbon and nitrogen contents under different slope positions presented fluctuating downward trends from May to September, with the ranges of 74.33 to 515.33 mg/kg and 15.33 to 240.57 mg/kg, respectively. The microbial biomass carbon-nitrogen radio was between 1.04 and 5.73, which was significantly different among varied site conditions during the measuring periods. The mean values of soil microbial biological carbon and nitrogen in the lower and middle regions of slopes were significantly higher than those in the top regions of slope (P < 0.05). Site conditions had significant effects on soil microbial biomass carbon, nitrogen and soil microbial biomass carbon-nitrogen ratio (P < 0.01). The soil microbial biomass carbon and nitrogen contents in 0 - 10 cm soil layer were significantly larger than those in 10 - 20 cm soil layer. Soil microbial biomass carbon and nitrogen were significantly positively correlated with soil total organic carbon, total nitrogen and soil water content, but not correlated with soil temperature and pH.ConclusionThe study shows that slope position has significant influence on soil microbial biomass in the Pinus sylvestris var. mongolia forest in the cold temperature zone, and its content has obvious site-differentiation rule. Soil total organic carbon, total nitrogen and soil water content are the main influencing factors leading to soil microbial biomass carbon and nitrogen difference.
Impact of Land Surface Types Change on Urban Heat Island: A Case Study of Chaoyang District, Beijing
Li Pengli, Muhammad Amir Siddique, Fan Boqing, Huang Huaguo, Liu Dongyun
Corrected proof  doi: 10.12171/j.1000-1522.20190045
[Abstract](189) [FullText HTML](39) [PDF 1457KB](11)
Abstract:
ObjectiveThe rapid development of urbanization has changed the nature and structure of underlying surface, which has affected the urban heat balance and led to the gradual spread of the urban heat island effect.MethodIn this paper, the change of regional normalized difference vegetation index (NDVI) is calculated and studied by using Landsat remote sensing images from 2002 to 2017 in Chaoyang District of Beijing. Based on the atmospheric correction method, the land surface temperature (LST) is retrieved by using Landsat thermal infrared band, and the obtained land surface temperature is further normalized. At the same time, using Google panchromatic satellite images from 2002 to 2017, based on DeepLabv3 + network, the underlying surface types in Chaoyang District is classified and its dynamic changes are analyzed by depth learning.Result(1) The average land surface temperature in Chaoyang District has been on the rise in the past 15 years, and the urban heat island has intensified year by year. By 2017, there was no longer a single heat island center in the area, but it had become a complex mosaic structure and multi-center distribution. (2) The impervious surface area has decreased by 71.02 km2, a decrease of 20.98% in 15 years; The total water area decreased by 2.53 km2, a decrease of 24.12%; Vegetation area increased 73.54 km2, an increase of 56.57%; (3) The correlation analysis between the land surface temperature and the dynamic change of underlying surface type shows that the land surface temperature is positively correlated with the impervious surface area and negatively correlated with the vegetation area. (4) From the perspective of total amount, the total amount of vegetation and water area negatively correlated with the urban heat island effect in Chaoyang District increased significantly from 2012 to 2017, but the urban heat island effect did not decrease but increased instead.ConclusionThe mitigation effect of vegetation and water area on urban heat island effect has gradually become limited under the premise of increasing land use intensity, building density and human activities. Under the current urban development model, the land surface temperature in Chaoyang district will continue to rise and the urban heat island will further intensify.
Tree Volume Equation of Pinus sylvestris Based on Different Form quotients of Trunk
Jin Xiaodong, Jang Lichun
Corrected proof  doi: 10.12171/j.1000-1522.20190047
[Abstract](99) [FullText HTML](58) [PDF 743KB](11)
Abstract:
ObjectivesThe tree volume equation has been widely used in forest productivity, biomass and carbon storage. Therefore, improving the prediction precision of tree volume has always been an important task for forestry model researchers. two-variables and three-variables volume equations were established based on different form quotient of the trunk, and compared and tested the predictive effect for Pinus sylvestris in Daxinganling. The aim is to improve the prediction precision of traditional tree volume to a new level.MethodsUsing the 15 different form quotient of the trunk, two-variables and three-variables volume equations were established based on the traditional one-variable and two-variables volume equations, respectively, and compared with the traditional one-variable and two-variables volume equations. All models were fitted using GNLS in S-PLUS. And the optimal form quotient model is selected. Variance functions (power function, constant plus power function and exponential function) were incorporated into generalized models to decrease heteroscedasticity. And the precision of different individual volume models was evaluated using four factors: mean absolute bias (MAB), mean percentage of bias (MPB), root mean square error (RMSE), and coefficient determination (R2). Finally, the prediction precision of four kinds of equations in different diameter classes is compared by the method of different diameter classes testing.ResultsThe results show that the two-variable model based on 70% of the relative height has the best fitting effect, and the three-variable model based on the relative height of 50% is the best. The model test results show that based on the traditional one-variable model, the RMSE, MAB and MPB of the model after adding form quotient were reduced by 33.7%, 30.7%, and 29.9%, respectively. Based on the traditional two-variable model, the RMSE, MAB and MPB of the model after adding form quotient, were reduced by 70.5%, 70.9%, and 71.2%, respectively. From evaluation results of different diameter classes testing, for small and medium diameter classes, the order of test precision is: model (13) > model (2) > model (12) > model (1); for large diameter classes, the order of test precision is: model (13) > model (12) > model (2) > model (1).ConclusionsThe form quotient is a important index of stem form. The introduction of form quotient factor into traditional tree volume model can improve the prediction precision of tree volume. Therefore, the three-variables volume model with form quotient factor is recommended for estimating tree volume of Pinus sylvestris, especially for medium and large diameter trees.
Relationship between vegetation biomass and soil bulk density on unstable slopes in different climatic regions: a case study of Jiangjiagou Watershed in Dongchuan District of Kunming City, Yunnan Province of southwestern China
Wu Jianzhao, Sun Fan, Cui Yu, He Jingwen, Liu Ying, Li Jian, Lin Yongming, Wang Daojie
Corrected proof  doi: 10.12171/j.1000-1522.20190066
[Abstract](496) [FullText HTML](136) [PDF 802KB](11)
Abstract:
ObjectiveThis paper aims to investigate the characteristics and relationships between soil bulk density and biomass of unstable slopes in debris flows for different climate types, which is a prerequisite for ecological restoration based on local conditions and is very important for the accurate assessment of the stable development and changes of the ecosystem in this region.MethodThe temperate humid mountain ridge region (Dadi shady slope, Xiaojianfeng sunny slope), subtropical and warm temperate subhumid region (Duozhao Gully sunny slope), subtropical dry-hot valley region (Daaozi Gully shade slope, Chajing Gully sunny slope) for the Jiangjiagou Basin were selected as a study area. Taking the stable area, the unstable area and the accumulation area of the unstable slope of each climatic region as the sample plot, and conducting vegetation community surveys, plant and stratified soil sample (0 − 5 cm, 5 − 10 cm, 10 − 20 cm) collection, then soil bulk density, and the biomass of the aboveground and underground parts of the plants were determined.Result(1) The biomass of arbor in subtropical and warm temperate subhumid region was significantly higher than that in temperate humid mountain ridge region (P < 0.05). However, the biomass of litter was significantly higher in temperate humid mountain ridge region than in subtropical and warm temperate subhumid region (P < 0.05). In unstable slopes of subtropical dry-hot valley region without trees, aboveground biomass, underground biomass and total biomass showed stable area > unstable area > accumulation area (P<0.05). (2) The relationship between aboveground biomass and underground biomass of herbaceous plants with unstable slopes in different climatic regions was in accordance with the allometric growth model of root and crown, showing a steady growth ratio. (3) In general, climatic factors and section factors and their interactions had significant effects on biomass and stratified soil bulk density(P < 0.05), however, in this study, the soil bulk density of unstable slopes in different climate regions had little spatial variability, showing weak variability. (4) With the increase of soil bulk density of 0 − 5 cm, the underground and aboveground biomass and total biomass all decreased, however, there was no significant change in the root shoot ratio.ConclusionThis study elucidates the spatial distribution pattern of soil bulk density, underground biomass, aboveground biomass and root/canopy ratio along the environmental gradient in the watershed with frequent debris flow. The systematic analysis of the relationship between them will be conducive to the analysis of the regulation characteristics of environmental factors, and is of great significance for further ecological restoration research on the effects of environmental factors.
The Study on the Number of Missing-Rings in Branch of Larix olgensis Plantation Based on Knots’ Section Data Analysis
Jia Weiwei, Feng Wanju, Li Fengri
Corrected proof  doi: 10.12171/j.1000-1522.20190038
[Abstract](8939) [FullText HTML](89) [PDF 903KB](12)
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ObjectiveIn order to improve the quality of wood, the mixed effect model of the number of missing-rings is established based on knot analysis data in order to predict the number of missing-rings and provide a theoretical basis for artificial pruningMethodIn this paper, the Larix olgensis plantation in Mengjiagang Forest Farm of Heilongjiang Province is used as the research object. Using 1434 knot data of 50 Larix olgensis trees, based on the poisson distribution, the glimmix module in SAS9.4 software is used to establish the generalized linear mixed model of the number of missing-rings in the knot. The best hybrid model is selected by calculating the corresponding indicators.ResultConsidering the tree effects, the optimal mixed effect model is a model that adds the random effect parameters to the intercept, knot height and knot relative height; Considering the rank effect, the optimal mixed fect model is a model that adds random effect parameters to the knot relative height and the diameter of the knot.Comprehensive comparison, the fitting effect of the two hybrid models is better than the basic model, and the fitting effect of considering the tree effect is the best. The fitting results of the model show that the number of missing-rings is closely related to the height of the knot and the diameter of the knot. The knots with lower position and larger diameter are inhibited by competition, but the survival ability is strong, so the number of missing-rings is large. The higher the position of the birth position, the better the living conditions and the less the number of missing-rings.ConclusionThrough the establishment of the mixed model of the number of missing-rings in the Larix olgensis plantation, the prediction effect of the model is tested. The test results show that the hybrid model can predict the number of missing-rings and the deviation is small. In the next study, it can be further improved to provide a theoretical basis for artificial pruning.
Extraction of tree crown parameters from high-density Chinese fir plantation - Based on UAV image
Sun zhao, Pan Lei, Sun yujun
Corrected proof  doi: 10.12171/j.1000-1522.20190386
[Abstract](2763) [FullText HTML](82) [PDF 863KB](10)
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ObjectiveCrown width is an important characteristic factor of canopy structure, which directly affects the productivity and vitality of trees. The forest canopy density is one of the important indexes to reflect forest canopy structure and density and to evaluate forest management and logging intensity. UAV has the advantages of easily getting high-resolution remote sensing images with high precision and low cost. Studying the method of extracting canopy parameters using UAV images is of great significance for improving the accuracy and efficiency of forest resource inventory and monitoringMethodTaking Chinese fir plantation in Jiangle Forest Farm of Fujian Province as the research object, using the quadrotor UAV CCD image data as the data source, based on the object-oriented classification method, the canopy parameters of the Chinese fir plantation were extracted from the UAV image. Then the canopy objects were grouped into one group according to the segmentation results of the image, and the number of raster pixels of each canopy object was counted to calculate the canopy width area and canopy density.ResultThe object-oriented classification effectively extracted the canopy of high canopy density stand. When the segmentation scale is 70, the segmentation of single tree has the best effect. Some single trees were lost during the segmentation process because of over-segmentation and under-segmentation. After the segmentation is completed, optimize the feature space of the segmented object and select appropriate classification features. Finally, the study area is divided into two types: crown and gap. By counting the number of grid points of each object, the calculated stand factors include canopy density and crown area. With the measured data on the ground as reference, the crown area extraction accuracy is 0.829 1, and the forest canopy density measurement accuracy is 0.973 1.ConclusionThe results show that the canopy parameter extraction based on high-resolution image of UAV is also applicable in high-canopy closed forest stands, which can effectively improve the efficiency and accuracy of forest resource survey.
Dyeing process and mechanism of eucalyptus veneer with Dalbergia bariensis heartwood pigment as dye
Zhang Qingshuo, Yang Yutong, Fu Yunlin, Sun Jing
Corrected proof  doi: 10.12171/j.1000-1522.20190270
[Abstract](941) [FullText HTML](416) [PDF 1177KB](30)
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ObjectiveIn order to make full use of the processing residues of Dalbergia bariensis and improve the added value of eucalyptu, natural dye has been extracted from the Dalbergia bariensis heartwood.MethodThe main components of Dalbergia bariensis heartwood content were analyzed by ultra-high performance liquid chromatography with quadrupole-electrostatic field orbitrap high resolution mass spectrometry. The best dyeing process and color fastness were measured. The binding mechanism of Dalbergia bariensis dye and eucalyptus veneer was analyzed by Fourier transform infrared spectroscopy (FTIR).The distribution characteristics of the dye in eucalyptus veneer were observed by the field emission scanning electron microscope (FESEM).ResultNine phenols were identified from the pigment of Dalbergia bariensis heartwood by UPLC-Q-EXACTIVE-MS: malvidin, rhamnetin, butein, sakuranetin, alizarin, luteolin, hemotoxylin, pinocembrin, taxifolin. The optimal dyeing process of eucalyptus veneer was: dyeing temperature 90 ℃, dyeing time 12 hours, pigment mass fraction 4%, NaCl mass fraction 2%. The order of influence factors of dyeing test was: temperature > pigment mass fraction > dyeing time > NaCl mass fraction. The order of influence factor of color fastness was: temperature > pigment mass fraction > dyeing time > NaCl mass fraction. It was preliminarily determined as physical adsorption and intermolecular hydrogen bonding through the analysis of FTIR’s and FESEM’s reaction to the dyeing mechanism.ConclusionNatural dye extracted from Dalbergia bariensis heartwood was used to imitate the precious rosewood by dyeing eucalyptus veneer, which blazes a trail in the full utilization of precious rosewood and explores the high value-added utilization of fast-growing wood.
Flame retardant properties of phytic acid and melamine treated wood
Wu Yuhui, Zhang Shaodi, Ren Zizhong, Wang Mingzhi
Corrected proof  doi: 10.12171/j.1000-1522.20190406
[Abstract](4922) [FullText HTML](190) [PDF 1325KB](28)
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ObjectiveWooden materials are easy to get ignited when furniture and buildings go up in flames. It can cause the fast fire spread and produce much toxic gases leading to the human death. In order to reduce the fire hazard of furniture and buildings, wood must be treated for fire retardancy. In this study, an intumescent flame retardant (IFR) system of phytic acid and melamine was prepared and used as a flame retardant of wood, the flame retardancy of the treated wood was then investigated. The purpose of this paper is to provide a new thought and enrich the IFR system.MethodTwo-step impregnation method was conducted to assemble the phytic acid-melamine flame retardant in the interior of Populus cathayana. The weight percent gain, bulking, pyrolysis and combustion behavior of the modified wood was assessed. The morphology of the residue of treated wood after combustion was analyzed in order to discuss the mechanism of phytic acid-melamine IFR system.ResultThe first peak of heat release rate and the total heat release of 15% phytic acid and 5% melamine treatment group (PM2) were reduced by 91.24% and 79.05% compared with that of control, respectively. The PM2 group showed stronger smoke suppression performance, and reduced the total smoke emission by 52.94% compared with the control group. The mean carbon monoxide yield of PM2 group was reduced by 51.29% compared with the P15% group. The amount of carbon residue of PM2 group was significantly increased, which was 69.58% higher than that of P15% group and 278.4% higher than that of the control group. The PM2 group had the optimum effect on promoting the residue and reducing the heat release.ConclusionThe phytic acid and melamine flame retardant system can be penetrated into the wood. The combined treatment of phytic acid and melamine can reduce the heat release rate, total heat release, total smoke release and CO yield of flame retardant treated wood. Phytic acid takes part in catalyzing the dehydration and carbonization of wood which leads to the lower temperature of degradation reaction and promotion of the formation of carbon residue of wood. The synergistic effect between phytic acid and melamine can enhance the formation of carbon residue of wood.
Growth of Lasiodiplodia theobromae and its effect on the surface properties of rubber wood
Zhao Boshi, Yu Zhiming, Zhang Yang, Qi Chusheng, Tang Ruilin, Liu Yuansong, Wang Haowei, Han Yiyun
Corrected proof  doi: 10.12171/j.1000-1522.20190382
[Abstract](341) [FullText HTML](188) [PDF 1038KB](24)
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ObjectiveLasiodiplodia theobromae is one of the main fungi that causes the blue stain of rubber wood, and most researches focused on prevention of blue stain. This paper uses the diversity of blue stain from prevention to induction, to improve the utilization value of blue phenomenon.MethodBy analyzing the effects of different proportions of czapek-dox medium on the growth rate of Lasiodiplodia theobromae on the culture medium and the surface of rubber wood, the optimum environment was optimized, and we investigated the effects of Lasiodiplodia theobromae on the surface properties of rubber wood.ResultThe results showed that optimum environment was yeast extract 9 g/L, glucose 20 g/L, pH weak acidity, MgSO4 1.0 g/L, FeSO4 0.03 g/L, KCl 0.2 g/L. With the increase of time, the dyeing area of surface color gradually increased, and the color changed from red and yellow to blue and green, and the light fastness gradually increased, and static state contact angle was improved by 13.04%, and the dynamic state contact angle inproved prominently, and surface roughness and wear resistance gradually decreased.ConclusionIn this study, Lasiodiplodia theobromae dyed rubber wood was prepared, and the surface texture and color of rubber wood were controlled by different time gradients, which verified the feasibility of biological wood processing and expanded the utilization value of microorganisms in wood processing.
Study on regeneration of Pinus tabulaeformis burned area in Liaoheyuan Nature Reserve
Wang Bo, Gu Xinghan, Han Shuwen, Zhang Jianan, Niu Shukui, Liu Xiaodong
Corrected proof  doi: 10.12171/j.1000-1522.20190315
[Abstract](568) [FullText HTML](326) [PDF 627KB](43)
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ObjectivesFrom the four aspects of tree species composition, density, growth character (base diameter, plant height, crown diameter) and spatial distribution pattern, the forest characteristics of Pinus tabulaeformis plantation in Liaoheyuan Nature Reserve were discussed, which could provide reference for vegetation restoration and forest management.MethodsTo reserve the burns community slightly into the research object, according to different renewal methods (natural renewal and artificial promotion of natural renewal) under natural renewal, 3 20 × 20 m sample plots were set up under natural renewal with different fire intensity (severe fire, moderate fire and light fire) and control (not burned), the natural renewal sample land under severe fire is the same as that under severe fire land under natural fire, there are 15 sample lands in total, survey to update the amount and type of trees, measurement update forest base diameter, plant height, crown diameter, for each wood gauging sample and record the information such as the geographic coordinates and site factor. Single factor variance analysis was used to analyze the difference of tree regeneration density and growth character, and variance/mean method was used to analyze the spatial distribution pattern of tree regeneration.Result(1) The tree species of tree regeneration in the burned area of Pinus tabulaeformis are mainly Quercus mongolica and Populus davidiana, accounting for 38.1% and 42.3% of all tree regeneration respectively, in addition to that of Pinus tabulaeformis, Ulmus laciniata, Ulmus macrocarpa Hance, Ulmus pumila, Acer mono Maxim and so on. Under severe fire, there was a significant difference in the density of tree regeneration between different regeneration methods (P < 0.05), there was no significant difference in the density of tree regeneration between different fire intensities under natural renewal (P > 0.05). (2) There was no significant difference in the growth traits and characteristics of all tree regeneration in different regeneration modes under severe fire (P > 0.05), there was an extremely significant difference in the growth characters and characteristics of all tree regeneration under natural renewal with different fire intensity (P < 0.01). (3) The spatial distribution pattern of tree regeneration was different with different fire intensity, regeneration mode and tree species.ConclusionsAfter 4 years of fire, the regeneration tree species in the burned area of Pinus tabuliformis were mainly Quercus mongolica and Populus davidiana. Moderate and low intensity surface fire could promote the natural regeneration of stands. Adopting salvage logging and other management measures to artificially promote natural renewal can speed up the restoration of vegetation in fire marks.
Clogging processes of permeable paver systems under different maintenance methods in Beijing
Li Meiyu, Zhang Shouhong, Wang Yunqi, Xie Chaoshuai, Li Ruixian
Corrected proof  doi: 10.12171/j.1000-1522.20190062
[Abstract](446) [FullText HTML](257) [PDF 1035KB](25)
Abstract:
ObjectivesAs one of the promising stormwater management practices, permeable paver systems are more and more widely used in the Sponge City constructions. However, due to the lack of long-term monitoring data, the clogging processes of permeable paver systems and the recovery effects of maintenance methods are not clear. Based on the laboratory experiments, the clogging processes of permeable paver systems under different maintenance methods were measured and analyzed.MethodsBased on inflow-infiltration experiments, long-term changes in permeable pavement permeability and grain size distributions of bedding layers are measured and analyzed for three permeable pavement systems maintained with different methods including non-cleaned, vacuum suction and high pressure washing.ResultsThe results showed that the permeabilities decayed exponentially in the permeable paver systems, the infiltration rates of permeable paver systems were 26, 229, and 19 mm/h respectively, which attenuated 99.6%, 96.3% and 99.7% of the newly-installed systems, vacuuming is preferable to pressure washing in the long-term performances of permeable paver systems. The removal efficiencies of suspended solids of permeable paver systems were between 95%−98%, which performed similarly (P < 0.05, n = 7). The contents of fine particles (0−200 μm) in the upper layers of old bedding layers increased 15.6%−29.2% compared with the new bedding layers. The infiltration rates of " new paver + old bedding layer + old geotextile” were 28.3%−32.4% of the newly-installed systems for the replacement of old bedding layers and geotextiles in permeable paver systems. While the infiltration rates could recovery to 63.8%−72.6% in the " old paver + new bedding layer + new geotextile” systems.ConclusionsTherefore, the measures of periodic maintenance of vacuuming and the renewal of bedding layers and geotextiles can be considered to obtain better permeability and recovery effect of permeable paver systems.
Determination and analysis of the relationship between microclimate elements and greening structures in the city streets of Shanghai: taking Xuhui District and Yangpu District as examples
Zhang Deshun, Xue Kaihua, Wang Zhen, Cao Wei, Ma Chundong
Corrected proof  doi: 10.12171/j.1000-1522.20170359
[Abstract](695) [FullText HTML](497) [PDF 1087KB](51)
Abstract:
ObjectiveThis paper aims to explain the corresponding relationship between the microclimate elements and the street greening layout, guide the adaptability design of urban street green space.MethodBased on the field survey, the correlation between the microclimate factors and the street greening layout was elaborated, and the influence of several factors as solar radiation, air temperature and wind speed on vertical structure of street greening was explored in this study.Result(1) The relationship between street shade coverage and microclimatic factors: The higher the shade coverage, the better the reduction efficiency of solar radiation, The effect is most pronounced when coverage reaches more than 90 percent, And the rule characteristic of its cooling effect is more obvious, However, the excessive shade coverage makes the street space closed, resulting in a reduced cooling effect. The efficiency of wind speed reduction is more than 21% higher than that of 50% ~ 70% for the street greening with a green coverage rate of more than 90%. (2) Relationship between street greening cladding structure and microclimatic elements: In the multi-layer vertical structure, the more complex the structure is, the greater the greening amount will be, and the higher the solar radiation reduction efficiency will be. Its overall average reduction efficiency of solar radiation is 88.78%. The average daily cooling efficiency of the layered vertical structure is 8.69%. In the natural cycle of one day, the weakening efficiency of the wind speed is the best, followed by that of the tree-shrub-grass, the tree-shrub next, tree-grass third, shrub-grass is the last. The average daily wind speed reduction efficiency of the laminated structure is about 77.61%. (3) Relationship between vertical green ratio and microclimatic elements: The ratio of total green content of trees and shrubs was positively correlated with the solar radiation reduction efficiency. The higher the proportion of trees and shrubs, the higher the average cooling efficiency. During the natural cycle of a day, the closer the ratio of trees and shrubs to grass, the better the weakening effect on wind speedConclusionBased on the relationship between the layout of street greening and microclimate elements, the technical countermeasures for improving the comfort of microclimate by regulating the composition of street greening are proposed: (1) To build comfortable street summer microclimate, appropriate maintains 70 ~ 90% green shade coverage rate. (2) Shade and ventilation should be increased through a moderate greening cladding structure, but it should be avoided that it is too complicated to affect the normal ventilation. (3) According to the scientific proportion of vertical green quantity, taking into account the requirements of green shade coverage in summer and temperature increase in winter, planting deciduous trees and keeping trees and shrubs account for more than 50% of the street greening.
Effects of Syringa pinnatifolia var. alanshanica on soil physicochemical properties, enzyme activities and microbial diversity
Wang Tao, Guo Yang, Su Jianyu, Xu Chunyan
Corrected proof  doi: 10.12171/j.1000-1522.20180365
[Abstract](371) [FullText HTML](270) [PDF 1167KB](33)
Abstract:
ObjectiveThe purpose of this study was to investigate the effect of S. pinnatifolia var. alanshanica on the soil nutrients, soil enzymes, and soil microorganisms.MethodsFive-point sampling method was employed to collect three soil samples (treatment group) under the S. pinnatifolia var. alanshanica shrub and three control samples (control group) from the naked land near the plant. After the physicochemical properties and enzyme activities determination, the microbial community structure was further analyzed via high-throughput sequencing technique.ResultsResults showed the soil pH value remained unchanged, while the contents of water, organic matter, total nitrogen, available potassium and nitrogen were increased significantly (P < 0.05), and the available phosphorus content was decreased significantly (P < 0.05) by S. pinnatifolia var. alanshanica. At the same time, the activities of sucrase, urease, and laccase were increased significantly (P < 0.05). Under the S. pinnatifolia var. alanshanica shrub, the diversity of soil bacteria was decreased with the richness of bacteria being almost unchanged, but both the diversity and abundance of ffungi were increased significantly. The numbers of Bacillus in bacteria and Saccharomycopsis, Clonostachys, Trichoderma, Paranamyces in fungi were increased by S. pinnatifolia var. Alanshanica. However, the numbers of Sphingomonas and Flavobacterium in bacteria, Lentinula, Fusarium, Gibberella, Lycogalopsis, Ilyonectria, Aspergillus, Synchytrium, and Acremonium in fungi were decreased significantly. All the alterations of microorganisms were closely associated with the changes of nutrients and enzymes.ConclusionsS. pinnatifolia var. alanshanica increased the activities of soil enzymes by altering the community structure of soil fungi, and enhanced the contents of soil nutrients and water and promoted the cycling of carbon, nitrogen, phosphorus and potassium by increasing the richness of functional bacteria.
Anatomical structure characteristics and growth ring analysis of underground rhizome of herbaceous peony
Zhang Jianjun, Chen Liqi, Li Jianguang, Sun Miao, Fan Yongming, Yu Xiaonan
Corrected proof  doi: 10.13332/j.1000-1522.20190096
[Abstract](888) [FullText HTML](656) [PDF 886KB](45)
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ObjectiveBy observing and analyzing the rhizome structure and development characteristics of different varieties of peony, the anatomical study on the rhizome was conducted to preliminarily analyze the secondary structure and growth ring characteristics of the rhizome of herbaceous peony, so as to provide theoretical basis for judging the plant age of peony and optimizing the asexual reproduction and cultivation management technology, and promote the development and utilization of resources.MethodThe underground rhizomes of different developmental stages of six varieties of different peony groups were studied, and their development and renewal characteristics were observed and analyzed. Paraffin sections and freehand slicing techniques were used to observe and analyze the secondary structural characteristics of rhizomes of different cultivars and different cultivars with different growth years.ResultThe underground rhizome structure of different varieties was basically the same, that is, the underground organs of the peony were composed of rhizome, rhizome buds and roots growing on the rhizome. The rhizome was updated regularly every year, and the age grading characteristics were obvious; the developmental characteristics of the tetraploid cultivar ‘Cream Delight’ were significantly different from the other five varieties.The rhizomes of 6 varieties of peony were composed of peridermis, cortex, secondary phloem, cambium, secondary xylem and central pith. The large and small conduits of the secondary xylem of the rhizomes of diploid variety ‘Zhongshengfen ’, diploid variety ‘Fenyunu’, triploid variety ‘Coral Sunset’ and tetraploid variety ‘Cream Delight’ were arranged sequentially.The larger diameter catheter and the surrounding small catheter gathered to form a cluster, and the catheter group was sparsely distributed. The spacing between the two catheter groups was significant. The interval between the catheter clusters of ‘Coral Sunset’ was smaller than ‘Cream Delight’.The large and small ducts in the secondary xylem of the rhizomes of the two triploid Itoh varieties ‘Prairie Charm’ and ‘Going Bananas’ were evenly distributed and formed a relatively continuous ring zone, and they don't clump together. After dehydration, the vascular structure of the rhizome of the peony was white or yellowish, with intermittent distribution of the ring, and the central medullary tissue was concave.Vascular tissues located in different rings were radially arranged from the pith to the cortex. The larger diameter catheters in the secondary xylem and the small ones around them were clustered in clumps in the rhizomes of different growth years.The catheter group was tangentially intermittently arranged in a sequence parallel to the cambium to form a clear growth ring, and the number of growth ring was consistent with the actual growth age of the rhizome of the peony.ConclusionThe structural characteristics of underground rhizome of different varieties of peony are basically the same, and there are obvious grading characteristics.The rhizome development characteristics of diploid and triploid are similar, but different from tetraploid. The secondary structural characteristics of rhizome of varieties belonging to lactiflora and hybrid groups are similar, but are significantly different in the varieties of Itoh group. There are significant differences in secondary structure of the rhizomes between triploid and tetraploid varieties of hybrid peony, and there is no direct correlation between the secondary structure characteristics of root growth ring and chromosome ploidy of herbaceous peony. The growth rings in the rhizome of peony are its annual rings, and the number of growth rings can reflect the actual growth years of peony.
Numerical simulation of the safety influence of defects on Qijia-beams of ancient timber building
Ou Zina, Zhang Houjiang, Guan Cheng
Corrected proof  doi: 10.13332/j.1000-1522.20190328
[Abstract](265) [FullText HTML](197) [PDF 2055KB](22)
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ObjectiveThe Qijia-beams are used as the main load-bearing members for Chinese ancient timber building. The safety performance of whole wood structure is directly affected by the bearing capacity safety of Qijia-beam. Factors, such as surrounding environment and load for a long period, lead to different degrees of the defects in the wooden beam. These defects will affect the tensile stress and shear stress distribution, as well as the bearing capacity safety of the wooden beam. Therefore, it is necessary to study the influence of different defect types, sizes and locations on the safety of bearing capacity of the Qijia-beam.MethodAbaqus finite element software was used to simulate the stress state of the beam with different defects such as crack, decay and hole. By quantifying the size and location of the defects, the single parameter numerical simulation analysis of different damage factors was carried out to determine the maximum working stress location of the wood beam with defects, analyze the sensitive location of the damage of the wood beam, and investigate the variation patterns of the bearing capacity of wood beams.ResultThe results showed that the types of different defects had different influence on the safety of the Qijia-beam. External decay had the greatest influence on the bearing capacity of the Qijia-beam, followed by hole defect, and the impact of crack defect was relatively minimal. For the bending beams in the elastic stage, the defects had the greatest influence on the bearing capacity safety of the Qijia-beam when it was located in the tension zone between two under Jiagua-columns. The influence of different defect sizes on the bearing capacity of the Qijia-beam was different. With the increase of the crack depth, the decay depth, and the hole size, the safety of the wooden beam was gradually reduced.ConclusionDue to the existence of local defects, the bearing capacity of the Qijia-beams would be decreased. The research of this paper provided numerical simulation, which could accurately determine the maximum tensile stress of the wooden beam. It was a good method to quantitatively study the influence of defect on the safety of Qijia-beam and to determine the location of Qijia-beam safety monitoring.
Display Method:
2020, 42(1): 1-2.  
[Abstract](94) [FullText HTML](77) [PDF 332KB](10)
Abstract:
Forest Sciences
Construction of biodiversity protection value model for forest based on habitat quality
Hong Yu, Liu Jinfu, Tu Weihao, Lin Zhiwei, Tan Fanglin
2020, 42(1): 1-9.   doi: 10.12171/j.1000-1522.20190289
[Abstract](2519) [FullText HTML](204) [PDF 1033KB](34)
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ObjectiveThe traditional forest biodiversity conservation value lacks the unified evaluation standard, which is not convenient for comparison of results. At present, the models of the species protection value mainly calculate the current protection value of forests by the richness of forest, but do not consider the potential impacts of the types of land use on the growth process of tree species, they cannot measure the long-term protection value of forests. In recent years, new theories of biodiversity value evaluation have been gradually improved, but the method which is suitable for assessing the protection value of forest biodiversity has not yet existed.MethodWe calculated and graded the habitat quality by analyzing the land use in Fujian Province of southern China and firstly proposed the adjustment coefficient of habitat quality. The biodiversity conservation value model of forest based on the habitat quality was constructed by the geographical correspondence between habitat quality and forest distribution (HQ-BPV model), it integrated the impact of land use into the assessment of forest biodiversity protection value of Fujian Province.Result(1) The distribution of habitat quality in Fujian Province is generally high in the north and low in the south, high in the inland and low in the coastal areas, and low in the nature reserves and non-nature reserves. (2) The average habitat quality of the main plant types in Fujian Province was ranked in the descending order and be presented as theropencedrymion > bamboo forest > broadleaved mixed forest > broadleaved forest > bushwood > coniferous forest > economic forest. (3) After adjustment, the species of Quercus spp. and Castanopsis spp. had the highest protection value per unit area, which was 35 800 CNY/ha, the broadleaved mixed forest had the highest protection value, which was 65 842 million CNY by comparing with each dominant tree species (set), the total biodiversity conservation value of the forest in Fujian Province was 205.639 billion CNY.ConclusionHQ-BPV model is constructed based on the habitat quality index, which can quantify the impact of land use for evaluating the protection value of forest biodiversity in Fujian Province. It provides new ideas for the protection value accounting of forest biodiversity and is useful for the forest resource monitoring and the structure optimization.
Effects of stand density on community structure and species diversity of Cupressus funebris plantation in Yunding Mountain, southwestern China
Jin Suo, Bi Haojie, Liu Jia, Liu Yuhang, Wang Yu, Qi Jinqiu, Hao Jianfeng
2020, 42(1): 10-17.   doi: 10.12171/j.1000-1522.20190202
[Abstract](24734) [FullText HTML](92) [PDF 723KB](13)
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ObjectiveThe effects of stand density on the community structure and species diversity of Cupressus funebris plantation and the correlation between species diversity and stand factors were explored, providing a basis for the management of Cupressus funebris plantation in Yunding Mountains, southwestern China.MethodThe research objects were five different stand densities (A−E: 500, 650, 800, 950, 1 100 tree/ha) of 60 years Cupressus funebris in Yunding Mountain, Sichuan Province, southwestern China. The vegetation was investigated by typical plot method. The community structure, species composition and species diversity index (Pielou evenness index Jsw, Simpson dominance index H', Shannon-Wiener diversity index H and species richness index D) were comprehensively analyzed.Result(1) A total of 170 species of plants were recorded in the study area, belonging to 136 genera and 68 families. The dominant species in shrub layer or herb layer under different densities were mostly shady, shade-tolerant or adaptable plants. (2) With the decrease of stand density, the trend of species diversity index in shrub layer increased first and then decreased. It reached the maximum at density B, with no significant difference except D (P > 0.05). The trend of D, H and H' in herbaceous layer increased first, then decreased, then increased and then decreased. The peak values appeared in density B and D, and there were significant differences among different densities. Stand density and canopy density were negatively correlated with shrub layer D, and significantly positively correlated with herb layer H, H' and Jsw. (3) Distribution between diameter and height structure of density A community was irregular and fluctuated, while distribution of other densities was unimodal. In density B community, medium and large individual trees accounted for a relatively large proportion of individuals, and the stability of the community was better.ConclusionThe relative optimum stand density of cypress plantation in Yunding Mountain is 650 tree/ha, which is very helpful to maintain the stability of community structure and improve the species diversity under the forest.
Nutrient reabsorption efficiency of dominant shrubs in dry-hot valley and its C∶N∶P stoichiometry
He Jingwen, Liu Ying, Yu Hang, Wu Jianzhao, Cui Yu, Lin Yongming, Wang Daojie, Li Jian
2020, 42(1): 18-26.   doi: 10.12171/j.1000-1522.20190185
[Abstract](309) [FullText HTML](235) [PDF 627KB](20)
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ObjectiveThis paper aims to explore the leaf nutrient content before and after senescing, nutrient reabsorption efficiency(RE) and C∶N∶P stoichiometry of Dodonaea viscose, Coriaria sinica and Sophora davidii in hot and dry valley.MethodOne way analysis of variance and Pearson correlation analysis were used.ResultThe results showed that the contents of nitrogen (N) in litter were as follows: C. sinica > S. davidii > D. viscose, the contents of nitrogen (N) and phosphorus (P) in fresh leaves, P in litter followed an order of S. davidii > D. viscose > C. sinica. S. davidii’s N had the highest reabsorption efficiency. And the reabsorption efficiency of D. viscose’s P was the highest. There were significant differences (P < 0.05) between the three shrub fresh leaves and litter C∶N, C∶P, however, N∶P had no significant difference. In addition, N reabsorption efficiency of D. viscose was significantly correlated (P < 0.05) with C∶N of the litter, and P reabsorption efficiency was significantly correlated with C∶N of the fresh leaf. At the same time, N reabsorption efficiency of C. sinica was significantly and negatively correlated with C∶N of the fresh leaf, N∶P of the litter, P reabsorption efficiency was significantly and negatively correlated with C∶N, N∶P of the fresh leaf, and N reabsorption efficiency of S. davidii was significantly correlated with C∶N, N∶P of the litter. Except for the significant correlation between the N content of fresh leaves and the AN content in soil, there was no significant correlation between the contents of C, N and P in the leaves and the contents of nutrients in the soil.ConclusionOn the whole, the three shrubs are restricted by P during the growth process, and the N and P contents are all incompletely absorbed. In addition, the N and P reabsorption rates are lower than the nutrient reabsorption rates of various terrestrial plants on a global scale. It shows that the ability of the dry heat valley D. viscose, C. sinica and S. davidii shrubs to adapt to the barren land through nutrient reabsorption is gradually weakened, and the N and P nutrient preservation ability is reduced.
Axial variation of characteristics of water conducting tissue in xylem of Catalpa bungei
Li Xin, Li Shan, Deng Liping, Li Ren, Yin Yafang, Zheng Jingming
2020, 42(1): 27-34.   doi: 10.12171/j.1000-1522.20190238
[Abstract](1103) [FullText HTML](149) [PDF 976KB](14)
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ObjectiveThis paper intends to explore the axial variation of the anatomical structure of wood sapwood of Catalpa bungei, in order to deepen our understanding of the water conduction mechanism in broadleaved tree species, as well as to provide theoretical basis for the cultivation of C. bungei plantation, the protection of this precious tree species and the utilization of its wood.MethodThree trees of C. bungei were selected, sapwood samples were collected from tree height at 0, 1.3, 3.8, 6.3, 8.8 and 11.3 m, respectively. Meanwhile, sapwood area was measured, transverse and longitudinal sections of wood blocks were prepared. The anatomical traits of xylem such as vessel lumen diameter, vessel frequency were observed with light microscopy. Relationships among wood anatomical traits were tested by correlation analysis and analysis of variance, and axial changes of wood anatomical traits were analyzed by linear regression.Result(1) Earlywood vessel lumen diameter and vessel density do not change significantly with tree height, however, earlywood vessel lumen diameter decreased with height while vessel density had an opposite trend. Maximum vessel lumen diameter of early- and latewood, latewood vessel lumen diameter and pit membrane diameter varied significantly with tree height, which decreased with tree height. (2) Both sapwood area and hydraulic vessel diameter decreased significantly with tree height. (3) Both sapwood area and pit membrane diameter were significantly positively correlated with the hydraulic vessel diameter.ConclusionAxial variance of hydraulic structure of C. bungei is manifested in three aspects: sapwood area, vessel related traits and pit membrane properties. Growth ring of C. bungei was obvious, and the early and late vessel lumen diameter wood differed greatly with bigger variation of early wood than that of late wood. Axial variation of the maximum vessel lumen diameter, sapwood area and pit membrane diameter are significant for this tree species whereas axial variation of the vessel density is not significant. Taken together, wood at the base of C. bungei owned relatively large and sparse vessels and higher proportion of sapwood area compared to many small vessels and lower proportion of sapwood area in wood at the upper stem, and this architecture is an optimized structural design for the long-distance water transport function during xylem evolution, leading to reduction of embolization risk and improvement of efficiency and safety of water transport.
Effects of waterlogging stress on growth, physiological and piochemistry characteristics of Magnolia wufengensis
Wang Yanshuang, Fang Wen, Wang Xintong, Zhao Xiuting, Liao Guoli, Duan Jie, Ma Lüyi
2020, 42(1): 35-45.   doi: 10.12171/j.1000-1522.20190225
[Abstract](679) [FullText HTML](288) [PDF 1167KB](45)
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ObjectiveMagnolia wufengensis has fleshy roots, which are very sensitive to water. In this paper, the waterlogging stress test of Magnolia wufengensis was carried out to investigate the effects of waterlogging environment on its growth, physiological and biochemical characteristics, which provided a theoretical basis for determining the suitable water environment for the growth of Magnolia wufengensis and its promotion work.MethodOne-year-old Magnolia wufengensis seedlings were used as experimental materials, and potted waterlogging method was utilized for 5 treatments: control (CK), waterlogging for 4 days (W4), 7 days (W7), 11 days (W11) and 15 days (W15). The growth, physiological and biochemical indexes of seedlings on days 1, 4, 7, 11, 15 after waterlogging and on the 2nd (R2), 5th (R5), and 8th (R8) days after stress relief were measured to analyze the response of Magnolia wufengensis seedings to waterlogging stress and self-recovery ability after waterlogging stress.ResultWith the increase of waterlogging stress time, the survival rates of W4, W7, and W11 decreased to 95.00%, 70.00%, and 60.00%, respectively, and all W15 seedlings died after 2 days of stress relief; the growth of seedling height and ground diameter decreased, and the growth of W11 seedlings restored to a basic standstill after stress relief; the content of chlorophyll showed a downward trend, and the difference between W11, W15 and CK was significant; Net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) showed a downward trend. Net photosynthetic rate and was significantly lower than CK in all treatments; the difference of stomatal conductance between W11, W15 and CK was significant; the transpiration rate was significantly different from CK except W4. Soluble protein content and malondialdehyde content gradually increased. The malondialdehyde content was significantly different from CK in all treatments, and soluble protein content was significantly different from CK except for W4. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities showed the same trend, which increased first and then decreased. SOD and POD under W11 and W15 treatments were significantly different from CK, and CAT activities were significantly different from CK except W4.ConclusionWith the increase of waterlogging stress time, the growth and physiological activities of Magnolia wufengensis seedlings were inhibited to extent, but they had certain recovery ability after the relief of waterlogging stress, and the shorter the stress time was, the stronger the recovery ability was. The waterlogging stress lasts for about 11 days. And it can basically reduce the damage by regulating the activity of the protective enzyme system and the content of osmotic adjustment substance, and maintain the normal physiological and metabolic functions of the plant body. Thus, the result indicates that Magnolia wufengensis has a certain tolerance to waterlog. When the waterlogging stress lasts for 15 days, it exceeded the regulation capacity of the plant itself, which will lead to its death.
Effects of growth retardants on anatomy and non-structural carbohydrates of chestnut leaves
Zhang Yichi, Guo Sujuan, Sun Chuanhao
2020, 42(1): 46-53.   doi: 10.12171/j.1000-1522.20180437
[Abstract](309) [FullText HTML](102) [PDF 790KB](8)
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ObjectiveThe purpose of this study was to investigate the effects of plant growth retardants on the leaf anatomy and non-structural carbohydrates of chestnut saplings, and the effects of leaf anatomical changes on non-structural carbohydrate content,in order to provide a theoretical basis for the application of plant growth retardants in the regulation of chestnut growth.MethodIn this experiment, chestnut (Castanea) cultivar ‘Yanshanzaofeng’ was taken as the experimental material, and exposed to different concentrations of paclobutrazol, chlormequat and uniconazole,then the anatomy and non-structural carbohydrates of the leaf were analysed.Result(1) Paclobutrazol, chlormequat and uniconazole could increase the thickness of the cuticle of chestnut leaves. The maximum thickness of the upper cuticle was 5.46 μm treated with 90 mg/L uniconazole, and the thickness of the lower cuticle was 1.76 μm treated with 60 mg/L uniconazole; (2) except for treatment with 60 mg/L uniconazole, the other treatments could increase the thickness of leaves and palisade tissue. The most significant effects of leaf and palisade tissue thickness were 100 mg/L paclobutrazol treatments; (3) three kinds of retardants could increase the palisade to sponge tissue ratio, it was up to 1.52, which was treated with 90 mg/L uniconazole; (4) except 60 mg/L uniconazole treatment, the other treatments could effectively increase the non-structural carbohydrate content of chestnut leaves, the increase of non-structural carbohydrate content was most significant at 120 days after treatment.ConclusionSpraying paclobutrazol, chlormequat and uniconazole on the leaf surface in the period of chestnut flower buds could affect the anatomy of chestnut leaves, thereby enhancing the photosynthesis of chestnut,and the best treatment was 100 mg/L paclobutrazol. Paclobutrazol, chlormequat and uniconazole could effectively increase the non-structural carbohydrates content of chestnut leaves, and 60–90 mg/L of uniconazole was the best treatment. Due to the application of retardants, the leaf anatomy changed the photosynthesis of the leaves, which increased the assimilation, and it made the non-structural carbohydrate content of the leaves increase.
Effects of different filter algorithms on deriving leaf area index (LAI)
Liang Yongqi, Li Mingze, Yang Ruixia, Geng Tong, Li Huan
2020, 42(1): 54-64.   doi: 10.12171/j.1000-1522.20180268
[Abstract](364) [FullText HTML](275) [PDF 1421KB](47)
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ObjectiveFiltering is an important part of data preprocessing when using discrete-return LiDAR to derive leaf area index (LAI). Laser penetration index (LPI), which responses to the canopy’s gap fraction, is a pivotal argument, and can be defined by echoes intensity or count, and is directly influenced by filter precision. So, filter algorithms can affect deriving LAI indirectly.MethodIn this paper, we used the open source filter algorithms without manual operation to filter the error points. Using the LPI defined on count, we built model in larch forest and elm forest, Maor Mountain National Park, based on Beer-Lambert law. We compared the filter algorithm of adaptive triangulated irregular network, morphology, local slope, using hybrid filtering as standard. In order to avoid the subjective influence during modelling, we built 100 models by choosing samples randomly.ResultIn larch forest, the models’ R-squared under larch was 0.900 3, 0.876 3, 0.892 5,0.877 0, root mean squared error (RMSE) was 0.105 6, 0.134 5, 0.109 7,0.133 2; in elm forest, the models’ R-squared was 0.914 4, 0.903 0, 0.887 2, 0.900 0, root mean squared error (RMSE) was 0.269 0, 0.201 7, 0.189 4, 0.207 0, respectively.ConclusionConsidering the sample’s topography, when using discrete-return LiDAR data derive LAI based on LPI, the hybrid algorithm has a better performance on deriving LAI. II error has more influence on deriving LAI than I error.
Estimation of above-ground carbon density of arbor forest in Zhejiang Province of southern China based on ZY-3 satellite multispectral image
Zheng Dongmei, Wang Haibin, Xia Chaozong, Chen Jian, Hou Ruiping, Hao Yuelan, An Tianyu
2020, 42(1): 65-74.   doi: 10.12171/j.1000-1522.20180351
[Abstract](512) [FullText HTML](240) [PDF 1254KB](26)
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ObjectiveBased on the ZY-3 satellite imagery and the LULUCF carbon sink monitoring plot data covering Zhejiang Province of southern China, the study attempted to construct a technical method for automatically extracting the above-ground carbon density of arbor forest in this area.MethodTaking the carbon density of arbor forest in Zhejiang Province as the research object, relevant research tests were carried out in the aspects of vector sign constructing, extraction of spectral information, purification of interpretation sign, ZY-3 satellite image classification, optimization of independent variables, optimization of modeling methods, production of carbon density map, etc.ResultThe results showed that the accuracy of classification of ZY-3 imagery after purification of interpretation signs was higher than that of image classification before purification. The accuracy of classification of ZY-3 images by kNN method (average total accuracy was 80.31%, average Kappa coefficient was 0.69, average user accuracy of arbor forest was 91.86%, and the average producer accuracy of arbor forest was 80.85%), which was higher than the maximum likelihood classification method (average total accuracy was 78.56%, average Kappa coefficient was 0.62, average user accuracy of arbor forest was 89.68%, and the average producer accuracy of arbor forest was 77.79%). Among the selected modeling methods, the model accuracy constructed by the kNN method (average RMSE was 15.64 t/ha, average RRMSE was 23.53%) was better than the robust estimation method (average RMSE was 17.63 t/ha, average RRMSE was 25.11%). Finally, the above-mentioned carbon density distribution map of arbor forest in Zhejiang Province was generated.ConclusionThis study provides a new path for arbor forest or forest carbon density estimation at the provincial or larger scale, providing a reference for automated estimation of carbon density and other forest parameters.
Effects of water and fertilizer coupling on soil nitrogen, fine root distribution and biomass of Populus tomentosa
Liu Feng, Xi Benye, Dai Tengfei, Yu Jinglin, Li Guangde, Chen Yushan, Wang Jie, Jia Liming
2020, 42(1): 75-83.   doi: 10.12171/j.1000-1522.20190222
[Abstract](327) [FullText HTML](140) [PDF 891KB](17)
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ObjectiveFast-growing and high-yield poplar forest is the main pulp and timber forest in China. However, lower water and fertilizer use efficiency causes soil degradation, environmental pollution and even decline in forest yield. Therefore, it is urgent to explore appropriate water and fertilizer coupling strategies to achieve sustainable development. In this study, we investigated the effects of different water and fertilizer coupling treatments on the soil nitrogen distribution, root distribution and forest yield, aiming to screen out the optimal water and fertilizer coupling measures for the yield of Populus tomentosa plantation.MethodIn this experiment, triploid Populus tomentosa was used as the research object. Three irrigation levels: − 20 kPa (I20), − 33 kPa (I33), − 45 kPa (I45), four application N levels: 0 (F0), 120 kg/(hm2·year) (F120), 190 kg/(hm2·year) (F190), 260 kg/(hm2·year) (F260), and a CK control were set to determine the soil NO3-N dynamics, absorption root distribution and the biomass yield throughout the year.Result(1) The amount of N applied, and the amount of irrigation significantly increased the migration, distribution and deep accumulation of NO3-N. Among them, the deep leaching of NO3-N treated by I20F260 was serious, while the amount of leaching of I20F120 was the smallest. (2) The coupling of water and fertilizer can make the root distribution shallow; the supply of N fertilizer can change the distribution of root system, and the irrigation promotes the surface distribution of roots; the response of root growth to N depends on the irrigation level, and I20F260 treating the root length density (RLD) was significantly better than other treatments (P < 0.05). (3) NO3-N content, RLD, and whole plant biomass (TB) of different treatments showed significant correlations with each other. There was a significant parabolic regression relationship between soil NO3-N content and RLD (P < 0.05). Therefore, soil nutrient difference is an important factor in the difference of fine root distribution. The RLD and TB in 0 – 10 cm and 20 – 40 cm soil layers showed a very significant parabolic regression relationship (P < 0.01). It can be seen that an appropriate amount of RLD in 0 – 10 cm, 20 – 40 cm soil layer is beneficial to increase forest yield. In this study, the annual average biomass of forest trees was highest with I20F120 water and fertilizer coupling treatment.ConclusionThe amount of N applied by I20F120 is one quarter of the traditional amount of N applied, and the deep NO3-N leaching amount is the smallest, which effectively reduces the pollution to the environment; in addition, it can form an appropriate amount of RLD to promote the absorption and utilization of nutrients, and ultimately the formation of higher forest yields and higher water and fertilizer utilization. Therefore, I20F120 is recommended as the best water and fertilizer coupling measure.
Changes of inorganic nitrogen in the leachates of urban forest soil and its soil nitrogen under the irrigation of different mass concentrations of ammonium nitrogen: taking Harbin City of northeastern China as an example
Duan Wenjing, Duan Wenbiao, Chen Lixin, Shen Hailong, Mu Yu, Han Donghui
2020, 42(1): 84-93.   doi: 10.12171/j.1000-1522.20180193
[Abstract](318) [FullText HTML](134) [PDF 1031KB](12)
Abstract:
ObjectiveThis paper aims to ascertain the changes of soil nitrogen and ammonium nitrogen, nitrate nitrogen in the urban forest soil leachate irrigated with different mass concentrations of ammonium nitrogen.MethodThis paper selects 3 typical forest types in the demonstration base of urban forest in Harbin City of northeastern China (Quercus mongolia plantation, Fraxinus mandshurica plantation, Phellodendron amurense plantation) as the object of this study. Bare ground without vegetative growth was used as control. Through the method of field collecting soil column and indoor soil column simulation, different mass concentrations of ammonium nitrogen solutions (100, 50, 25, 0 mg/L) were prepared by ammonium sulfate for indoor simulation irrigation, ammonium nitrogen and nitrate nitrogen in soil column leachate and soil nitrogen in column after treatment being measured and analyzed.ResultThe effects of three forest types on the removal of ammonium nitrogen were significant, the removal rate was above 95%; there was no significant difference in the removal of ammonium nitrogen by different forest types under the load of different mass concentration of ammonium nitrogen; the mass concentrations of nitrate nitrogen in original soil column leachate for three forest types and a control was higher, it ranged from 4.41 to 5.53 mg/L; when the influent ammonium nitrogen mass concentration was 100 mg/L, except for control, the content of ammonium nitrogen in soil columns for the three forest types was increased; when it was lower than 100 mg/L, except for the Quercus mongolia plantation, the content of ammonium nitrogen in the soil columns for the other two forest types was reduced; the content of nitrate nitrogen in soil column for each forest type and the control was significantly increased, but the difference in total nitrogen content between them was not significant. After irrigation with different mass concentrations of ammonium nitrogen, the change of ammonium nitrogen in soil column leachate was not significantly affected by the forest type, influent water amount and their interaction. But their effects on nitrate nitrogen reached a significant level. The change of nitrogen in the soil column after irrigation was significantly influenced by the above three factors.ConclusionFor the original soil column in three forest types and bare soil, ammonium nitrogen removal and nitrate nitrogen leaching loss in the soil in Quercus mongolia plantation were most significant, followed by the soil in Phellodendron amurense plantation, Fraxinus mandshurica plantation soil and bare soil.
Effects of the conversion time of cropland into forestry on soil physical properties in loess area of western Shanxi Province of northern China
Liu Junting, Zhang Jianjun, Sun Ruoxiu, Li Liang
2020, 42(1): 94-103.   doi: 10.12171/j.1000-1522.20180376
[Abstract](500) [FullText HTML](360) [PDF 1167KB](27)
Abstract:
ObjectiveIn order to discuss the “Grain for Green Project” on improving the soil physical property, we did an analysis about the change of soil physical property in different ages.MethodThe paper selects three kinds of land use (grass, pure plantation, mixed plantation) in the loess area of western Shanxi Province, contrasting with farmland, to discuss the effects of various ages in the Grain for Green Project on soil physical properties such as soil bulk density, soil total porosity and capillary porosity.ResultThe soil bulk density increased significantly with soil depth. The mean soil bulk density of 0−60 cm soil layer was farmland (1.38 g/cm3) > grassland (1.27 g/cm3) > pure plantation (1.20 g/cm3)> mixed plantation (1.18 g/cm3). There were significant differences in the soil bulk density of woodland and grass, farmland (P < 0.05). Besides, the soil bulk density decreased as the increasing year since abandoned. The value of it had been stable in 1.16 g/cm3 after 23 years old. The best improvement effect was the topsoil, but faded away with the increasing soil depth. The total porosity was inversely proportional to the age and tended to vary gently with increasing age of stand. The value of total porosity of topsoil was the biggest, which was 50.8%−57.6%, and the periods of greatest change was 5−10 years old. The value of it had been stable in 55.61% after 25 years old. The mean in the layers of 0−60 cm was mixed plantation (53.67%) > pure plantation (52.87%) > farmland (47.82%) > grassland (45.97%). There were significant differences between the grassland, farmland and woodland in the total porosity (P < 0.05), and the pure plantation was significantly different from the mixed plantation. With the growth of forest age, the capillary porosity also increased. The value of the mixed plantation and the pure plantation was 52.21% and 50.37%, which was significantly different from the farmland (45.62%).ConclusionThe project of the Grain for Green can obviously improve soil physical properties, and the effect of mixed plantation on soil improvement is better than pure plantation.
Evaluation of soil quality in iron tailing ore wastelands of various reclamation periods
Wang Anning, Liu Gechang, Xu Xuehua, Li Xiaogang, Li Yuling
2020, 42(1): 104-113.   doi: 10.12171/j.1000-1522.20180240
[Abstract](1151) [FullText HTML](109) [PDF 827KB](4)
Abstract:
ObjectiveThe effects of different reclamation periods on the soil quality of iron tailing ore wasteland were studied, which provided a basis for revealing the succession law and ecological management of reclaimed soil in iron tailing ore wasteland.MethodThis paper treats the iron tailing ore wastelands with various reclamation periods (1, 3, 5, 7 and 15 years) in Malanzhuang Town, Qian’an of Tangshan, northern China as the objects of study, while the bare tailings as the control; meanwhile, the minimum dataset (MDS) for evaluating soil quality was constructed through the gray correlation degree model and correlation analysis, after taking the soil physiochemical and biological characters in 0−20 cm, 20−40 cm and 40−60 cm soil layers into comprehensive consideration. Moreover, the index membership was calculated by the membership function, while the index weight was determined using principal component analysis (PCA), and the quality of the reclaimed soils in iron tailings was finally evaluated using the weighted summation model.ResultThe results suggested that the MDS applicable for soil quality evaluation should include 5 indexes, namely, fungus, phosphatase, urease, non-capillary porosity and total nitrogen, among which, phosphatase and urease factor loading amount displayed great gray correlation degrees, which were the key indexes for evaluating the reclaimed soil quality in that area. Besides, the MDS-based soil quality index (MDS-SQI) displayed extremely significant correlation with the total data set-based SQI (TDS-SQI) (R2 = 0.911), the results calculated by the weighted summation model indicated that, the SQI of various reclamation years followed the order of reclamation for 15 years > 7 years > 5 years > 3 years > 1 year > bare tailings. In addition, the soil quality comprehensive value during reclamation for 1−15 years was increased in a regression parabola manner, among which, the soil quality was slowly improved within reclamation for 1−7 years, but it was rapidly recovered after reclamation for 7 years and peaked at 15 years of reclamation. Additionally, the vertical section variation trend of soil quality at various reclamation years was basically decreased with the increase in soil depth.ConclusionSoil reclamation can improve the soil quality in iron tailing ore wasteland, which can provide reference for revealing the evolutionary changes and ecological management of reclaimed soils in iron tailing ore wastelands.
Effects of mixing sand on unconfined compressive strength of soil in collapsing gully
Huang Qiannan, Zhang Xiaoming, Wei Jie, Zhang Ziyou, Hu Jie
2020, 42(1): 114-120.   doi: 10.12171/j.1000-1522.20180235
[Abstract](532) [FullText HTML](223) [PDF 1107KB](7)
Abstract:
ObjectiveIn order to study the mechanics characteristic of colluvial deposits of collapsing gully, soil simulation of the collapsing had been made and the unconfined compressive strength was measured.MethodTwo methods to mix the sand and soil and different sand content were taken.ResultThe results showed that unconfined compressive strength reducted along with the reduction of sand content because of the lesser axial stress. From 0% to 100% of sand content, unconfined compressive strength reduction from 71.1 kPa to 14.6 kPa. The specimen mixed sand to soil with separated layer destroyed seriously and the strength was smaller result to the unstable substratum. The highest strength occurred to the specimen which was low sand content and mixed uniformly.ConclusionMixing sand dramatically reduces the unconfined compressive strength of soil in collapsing gully. Under the same sand content circumstances, specimen mixed uniformly has a high strength and brittle failure at the end of test.
Characterization and distribution rule of quebrachitol in Hippophae rhamnoides
Tao Cui, Wang Jie, Yao Yujun, Han Xue, Lü Zhaolin
2020, 42(1): 121-126.   doi: 10.12171/j.1000-1522.20190200
[Abstract](389) [FullText HTML](201) [PDF 845KB](19)
Abstract:
ObjectiveBased on an efficient and accurate characterization method, we accurately quantified quebrachitol and explored the changing rules of its content in seabuckthorn, providing references for the development and utilization of seabuckthorn resources.MethodAfter the comparison of the two methods, HPLC was selected for the determination of content of quebrachitol in three different parts of seabuckthorn, including the flesh, seed and leaf.ResultThis method showed a good linear relationship (R2 = 0.998 5), with high precision (RSD ≤ 0.53%), high accuracy (RSD ≤ 1.16%) and good repeatability (RSD ≤ 1.71%). The results showed that there was a significant difference in the content of alcohol in different parts of seabuckthorn (P < 0.01), and the content in the leaves of seabuckthorn was the highest (59.73 mg/g dry leaves), followed by the flesh of seabuckthorn (2.19 mg/g fresh flesh) and the seeds of seabuckthorn (0.39 mg/g fresh seeds). The leaves of seabuckthorn at different growth stages from May to September were collected, and the results showed that the content of quebrachitol increased gradually with the growth of leaves, and the growth rate was the largest from July to August, and the content accumulated to the highest in September (64.79 mg/g dry leaves).ConclusionLiquid chromatography-evaporative light scattering detector was found easy operating, accurate, and repeatable for the determination of quebrachitol content. The quebrachitol content in the leaves of seabuckthorn was more abundant than that in the fruits, and it reached the highest in September. This study can provide effective data support for the development and application of quebrachitol in seabuckthorn resources.
Landscape Architecture
Urban forest construction based on ecosystem service function improvement in warm temperate semi-humid areas
Ge Yunyu, Xin Boyu, Li Xiong
2020, 42(1): 127-141.   doi: 10.12171/j.1000-1522.20180433
[Abstract](1252) [FullText HTML](186) [PDF 1529KB](16)
Abstract:
ObjectiveBuilding harmonious and healthy urban forest is an important means to solve urban problems. This study intends to explore the urban forest construction mode based on the improvement of ecosystem service function, so as to effectively guide urban forest construction and implement the concept of ecological civilization development.MethodBased on the coastal urban forest of Qinhuangdao, Hebei Province of northern China, this paper constructs an urban forest ecosystem service function evaluation system using Delphi method, and determines the weight of each index by constructing evaluation index judgment matrix. Based on the weight comparison, the urban forest planning scheme of the project area was proposed for the purpose of improving the ecosystem service of the project. The i-Tree software component was used to simulate and calculate the ecosystem service value generated before and after the construction of urban forest, so as to verify the significance of urban forest construction based on the improvement of ecosystem service function.ResultThe simulation results show that the urban forest construction design based on the improvement of ecosystem service function not only has important ecological significance, but also can produce great economic value, among which the forest recreation value is the most significant.ConclusionThe regulation service, support service and cultural service functions of urban forest are the core service functions of urban forest ecosystem. According to the results of the evaluation of ecosystem service value and the situation of the study area, this study, from the perspective of the core service function, plaque build in the plant community, plant, tree species selection, biological habitat construction and recreation experience forward design scheme of the urban forest, provides useful reference for urban forest construction in warm temperate semi-humid areas.
Forestry Engineering
Experimental study on in situ monitoring of the evolution law of cracks in wood components with transverse cracks based on acoustic emission and image correlation
Tu Juncheng, Zhao Dong, Zhao Jian
2020, 42(1): 142-148.   doi: 10.12171/j.1000-1522.20190276
[Abstract](7518) [FullText HTML](217) [PDF 1067KB](21)
Abstract:
ObjectiveThe defects of the wood component with transverse cracks will cause fracture damage under bending load. It is important to study the law of crack initiation and propagation to predict and evaluate the fracture damage of the timber-containing members.MethodThis paper was performed on Chinese fir and damage was monitored in-situ in real time based on acoustic emission (AE) and digital image technology (DIC) during three-point bending failure of wooden beams with prefabricated transverse cracks. The AE parameter analysis method was used to study the characteristics of AE signals during the crack initiation and propagation of Chinese fir. The strain characteristics of the surface of the wooden beam are also analyzed according to the strain and displacement changes of the crack tip region.ResultThe results showed that the crack initiation and propagation laws reflected by the AE and DIC measurements during the damage evolution of prefabricated cracks in wood beam specimens were consistent, the digital images of damage evolution from monitoring the crack tip region of wooden beams verify the prediction of AE signals, and AE ring count, energy and amplitude were effective indicators to predict the crack initiation of wooden beams. The strain of the wooden beam surface can effectively observe the evolution of crack initiation and extension.ConclusionThe results of this study establish the relationship between wood microcrack initiation, propagation behavior and acoustic emission parameters and surface strain, and it successfully construct the evolutionary measurement and evaluation system for in-situ monitoring of cracks in wood components with transverse cracks based on acoustic emission technology and digital image correlation method. The experimental results provide a reference for the further study of the damage mechanism and in-situ monitoring methods for the crack evolution behavior of wood components with transverse cracks.
Variation of microscopic morphology and chemical composition of marigold stalk
Yang Guochao, Wang Nan, Huang Xinxin, Geng Yaru, Liu Jing, Zhang Qiuhui
2020, 42(1): 149-156.   doi: 10.12171/j.1000-1522.20190311
[Abstract](4248) [FullText HTML](198) [PDF 1361KB](8)
Abstract:
ObjectiveThe variation of micromorphology, chemical composition and functional groups of marigold straw was studied to provide scientific and reasonable technical basis for the utilization of crop straw at the micro-scale and molecular level.MethodField emission scanning electron microscopy (FE-SEM) and energy dispersive spectrometer (EDS) were used to characterize the microstructural variation and chemical element composition difference of the cross section of marigold straw. The cell wall percentage of marigold straw was measured by color image computer analysis system. And the functional group distribution rule of marigold straw along the direction of height was characterized by Fourier transform infrared spectrometer (FTIR), second derivative infrared (SDIR) and two-dimensional correlation infrared (2DIR).ResultThe results showed that: (1) the radial size of marigold straw had a small variation in the upper part (range 7.3), but a large variation in the middle and root (range 10.0 and 10.7, respectively). (2) The upper structure of marigold straw was “sparse”, but the diameter and distribution of tube holes in the middle and lower segments were not significantly different. The type of catheter was mainly single-tube or complex tube. The carbon and oxygen ratio of marigold straw was 0.73, 0.79 and 0.83 from tip to root, showing an increasing trend. The content of nitrogen atom percentage also had the same trend. (3) The cell wall ratio showed an increasing trend from the inside to outside and the height direction from the tip to root. 4) FTIR spectra corresponding to different heights were significant changes in 2 816−2 972 cm− 1, 1 651, 1 461 cm− 1 and 800−849 cm− 1. 1 700, 1 280 cm− 1 of the SDIR curve and 3 240−3 409 cm− 1, 2 921, 2 850 cm− 1, 1 619 cm− 1 of the 2DIR. The results indicated that the species and quantity of corresponding functional groups were correlated with the variation of straw height, it could infer changes of three kinds of basic units of straw.ConclusionThrough the analysis of Micromorphology and functional groups of marigold straw, the corresponding relationship between radial size, internal structure, percentage of carbon and oxygen atoms, cell wall percentage and height direction of marigold straw were revealed. The variation of the types and quantities of functional groups contained in the main chemical constituents of straw in the direction of straw height was deduced.

Establishment Time:1979

CN 11-1932/S

ISSN 1000-1522

Supervisor:Sinopec Research Institute of Petroleum Engineering

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