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Vegetation coverage information extraction of mine dump slope in Wuhai city based on visible vegetation index
Li Pengfei, Guo Xiaoping, Gu Qingmin, Zhang Xin, Feng Changdong, Guo Guang
Corrected proof  doi: 10.12171/j.1000-1522.20190252
[Abstract](0) [FullText HTML](0) [PDF 1630KB](0)
ObjectiveUse visible vegetation index to get the slope vegetation coverage of mine dump quickly and accurately, and to provide an effective method for the vegetation investigation of slope in Wuhai mining area.MethodThis study selecting one of the typical mine dumps in the Wuhai city aims at choosing a suitable visible vegetation index for local research, estimating the dump vegetation coverage, and furthermore trying to provide a new method for extracting the dump slope vegetation coverage by means of Quadrat survey, UAV remote sensing and visible vegetation index.ResultThe results show that: (1) Different visible vegetation indexes have different vegetation extraction effects. Among them, the darker part of red-green ratio index (RGRI) and blue-green ratio index (BGRI) represents the larger vegetation index, while the brighter part of other common visible vegetation indexes represents the larger vegetation index. (2) Gray image feature values of different visible vegetation indexes mainly distributed in range of [−1, 1] in the research area. There is a big overlap of pixel value between vegetation and land in the gray image of normalized green-blue difference index (NGBDI) and BGRI constructed from blue and green bands, which means some partial confusion between them. (3) visible-band difference vegetation index (VDVI) can extract slope vegetation quickly and accurately among common visible vegetation indices. The average recognition accuracy of VDVI vegetation index is 93.4% by manual visual interpretation and error matrix, which shows VDVI vegetation index could be more suitable for the vegetation extraction on the mine dump in Wuhai city, is better than the vegetation index of other common visible light. The vegetation coverage of the study area is approximately 20.4% by this method.ConclusionVisible vegetation index, an unsupervised classified method, could be a new method for investigating vegetation coverage of mine dump slope without selecting reference features by people but extract slope vegetation coverage directly and has a broad application prospect. The study also indicates that VDVI shows higher extraction accuracy of extracting vegetation coverage of mine dump slope in the Wuhai city, which means a practical significance to guide the vegetation restoration in local mine dump.
Genetic transformation of Populus alba × P. glandulosa ‘84K’ with AtDME1 and its chemical-inducible expression analysis
Wu Xiaojuan, Lu Junqian, Chang Yingying, Zhong Shanchen, Su Xiaohua, Zhang Bingyu
Corrected proof  doi: 10.12171/j.1000-1522.20190068
[Abstract](4) [FullText HTML](3) [PDF 730KB](0)
ObjectiveDNA methylation is an important epigenetic modification that plays an essential role in plant growth and development. In this study, the chemically-induced promoter and the Arabidopsis thaliana demethylation transferase gene AtDME1 were introduced into the genome of Populus alba × P. glandulosa ‘84K’, and the expression of AtDME1 was effectively induced by 17-β-estradiol treatment. The expression characteristic of the AtDME1 in transgenic poplar plants was investigated. This study laid a foundation for the establishment of the poplar methylation-induced variation system and genetic improvement of poplars.MethodThe chemically-induced promoter and AtDME1 were transformed into genome of P. alba × P. glandulosa ‘84K’ using Agrobacterium-mediated transformation. Traditional PCR and DNA sequencing were used to identify the transgenic plants in hygromycin resistant plants. The chemical inducer 17-β-estradiol was used to induce expression of AtDME1 in in vitro leaves of a transgenic clone for 0, 3, 6, 12, 24, 48, 96 and 144 h, and the expression of AtDME1 gene was detected by Quantitative Real-time PCR (qRT-PCR).ResultA total of 224 hygromycin resistant buds were obtained, among them six hygromycin resistant plants were screened. Finally, six transgenic plants were identified by molecular methods, which were named as AD-1 ~ 6. Results of qRT-PCR showed that the expression of AtDME1 reached its highest level after 3 h treatment of 17-β-estradiol, and its expression gradually decreased after 12 h’s treatment.ConclusionThe chemical inducer 17-β-estradiol can rapidly and efficiently induce the expression of AtDME1 gene in transgenic poplar, which lays a solid foundation for further study on the mechanism of DME1 gene in the regulation of poplar genome methylation. It lays a solid foundation for the study of the chemical expression characteristics of poplar.
Establishment of an effective protocol for cultivation of tissue cultured seedlings in Pinus massoniana superior provenance
Wang Yin, Yao Ruiling
Corrected proof  doi: 10.12171/j.1000-1522.20190396
[Abstract](16) [FullText HTML](12) [PDF 1114KB](6)
ObjectivePinus massoniana is a main tree species for ecological construction and timber in southern areas of China. However, the productivity of plantation is generally low resulting from the limitation of improved varieties, which leads to the slow development of industrialization in P. massoniana. It is necessary to develop an effective propagation system of elite germplasm for P. massoniana in order to promote the use of improved varieties, accelerate the industrial development, and enhance the competitiveness of industry.MethodIn this study, ‘Tongmiansong’ (TM), the backbone of P. massoniana breeding resources was used as the research object, zygotic embryos excised from immature cones were applied to explants, and mature somatic embryos (SE) obtained via somatic embryogenesis were used for tested materials. Concerning the technical bottlenecks of P. massoniana tissue culture, including low germination rate, poor shoot growth, and recalcitrance to rooting, effects of active charcoal (AC), basal media, and plant hormones on SE germination as well as reinvigoration and adventitious rooting of shoots were investigated in the present study.Result(1) AC significantly improved germination of TM mature SE, while a high level of AC was able to weaken their germination effects, and the best effect was observed at the 0.83 mol/L AC treatment. Based on the application of AC in the medium, the basal medium composed with high N, low ratio of NH4+/NO3, and moderate K and Ca furtherly enhanced the germination of SE, reaching 94.1% of germinating rate. (2) 0.42 mol/L AC effectively promoted the elongation of germinated SE. Under the treatment of 4 μmol/L TDZ, induction of axillary buds was better, achieving effective buds proliferation coefficient of 5.6 (35 d), and shoot height of 9.2 cm (50 d). (3) After 60 days of 1.2 μmol/L NAA + 2 μmol/L PBZ application in the rooting medium, rooting rate was 94.3%, root number was 6.4, and survival rate was 95.8% following 3-month transplanting.ConclusionThe effective breeding system by tissue culture for TM was firstly established via a combined approach of somatic embryogenesis and organogeneis in this study, which would be used for the rapid propagation of elite germplasm for P. massoniana as well as for the research on genetic transformation, providing solid foundation for industrialization of improved varieties and molecular breeding in P. massoniana.
Wind Resistance of 25 Landscape Tree Species in Coastal Area of Shanghai
Zhang Deshun, Li Keke, Li Linglu, Zhang Liyao, Liu Ming
Corrected proof  doi: 10.12171/j.1000-1522.20190253
[Abstract](86) [FullText HTML](84) [PDF 1242KB](2)
ObjectiveTyphoon is one of the main meteorological disasters in the east coast of China. The frequency and intensity of wind damage caused by climate change have been increasing in recent years. The study on wind resistance of landscape tree species is directly related to the ecological stability of urban green space system.MethodThe comprehensive evaluation of the wind resistance of 25 tree species by the static tension test, morphological stability evaluation, timber property determination and soil compactness measurement.ResultThe result shows that there is a logarithmic function relationship between the tensile torque and the tensile angle of each species; the stability index decreases with the increase of height, canopy/height, canopy size and asymmetry; there is a linear relationship between the compressive strength and the bending strength of tree cores.ConclusionFinally, 25 species were categorized into two groups: the first is a rigid tree with a large static tension and a small bending angle like Magnolia grandiflora, Firmiana simplex,Catalpa bungei ‘Jinsi’ and Liquidambar formosana. Another group is toughness trees with small static tension and large bending angle like Ginkgo biloba.
The study of tree recruitment of Mongolian oak (Quercus mongolica) based on zero-inflated model and mixed effect model methods
Li Chunming, Li LiXue
Corrected proof  doi: 10.12171/j.1000-1522.20190216
[Abstract](25) [FullText HTML](22) [PDF 606KB](4)
ObjectiveTree recruitment is the basic to ensure forest long-term maintenance, the recruitment model can predict the development of forest, and quantify the future health and productivity of forest ecosystem.MethodAbout 295 permanent sample plots were established across the natural range of Mongolian oak in the Jilin province in 1995. Stand factor, site factor, and climate factor were selected to construct recruitment model of Mongolian oak. The basic forms of model include Poisson distribution and negative binomial distribution. The zero-inflated model was added to these basic models because of the existence of a large number of zero values in the sample plots. The plot’s random effect was taken into account in order to solve the problem of nested and longitudinal data in the model. Finally, the validation data was used to verify the fitness of model.ResultThe result showed that stand arithmetic mean diameter and the number of trees per hectare were the most important factors, and both were negatively correlated with the probability and quantity of tree recruitment. Both site and climate factors have no significant effect on tree recruitment. The accuracy of the negative binomial distribution model was higher than that of the Poisson distribution due to the over-dispersed of the data. After considering plot’s random effect, all the models obviously improved the simulation accuracy of the model except for the standard negative binomial distribution model. The simulation effect of the negative binomial distribution model was the best when considering random effect and zero-inflated model.ConclusionIn order to ensure the occurrence of tree recruitment, it is very important to determine science management and initial planting density in forest management.
Study on forest structure diversity based on the neighborhood trees
Bai Yu, Yang Hua, Wen Jing, Wang Quanjun
Corrected proof  doi: 10.12171/j.1000-1522.20190120
[Abstract](339) [FullText HTML](112) [PDF 733KB](25)
ObjectiveStand is an important part of forest biodiversity. Due to its complexity or lack of ecological relevance, the typical diversity index cannot be analyzed on a spatial scale and therefore cannot reflect the internal changes of species and spatial structure.MethodTaking the spruce-fir forest in Jin’gouling Forest Farm in Wangqing County of Jilin Province as an example, two 60 m × 60 m typical plots were set by contiguous grid quadrat method, and a new index describing the diversity of spatial structural units-neighbourhood diversity index is evaluated.Result(1) The diameter structure curve of spruce-fir forest in the study area is multi-peak anti-J-shaped curve. The proportion of forests with small and medium-order diameter is higher, the trees with large diameter are less, and the distribution of diameters is continuous and reasonable. (2) The species diversity and tree diameter of the spruce-fir forest are high, the tree species and the diameter distribution are relatively uniform, the degree of mixing is strong, the horizontal structure is highly variable, and the stand structure is complex. (3) The results of the analysis of the three neighbourhood diversity indices (species diversity, structural diversity by diameter distribution, and structural diversity by diameter variation) are consistent with the results of the Shannon diversity index, and the close index values are obtained for stand with similar structure.ConclusionThe neighbourhood diversity index can describe the diversity of forest stands and spatial structure characteristics, and reflect the spatial variation of species and structure diversity, and has obvious ecological significance. It can be applied to the structural adjustment of forest stands and provide a theoretical basis for rational forest management.
Spatial layout of biological fuelbreaks in Jiangle County, Fujian Province of eastern China
Yuan Shuo, Li Chao, Chen Hao, Muhammad Amir, Liu Xiaodong
Corrected proof  doi: 10.12171/j.1000-1522.20190365
[Abstract](152) [FullText HTML](74) [PDF 1031KB](12)
ObjectiveSanming area of Fujian Province, eastern China is a forest fire-prone area. This study aims to reduce losses caused by fires and cutting off fire sources through the overall layout of biological fuelbreaks in the research area of Jiangle County, Sanming City of Fujian Province.MethodIn order to comprehensively plan the biological fuelbreaks in Jiangle County, we obtained the minimum control area by analyzing the spatial and temporal distribution of forest fires in Jiangle County over the past 12 years, determined the location of biological fuelbreaks through spatial analysis, hydrological analysis, and object-oriented spatial feature extraction and other methods and finally calculated the fire belt network density after selecting optimal fire-resistant tree species and determining the biological fuelbreak width based on statistics of the current status of biological fuelbreaks in Jiangle County.ResultThe density of biological fuelbreaks was finally determined to be 19.04 m/ha and the minimum control area was finally determined to be 10 ha. The final biological fuelbreaks need to be built were 3 591.67 km, including 1 846. 64 km in ridges, 384.21 km in valleys and 1 360.83 km in forest edges. The width of biological fuelbreaks of ridges was 12 m, and valleys and forest edges were both an average value, i.e. 9 m. Thus, the total area of the planned biological fuelbreaks was 3 786.49 ha. Choosing Schima superba as the major species, and Camellia oleifera and Phyllostachys heterocycla as subsidiary species after comparing the fire-resistant ability of main tree species in Jiangle County not only achieved a better result of fire prevention but also had economic benefits.ConclusionBased on the previous studies on fuelbreak construction in Fujian Province, and taking its density, minimum control area, construction location, and appropriate width into consideration, as well as the choose of fire-resistant tree species, this study has managed to optimize the spatial layout of fuelbreaks in Jangle County. This economical and pragmatical engineering, which is adaptative to local conditions will play an important role in fire prevention in Jiangle County of Fujian Province, eastern China.
Lateral resistance of wood frame shear walls integrated with wood-plastic composites
Yang Xiaojun, Hao Dan, Fu Shuai, Wang Jiayang, Zhang Lu, Yu Yihao
Corrected proof  doi: 10.12171/j.1000-1522.20190391
[Abstract](166) [FullText HTML](73) [PDF 1765KB](17)
ObjectiveUsing wood-plastic composites (WPC) as the main material to combine WPC with wood structure, exploring a WPC building based on wood structure is an important way to overcome the shortcomings of existing WPC building based on light steel structure. The lateral resistance of the wall is an important factor determining the safety of WPC building under the earthquake disaster. Studying the lateral resistance of wood frame-shear wall integrated with WPC provides a basis for maintaining the safety of WPC building.MethodFive ordinary frame-shear walls integrated with WPC and three frame-shear walls with diagonal brace were designed. Through the low-cycle loading test method, the lateral stiffness, shear strength, uplift of the column, stiffness degradation and unit energy consumption of the walls were studied.ResultThe lateral resistance of the WPC integrated wood walls mainly depended on the structural support of the WPC and the connection of the wall panels. The failure characteristics of the walls were the failure of scew connection and the fracture of WPC joints. For ordinary wall, the shear strength, lateral stiffness and unit energy consumption of the wall with 75 mm in slab screw spacing were 35.40%, 16.88% and 76.22% higher than those of the conventional wall, respectively. The lateral performance of the walls with diagonal brace was obviously superior to the ordinary conventional wall. The lateral resistance of the Λ-type bracing wall and the K-type bracing wall was similar to the X-type bracing wall. The lateral stiffness and unit energy consumption of the K-type bracing wall were 14.76% and 16.44% higher than the X-type bracing wall, respectively. And its shear strength was 11.34% lower than the latter. The restraint effect of the thickness of wall panel, diagonal bracing and slab screw connection on the wall could significantly reduce the uplift of the wall frame columns.ConclusionThe WPC integration method is an important factor affecting the wall’s lateral performance. Adopting frame-shear structure, setting up diagonal bracing and improving the reliability of slab srew connection can full exert the excellent performance of WPC and make the WPC integrated wall meet the seismic requirements of WPC buildings.
Effects of nitrogen, phosphorus addition and drought on leaf stoichiometry in dominant species of alpine meadow
Fu Yiwen, Tian Dashuan, Niu Shuli, Zhao Kentian
Corrected proof  doi: 10.12171/j.1000-1522.20190469
[Abstract](329) [FullText HTML](332) [PDF 1004KB](30)
ObjectiveGlobal change has substantially changed soil nitrogen (N), phosphorus (P) and water availability, which further impacts plant growth and physiological processes. However, so far few studies have been conducted to analyze the interaction effects of soil N, P and water on plant growth and physiological traits, especially for alpine meadow plants. This study aims to reveal the impacts of N addition, P addition, drought and their interactions on plant growth, leaf N and P content and N:P ratios in dominant species of alpine meadows, providing scientific evidence for grassland management.MethodBased on an experiment of N addition (10 g/(m2· year)), P addition (10 g/(m2· year)) and drought (50% rainfall reduction) in an alpine meadow of northwestern Sichuan, we measured aboveground biomass, leaf N, P content and their ratio in Elymus nutans, Deschampsia caespitosa and Anemone rivularis. Then we analyzed the influence of different treatments and their interactions on plant biomass and leaf nutrient.ResultFor plant growth, N addition significantly increased plant biomass of three species, but the impacts of P addition, drought, and the interactions among different treatments were not significant. For leaf nutrient, N addition significantly enhanced leaf N content and N:P ratio of three species, and P addition also promoted leaf P content but reduced N:P ratio. Drought raised leaf N content of E. nutans and D. caespitosa, but had no significant effect on leaf P content and N:P ratio. The interaction of N addition and drought promoted leaf N content and N:P ratio of E. nutans and D. caespitosa. Nevertheless, the interaction of N and P addition was not significant for leaf nutrient of all species.ConclusionThis study indicates that alpine species have quite different responses of plant growth versus nutrient traits to nutrient enrichment, drought and their interactions. N input mainly facilitates plant growth, but the complex impacts of soil N, P, drought and their interactions all affect plant nutrient and stoichiometric balance. These results imply that more future studies are needed to detect the mechanisms underlying alpine plant physiological responses to the interactions of various global changes.
Improvement research and application of urban green zone allergenicity index
Yan Ke, Yang Hua, Li Wenfang, Li Yun
Corrected proof  doi: 10.12171/j.1000-1522.20190376
[Abstract](84) [FullText HTML](48) [PDF 1001KB](22)
ObjectiveThe construction of urban green zone allergenicity index (IUGZA) takes into account the unique biological characteristics and morphological characteristics of plants in green space. In order to make the index more widely used, this paper improves its research and discusses the practical application of the index. Application can provide theoretical basis for the management and maintenance of urban green space.MethodBased on Gauss formula, the IUGZA was analyzed and improved, and it was used to evaluate the allergenic potential of green space, and the allergenic potential of different regions was compared. The practical application of the index in estimating the allergenic potential of green space was explored. Spearman correlation analysis and principal component analysis (PCA) were used to analyze the correlation between IUGZA and other parameters (surface area, number of plants, density, species richness and Shannon-Wiener index (H’)).s richness and Shannon-Wiener index (H').Result(1) The overall IUGZA value of green space was 0.214 1, and the I'UGZA value was 0.219 3. It had hypoallergenic potential, and the pollen of plants growing in the study area did not pose a high risk to patients with pollen allergy. However, when the study area was compared, the IUGZA value of some areas was greater than 0.3, which had high allergenic potential. At the same time, allergic symptoms of allergenic people can be caused within 346 m range of allergenic plants. The I'UGZA value at 1 000 m from the center of the field source approached 0, and there was almost no allergenicity. (2) There were many low allergenicity plants in green space, accounting for 65.7 %. Highly allergenicity plants are Pinus tabuliformis, Quercus variabilis, Fraxinus pennsylvanica, Populus tomentosa, Ailanthus altissima, Betula platyphylla, Ulmus pumila, Juniperus chinensis and other plants, mainly belonging to Cupressaceae, Pinaceae, Salicaceae, Platanaceae, Leguminosae, Simaroubaceae, Ulmaceae, Betulaceae, and Fagaceae. (3) The results of principal component analysis (PCA) analysis were consistent with those of Spearman correlation analysis. There was a significant correlation between IUGZA and species richness (P< 0.05), and the correlation with other parameters was not significant.ConclusionThe improved index can reflect the allergenic potential from different locations in the green space and the allergenic effect on the surrounding environment. It is an effective tool for assessing the allergenic potential of urban green space and is used to quantify the formation of pollen emissions in the air in different regions of the green space; it can reflect the contribution of pollen produced by each plant in green space, and then identify plants with high allergenicity in urban green space; it can also be used as a tool to analyze the richness of plant species in green areas.
Radial variation law of wood properties for Populus deltoides, Populus nigra and their hybrid progenies
Shen Hao, Rao Jun, Guan Ying, Zhang Liping, Liu Shengquan, Gao Hui
Corrected proof  doi: 10.12171/j.1000-1522.20190352
[Abstract](277) [FullText HTML](98) [PDF 743KB](9)
ObjectiveTaking Populus deltoides CL. ‘55/65’, Populus nigra CL. ‘N179’ and their three hybrid progenies (Populus euramericana cv. ‘Zhonglin46’, Populus euramericana cv. ‘Guariento’, Populus euramericana CL. ‘Sangju’) as the research objects, the radial variation law of wood properties between parents and offsprings was analyzed. The purpose of this study was to provide a certain theoretical basis for cultivating high-quality poplar germplasm resources.MethodThe chemical, physical and anatomical properties were determined by national standard.ResultThe results of wood properties showed that the mass fractions of benzene alcohol extractives of parents and their three offsprings varied in 1.36%−2.15%, and the mass fractions of holocelluloses were 79.23%−83.19%, respectively. The mass fractions of hemicelluloses were 35.09%−35.94%, and α-celluloses were 43.34%−47.25%. The lignin content of Lin 46 was 20.70%−24.73%, which was lower than that of its parents. However, the chemical content of other offsprings was between their male parent and female parent. The basic densities of the five poplar species varied from 0.33 to 0.39 g/cm3, the fiber length was 971.06−1 145.65 μm, the fiber width was 16.19−19.36 μm, and the ratio of fiber length to width was 57.07−67.28. The ratio of wall to cavity was 0.26−0.31, and the ratio of cavity to diameter was 0.76−0.80. With the increase of age of the trees, the mass fraction of benzene alcohol extractive increased first and then decreased, the holocellulose increased rapidly at first 5 years, and then tended to be stable. The mass fraction of α-cellulose increased gradually with the increment of tree age, the wood mass fraction decreased gradually, and the basic density of ‘Zhonglin46’ and the female parent increased gradually, but decreased gradually in the male parent and another two offsprings. The fiber length increased gradually with the increment of tree age, and the increasing rate decreased obviously at the tree age of 7 to 8 years old. The fiber width and the fiber length-width ratio both increased gradually, and the increasing rate became slower after 7 years old. The wall-cavity ratio decreased first and then increased, reaching the lowest at 6 to 7 years old, while the cavity-diameter ratio increased first and then decreased, reaching the highest at 6 to 7 years old.ConclusionThere are significant differences in wood properties between Populus deltoides and Populus nigra and their hybrid progenies, each wood property showed different degrees of variation, and the radial variation of parents was consistent with that of offsprings. The benzene alcohol extract and lignin of female parent Populus deltoides CL. ‘55/65’ were low, α-cellulose was high, fiber length-width ratio and wall-cavity ratio were large, and the coefficient of variation of these characters was small, which was beneficial to genetic control, and was the best of the five clones. The indexes of lignin and anatomical characteristics of ‘Zhonglin46’ have the transgressive segregation phenomenon, which has great potential for selection, and could be utilized in tree breeding in the future.
Optimal growth model of Populus simonii seedling combination based on Logistic and Gompertz models
Ge Huishuo, Song Yuepeng, Su Xuehui, Zhang Deqiang, Zhang Xiaoyu
Corrected proof  doi: 10.12171/j.1000-1522.20190296
[Abstract](1285) [FullText HTML](688) [PDF 780KB](12)
ObjectiveThrough the research on the growth regularity and growth model of Populus simonii seedlings, it could provide reference for its growth prediction and scientific seedling raising.MethodTaking P. simonii seedlings in 16 regions of China as the research object, basic data were obtained by means of experimental field investigation and measurement, and the growth rules of plant height were analyzed from the time dimension. We used existed growth equations to select the optimal basic growth model according to the model goodness of fit and evaluation indexes, and constructed optimal growth models suitable for seedling growth in different regions with the basis of the optimal model.Result(1) The comprehensive optimal basic models of sample plant height in different regions were Logistic equation and Gompertz equation, respectively. The Logistic model’s R2 and prediction accuracy were above 0.847 9 and 92.23%, and the Gompertz model’s R2 and prediction accuracy were above 0.891 5 and 92.60%, respectively. (2) On this basis, the combinative optimization model constructed showed a larger F value (α = 0.01) and a higher prediction accuracy for the growth of P. simonii seedlings in 7 regions of China, among which the prediction accuracy of samples in Menyuan County increased by 0.90%, and the sample prediction accuracy of samples in Fuping County and Dulan County increased by 0.37% and 0.34%, respectively. (3) Through combinatorial optimization of model parameters, it was found that samples from 16 regions reached the maximum growth rate in the 17.73th day on average.ConclusionThe growth of P. simonii seedlings was affected by geographical location and climate and other conditions. Establishing models suitable for the growth of seedlings of P. simonii in different regions was conducive to improve the accuracy and applicability of the models, which could not only provide a scientific basis for seedling research, but also lay a foundation for further genome-wide association analysis.
Diurnal variations of stand transpiration of Larix principis-rupprechtii forest and its response to environmental factors in Liupan Mountains of northwestern China
Ma Jing, Guo Jianbin, Liu Zebin, Wang Yanhui, Zhang Ziyou
Corrected proof  doi: 10.12171/j.1000-1522.20190468
[Abstract](517) [FullText HTML](412) [PDF 1798KB](37)
ObjectiveThis paper aims to examine the diurnal variations of stand transpiration and its response to environmental factors in a Larix principis-rupprechtii plantation, and to further explain the regulation mechanism of environmental conditions to the stand transpiration in short time scale.MethodA field experiment was conducted in a Larix principis-rupprechtii plantation stand located in the Xiangshuihe Watershed within the Natural Reserve of Liupan Mountains, Ningxia of northwestern China. The sap flow of sample trees was continuously monitored in the growth season (from May to October) in 2018. The meteorological and soil moisture conditions were continuously measured simultaneously. The response of hourly stand transpiration (T) to environmental factors was analyzed, and a T model coupling the effects of multiple influencing factors was established.ResultIt was shown that: (1) the response of T to solar radiation (Rs) and vapor pressure deficit (VPD) followed a binomial equation. The T firstly increased with rising Rs and VPD till to peak at the thresholds of 666.7 W/m2 and 1.86 kPa, and then gradually decreased afterwards. (2) The T response to relative extractable water (REW) of the 0-60 cm soil layer followed a saturated exponential growth function. The T increased firstly with rising REW, and then became stable when the REW was above 0.3. (3) The response functions of T each individual driving factors (Rs, VPD and REW) were determined using the upper boundary line method, and then were coupled to form the frame of T model. Thereafter, the observed data of odd-days and even-days were used for model fitting and validation. The fitted model is: T = (− 6.347 0 × 10− 5\begin{document}${R_{\rm{s}}^2}$\end{document} − 0.637 0Rs − 208.734 8) × (− 0.003 2VPD2 + 0.013 8VPD + 0.001 7) × (− 0.008 1 − 0.004 6(1 − exp(− 12.469 6REW))). The model was well calibrated (R2 = 0.74, Nash coefficient (NSE) = 0.82) and validated (R2 = 0.77, NSE = 0.84).ConclusionThe T variation can be well predict by the T model coupling the effects of solar radiation, vapor pressure deficit, and soil moisture conditions. This model can accurately predict the variation of T of Larix principis-rupprechtii plantation under changing environment. Meanwhile, the model establishment approach used here can be a reference for developing the stand transpiration model in other regions and for other tree species.
Interspecific and intraspecific competitions of Pinus kwangtungensis in Nanling National Nature Reserve, Guangdong Province of southern China
Wang Jun, Wang Yongteng, Duan Yangbo, Xie Lei, Cui Guofa
Corrected proof  doi: 10.12171/j.1000-1522.20180436
[Abstract](342) [FullText HTML](58) [PDF 750KB](1)
ObjectiveIn order to reveal the rule of dynamic changes of competition intensity within the community and the ecological adaptation mechanism, the intraspecific and interspecific competition of Pinus kwangtungensis were analyzed by investigating the 118 target trees and 253 associated species in Xiaohuangshan of Nanling National Nature Reserve, Guangdong Province of southern China.MethodWe set standard community plots along the elevation gradient. The competition index of P. kwangtungensis was calculated by Hegyi individual competitive indices (CI) model. The function model between diameter at breast height(DBH), the competitive index of stand, and interspecific competition were established by regression method.Result(1) There was a significant power function relationship between DBH and tree height. (2) Intraspecific and interspecific competition intensities of P. kwangtungensis were 893.736 and 559.682, respectively. (3) There were many associated species of P. kwangtungensis, and the order of main interspecific competition species was Schima superba > Castanopsis eyrei > Pentaphylax euryoidex > Pinus massoniana > Tsuga longibracteata > Delonix regia > Fokienia hodginsii > Exbucklandia populnea. (4)There was a significantly negative correlation between the competition index with the stand, accompanying species, and the DBH of the objective trees.ConclusionIntraspecific competition was dominant in the community. The competition intensity of P. kwangtungensis decreases inversely with the growth of the DBH. When the DBH of P. kwangtungensis reached 30 cm, the competition intensity declined stably, and the relationship between the forest stand competition intensity and DBH of the target trees is conformed to power function. This model can effectively predict the intraspecific and interspecific competitions of P. kwangtungensis.
Species diversity of plant communities and its main influencing factors in Horqin Sandy Land, Inner Mongolia of northern China
Chen Chen, Wang Yin, Wang Jianming, Yang Huan, Wang Yuchen, Xu Chao, Li Jingwen, Chu Jianmin
Corrected proof  doi: 10.12171/j.1000-1522.20190284
[Abstract](427) [FullText HTML](155) [PDF 767KB](51)
ObjectiveThe Horqin Sandy Land is located in agro-pastoral ecotone of northern China, and its species composition and diversity patterns are quite vulnerable to the changes of human disturbance and environmental factors. Because of the fast development of agriculture and animal husbandry industry in recent years, human disturbance has become an essential role in the Horqin Sandy Land. However, further systematic studies are needed to understand the relative influence of grazing disturbance and environmental factors on the α, β and γ diversity of plant communities in the Horqin Sandy Land.MethodThe grazing disturbance data and environmental data of 44 sampling points were used to study the distribution characteristics of the α, β and γ diversity of plant communities and their main influencing factors in the Horqin Sandy Land by one-way ANOVA, simple linear regression analysis, polynomial regression analysis, and variance decomposition.Result(1) The α, β and γ diversity of plant communities declined as grazing intensity increased, and the peak species diversity appeared under grazing exclusion. There was a significant difference in the α, β and γ diversity of plant communities among different grazing intensities (P <0.05). The α, β and γ diversity under heavy grazing intensity were significantly lower than under grazing exclusion (P < 0.05). (2) The α diversity of plant communities had a significantly negative correlation with grazing intensity and mean temperature of the hotest month (P < 0.01), and a positive correlation with mean diurnal range, soil organic carbon and soil total phosphorus (P < 0.01); it had a significant U-shaped relationship with mean annual precipitation, and a hump-shaped relationship with mean temperature of the coldest month and soil total nitrogen (P < 0.05). The β diversity of plant communities had a significantly negative correlation with grazing intensity, potential evapotranspiration, and mean temperature of the coldest month (P < 0.05), and a positive correlation with mean annual precipitation (P < 0.05). The γ diversity of plant communities had a significantly negative correlation with grazing intensity (P < 0.001), and a positive correlation with soil organic carbon and soil total nitrogen (P < 0.01). (3) Grazing disturbance was the main influencing factor affecting the α and β diversity of plant communities; the synergism between grazing disturbance and soil factors was the main influencing factor affecting the γ diversity of plant communities.ConclusionGrazing disturbance has a critical effect on species diversity of plant communities in the Horqin Sandy Land. Therefore, in order to enhance biodiversity conservation and restore the degraded ecosystem in the Horqin Sandy Land, local government should formulate polices to forbid overgrazing and enhance supervision to reduce the occurrence of grazing without permission.
Mixed model of forest space utilization in spruce-fir coniferous and broadleaved mixed forest of Changbai Mountains, northeastern China
Li Yang, Kang Xingang
Corrected proof  doi: 10.12171/j.1000-1522.20190112
[Abstract](375) [FullText HTML](79) [PDF 893KB](24)
ObjectiveIn this paper, the forest space utilization model was established to provide the basis for the comparison of productivity among different tree species in the natural mixed forest, and provide reference for the judgement of tree maturity.MethodThe combination of tree growth and canopy size was used to define the forest space utilization. Based on the 2 268 individuals of 20 standard sites, which located in spruce-fir and broadleaved mixed forests in Changbai Mountain area of northeastern China, a mixed-effects model of forest space utilization was established to fit the spatial utilization of different species.Result(1) The correlation coefficient between DBH and the ratio of volume growth to the crown projection area was the highest, so it is suitable to be the calculation index. (2) Through the stepwise regression, the tree DBH, DBH square (represent area), tree height, crown width, plot accumulation, proportion of coniferous trees, slope gradient and competition index were selected as the independent variables of forest space utilization. (3) Mixed effects model was developed, including the DBH square and intercept random effect parameters by species groups and the exponential function heteroscedasticity structure. The results showed that the mixed effects model was better than the general linear model both in the modeling data and the test data. (4) Using the mixed effect model to predict the research area data, the DBH of the highest spatial utilization of each tree species was obtained: spruce (Picea koraiensis) was about 40 cm; fir (Abies holophylla), Korean pine (Pinus koraiensis), larch (Larix olgensis), and medium-speed broadleaf trees were about 37 cm; slow broadleaf trees were about 32 cm.ConclusionThe mature DBH obtained from the forest utilization model is based on the productivity of the unit nutrient space, so that the comparison between different tree species is more reasonable. The calculation results are in accordance with the general forest rule, so it can be used as a reference to judge the tree maturity, optimize the stand structure in the coniferous and broadleaved mixed forest in that area.
Research on stormwater management measures in Beijing suburban hilly area based on hydrological model: taking the upper reaches of Jiakuohe River as an example
Lin Qiao, Liu Zhe, Lü Yingshuo, Yu Xixuan, Zheng Xi
Corrected proof  doi: 10.12171/j.1000-1522.20190116
[Abstract](158) [FullText HTML](53) [PDF 1838KB](15)
ObjectiveThe suburban hilly area is the ecological barrier of the city. Due to the steep slope of the terrain in the suburban hilly area and the short peak time of the flood peak, it is easy to form seasonal floods, resulting in flood disasters. The purpose of this paper is to explore reasonable stormwater management methods in suburban hilly area and to study the applicability of different stormwater management scenarios in mountainous area.MethodTaking the upper reaches of the Jiakuohe River in the shallow mountainous area of Beijing as an example, the hydrological model of HEC-HMS and HEC-RAS was used to simulate the stormwater runoff process under the once in 10 years stormwater. The three different stormwater management scenarios(traditional management scenarios, low-impact development scenarios, and natural scenarios) were compared and analyzed in stormwater control effects, ecological environmental impacts, and landscape effects, thereby exploring the effectiveness of stormwater management measures in different suburban hilly areas.Result(1) In terms of stormwater control effects, the storage capacity under traditional management scenarios and low-impact development scenarios were 3.8 times and 5.0 times of natural scenarios, and the maximum flooding range was 2.0% and 1.2% higher than natural scenarios. The reduction rate of peak traffic flow in traditional management scenarios and low-impact development scenarios was 18.3% and 31.5%, respectively, and the peak current time was delayed by 35 min and45 min, respectively. (2) In terms of ecological environment impact, the positive effects of low-impact development models on river vegetation environment and hydrological connectivity were greater than traditional management models and natural models. (3) In terms of landscape effects, low-impact development scenarios had great advantages in terms of water body scope and environmental fit.Conclusion(1) Compared with the traditional stormwater management model, the low-impact development model has a good stormwater storage and storage function, which can increase the stormwater storage capacity, reduce the peak flow rate, delay the peak time, and further reduce the development mode. It can improve the river ecological environment and has a good landscape effect. Therefore, through comprehensive judgement, low-impact development scenarios are more suitable for the research basin of this paper. (2) The low-impact development model can take advantage of the topography of the suburban hilly area and collect upstream water collection by designing a stormwater reservoir in a gentle terrain. At the same time, the low-impact development model formulates the stormwater flood target according to the design specifications of the sponge city, and realizes that the annual total runoff control rate of the upper reaches of the river channel is greater than 85%, taking into account the river ecological and landscape needs. (3) the HEC-RAS hydrological model can quantify and visualize different stormwater management scenarios and provide technical support for stormwater management in suburban hilly area. (4) The study emphasizes the particularity of each region. The stormwater management measures in suburban hilly area extend the application of low-impact development scenarios from another level, indicating that traditional water conservancy facilities are also applicable to the stormwater management concept of low-impact development.
Fine root anatomical and morphological traits of three temperate liana species in northeastern China
Wang Yuanmin, Wang Yan, Wang Siyuan, Gao Guoqiang, Gu Jiacun
Corrected proof  doi: 10.12171/j.1000-1522.20190419
[Abstract](42) [FullText HTML](37) [PDF 827KB](6)
ObjectiveThe objective was to investigate the functional traits and potential absorbing capacity in fine roots of liana (woody climbing plants) in temperate forests.MethodWe sampled three typical temperate liana species in northeastern China, including two twining climbers (Actinidia kolomikta and Schisandra chinensis) and one tendril climber (Vitis amurensis). The anatomical, morphological, and branching traits, as well as the composition of absorptive roots were examined for the grade 1−5 fine roots in the three species.ResultThe results showed that the cortical thickness of Actinidia kolomikta and Schisandra chinensis increased by ascending branch order, while that of Vitis amurensis decreased. The stele diameter of all three liana species significantly increased with increasing branch order, but the ratio of cortical thickness to stele diameter significantly reduced. In term of the status of cortex appearance, the proportion of roots with absorbing function apparently decreased with ascending branch order across all three species, with the grade 1 fine roots as typical absorptive roots. From grade 1 to grade 5, specific root length significantly decreased, but root diameter and tissue density increased. The decline in root branching ratio associated with increasing branch order was only found in V. amurensis. Those root functional traits in liana were significantly influenced by species, but showing significant interaction with branch orders. Compared with two twining climbers, tendril climber of V. amurensis had wider stele, lower ratio of cortical thickness to stele diameter, and much higher branching ratio to the grade 2 and grade 3 roots. In comparison to other woody plants and herbaceous ferns at the same study site, mean root diameter of three liana species was thicker but mean specific root length was lower, with intermediate mean tissue root density.ConclusionAlthough the interspecific differences in root anatomical and morphological traits exist in three temperate liana species, the variation patterns of those root traits associated with increasing branch order are consistent with other woody plants. The morphological traits of the grade 1 roots in these lianas display distinctive characteristics compared with other plant taxa in this region.
Prediction models and change rule of the dead fuel moisture content of 8 forest species in Beijing area
Zhan Hang, Niu Shukui, Wang Bo
Corrected proof  doi: 10.12171/j.1000-1522.20190370
[Abstract](866) [FullText HTML](22) [PDF 1076KB](1)
ObjectiveThe forest fuel moisture content made sense for the occurrence and spread of forest fire, particularly important for the fire behavior, and its prediction forecast models have had a significant effect on predicting forest fire and forest fire behavior.MethodsThrough the continuous determination of the dead fuel moisture content of 8 kinds of forest trees in Beijing area during the period of fire prevention, we researched the relationship between the fuel moisture content and the current and previous meteorological data, and established the prediction models by selecting the meteorological factors which with great influence on the fuel moisture content. On this basis, we quantitatively analyzed the diurnal variation and the fire protection period variation of the fuel moisture content.ResultsThe fuel moisture content of different tree species was significantly different, The fuel moisture content from descending order was Quercus variabilis, Q. aliena, Ulmus pumila, Robinia pseudoacacia, Acer truncatum, Platycladus orientalis, Pinus tabulaeformis, Larix principis-rupprechtii. And the fuel moisture content of different types was also significantly different. Generally the broad-leaf trees fuel moisture content were higher than that of coniferous trees, and the dead leaves and 1hr branches fuel moisture content were higher than of 10 hr and 100 hr. The dead leaves and 1hr dead branches were mainly affected by the current meteorological factors, while the 10hr and 100 hr were affected by the early meteorological factors. The test indexes of 32 linear prediction models showed that the fitting effect was perfect. The diurnal variation of the fuel moisture content was higher and more stable at night, lower and varied greatly during the day, which peaked at 06:00-08:00 then dropped sharply, and later reached to lowest value at about 12:00-14:00. During the fire protection period, the fuel moisture content showed a trend of rising first, then decreasing. It was low in November but increased slowly,and reached a high level in from December to January of the following year. In from early March to the end of April, the fuel moisture content kept a very low level.ConclusionHigh-precision prediction methods of different tree species and among different fuel types could offer theoretical support for forest fire prevention, which can be used in practice. In March and at noon time with being windy, drying and hot, it was lower fuel moisture content, which should be reinforced management of fire in such a dangerous fire danger rating of that period of time.
Characteristics analysis of quantity and spatial structure of standing live and dead trees in Tilia amurensis secondary forest on the west slope of Zhangguangcailing, China
Liu Yue, Xu Li Ying, Wang Yu Jiao, Yu Jiang Bo, Yang Li Xue
Corrected proof  doi: 10.12171/j.1000-1522.20190305
[Abstract](27) [FullText HTML](22) [PDF 1146KB](4)
ObjectiveThe aim was to provide a basis for the growth, protection and management of Tilia amurensis secondary forest by analyzing the quantity and spatial structure characteristics of standing live and dead trees and exploring the growth state, succession process and the main causes of standing dead trees under two disturbance modes (non-cutting and selective cutting).MethodThe research was conducted by analyzing the species composition, diameter structure, height structure and spatial structure of standing live and dead trees.Result(1) Tilia amurensis, Acer mono, as well as other dominant species of standing live trees also had a dominant position among dead trees in selective cutting stand. while only Tilia amurensis was dominate among the standing live trees and standing dead trees in non-cutting stand, but Acer mono was only dominate of the standing live trees, and it was rare in dead standing trees. (2) The standing live and dead trees of the small diameter were dominant in all two stands, and the diameter distribution was roughly inverted J type. The height class distribution of standing live trees were roughly left-skewed distribution in two stands, while the standing dead trees were inverted J type, meanwhile, the small standing dead trees accounted for a large proportion. Therefore, it could be analyzed that the main reason for the formation of dead trees in the two stands was the competition between the trees. (3) The trivariate distribution of spatial structure parameters has shown that there were more dominant standing live trees which were randomly distributed, highly mixed and dominant in two stands. Whereas, most of the standing dead trees with randomly distributed, disadvantaged state, and the surrounding trees were all other tree species or only one was the same tree species. (4) The quadrivariate distribution of spatial structure parameters showed that the standing dead trees of the two stands were randomly distributed in general, with good mixture of species and obvious size differentiation. There were three or four standing live trees around one standing dead tree in that state. It further indicated that inter-species competition was the main reason for the formation of the standing dead trees. This study analyzed the spatial structure and quantitative characteristics of standing live and dead trees in the secondary forest of Tilia amurensis. Therefore it was not only exploring the formation of dead standing trees in the secondary forest, but also provided a theoretical basis for its protection and management.
Study on Vegetation Type Distribution in Nature Reserve Based on CART Decision Tree
Bai Ying, Hu Shu-ping
Corrected proof  doi: 10.12171/j.1000-1522.20190269
[Abstract](814) [FullText HTML](28) [PDF 845KB](0)
ObjectiveIn order to meet the needs of nature reserve monitoring, improve the precision of remote sensing inventory on vegetation types, an object-oriented classification method and machine learning algorithms were developed in vegetation classification by using GF-1 WFV remote sensing data.MethodThe study site is located in Baishuijiang National Natural reserve, Gansu Province. The GF-1 WFV multispectral data, Landsat-8 OLI remote sensing data, DEM data and field survey data were employed as the key data sources. Firstly, the multiresolution segmentation of GF-1 WFV data was carried out, and the research area was divided into many polygon objects. Then spectral features, geometric features and texture features from polygon objects were extracted to vegetation classification by using CART decision tree. Finally, the accuracy of classification was analyzed by error matrix based on TTA mask.ResultIn the multiresolution segmentation process, the shape factor and compactness were set to 0.2 and 0.5 respectively, the boundary of the polygon objects were identical with ground objects. When the shape factor and compactness were fixed, the optimal segmentation scale is 40. The accuracy results showed that the overall accuracy and Kappa coefficient were exceed of 83 % and 0.80 in three CART decision trees, which was superior to KNN algorithm and SVM algorithm. Overall accuracy and Kappa coefficient of CART decision tree reached 85.18 % and 0.832 2 by using spectral, geometric and texture features, which was better than CART decision tree by using spectral features or spectral combined with geometric features.ConclusionThe image classification based on CART decision tree algorithm and object-oriented classification method were suitable for vegetation classification in nature reserve by using GF-1 WFV image, which could effectively assist the nature reserve monitoring.
Quantitative detection of log defects based on stress wave propagation velocity model
Wei Xiwen, Sun Liping, Xu Shuzheng, Yang Yang, Du Chunxiao
Corrected proof  doi: 10.12171/j.1000-1522.20190420
[Abstract](105) [FullText HTML](280) [PDF 1589KB](6)
ObjectiveThis paper aims to study the variation of stress wave propagation velocity in the longitudinal section of trees at different angles, and to establish the corresponding propagation velocity model, so as to further understand the propagation law of stress wave in the longitudinal section of trees at different angles, and to provide theoretical and experimental basis for the two-dimensional imaging technology of internal defects of logs.MethodFirstly, through theoretical analysis, the propagation velocity model of stress wave in longitudinal section of logs with different directions was established. Then, four representative tree species in the northeastern region of China were taken as test samples, and the propagation velocity of stress wave in longitudinal section of logs with different directions, angles of different sections and angles of different directions was measured by stress wave wood nondestructive testing instrument. The relationship of healthy samples between stress wave propagation velocity \begin{document}$v\left(\alpha \right)$\end{document} and direction angle α, propagation velocity \begin{document}$v\left(\beta \right)$\end{document} and longitudinal section angle β, \begin{document}$v\left({\alpha,\beta } \right)$\end{document} and α, β were obtained, respectively by regression analysis.ResultIn the same longitudinal section, the propagation velocity of stress wave increased with the increase of direction angle, and the velocity of the horizontal direction was the smallest. At the same direction angle, the propagation velocity of the stress wave increased with the increase of longitudinal section angle, and the propagation velocity of radial direction was the greatest. The fitting results of the health sample test data were in good agreement with the theoretical mathematical model. The determination coefficient R2 was all greater than 0.87, and the significance P was less than 0.01. The models had higher goodness of fit. For the larch log samples, the cavity defects with diameters of 7.5 cm were designed artificially, and the two-dimensional imaging was performed using the healthy multiple regression model \begin{document}$v\left({\alpha,\beta } \right) = 109.2{\alpha ^2} - 182.1{\beta ^2} + $\end{document} \begin{document}$36.78{\alpha ^2}{\beta ^2} - 34.76{\alpha ^2}{\beta ^4} + 1 \; 627$\end{document} with correlation coefficient R2 of 0.97 and root mean square error RMSE of 17.81. When the propagation path of stress wave was located in the healthy area of the wood, the variation trend of the propagation velocity with the direction angle and longitudinal section angle fitting the model; but when the stress wave passed through the defective area of the wood, the propagation velocity was significantly reduced, no longer in normal condition. Based on the results of two-dimensional imaging, the fitness of the images was 92.06%, and the error rate of measuring defect cavities was 8.63%.ConclusionThe analysis showes that the regression model of stress wave propagation in different longitudinal sections of healthy logs is in good agreement with the theoretical model proposed in this paper, and further verifies that the velocity model has a good guiding role in the detection of internal defects of healthy logs.
Analysis of differential expression of miRNA and function of target genes in heteromorphic leaves of Populus euphratica
Zeng Ming, He Shuhang, Li Wenhai, Feng Jun, Zhao Yuanyuan, Zheng Caixia
Corrected proof  doi: 10.12171/j.1000-1522.20190464
[Abstract](31) [FullText HTML](27) [PDF 985KB](2)
ObjectiveHeterophylly is the phenomenon that plants form multiple types of mature leaves on the same plant to adapt to the environment. Populus euphratica is a typical woody heterophyllous plant, and previous research found that there are differences between heteromorphic leaves of P. euphratica in physiological characteristics and enironmental adaption. In this study, to reveal the molecular regulation of morphological and physiological characteristics in heteromorphic leaves of P. euphratica, we analyzed the differential expression of miRNAs and functions of target genes in heteromorphic leaves of P. euphratica.MethodIn this paper, by using high-throughput sequencing, comparative study for miRNA expression patterns and functions of target genes were conducted in lanceolate leaves and dentate broad-ovate leaves.ResultA total of 6 high-quality sRNA libraries were obtained, and the valid sequence of each library accounts for 56%-81% of the raw data. Total 517 known miRNAs and 127 predicted novel miRNAs were identified the length of which were mainly distributed in 20-22 nt. Besides, 389 of the identified miRNAs were mapped to 54 known miRNA families, and there were 369 miRNAs detected in both two types of leaves. Compared to lanceolate leaves, 7 miRNAs were up-regulated and in dentate broad-ovate leaves, while 15 miRNAs were down-regulated. Based on the prediction of target genes and function annotation, differentially expressed miRNAs were involved in stress-resistant pathways in Populus euphratica, such as cellular response to salt stress, inositol phosphate metabolism, cutin, suberine and wax biosynthesis, base excision repair, and RNA degradation pathways. Moreover, expression levels of 5 differentially expressed miRNAs and their corresponding target genes were examined by Quantitative Real-time PCR, which could confirm the expression profile of the sRNA-sequencing and the negative regulation of miRNAs on their target genes.ConclusionOur study revealed that the expression patterns of miRNA between the heteromorphic leaves of P. euphratica are different. The miR167 and miR166 that involved in growth and development of plant and miR172 that associated with stress resistance of plant were up-regulated in dentate broad-ovate leaves. Besides, the miR169 and miR396 that involved in stress resistance of plant were down-regulated in dentate broad-ovate leaves in comparison to lanceolate leaves. We speculated that the differential expression of miRNA may induce the morphological difference between heteromorphic leaves, and could increase the resistance of dentate broad-ovate leaves to adverse environments, which were consistent with our previous results of morphological and physiological characteristics in heteromorphic leaves of P. euphratica.
Effects of Crucibulum laeve inoculation on photosynthesis of Salix viminalis cultivated in PAHs-contaminated soil
Ma Xiaodong, Li Xia, Liu Junxiang, Zhai Feifei, Sun Zhenyuan, Han Lei
Corrected proof  doi: 10.12171/j.1000-1522.20190340
[Abstract](465) [FullText HTML](167) [PDF 860KB](18)
ObjectiveAlthough the study has shown that plant-white rot fungi (WRF) combined remediation is a more efficient remediation strategy for PAHs-contaminated soil, the mechanism of this strategy is still unclear, and its application prospects remain questionable. Photosynthesis is the basis of plant growth and development, and it affects the release level of root exudates, which in turn alters the growth of rhizosphere microorganisms and the degradation of soil-borne PAHs. Based on this, for the first time, this study reported the effects of WRF inoculation on photosynthesis of Salix viminalis cultivated in PAHs-contaminated soil.MethodIn this study, a pot experiment was conducted in greenhouse for bioremediation of PAHs-contaminated soils and S. viminalis was used as phytoremediation materials. Photosynthetic pigment content, light response curve of gas exchange parameters and chlorophyll fluorescence parameters were selected as the photosynthetic physiological indexes of S. viminalis and the effects of WRF inoculation on the photosynthesis of S. viminalis were reported.ResultResults showed that the inoculated WRF positively promoted photosynthetic pigment content, net photosynthetic rate (Pn) and transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm), potential activity of PSII (Fv/F0) of S. viminalis, but reduced their stomatal conductance (Gs) and intercellular CO2 concentrations (Ci), non-photochemical quenching (NPQ) and photochemical quenching (qP). Different inoculation methods changed variation trend of light response curve of Gs and Tr. Besides, the combination of S. viminalis and WRF significantly increased the removal rate of soil-borne phenanthrene and pyrene.ConclusionIn this study, WRF increases the photosynthetic rate and transpiration efficiency of S. viminalis, enhances the removal of soil-borne PHE and PYR. In general, our study is significant to reveal the mechanism of plant-WRF combined remediation.
he Response of litter decomposition to warming of Artemisia ordosica in Mu Us Desert of northwestern China
Mu Yu, Xin jia, Zheng Jiajia, Huang Songyu, Yuan Yuan, Bai Yuxuan, Qin Shugao
Corrected proof  doi: 10.12171/j.1000-1522.20190092
[Abstract](463) [FullText HTML](41) [PDF 863KB](4)
ObjectiveThe response rate of litter decomposition rate of Artemisia ordosica to warming is helpful to understand and predict the carbon cycle and nutrient cycling of the Mu Us Desert shrub ecosystem under the background of climate change.MethodThe Open Top Chamber (OTC) was used to simulate the warming, and the natural state was used as the control. Combined with the decomposition bag method, the effect of warming on the decomposition of Artemisia ordosica litter was studied.ResultThe residual rate of litter quality of each part under the warming treatment was higher than that of the control group, simulated warming reduced the rate of litter decomposition. (1) From May 2017 to October 2017, under the warming treatment, the residual rate of the twigs litter and leaves litter were 91.07% and 71.73%, but under the control treatment, the two indicators were 86.08% and 60.74%; (2) Different types of litter decomposition rates are different under different treatment conditions at different time periods, and there is interaction between each influence factor; (3) The Olson negative index model showed that under the warming treatment, the decomposition coefficient k of the twigs and leaves of Artemisia ordosica litter was lower than that of the control treatment. (4) Warming has no effect on bacterial diversity and structure of litter.ConclusionWarming may slow down the decomposition of plant litter in arid and semi-arid areas, and the inhibition of warming on litter decomposition is related to decomposition time and litter type.
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: 10.12171/j.1000-1522.20190096
[Abstract](1359) [FullText HTML](1094) [PDF 884KB](65)
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 varied 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.
Effects of Converting Years from farmland to forest on Soil Physical Properties in the Loess Area of Western Shanxi Province
Zhang Hengshuo, Zha Tonggang, Zhang Xiaoxia
Corrected proof  doi: 10.12171/j.1000-1522.20190087
[Abstract](73) [FullText HTML](46) [PDF 1559KB](3)
ObjectiveTo evaluate the effects of converting time from cropland to forest on soil physical properties, and provide a basis for the construction of soil and water conservation forests in the region.MethodThe 23 years positioning continuous monitoring was taken on soil physical properties under five typical forests,including one natural restoration aspen forest, two mixed plantations of Platycladus and orientalis, Pinus tabulaeformis and robinia, two pure plantation of Robinia pseudoacacia and Pinus tabulaeform,and taking the corn farmland as a control.Result(1) With the increasing of converted years, the soil bulk density(BD) under the four plantations increased first and then decreased to a stable value which is lower than initial at about 10−15years. In the natural restoration forest (NF), the soil bulk density showed a downward tendency with he highest weight loss of 11.21% at the 0−20 cm soil depth. (2) The soil total porosity (TP) under the 4 plantations decreased first and then increased to a stable value which is higher than initial at about 10−15 years. The cumulative increased rate of TP at the soil depths of 0−20 cm and 20−40 cm were 1.4% and 0.6% respectively under NF. (3) The capillary porosity (CP) under the five typical forests all showed an increased trend with the increasing of converting time. The CP at 0−20 cm changed more than at 20−40 cm in the plantations; The cumulative increased rate of CP at 0−20 cm and 20−40 cm were 2.5% and 1.5% respectively under NF.Conclution The converted years showed a significant effects on soil physical properties(p < 0.05) under the typical forests, while for the plantations, the change of BD and TP mostly occurred in the first 10−15 years. The mixed forests of Pinus tabulaeformis and robinia should be the prioritized for the artificial vegetation restoration in the research area based on its remarkable improvement effects on soil physical property.
Extraction of tree crown parameters from high-density pure Chinese fir plantations based on UAV image
Sun Zhao, Pan Lei, Sun Yujun
Corrected proof  doi: 10.12171/j.1000-1522.20190386
[Abstract](3175) [FullText HTML](520) [PDF 9380KB](49)
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 was 70, the segmentation of single tree had the best effect. Some single trees were lost during the segmentation process because of over-segmentation and under-segmentation. After the segmentation was completed, optimizing the feature space of the segmented object and selecting appropriate classification features, finally the study area was divided into two types: crown and gap. By counting the number of grid points of each object, the calculated stand factors included canopy density and crown area. With the measured data on the ground as reference, the crown area extraction accuracy was 0.829 1, and the forest canopy density measurement accuracy was 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.
Coarse root distribution and its influencing factors of typical species in Lesser Xing’an Range based on tree radar unit
Ji Wenwen, Wang Lihai, Shi Xiaolong, Xu Mingxian, Hao Quanling, Zhang Guanghui, Meng Qingkai, Hou Shengming
Corrected proof  doi: 10.12171/j.1000-1522.20190285
[Abstract](396) [FullText HTML](262) [PDF 619KB](33)
ObjectiveThis paper aims to study the distribution and its influencing factors of coarse roots of typical tree species, and provide scientific basis and data support for the good growth of trees in Lesser Xing’an Range of northeastern China.MethodPinus koraiensis, Larix gmelini, Picea koraiensis and Pinus sylvestris as the research object, 8 plots were selected for testing in the Liangshui Experimental Forest Farm. Taking the sample tree as the center, using the tree radar unit to scan the coarse root on the circumference of 0.5, 1, 1.5, 2 m radius. The soil physical and chemical properties were determined by cutting ring method and soil sample method. The tree height, DBH and crown width were measured. The distribution of coarse root in Lesser Xing’an Range was analyzed. The correlation between the density of coarse root and tree and soil factors was analyzed.Result(1) In the horizontal direction, the coarse root density of four typical tree species decreased with the increase of distance from the trunk. In the vertical direction, with the increase of soil depth, the coarse root density of Pinus koraiensis and Larix gmelini decreased gradually, while that of Picea koraiensis and Pinus sylvestris increased first and then decreased. There were 82.1%, 82.0%, 89.6% and 67.6% coarse roots for Pinus koraiensis, Larix gmelini, Picea koraiensis and Pinus sylvestris distributing in the 0−40 cm depth of soil, respectively. (2) There was a significant positive correlation (P < 0.05) between the coarse root density and tree height, DBH and crown width, and no significant correlation with tree average resistance value (P > 0.05). (3) The coarse root density of trees was significantly positively correlated (P < 0.05) with soil moisture content, saturated water-retaining capacity, and capillary water capacity. The coarse root density was significantly negatively correlated with soil bulk density (P < 0.05) and had the highest correlation with capillary water capacity (R2 = 0.538, P = 0.012). The coarse root density was significantly positively correlated with the content of soil organic matter, total nitrogen, total phosphorus and hydrolyzed nitrogen (P < 0.05), and had the highest correlation with total nitrogen content (R2= 0.646, P = 0.002).ConclusionThe results show that both tree and soil factors have different effects on the coarse root distribution of four typical tree species in the Lesser Xing’an Range of northeastern China. The distribution of coarse roots is not only related to their own characteristics, but also related to their living environment, and not related to the material quality of trees.
Study on photosynthetic, spectral reflectance characteristics and primary productivity of main tree species in broad-leaved Korean pine forest
Hu Chengfeng, Chen Qiaoling, Qiao Xuetao, Cheng Yanxia
Corrected proof  doi: 10.12171/j.1000-1522.20190364
[Abstract](386) [FullText HTML](305) [PDF 768KB](11)
ObjectiveThis paper aims to explore the adaptability of five main species in different succession stages of mixes broad-leaved Korean pine forests(MBKPFs) to light stress from the physiological perspective; reveal whether different heights and canopy direction have influences on photosynthetic characteristics, spectral reflectance characteristics and related physiological functions of leaves; evaluate the organic matter accumulation rate of various tree species to provide reference for the study of primary productivity of MBKPFs in northeast China.MethodFive species of arbor plants in the canopy of MBKPFs, Ulmus davidiana, Tilia amurensis, Juglans mandshurica, Quercus mongolica and Pinus koraiensis, were selected to determine physiological index of photosynthetic characteristics, spectral reflectance characteristics and functional traits at different sample position, conducting ANOVA and LSD test and establishing correlation between various physiological parameters, so as to estimate the primary productivity of each tree species with reference to the allometric biomass equation established by previous studies.Results(1) There were significant differences in the photosynthetic characteristics, spectral reflectance characteristics, specific leaf area, blade thickness and leaf nitrogen content and potassium content among species (P < 0.05). The lowest apparent quantum efficiency, specific leaf area, nitrogen content and potassium content was found in P. koraiensis, with higher dark respiration rate, light compensation point and blade thickness. (2) There were no significant differences in the photosynthetic characteristics, spectral reflectance characteristics, specific leaf area, leaf thickness, leaf nitrogen content and potassium content among sample position within species (P > 0.05). (3) Among species, dark respiration rate and light compensation point were significantly negatively correlated with PRI with R-squared 0.96 and 0.94 respectively (P < 0.05), indicating that the adaptation of plants to light environment was reflected in both photosynthetic and spectral characteristics. (4) The maximum primary production rates of population was estimated with U. pumila at 4.806 kg/s, T. amurensis at 1.637 kg/s, J. mandshurica at 1.981 kg/s, Q. mongolica at 0.350 kg/s and P. koraiensis at 0.106 kg/s.ConclusionThe adaptability differences of tree species to light stress were reflected both in photosynthetic characteristics and spectral reflectance characteristics, and the photosynthetic characteristics of leaves were closely related to the community succession, in the later stage of which the adaptability of plants in the canopy layer to the light environment determined the canopy species composition of the community; The difference of plant height below 15 m and canopy direction is not enough to cause adaptive changes in photosynthetic physiological characteristics of leaves; U. pumila contributed the most to the community productivity and P. koraiensis the least.
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](982) [FullText HTML](717) [PDF 1087KB](70)
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.
Display Method:
2020, 42(4): 1-2.  
[Abstract](106) [FullText HTML](81) [PDF 320KB](14)
2020, 42(4): 162-162.  
[Abstract](60) [FullText HTML](51) [PDF 136KB](2)
Forest Sciences
Spatial distribution and association of seedlings and saplings in a spruce-fir forest in the Changbai Mountains area of northeastern China
Shi Mengmeng, Yang Hua, Wang Quanjun, Yang Chao
2020, 42(4): 1-11.   doi: 10.12171/j.1000-1522.20190071
[Abstract](234) [FullText HTML](173) [PDF 2736KB](40)
ObjectiveSpatial distribution of seedlings and saplings is an important factor affecting the dynamic changes of forest communities. Spatial distribution of Picea jezoensis and Abies nephrolepis seedlings at different height levels was analyzed, and spatial association between their seedlings and surrounding small and large trees was studied in this paper to explore the spatial changes in a Picea jezoensis and Abies nephrolepis forest and to find the impact of spatial structure on Picea jezoensis and Abies nephrolepis seedlings. The measures were proposed for promoting natural regeneration, and theoretical basis was provided for the management plans in a Picea jezoensis and Abies nephrolepis forest.MethodA sample plot of typical coniferous and broadleaved mixed forest with the area of 0.36 ha was set up in Jingouling Forest Farm, Jilin of northeastern China in August 2017. The SADIE spatial analysis method was used to analyze the spatial distribution of seedlings at different height levels.ResultWithin the forest stand, the diameter distribution showed an inverted “J” curve, the diameters of the Acer mono and Abies nephrolepis showed growth distribution pattern, and the diameter distribution of Picea jezoensis and Korean pine showed multi-peak fluctuation curves. The diameters of small trees in the forest stand showed an aggregate distribution with the aggregation index of Ia > 1 and randomization test probability of Pa < 0.025. The diameters of large trees were randomly distributed with Pa value between 0.025 and 0.975. The spatial distribution of forest stands changed from aggregation to randomization with the growth and development of forest trees. Since the Abies nephrolepis was one of the main tree species, its spatial distribution was similar to the overall spatial distribution in the forest stand. The diameters of Picea jezoensis had a random distribution. The locations of Abies nephrolepis seedlings had obvious spatial association with the locations of large Abies nephrolepis trees, and they were positively spatial associated with locations of all Picea jezoensis trees. Abies nephrolepis seedlings had good shade tolerance. The locations of Picea jezoensis seedlings generally showed spatial segregation or spatial irrelevance, which was only positively correlated with the locations of Abies nephrolepis trees, so Picea jezoensis and Abies nephrolepis are good companion species. The locations of Abies nephrolepis seedlings at Ⅰ to Ⅲ height levels had similar spatial associations, the locations of Abies nephrolepis seedlings at Ⅳ and Ⅴ height levels had similar spatial associations, and the locations of Picea jezoensis seedlings at Ⅰ and Ⅱ height levels had similar spatial associations.ConclusionWithin the forest stand, the number of Abies nephrolepis seedlings is more than Picea jezoensis seedlings. Abies nephrolepis seedlings are positively spatial associated with the trees, which is beneficial to the regeneration of Abies nephrolepis. The quality of Picea jezoensis wood is good. As the main target species, the number of Picea jezoensis and its seedlings is small, and seedlings and saplings of Picea jezoensis show a separated spatial distribution with small trees and large trees. The regeneration status of Picea jezoensis under the forest is poor. As a result, appropriate shelter measures should be adopted for Picea jezoensis at the seedling stage, and management measures like cutting in the sapling period may be proposed to promote the growth of Picea jezoensis seedlings. In addition, the spatial structure of the stand could be adjusted for releasing the growth space of Picea jezoensis by appropriate controlled number of Abies nephrolepis in order to increase the number of Picea jezoensis mother trees. Then, seed production capacity will be improved, and the regeneration of Picea jezoensis will be promoted.
Physiological and biochemical properties and growth of Aigeiros clones under cadmium stress
Yao Junxiu, Chen Ganniu, Li Shanwen, Qiao Yanhui, Zhong Weiguo, Li Qinghua, Dong Yufeng, Wu Dejun
2020, 42(4): 12-20.   doi: 10.12171/j.1000-1522.20190462
[Abstract](177) [FullText HTML](110) [PDF 1512KB](11)
ObjectiveIn order to study the effects of heavy metal stress on physiological and biochemical properties of trees, the response mechanism of trees to Cd stress was discussed to provide a theoretical basis for the increasingly serious soil heavy metal pollution problem.MethodSand culture experiments were carried out on five Aigeiros clones, ground diameter, seedling height and 8 physiological and biochemical indexes were measured to evaluate the resistance of different clones to Cd stress.ResultThe content of CAT and MDA of Aigeiros clones increased first and then decreased under Cd stress compared with control. POD and SOD activities also increased first and then decreased compared with control. The POD activities of ‘L35’, ‘Lulin 9’ and ‘Lulin 16’ were always in the top three. With the increase of Cd2+ concentration, the proline and soluble sugar contents of ‘L35’, ‘I-107’ and ‘Zhonghe 1’ increased gradually, while the chlorophyll contents increased first and then decreased. The chlorophyll contents of ‘L35’, ‘I-107’ and ‘Zhonghe 1’ were always in the top three.There were differences in ground diameter and seedling height among clones under the Cd stress, the seedling height reached a significant level, while the ground diameter did not reach a significant level, which indicated that the seedling height traits of the tested clones were more sensitive to Cd stress than the ground diameter.ConclusionThe growth and physiological and biochemical properties of five clones were comprehensively evaluated by principal component analysis, ‘L35’, ‘Zhonghe 1’ and ‘I-107’ had strong resistance to Cd stress, which could be used as ideal clones for remediation of cadmium-contaminated soils.
Evaluation on field heat resistance of Sorbus pohuashanensis clonal seedlings introduced from different regions
Liu Di, Sun Caowen, Wang Lixian, Jia Liming
2020, 42(4): 21-31.   doi: 10.12171/j.1000-1522.20190266
[Abstract](576) [FullText HTML](118) [PDF 1055KB](16)
ObjectiveSorbus pohuashanensis is one of the important Chinese native tree species with high ornamental value ranging from 500 to 2 000 m altitude. In this study, the field trial for heat resistance of different clones was evaluated comprehensively, which provided scientific basis for early selecting fine varieties adapting to high plains in Beijing.Method2-year-old grafted seedlings of 14 clones from 5 provenances were used as materials. In the field trial, which performed in Yanqing County of Beijing with 500 m altitude, the height and stem growth of seedlings, content of malondialdehyde (MDA), soluble protein, soluble sugar, chlorophyll in the leaves, activity of superoxide dismutase (SOD) and peroxidase (POD) in the leaves were measured; and the heat resistance of 14 clones was evaluated comprehensively by membership function analysis based on principal component analysis.ResultThe value of each single index showed significant difference among 4 months and was significantly different among different clones. The growth performance of Wuling1 (WL1),Wuling2 (WL2), Shihui1 (SH1) and Shihui2 (SH2) was significantly better than other clones. The growth performance of Taibai1 (TB1) and Taibai2 (TB2) was the worst; the MDA contents of TB1 and TB2 increased most significantly from May to June, showing poor heat resistance. However, the MDA contents of Fengning2 (FN2) and WL2 decreased, showing stronger heat resistance than other clones. The activity of two protective enzymes of WL2, Fengning1 (FN1) and FN2 was higher than other clones. The chlorophyll content of FN1 and FN2 was minimally impacted by high temperature; the content of osmotic regulator of Songshan1 (SS1), Songshan2 (SS2), Songshan3 (SS3) and Songshan4 (SS4) was higher than other clones. Correlation analysis showed significantly positive correlation between every two groups of chlorophyll content (P < 0.01); chlorophyll and ground diameter growth (P < 0.05) were significantly negatively correlated. Significantly positive correlation was found between seedling height and ground diameter of seedlings; after principal component analysis, 10 single indexes were transformed into 4 new independent comprehensive indexes;ConclusionAfter the comprehensive evaluation of membership function, the sequence of field heat resistance of each clone seedling from strong to weak is: WL2, WL1, FN1, SH2, SH1, FN2, SS2, Huangshan shuiyu2 (HS2), SS4, SS3, SS1, Huangshan shuiyu1 (HS1), TB2, TB1.
Effects of lead and cadmium combined stress on seed germination and seedling growth of mulberry
Qiao Yong, Zhou Jinxing, Wang Xiaoping
2020, 42(4): 32-40.   doi: 10.12171/j.1000-1522.20190244
[Abstract](343) [FullText HTML](368) [PDF 816KB](19)
ObjectiveThis paper aims to study the effects of single and combined stress of lead and cadmium at different concentrations on seed germination and seedling growth of mulberry, as well as the bio-enrichment and transfer of Pb and Cd in mulberry to explore the repair capacity of mulberry on contaminated soil.MethodThe germination and pot-based experiment was designed with different concentrations Pb (0, 250, 500, 750, 1 000, 1 250 mg/kg) and Cd (0, 0.2, 1, 25, 75, 100 mg/kg) to study the germination rate of seed, plant height and biomass of mulberry, as well as the enrichment and transfer coefficients of Pb and Cd in mulberry roots, stems and leaves.Result(1) The germination of mulberry seeds was inhibited by single and combined stress at different concentrations of Pb and Cd. (2) Low concentrations of Pb and Cd (250, 0.2 mg/kg) promoted the high biomass of mulberry seedlings, which turned into inhibition when the concentration increased. (3) Pb and Cd were mainly accumulated in mulberry roots, and low concentration of Pb (250 mg/kg) would promote Cd enrichment and transfer in mulberry. The enrichment coefficient and transfer coefficient of Cd were higher than Pb, but the maximum values of both were less than 1. The bio-enrichment coefficient and transfer coefficient of combined stress were lower than those of single stress. The enrichment coefficient and transfer coefficient of Pb and Cd will be reduced when the concentration of Pb and Cd increased.ConclusionThe germination of mulberry seeds is inhibited by different concentrations of Pb and Cd, and the inhibitory effect increases with the increase of Pb and Cd concentration. Although mulberry is not a hyper-accumulator, the enrichment coefficient and transfer coefficient of low-concentration Pb and Cd are relatively high, and low-concentration Pb and Cd would promote the growth of mulberry, which can be used to plant mulberry and raise silkworm in soil contaminated with low-concentration Pb and Cd for soil heavy metal pollution remediation.
Forest regeneration of Pinus tabuliformis burned area in Liaoheyuan Nature Reserve of northern China
Wang Bo, Han Shuwen, Wu Yingda, Niu Shukui, Liu Xiaodong
2020, 42(4): 41-50.   doi: 10.12171/j.1000-1522.20190315
[Abstract](1030) [FullText HTML](658) [PDF 637KB](75)
ObjectiveFrom 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 tabuliformis plantation in Liaoheyuan Nature Reserve of northern China were discussed, which could provide reference for vegetation restoration and forest management.MethodTaking the Pinus tabuliformis plantation in burned area of Liaoheyuan Nature Reserve as research object, three 20 m × 20 m sample plots were set separately according to different renewal methods (natural renewal and artificial promoting natural renewal) under severe fire, different fire intensities (severe fire, moderate fire and light fire) under natural renewal and control (not burned). The natural renewal sample land under severe fire was the same as severe fire land under natural renewal, so there were 15 sample plots in total. We investigated the amount and type of trees after updating, measured the ground diameter, plant height, crown diameter of renewed trees. For each wood gauging sample, we recorded 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 tabuliformis were mainly Quercus mongolica and Populus davidiana, accounting for 38.1% and 42.3% of all regenerated trees, respectively, also including Pinus tabuliformis, Ulmus laciniata, Ulmus macrocarpa, Ulmus pumila, Acer mono, etc. Under severe fire, there was a significant difference in the density of tree regeneration between different renewal 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 traits of all tree regeneration under natural renewal with different fire intensities (P < 0.01). (3) The spatial distribution pattern of tree regeneration was affected by fire intensity, regeneration mode and tree species. The factors such as suitable microhabitat, animal carried seed diffusion can promote the small scale aggregation of renewal.Conclusion4 years after fire, the regenerated tree species in the burned area of Pinus tabuliformis forest 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 area.
Effects of litter extracts from Castanopsis kawakamii natural forest on seed germination and radicle growth of Chinese fir
Jin Mengran, Wang Zhe, Li Mengjia, Liu Jinfu, He Zhongsheng, Xing Cong, Shi Youwen, Shen Caixia
2020, 42(4): 51-59.   doi: 10.12171/j.1000-1522.20190292
[Abstract](277) [FullText HTML](117) [PDF 716KB](22)
ObjectiveWe tested the effects of litter extracts from Castanopsis kawakamii natural forest on seed germination and radicle growth of coexistence species Chinese fir (Cunninghamia lanceolate), thus to explore the mechanism for the natural regeneration barrier of C. kawakamii species.MethodThe litter extracts of C. kawakamii natural forest were used as the source of allelochemicals, and the seeds of coexistence species C. lanceolate were used as the tested seeds. We analyzed the influence of litter extracts of undecomposed (branches, leaves, bark, and nutshells), semi-decomposed and fully decomposed layer with different concentrations on the germination rate, germination potential, germination index and radicle growth of C. lanceolate seeds.ResultThe undecomposed layer litter extract promoted the germination rate of C. lanceolate at the low concentration, and promoted or weakly inhibited the germination rate at high concentration. The germination potential and germination index were inhibited under each concentration. The litter extracts from semi-decomposed and the fully decomposed layer inhibited the germination index of C. lanceolate seeds, and the inhibition was stronger at the low concentrations (1∶50, 1∶100). The effects of undecomposed litter extracts on the radicle growth of C. lanceolate showed a double concentration effect of “low promotion and high inhibition”, and significant inhibition at high concentration (P < 0.05). At the 18th day under the leaf extract concentration of 1∶100, the radicle length increased by 14.3% compared with control, which significantly promoted the growth of C. lanceolate’s radicle length (P < 0.05). The litter extracts from the semi-decomposed layer promoted the radicle growth of C. lanceolate, but it was not significant. The litter extracts of the fully decomposed layer promoted the growth of C. lanceolate’s radicle length under the concentrations of 1∶5, 1∶10 and 1∶50, and the concentration of 1∶30 showed a significant inhibition (P < 0.05).ConclusionThe low concentration litter extracts of the C. kawakamii natural forest can generally promote or slightly inhibit the germination of C. lanceolate seed and promote its radicle growth, which promoted the regeneration of C. lanceolate and enhanced the competition between species in the forest, and thus indirectly lead to the suppression of natural regeneration of C. kawakamii.
Effects of nitrogen application on growth and triterpenoids accumulation of 1-year-old Cyclocarya paliurus
Zhang Xiaoyan, Li Yufei, Liu Guihua, Xu Zaoshi, Deng Bo
2020, 42(4): 60-68.   doi: 10.12171/j.1000-1522.20190294
[Abstract](326) [FullText HTML](222) [PDF 868KB](9)
ObjectiveThe effects of nitrogen application on the growth and triterpenoids accumulation of Cyclocarya paliurus were studied in order to provide theoretical basis for regulating the cultivation of medicinal plantation and improving the triterpenoids yield per unit area of medicinal plants.MethodThe 1-year-old seedlings of C. paliurus were used as test materials under five different N levels, including N1 (0 g/plant), N2 (1 g/plant), N3 (3.4 g/plant), N4 (6 g/plant), N5 (10 g/plant). And the seedling height, ground diameter, biomass, total triterpenoid and three main triterpenoids were measured in the middle and late days of each month from May to August.Result(1) The seedling height and ground diameter growth of C. paliurus increased first and then decreased with increased N application, and the highest net growth of seedling height and basal diameter were got in treatment N4, increased by 103.90% and 57.58%, respectively compared with N1. Similar variation pattern was also observed for the biomass and total biomass accumulation in roots, stalks and leaves, and the greatest total biomass accumulation was got in treatment N4, reaching 7.24 g. (2) With the increase of N application, the N content in leaves of plants increased linearly (that in roots and stalks was comparatively stable), while the C content did not change significantly, resulting in the C/N in leaves decreased linearly, and ranged from 20.42% to 12.19%. (3) Leaf was the main accumulating organ in C. paliurus, and the largest total accumulation and three individual triterpenoids (arjunolic acid, cyclocaric acid B and cyclocarioside I) in leaf showed a single peak variation pattern, with the peak values of 2.45, 0.73, 0.44 and 22.95 mg/g, respectively under relatively low N condition (N2). In addition, among the three individual triterpenoids tested, the main individual triterpenoid was arjunolic acid (0.73 mg/g, dry mass), followed by cyclocaric acid B (0.23 mg/g, dry mass) and cyclocarioside I (0.12 mg/g, dry mass). (4) N application significantly affected the yield of total and three individual triterpenoids in C. paliurus and the triterpenoid and arjunolic acid per plant reached highest under treatment N3, ranged in 95.21−279.45 mg/plant and 4.64−17.21 mg/plant. The yield of total triterpenoid and three individual triterpenoids per plant were found lowest under treatment N1 or N5.ConclusionModerately high N application could promote the growth of C. paliurus seedlings, while moderately low N application could promote the accumulation of triterpenoid.
Overexpression of LpNAC6 gene in Lilium pumilum enhancing salt tolerance in transgenic tobacco
Liu Bin, Cao Shangjie, Wang Ying, Cui Ying, Yue Hua, Zhang Yanni
2020, 42(4): 69-79.   doi: 10.12171/j.1000-1522.20190342
[Abstract](277) [FullText HTML](117) [PDF 1932KB](14)
ObjectiveNAC transcription factor is a new kind of transcription factor with many biological functions, which plays an important role in stress response. This paper aims to explore the expression pattern of LpNAC6 gene under stress and its response to salt stress in transgenic tobacco.MethodLpNAC6 gene from Lilium pumilum was cloned by homologous cloning and analyzed by bioinformatics softwares. Subcellular localization of LpNAC6 protein was performed by particle bombardment. The expression patterns of LpNAC6 gene in different abiotic stresses and different tissues were analyzed by RT-qPCR. The plant expression vector pBI121-LpNAC6-GFP was constructed, and tobacco was transformed for verifying the function of LpNAC6 gene under salt stress.ResultThe LpNAC6 gene was 909 bp in length and encoded 302 amino acids, it had a highly conserved NAM domain and belongs to the NAC gene family. LpNAC6 protein was a hydrophilic protein with no signal peptide and trans-membrane domain. It had 5 glycosylation sites, 20 phosphorylation sites and subcellular localization of LpNAC6 protein in nucleus. The evolutionary relationship between LpNAC6 gene and NAC transcription factor of Gossypium mustelinum was closest. LpNAC6 gene in L. pumilum responded to ABA, drought, low temperature and salt stress. Under salt stress, the activity of SOD, POD, CAT and the contents of chlorophyll, proline and soluble protein in transgenic tobacco overexpressing LpNAC6 gene were significantly higher than those in wild-type.ConclusionLpNAC6 gene of L. pumilum can respond to ABA, drought, low temperature and salt stress. Its overexpression can increase the metabolic activity and antioxidant enzyme activity of transgenic tobacco under salt stress, thus enhancing the salt tolerance of tobacco.
Anatomical characteristics and adaptability plasticity of Qiongzhuea tumidinoda stalk under different soil water and nutrient conditions
Wu Yiyuan, Dong Wenyuan, Liu Pei, Zhang Mengnan, Xie Zexuan, Tian Fakun
2020, 42(4): 80-90.   doi: 10.12171/j.1000-1522.20190290
[Abstract](195) [FullText HTML](89) [PDF 883KB](11)
Objective This paper aims to explore adaptive strategies of natural Qiongzhuea tumidinoda stalk under different soil water and nutrient conditions. We studied the changes of stalk anatomical structure of Q. tumidinoda in habitats with different soil thickness to provide theoretical guidance for the cultivation of processing timber forest of Q. tumidinoda. Method In this paper, we used redundant analysis and Monte Carlo test methods to analyze the relationship between stalk anatomical structure characteristics of Q. tumidinoda and soil nutrients and water in three soil layers of thin soil (0−40 cm), medium soil (0−80 cm) and thick soil layer (0−120 cm). Result(1) With the increase of soil moisture and nutrient content, the stalk anatomy of Q. tumidinoda had a significant decreasing trend of basic tissue ratio and vascular bundle density (P < 0.05). The ratio of transmission tissue, fiber tissue, length and width of vascular bundle showed an obvious increasing trend (P < 0.05), i.e. compared with the habitats in medium and thick soil layers, the vascular bundles of bamboo stalk in thin soil layers had important adaptability characteristics of small shape and large density. (2) Among three types of soil thickness habitats, the variation coefficient and plasticity index of Q. tumidinoda stalk tissue proportions and vascular bundle size in thin soil habitats were the largest, i.e. compared with the habitats in medium and thick soil layers, the vascular bundles of bamboo stalk in the habitats with thin soil layers had stronger regulation ability to adapt to the environment with low moisture and nutrients. (3) The stalk anatomical structure of Q. tumidinoda was affected by different degrees of soil moisture and nutrients (P < 0.05). Significance of single soil factor on the stalk anatomical structure of Q. tumidinoda was sequentially followed as total potassium > hydrolyzed potassium > available potassium > available phosphorus > total phosphorus > total nitrogen > water content > organic carbon > pH.Conclusion The difference in soil moisture and nutrient content is the root cause of stalk anatomical plasticity of Q. tumidinoda. Stalk anatomical plasticity makes Q. tumidinoda forming adaptive differences in different soil thickness habitats. The obvious plasticity of the size and density of bamboo vascular bundles is an important adaptation characteristic of Q. tumidinoda to soil factors. Anatomical characteristics of bamboo stalks and their adaptation plasticity play an important ecological role in adapting Q. tumidinoda to soil thickness heterogeneity.
Effects of Syringa pinnatifolia var. alanshanica on soil physicochemical properties, enzyme activities and microbial diversity
Wang Tao, Guo Yang, Su Jianyu, Xu Chunyan
2020, 42(4): 91-101.   doi: 10.12171/j.1000-1522.20180365
[Abstract](751) [FullText HTML](732) [PDF 1291KB](59)
ObjectiveThis paper aims to study the relationship between the endangered plant Syringa pinnatifolia var. alanshanica and soil nutrients, soil enzyme and soil microorganisms, and provide evidence for understanding its impact mechanism.MethodFive-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.ResultThe soil pH value remained unchanged, while the contents of water, organic matter, total nitrogen, available potassium and nitrogen was 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 fungi 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.ConclusionS. 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.
Landscape pattern change and its influencing factors of sand-binding vegetation
Gao Yan, Zhang Yuqing, Qin Shugao, Zhang Jutao, Liu Zhen
2020, 42(4): 102-112.   doi: 10.12171/j.1000-1522.20190061
[Abstract](260) [FullText HTML](142) [PDF 1170KB](24)
ObjectiveIntroducing and establishing sand-binding vegetation, as one of the important approaches for combating desertification, has already applied in the ecological restoration and recovery in northern China for more than 60 years. Study on the dynamics of landscape patterns of sand-blinding vegetation and their influencing factors is thus a crucial requirement for guiding and establishing sand-binding vegetation.MethodBased on vegetation map, this paper selects several typical vegetation types with varied dominant species (Artemisia sp., Caragana sp., Ulmus sp., and Pinus sylvestris var. mongolica) in four sandy lands (Mu Us, Otindag, Horqin and Hulun Buir sandy lands). We explored their landscape pattern dynamics during 1990 –2015 by the landscape vulnerability index (LVI), and detected their influencing factors by the geodetector method.ResultOver the study period (1990–2015), the Artemisia sp. and Caragana sp. shrublands showed stable expanding trends, and the average annual precipitation was the main factor influencing their landscape patterns (contribution ratio q = 0.31 and 0.41, respectively); Ulmus sp. and artificial P. sylvestris var. mongolica forestlands showed declining trends, and the land use and cover change (q = 0.34) and average annual air temperature in growth season (q = 0.24) were the main driving factors, respectively.ConclusionThe results indicate that, the Artemisia sp. and Caragana sp. shrublands could continue to play their ecological service for wind break and sand-fixation, whilst the Ulmus sp. and the artificial P. sylvestris var. mongolica forestlands could seriously degrade under the projected climate change.
Analysis on spatiotemporal trend of drought in the Central Asia region during 1901−2015 based on SPEI
Wei Wei, Wang Baitian, Zhang Kebin
2020, 42(4): 113-121.   doi: 10.12171/j.1000-1522.20190055
[Abstract](465) [FullText HTML](250) [PDF 2328KB](9)
ObjectiveCentral Asia region is a landlocked dryland located in the heart of the Eurasian continent and far from oceans, and its dryland ecosystems support a substantial proportion of the human population and economy. Thus, the monitoring and assessment of frequent drought is of great significance for the sustainable development of this region.MethodBased on gridded monthly standardized precipitation evapotranspiration index (SPEI) with high-resolution (0.5° × 0.5°), the spatial patterns of trends in SPEI for 1,3,6 and 12-month time scales (SPEI01, SPEI03, SPEI06, SPEI12) were analyzed by a contextual Mann-Kendall test and Theil-Sen (TS) slope estimator during the period of 1901 –2015 to evaluate the drought variation at different temporal scales in the Central Asia region.Result(1) SPEI01 experienced a significant downward trend in an area (P < 0.05) accounting for 39.24% of the study area, and the largest decline exhibited in the south of the Tianshan Mountains in Xinjiang of western China with a value of − 5×10− 4 yearly; SPEI01 experienced a significant up trend in an area (P < 0.05) accounting for 45.73% of the study area, of which the largest increase was remarked in Tajikistan with a value of 3×10− 4 yearly. (2) SPEI03 showed a significant downward trend in an area (P < 0.05) accounting for 76.32% of the study area, and the largest decline exhibited in Kyrgyzstan with a value of − 4×10− 4 yearly; SPEI03 presented a significant up trend in an area (P < 0.05) accounting for 15.39% of the study area, and the largest rise presented in Tajikistan with a value of 3×10− 4 yearly. (3) The spatial distribution trends of SPEI06 and SPEI12 were basically the same, and the largest decline was shown in Kazakhstan with a value of − 3×10− 4 and − 5×10− 4 yearly, respectively, while the largest increase was shown in Tajikistan with a value of 5×10− 4 and 6×10− 4 yearly, respectively.ConclusionThe temporal and spatial variations of annual and seasonal precipitation in Central Asia affect the spatial and temporal distribution of water resources, resulting in humidification and aridification trends at different temporal scales in varied regions. For the short and medium term drought trends in central Kazakhstan, southwestern Turkmenistan and the south of Tianshan Mountains in Xinjiang, as well as seasonal drought trends in a large area of Central Asia, it is then necessary for the local government to take corresponding measures to deal with drought in order to prevent vegetation degradation and desertification to ensure food production and their population wellbeing and safety. For the trend of wetting in other regions, especially the increase of extreme precipitation events, the local government should further improve the flood control and irrigation facilities to prevent flood and drought disasters from expanding and to realize the effective utilization of water resources.
Landscape Architecture
Floral town construction model under multi-participation approach in Japan
Ma Jia, Li Xiong
2020, 42(4): 122-131.   doi: 10.12171/j.1000-1522.20190078
[Abstract](341) [FullText HTML](111) [PDF 1461KB](8)
ObjectiveIn the context of improving the human settlements, floral town construction movement was launched by The Flower Association of Japan. Taken the Osaka Flower Green Expo in 1990 as an opportunity, the movement started in 1991 under a multi-participation approach. Based on the main theme of “the harmonious coexistence of nature and mankind”, the movement calls on all society to participate in the environmental construction activities. This paper aims to sort out the development model of the Japanese floral town construction movement from the perspective of multi-participation, and analyze the multi-participation path and the cooperation mode of multiple parties in the construction process. It will provide some reference for China’s new urbanization development and human settlements construction.MethodBased on the combing of operation and development mode of the movement under multi-participation process, this paper lists 279 construction samples by environmental, social and economic categories and 22 sub-categories of activities from 2003 to 2018. After converting the list into 0-1 variables, samples are clustered by a cluster analysis using SPSS software, with the Ward method and squared Euclidean distance.ResultThe tree diagram is cut according to the distance between groups and whether more than 3 groups, then 3 groups are obtained: (1) taking individuals and enterprises as main part creating flower landscapes for social contribution purpose, (2) NPOs and governments cooperating to organize public activities, (3) school groups conducting environmental education.ConclusionThe movement was created by NPO with the opportunity of urban events, and was continuously carried out with the support of the government, residents, other NPOs and corporate social responsibility. Those 4 types of subjects participate in social contribution, public activities and environmental education purpose. Each mode of activity has its focus and cooperates to form a cooperative system of multi-participation.
Assessment on socio-ecosystem vulnerability in shallow mountain area of Beijing under climate change background
Shi Yao, Li Jiayi, Gao Na, Zheng Xi
2020, 42(4): 132-141.   doi: 10.12171/j.1000-1522.20190091
[Abstract](215) [FullText HTML](120) [PDF 1078KB](12)
ObjectiveUnder the background of climate change, regional vulnerability assessment under the perspective of socio-ecosystem can identify regional climate risks more comprehensively. In urban areas, shallow mountain area has their uniqueness because of the importance of climate regulation and the vulnerability of climate adaptation, and the coupling between social system and ecosystem is more obvious. As an important link of climate adaptation, the socio-ecosystem vulnerability assessment under climate change background in Beijing shallow mountain area is helpful to provide quantitative reference for climate adaptation strategies in spatial planning.MethodIn this study, the assessment framework of “risk-exposure-sensitivity-adaptability” was adopted to construct an index set containing 44 indicators. Through the principal component analysis method, dimensionality reduction screening and weight determination of indicators were carried out to form the index system of social-ecosystem vulnerability assessment. Then the spatial distribution of the vulnerability of socio-ecosystem in the shallow mountainous areas of Beijing was evaluated under the present and future climatic conditions.ResultThe current and future climate vulnerability showed a trend of gradually decreasing from the central urban area to the deep mountains, and the degree of vulnerability was mainly moderate and severe, while the overall future vulnerability showed an upward trend. Among administrative zones, the vulnerability of Changping, Shunyi and Haidian districts was at a lower level, and the vulnerability of Fangshan, Fengtai and Mentougou districts was more serious.ConclusionBy evaluating the spatial distribution of the vulnerability of socio-ecological system in the shallow mountainous area of Beijing under current and future climatic conditions, the key areas of the climate adaptation in the shallow mountainous area of Beijing were obtained, which provide the basis for the climate adaptation policy in the shallow mountainous area, and provide the method or index reference for the regional vulnerability assessment under climate change background.
Forestry Engineering
Numerical simulation of the safety influence of defects on Qijia-beams of ancient timber building
Ou Zina, Zhang Houjiang, Guan Cheng
2020, 42(4): 142-154.   doi: 10.12171/j.1000-1522.20190328
[Abstract](1359) [FullText HTML](1015) [PDF 2045KB](36)
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 provides numerical simulation, which could accurately determine the maximum tensile stress of the wooden beam. It is 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.
Flame retardant properties of phytic acid and melamine treated wood
Wu Yuhui, Zhang Shaodi, Ren Zizhong, Wang Mingzhi
2020, 42(4): 155-161.   doi: 10.12171/j.1000-1522.20190406
[Abstract](5399) [FullText HTML](586) [PDF 1315KB](46)
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.

Establishment Time:1979

CN 11-1932/S

ISSN 1000-1522

Supervisor:Sinopec Research Institute of Petroleum Engineering

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