Advanced search

Message Board

Respected readers, authors and reviewers, you can add comments to this page on any questions about the contribution, review, editing and publication of this journal. We will give you an answer as soon as possible. Thank you for your support!

Name
Email
Phone
Title
Content
Verification Code

NewsMore+

Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Display Method:
Site selection methods of country park with priority of habitat protection in the second green isolated area of Beijing
Wang Ruiqi, Qiu Yuanxun, Li Xiong
Corrected proof  doi: 10.12171/j.1000-1522.20200135
[Abstract](17) [FullText HTML](4) [PDF 1112KB](2)
Abstract:
  Objective  Under the background of China’s rapid urbanization, the ecological environment in Beijing urban fringe areas is deteriorating. The green belt has become a means to control the disordered expansion of Beijing’s built-up areas and improve the urban ecological environment. The construction of country parks within the green belt is an effective way to implement the plan. The core goal of country parks is to provide a small amount of recreational activities with ecological conservation. It should be the basic principle to protect the area with high habitat quality within the green belts.  Method  On the basis of summarizing the relevant research of scholars at home and abroad, taking the second green belt area of Beijing as an example, this paper constructs a framework of country park site selection with priority of habitat protection, and uses the InVEST model to evaluate the habitat quality of research area. According to the habitat quality index, the habitat was divided into five grades: low habitat, general habitat, medium habitat, high habitat and extremely important habitat. Taking the most important habitat areas as the basic principle of country park site selection in the model evaluation results, the scope of priority alternative areas for habitat protection was selected, and the suitable construction area was selected by adding six external construction conditions and internal development conditions, including surrounding park resources, the built and proposed country parks, land use planning, basic farmland planning, road accessibility and current land use, and then according to the vegetation coverage type. Finally, the site selection and classification of country parks with priority of habitat protection were completed.  Result  According to different habitats, six types of country parks were defined: mixed forest, farmland, river, broadleaved forest or coniferous forest and shrub. A total of 41 rural parks with priority of habitat protection were demarcated in Jianchang Village of Tongzhou District, Shijiaqiao Village of Changping District, Li Village of Fangshan District and other villages and towns.  Conclusion  The evaluation results can provide a scientific basis for the location of country parks in the second green isolation area of Beijing.
Survival pressure of endangered species Phellodendron amurense
Wang Yongteng, Huang Zhihao, Wang Jun, Zhang Tong, Lang Lihua, Sun Guoming, Cui Guofa
Corrected proof  doi: 10.12171/j.1000-1522.20200130
[Abstract](202) [FullText HTML](48) [PDF 724KB](17)
Abstract:
  Objective  Based on the study on the survival pressure intensity of wild Phellodendron amurense in Yanshan Mountains, Tianjin of northern China from the aspects of diameter scale, area and vegetation type, a theoretical basis was provided for the protection of rare and endangered species.  Method  Twenty-five 20 m × 20 m sample plots were set by the method of typical sampling, and the survival pressure intensity of the wild Phellodendron amurense was analyzed through an individual survival pressure calculating method for rare and endangered tree species.  Result  (1) A total of 140 Phellodendron amurense pants were found in this study, scattered in 8 natural reserves, and had the highest density in Beijing Baihuashan National Nature Reserve, the lowest in Hebei Dahaituo National Nature Reserve, with the density of 5.63 plant/m2 and 1.25 plant/m2, respectively; (2) the number of Phellodendron amurense in the small tree stage (I−III diameter scales) was the largest in Yanshan area, with the intraspecific and interspecific competition indices maximally being 13.897 and 48.135, respectively. However, with the increase of DBH, the survival pressure decreased; (3) the highest survival pressure occurred in Hebei Wulingshan National Natural Reserve and the lowest in Hebei Maojingba National Natural Reserve, with the survival pressure of 30.363 and 1.763, respectively; (4) the population of Phellodendron amurense bore a comparably higher survival pressure in Tilia amurensis forest, Juglans mandshurica forest and Phellodendron amurense-Pinus tabuliformis mixed forest, and a lower survival pressure in Ulmus macrocarpa forest, Ulmus macrocarpa-Quercus mongolica-Fraxinus rhynchophylla mixed forest.  Conclusion  Interspecific survival pressure plays a major role in the whole population of Phellodendron amurense in Yanshan area. Therefore, it is necessary to prune or selectively cut some tall trees closing to each other and having strong competitiveness, such as Pinus tabuliformis and Juglans mandshurica, in order to reduce the competitive pressure of Phellodendron amurense and promote the regeneration of the natural forest.
Intelligent method of determining dimension of mortise and tenon joint based on parameterization
Tang Lin, Guan Huiyuan
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200104
[Abstract](3) [FullText HTML](0) [PDF 882KB](0)
Abstract:
  Objective  The determination of dimensions of mortise and tenon joint is the premise of editing NC codes of mortise and tenon joint. It is also the foundation of realizing CNC machining of mortise and tenon joint. But the existing method of determining the dimensions of mortise and tenon joint by modifying the geometric models repeatedly is low efficiency and high difficulty, that has seriously affected the development of digital machining of mortise and tenon joint. Therefore, it is necessary to design an intelligent method of determining dimension of mortise and tenon joint.  Method  This paper taken a modified lattice shoulder tenon as example. In the first, the mathematical models of lattices shoulder tenon were established and the dimension parameters of latticed shoulder tenon were extracted by using of parametric design ideas. Secondly, the correlation functions between dimension parameters of lattice tenon were established based on assembly constraints which include two perspectives: position relation and match relation. Then, the correlation functions between dimension parameters and process constraints were established, and value ranges and preset values of part dimensions were settled based on process constraints which include three aspects: NC machining technology, market research and process knowledge. Finally, taking the end dimensions of parts as the input parameters, integrating with associated functions, value ranges, and preset values, the relevant parameter function table was established.  Result  By establishing the mathematical model of mortise and tenon joint, the dimension parameters of mortise and tenon joint were extracted. According to the assembly and process constraints of mortise and tenon joint, the correlation functions between dimension parameters were established successfully, and the value ranges and the default values were obtained. By founding the correlation function table of dimension parameters, the system can automatically output other dimension parameters by just inputting the cross-section dimensions of the mortise and tenon parts.  Conclusion  The intelligent method of determining dimension of mortise and tenon joint was established on the combination of assembly and process constraints, that was also the scientific arrangement and reuse of process knowledge. This method can not only help to realize the intelligent determination of dimension, but also provide basic condition for intelligent manufacturing, even solid wood furniture processing of mortise and tenon joints.
Design and simulation of an automatic-leveling high-position platform in orchards
Yu Yongchao, Kang Feng, Zheng Yongjun, Lv Haotun, Wang Yaxiong
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200398
[Abstract](11) [FullText HTML](4) [PDF 1158KB](1)
Abstract:
  Objective  There is a low degree of mechanization in China, especially the lack of machinery for hilly orchards. At present, the flower thinning, fruit-separated, bagging, picking and other heavy works of orchards mainly rely on artificial ladders. In order to improve the harvest efficiency, safety and stability of orchard harvesting machinery, we designed an automatic-leveling high-position platform suitable for apple orchards in hilly areas.  Method  Based on the characteristics of orchard terrain and the height of fruit trees, the design requirements and leveling methods of the platform, the size of different parts of the pitch and roll, the thrust required by the hydraulic cylinder, the relationship between the platform angle and the displacement of the hydraulic cylinder were determined. A mathematical model of the platform control system was established. Then, we used an incremental PID controller to simulate the control leveling performance in Simulink with different interference signals. An extreme inclination slope experiment in Adams was designed, where the platform was simulated to verify the safety under different postures, different lifting heights and different loads.  Result  The mathematical relationship of each part was established, and the basic dimensions of each part were determined, so as to establish the three-dimensional model of the platform. In the control system simulation, the pitch and roll control systems can quickly return the platform to the horizontal position under the step interference signal. The leveling time was 1.6 and 2.1 s, respectively, and the overshoot was 0. Under the sinusoidal interference signal, the pitch and roll control system can keep the platform near 0°, and the fluctuation range was between 0.15° and 0.19°. The limit tilting slope simulation experiment of the platform revealed that the platform’s tilting stability decreased with the increase of lifting height and load. Compared with the case without leveling, the minimum limit tilt angle with leveling increased by 24.77%, so the safety of the platform significantly improved.  Conclusion  The designed automatic leveling high-position platform in orchards can always maintain level under different interferences, with good anti-tilting ability, safety and reliability, and can meet the needs of hilly orchards.
Seasonal dynamics of energy distribution in urban forest ecosystem of Beijing
Cui Wanjing, Hou Wei, Yang Ruizhi, Zhao Yunjie
Corrected proof  doi: 10.12171/j.1000-1522.20190392
[Abstract](73) [FullText HTML](24) [PDF 1325KB](18)
Abstract:
  Objective  As the main body of terrestrial ecosystems, forests play an important role in the global carbon water cycle and energy exchange process. However, the understanding of energy exchange process of urban forest ecosystems is still limited.  Method  In this study, eddy-covariance measurement was used to investigate the daily and seasonal variation of surface energy components of the Beijing Olympic Forest Park in 2018, and how the main biophysical factors control energy exchange.  Result  The daily mean net radiation flux (Rn) was 133 W/m2, the daily mean sensible heat flux (H) was 23.6 W/m2, and the daily average latent heat flux (LE) was 26.9 W/m2. The annual Bowen ratio (β, i.e. H/LE) was 0.88. In non-growing season, the sensible heat flux was greater than the latent heat flux. At the beginning of the growing season, the latent heat flux gradually exceeded the sensible heat flux and dominated in most of the growing season. Priestley-Taylor coefficient (α), surface conductance (gs) and decoupling coefficient (Ω) were all positively correlated with soil water content (VWC) and normalized difference vegetation index (NDVI). The enhancement of α, gs and Ω by vapor pressure deficit (VPD) was buffered when the VPD was too high. Bowen ratio (β) had a negative correlation with VWC, VPD and NDVI. VWC and VPD control latent heat flux and energy partitioning by affecting canopy conductance.  Conclusion  This study indicates that drought conditions can significantly reduce the canopy conductance of the ecosystem, thereby reducing latent heat flux and affecting energy partitioning. In addition, in order to increase the proportion of latent heat flux and maximize the cooling function and value of urban green space, irrigation during the canopy development period and drought period during growing season is a practical management measure.
Soil infiltration characteristics and influencing factors of Robinia pseudoacacia plantation in the loess gully region of western Shanxi Province, northern China
Cui Yanhong, Bi Huaxing, Hou Guirong, Wang Ning, Wang Shanshan, Zhao Danyang, Ma Xiaozhi, Yun Huiya
Corrected proof  doi: 10.12171/j.1000-1522.20200122
[Abstract](57) [FullText HTML](15) [PDF 855KB](16)
Abstract:
  Objective  This paper aims to study the soil infiltration characteristics and its influencing factors of Robinia pseudoacacia forest in the loess gully region of western Shanxi Province of northern China, which could provide functional guidance for the precise improvement of stand structure.  Method  We selected the stand age of 15, 25, and 35 years and the density of 800, 1 200, 1 600, 1 800, and 2 200 plant/ha Robinia pseudoacacia forest for double-ring infiltration test. Correlation between the physical and chemical properties of soil, such as soil porosity, bulk density, organic matter, and soil infiltration rate, was analyzed.  Result  (1) To some extent, the steady infiltration rate increased with the increase of forest age and stand density. The initial infiltration rate and average infiltration rate increased with the increase of stand age. (2) Four models (Horton, Kostiakov, Philip, and general empirical model) were used to simulate the infiltration process of Robinia pseudoacacia forest in different stand ages and densities. The results showed that the average regression coefficient of general empirical model (0.977) > Horton model (0.958) > Kostiakov model (0.953) > Philip model (0.945). Therefore, the fitting effect of general empirical model was best. (3) According to principal component and correlation analysis, the soil infiltration performance was significantly correlated with the soil bulk density, organic matter, and water-stable aggregates. The initial soil moisture content was the main factor affecting the initial infiltration rate. The 1−2 mm water-stable aggregates, soil bulk density, and capillary porosity were the main factors affecting stable infiltration rate. The main factors affecting average infiltration rate were the initial soil moisture content and 0.5−1 mmwater-stable aggregates.  Conclusion  In a certain range (800−2 200 plant/ha), with the increase of age and density of Robinia pseudoacacia forest, the soil structure is improved, and the soil infiltration performance is gradually improved. Under the same stand density, the 35-year Robinia pseudoacacia forest shows better infiltration performance than others.
Quantitative analysis of spatial structural characteristics of broadleaved Korean pine forest based on Voronoi diagram
Song Yuhan, Zhang Chen, Cai Tijiu, Ju Cunyong
Corrected proof  doi: 10.12171/j.1000-1522.20200056
[Abstract](60) [FullText HTML](22) [PDF 989KB](20)
Abstract:
  Objective  Forest spatial structure is the result of forest biophysical processes and dynamic succession, and determines the growth process of forests and the function of ecological services. The Xiaoxing’anling Mountains are important ecological function area for diversity protection and water conservation, but their forest degradation is already very serious. In order to provide theoretical support for the structural optimization and adjustment of degraded forests and promote the forest to play their due roles in forest ecological services, it is necessary to analyze the structural characteristics of existing zonal climax communities.  Method  In this paper, the broadleaved Korean pine forest in the Xilinhe National Nature Reserve was taken as the research object. Based on field survey data, the Voronoi polygons were established using ArcMap software to determine spatial structural units. By the spatial structural units, several spatial structural parameters such as Clark’s clustering index, size differentiation, Hegyi’s competition index, and diversity mingling were calculated. According to them, the spatial structural characteristics were further analyzed.  Result  The horizontal pattern of broadleaved Korean pine forest stand appeared aggregated distribution, and the results derived from Clark’s clustering index were consistent with those resulted from the standard deviation of Voronoi polygon edge number. The coniferous trees had greater competitive advantages than the broadleaved trees, and the broadleaved trees presented more intense intraspecific competition. However, the trends of Hegyi’s competition index and the size differentiation index were not completely consistent. The species diversity mingling indicated that the forest stand was at a moderate level, and the isolation of conifers was higher than that of broadleaved trees. Furthermore, the extent of isolation was not directly related to the abundance of tree species in the stand.  Conclusion  The broadleaved Korean pine forest in the Xiaoxing’anling Mountains is characterized by aggregated distribution, moderate mingling, and moderate competition. The structural units of Korean pine and Fabers fir have a high degree of mixing, and the Korean pine and Fabers fir have obvious competitive advantages in their respective structural units; while the structural units of Chinese birch, Manchustripe maple, and Amur lilac are low mixed, respectively. These three species are under great competitive pressure, and more manifested as intra-species competition, among them the Amur lilac is the most representative. These characteristics are not the same as those of the broadleaved Korean pine forest in the Changbai Mountains reported in the literatures. This maybe due to different parameters selected or the result of natural selection of topographic and climatic differences. Further investigation and research are needed.
Research on forest fire smoke detection technology based on video region dynamic features
Liu Changchun, Liu Pengju, Ji Yeyun
Corrected proof  doi: 10.12171/j.1000-1522.20200049
[Abstract](420) [FullText HTML](185) [PDF 1050KB](25)
Abstract:
  Objective  Video surveillance is increasingly applied to the early detection of forest fire smoke. The existing video forest fire smoke detection methods are mostly based on pixel extraction of smoke characteristics for analysis and detection, but when the smoke is early or the smoke is far from the camera, the smoke only appears in a small area on the video image. Moreover, the diffusion of smoke is irregular, and the background environment is complex and changeable, resulting in insignificant pixel-based features, which makes it more difficult to automatically detect pixel-based smoke. Based on the principle of visible light video image processing, this paper proposes a forest fire video smoke detection method based on local area image dynamic characteristics to improve the accuracy and sensitivity of forest fire video smoke detection.  Method  The video images were selected as the research object. One frame per second was taken to generate an image sequence, and the image sequences were divided into multiple levels and different scales; using the principle of image signal-to-noise ratio, we calculated the signal-to-noise ratio of continuous image sequences after blocking; the adaptive threshold was obtained according to the signal-to-noise ratio of the background image, and the image block whose brightness changes in the image sequence to be detected was determined to be the suspected smoke block; the LBP texture feature of the suspected smoke block was extracted, and the support vector machine was used to distinguish the smoke area.  Result  Using the value component of the HSV color space, smoke areas can be effectively extracted. The videos with forest fire smoke were selected to verify the proposed smoke change detection method. The analysis results showed that the method can determine the image block where the smoke occurred and excluded some non-smoke interference factors.  Conclusion  This paper proposes a video forest fire smoke detection technology based on brightness characteristics and LBP texture features of local area, which can accurately locate the smoke occurrence area and exclude some interference factors. The average detection recognition rate reaches more than 92%, which is helpful for real-time forest fire smoke automatic detection and improving the detection rate of forest fire smoke. It has a strong practicality.
Application strategies for GLCM textures from very high spatial resolution optical imagery over subtropical plantations
Li Ronghui, Chen Ling, Wu Mingjing, Yu Xiaolong, Zhao Xiuhai
Corrected proof  doi: 10.12171/j.1000-1522.20200139
[Abstract](84) [FullText HTML](25) [PDF 21757KB](6)
Abstract:
  Objective  Discussing textural variables and their corresponding input parameters, and clarifying a specific and simple strategy for the optimal utilization of textural information from very high spatial resolution (VHR) imagery in the field of forestry.  Method  Based on a case of Chinese fir plantation with different age classes under varied topographic conditions from Jiangle State-Owned Forest Farm of Fujian Province of eastern China, even gray level co-occurrence matrix (GLCM) textures and four input parameters were involved to demonstrate the optimal selection of textures and the setting of input parameters.  Result  Almost all textures had higher age class separability over shady slope than sunny slope, and both the measurement index and the correlation between different textures should be used to select the optimal textures. Among the four input parameters, moving window size was the most important for textures in statistic and orderliness groups. Optimal window sizes should be jointly determined by the spatial resolution of images and spatial scale of research objects. Textures in contrast group were independent of window size, which means that any window size can be set for those textures. No attention need to be paid to the setting of displacement for textures in statistic and orderliness groups, but the situation was different for textures in contrast group. Moreover, orientation setting should be more concerned with the increase of displacement for textures in statistic group, but not for textures in the other two groups. As for the most neglected parameter, the grayscale quantization level can be set to 32 or 64.  Conclusion  The texture information of VHR imagery can be used to distinguish objects with high spectral overlaps, which can “make up” the spectral information loss caused by shadows. However, textural variables and their input parameters should be optimized. The specific strategy and all the general rules from this study can provide practical suggestions for the optimal utilization of textural information from VHR imagery.
Effects of thinning intensity on the growth of interplanting broadleaved trees under Pinus massoniana plantation
Chen Beibei, Jiang Jun, Lu Yuanchang, Liu Xianzhao, Jia Hongyan, Ming Angang, Zhang Xianqiang
Corrected proof  doi: 10.12171/j.1000-1522.20200086
[Abstract](70) [FullText HTML](16) [PDF 814KB](23)
Abstract:
  Objective  This paper analyzes the thinning effect of replanting tree species of Pinus massoniana plantation in southwestern Guangxi, southern China in order to provide a better guidance and theoretical basis for scientific and reasonable management.  Method  Four kinds of artificial replanting tree species were used as the research objects to study the growth of replanting tree species under Pinus massoniana plantation after three thinning intensities (80%, 50%, 30%), and to analyze the influence of stand and habitat factors.  Result  The thinning intensity had a significant impact on the growth of interplanting broadleaved trees. The thinning intensity significantly affected the growth of broadleaf trees, and the growth of Castanopsis fissa and Manglietia glauca increased with thinning intensity increasing, but the influence of cutting intensity on Erythrophleum fordii was not significant. The DBH growth of Castanopsis fissa was higher than that of other three tree species, and the peak appeared in the third year or so. The effect of thinning intensity on the growth of Erythrophleum fordii was accelerated in 30% thinning intensity after nineth years. Castanopsis fissa and Castanopsis hystrix were suitable to grow under 50% thinning intensity, and the increase of DBH appeared in the fifth year. The main factors affecting the growth of replanted trees were tree density, organic matter and soil thickness, showing significant differences in replanted trees (P < 0.05).  Conclusion  Different tree species have better growth rate under medium and high intensity thinning. Castanopsis fissa and Castanopsis hystrix can make full use of the space left behind by high-intensity thinning, give full play to the advantages of rapid growth and improvement of forest soil, while Erythrophleum fordii and Castanopsis hystrix can keep the growth rate continuously by the environmental conditions created by Castanopsis fissa and Manglietia glauca. It is suggested that Quercus griffithii and Manglietia glauca are suitable tree species in the thinning intensity (80% or 50%), Castanopsis hystrix and Erythrophleum fordii are suitable tree species under the 30% thinning intensity of Pinus massoniana plantation.
Spatial Distribution Simulation of Recruitment Trees of Natural Secondary Forest Based on Geographical Weighted Regression
Chen Keyi, Zhang Huiru, Zhang Bo, He Youjun
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200157
[Abstract](20) [FullText HTML](6) [PDF 948KB](2)
Abstract:
  Objective  By studying the amount and spatial distribution pattern of recruitment trees in natural secondary forest, the response of recruitment trees to various variables was analyzed, the reasonable method of processing spatial non-stationary data was explored, and the optimal model of the amount of recruitment trees was constructed. It is expected to provide more accurate technical means for the study of the growth dynamics of natural secondary forests, and to provide a reference for the accurate improvement of forest quality of natural secondary forests.  Method  Based on the data collected from 106 bureau level permanent plots in Tazigou forest farm of Wangqing forestry bureau in Jilin province during 1997 and 2007, we taken stand factor, topography factor and soil factor as the influencing factors and established conventional Poisson regression model (PR), geographically weighted Poisson regression (GWPR) and semiparametric geographically weighted Poisson regression (SGWPR) respectively to simulate the status of amount and distribution of recruitment trees of natural secondary forest in the area. Coefficient of determination (R2), mean square error (MSE) and Akaike’s Information Criterion (AIC) were used to evaluate the fitting effect of the three models. The spatial autocorrelation and local spatial aggregation of residuals of the three models were analyzed by using global and local Moran’s I. The spatial distribution of recruitment trees in the research area was drawn with the fitting results of the semiparametric geographically weighted Poisson regression, and the distribution pattern of recruitment trees in the research area was analyzed.  Results  (1) In the three models, both stand factor and topographic factor have a great influence on the amount of recruitment trees, among which the average DBH of stand is the variable with the greatest influence, and there is a significant negative correlation between them; (2) the Poisson regression model with geographical weighting is obviously better than the conventional Poisson regression model in the fitting effect, among which the semiparametric geographically weighted Poisson regression model has the best fitting effect. For the fitting of the strong influence points which deviate far from the expected value, it shows excellent effect; (3) the Poisson regression model with geographical weighting has a better stability and can significantly reduce the spatial autocorrelation of model residual. By contrast, the semiparametric geographically weighted Poisson regression model can minimize the spatial distribution of residual with similar aggregation; (4) Ten years later, in more than 83% area of tazigou forest farm, the number of recruitment trees was 0 ~ 683 per hectare. The overall condition of the northern area is better than that of the southern area, and the maximum value of the local area is mainly located in the marginal hillside of the northeast of the forest farm.  Conclusion  The optimal model for the amount of recruitment trees can be obtained by using the semiparametric geographically weighted Poisson regression. When constructing the model of the amount of recruitment trees, not all variables need to consider the geographical weighting, which should be determined according to the specific research content and data.
Analysis of the Difference on Forest Soil Nutrients at Regional Scale
Liu Xiaotong, Li Haikui, Cao Lei, Zhang Yiru
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200164
[Abstract](22) [FullText HTML](5) [PDF 1057KB](4)
Abstract:
  Objective  The influence of different factors on forest soil nutrients were analyzed to explore the causes of forest soil nutrient diversity and support forest management and site quality evaluation.  Method  Based on the soil data of forest inventory in Guangdong province, organic matter (OM), alkali-hydro-nitrogen (AN), available phosphorus (AP) and available potassium (AK) were taken as dependent variables, and 20 variables (10 qualitative factors and 10 quantitative factors) were taken as independent variables in four categories, namely geographical factor, topographic factor, soil factor and stand factor. The main effector was selected based on the general linear model and backward elimination method. The influencing factors and degree of forest soil nutrient were analyzed by the interaction of qualitative and quantitative factors. The difference was analyzed by multiple linear regression analysis of quantitative factors and multiple comparative analysis of qualitative factors.  Result  (1)The results showed the soil nutrients are mainly affected by three geographical factors (longitude, latitude and watershed), three topographic factors (altitude, slope position and slope grade), and four stand factor (vegetation coverage under forest, mean DBH, mean age and dominant tree species). And the factors on different soil nutrients are various. (2)The influence factors have different degrees of interpretation for different soil nutrients. The interpretation degree of AN is more than 0.30, the interpretation degree of OM and AK are more than 0.25, and the interpretation degree of AN is more than 0.20. Interaction prominently enhance the interpretation of soil nutrients, with an average increase of 0.141. AN, OM and AK up to about 0.50, 0.45 and 0.40 respectively, AK is more than 0.30.(3)Through multiple comparative analysis, there were significant differences in soil nutrients among dominant tree species, watershed and slope.  Conclusion  The factors affecting forest soil heterogeneity in Guangdong Province include geographical factors, topographic factors and stand factors. The influence factors of different soil nutrients are not exactly the same. Latitude, watershed, altitude, slope position, parent rock, average DBH, average age and dominant tree species have influence on most soil nutrient factors. For different soil nutrients, OM and AN have a higher degree of interpretation, while AP and AK have a lower degree of interpretation. Interaction significantly improved the degree of interpretation of soil nutrients. In this study, the main effect screening method with qualitative factors is proposed and the interaction between first-order qualitative factors and quantitative factors is introduced, so that it can highly increase the interpretation of soil nutrients.
Distribution characteristics of commercial facilities around the comprehensive parks in 23 districts of Tokyo
Hu Shengjie, Chen Hongyu, Li Xiong
Corrected proof  doi: 10.12171/j.1000-1522.20200043
[Abstract](48) [FullText HTML](30) [PDF 23707KB](6)
Abstract:
  Objective  In the process of urban development, the use and function of comprehensive parks are no longer limited to their actual form boundaries, but gradually establish a relationship with external commercial facilities and jointly become the driving force of urban renewal and development. The analysis of distribution characteristics of commercial facilities around comprehensive parks and defining the potential connections between them can provide an important basis for planning and construction in the future.  Method  Taking 19 comprehensive parks in the 23 districts of Tokyo as research objects, basing on comprehensive park positioning, land price, commercial facility POI data, and using kernel density estimation and spatial interpolation method, this paper quantitatively analyzes the distribution characteristics of commercial facilities around comprehensive parks. Combined with the characteristics of parks, relevant policies and local culture, this paper summarizes the relationship between distribution characteristics of commercial facilities and comprehensive parks.  Result  (1) In the early stage of urban development, the macro policy focused on the establishment of city image and disaster prevention system, so as to make the commercial land around comprehensive parks large and closely integrated with parks. In the middle and later stages, the macro policy turned to solve the urban problems and update the urban environment, and made the commercial land around the comprehensive park small and loosely integrated with the park. (2) Comprehensive parks with prominent themes promoted the agglomeration of surrounding commercial facilities, which were manifested as high scale and degree of agglomeration and single agglomeration center around parks with history as theme, and low scale and degree of agglomeration and multi-center agglomeration around comprehensive parks with function and landscape as theme. (3) When the functional setting of comprehensive parks matched the agglomeration demands of the commercial facilities, the scale and degree of commercial facilities with strong agglomeration demands around the park were high and the agglomeration centers were relatively concentrated, while those with weak or no agglomeration demands were in the opposite situation. (4) The commercial land price around comprehensive parks was higher in core center 6 districts than in sub-center districts, and lower in the west and east of sub-center districts. 89.48% of the commercial land price around comprehensive parks was lower than the average land price in the district. Extreme value of land price usually occurred around the comprehensive park with rich functional configuration.  Conclusion  At the planning level, we suggest to formulate a planning scheme consistent with the actual situation and subsequent construction based on the urban development stage and core issues. At the construction level, we suggest that the park configuration should respond to the use needs of city and its surrounding environment, guide the appropriate types to gather around the comprehensive park, and realize the two as a whole to promote the organic renewal and sustainable and balance development of city.
A review on mass distribution of active components from Hippophae rhamnoides fruits
Lü Zhaolin, Yuan Weiqiong, Zhang Bolin, Xing Guoliang
Corrected proof  doi: 10.12171/j.1000-1522.20200236
[Abstract](72) [FullText HTML](24) [PDF 674KB](15)
Abstract:
Seabuckthorn (Hippophae rhamnoides) is a plant resource with strong resistance to stress, adaptability and sprouting. It is widely used in barren hill greening, soil improvement, soil and water conservation, and sandstone management in loess hilly areas. Seabuckthorn not only has good ecological value, but also its fruits are rich in various biologically active substances. This study summarized and analyzed the composition, distribution, and activity characteristics of activated substances in seabuckthorn fruits by literature data. The current research status of active substances in seabuckthorn fruits is also prospected. Based on the related literatures reviewed, the chemical constituents, which widely present in seabuckthorn fruits including flavonoids, anthocyanins, phenolic acids, organic acids, inositol, vitamins, carotenoids, unsaturated fatty acids and sterols, were described and summarized. And the purpose is to provide comprehensive information on the distribution of important active substances in seabuckthorn fruit. The current research on the composition, distribution and active characteristics of active substances in seabuckthorn fruits is abundant. However, there are still shortages in some areas, such as the impact of cultivation techniques on active substances, and the correlation between active substances and odors in seabuckthorn fruit processing, there is no relevant literature on the concerns of these compounds in the development of seabuckthorn. This article provides theoretical support for the comprehensive utilization of seabuckthorn fruits in food, pharmaceutical and health product industries. It also provides a reference for promoting the comprehensive development of seabuckthorn resources in the economy.
Preparation and properties of heat-treated poplar wood modified with composite silicon modifier
Liu Qiangqiang, Lü Wenhua, Shi Yuan, Du Haojia
Corrected proof  doi: 10.12171/j.1000-1522.20200266
[Abstract](72) [FullText HTML](31) [PDF 912KB](6)
Abstract:
  Objective  Considering the problems such as formaldehyde emission from wood resin modifier and high hygroscopicity of inorganic material modified wood, the easily available silica powder was used as the main raw material to prepare composite silicon wood modifier, which was water-soluble, high permeable, environmental friendly and fireproof. Through vacuum pressure impregnation and heat-treatment, the physical, mechanical and fire retardant properties of woods were effectively improved.  Method  Silicone oil composite silicon modifier (SC2) and coupling agent hybrid silicon modifier (HS2) were prepared respectively. Plantation poplar wood was impregnated, then the impregnated wood was heat-treated at a high temperature. The physical, mechanical and fire retardant properties of composite silicon modified wood and its heat-treated wood were finally tested and analyzed.  Result  After heat-treatment, the mass and oven-dry density of all samples decreased, and the oven-dry density loss rate and mass loss rate of heat-treated silicone oil composite silica modified wood (TW-SC2) were the largest. Compared with silicone oil composite silicon modified wood (W-SC2), the moisture absorption rate of TW-SC2 increased. The moisture absorption rate of the heat-treated coupling agent hybrid silica modified wood (TW-HS2) was significantly lower than that of the coupling agent hybrid silicon modified wood (W-HS2), and the moisture absorption resistance was significantly improved. Compared with the untreated wood (W), the mechanical properties of all the modified wood apparently improved, and were better than TW-SC2. The ignition time of W-HS2 was 8 s later than that of W, its fire performance index increased from 0.043 to 0.140 m2s/kW. The ignition time of TW-HS2 was 9 s later than that of W, and its fire performance index increased by 64.3% compared with W-HS2. Compared with W, the total heat release of TW-HS2 reduced by 29.4%, the peak heat release rate decreased, and the peak time of the second heat release rate was delayed. The total smoke release of W-HS2 or TW-HS2 was larger than that of W, the HS2 impregnation modification combined with heat-treatment can further promote the flame retardancy of wood. The thermal degradation rate of the modified wood was significantly lower than that of W, and the thermal stability was improved, indicating that the HS2 modifier had a significant effect on promoting char formation.  Conclusion  Taking silica as raw material, the coupling agent hybrid silicon modifier HS2, which was environmentally friendly and highly efficient, was prepared through organic hybridization. The combined modification process of vacuum pressure impregnation and heat-treatment can effectively improve the mechanical and fire-retardant properties of plantation poplar wood, realize green modification with broad application prospects.
Effects of photosynthesis on soil respiration of Quercus variabilis plantation in southern Taihang Mountain of northern China
Wang Xin, Tong Xiaojuan, Zhang Jinsong, Meng Ping, Xie Han, Hu Haiyang, Li Jun
Corrected proof  doi: 10.12171/j.1000-1522.20200010
[Abstract](88) [FullText HTML](33) [PDF 1403KB](15)
Abstract:
  Objective  This study aims to explore the effects of photosynthesis on soil respiration and build a new soil respiration model, which can improve the interpretation of soil respiration changes in the study area, and provide a theoretical basis for accurately estimating the intensity of soil respiration and the carbon budget in southern foot of the Taihang Mountains, northern China.  Method  Taking the Quercus variabilis on the southern foot of Taihang Mountain as research object using field control experiments, which compared the treatment of cut roots and non-cut roots and the contribution rate of photosynthetic products to soil respiration. Through the model fitting of soil respiration, soil temperature, humidity and photosynthesis data, we explored whether adding photosynthetic factors can optimize the traditional soil respiration model.  Result  On the hourly scale, soil temperature was the main factor affecting the soil respiration of the cork oak forests, and the relationship between them was significant (R2 = 0.74, P < 0.01). On the day scale, the curves of soil respiration and temperature were not consistent. The soil temperature in each month showed a continuous increase from 10:00−18:00, but the soil respiration rate did not show the same law. The daily change of soil respiration showed a single peak or a double peak curve, and the highest point generally appeared between 14: 00−16: 00. The temperature sensitivity (Q10 values) dissimilated under different conditions with the root cutting treatment component (1.90) > control group score (1.78). Results showed that forest photosynthesis can account for up to 36.5% of soil respiration, and there was a significant linear correlation between photosynthesis and soil respiration (R2 = 0.39, P < 0.01). Regression model with adding photosynthesis variable significantly improved the fitting R2.  Conclusion  Soil respiration is a complex process affected by multiple factors. It is not comprehensive to analyze and estimate soil respiration based on the function of a single factor. Soil temperature can only explain 74% variations of soil respiration, whereas soil temperature and photosynthesis in the model jointly determine the variation of soil respiration above 80%, and the model fit degree can reach up to 0.81.
Effects of different extraction methods on extraction effect and functional properties of Korean pine seed oil
Pan Xiaoli, Wang Fengjuan, Zhang Na, Guo Qingqi
Corrected proof  doi: 10.12171/j.1000-1522.20200109
[Abstract](38) [FullText HTML](17) [PDF 695KB](4)
Abstract:
  Objective  Based on solvent method, by comparing the yields of Korean pine seed oil separately treated by ultrasonic method, microwave method or light wave method, and the soaking yields of Korean pine seed oil after separate method treatment, the dominant method in the extraction process of Korean pine seed oil was identified. At the same time, the effects of four extraction methods on physicochemical indexes, fatty acids and antioxidant capacity of Korean pine seed oil were confirmed.  Method  According to the GB/T5009.229−2016 Determination of Acid Value in Food, GB/T5532−2008 Determination of Iodine Value of Animal and Vegetable Oils and GB/T5009.227−2016 Determination of Peroxide Value in Food, the acid value, iodine value and peroxide value of Korean pine seed oil extracted by the four methods were determined. The type and mass fraction of fatty acids in Korean pine seed oil were determined by gas chromatography-mass spectrometry method, and the scavenging abilities of Korean pine seed oil to DPPH· and ABTS+· were determined by spectrophotometry.  Result  The optimum extraction solvent was n-hexane. When the extraction temperature was 25 °C, the liquid to solid ratio was 18 mL/g, the extraction time was 5 h, the yield of Korean pine seed oil was 65.52%. The yield of Korean pine seed oil was 67.63%, 62.26% and 58.25% by ultrasonic (300 W, 10 min), microwave (380 W, 100 s) and light wave (400 W, 11 min), respectively. After the three methods treated separately and the extraction was carried out with n-hexane individually, the yield increased by 2.18%, 4.50% and 6.10%, respectively after the total time reaching 5 h. The Korean pine seed oil extracted by the four methods can meet the limit standard of acid value (≤ 4 mg/g) and peroxide value (≤ 0.25 g/100 g) in National Food Safety Standard Vegetable Oil GB/ T2716−2018. The acid value and peroxide value of Korean pine seed oil prepared by organic solvent method were the lowest (P < 0.05). The mass fractions of fatty acid from high to low were linoleic acid (44.54% − 46.32%), oleic acid (28.29% − 28.83%) and pinocyanic acid (13.15% − 14.51%). The DPPH· and ABTS+· IC50 values of Korean pine seed oil extracted by solvent, ultrasonic, microwave and light wave methods were 9.41, 8.80, 9.43, 9.61 g/L and 5.10, 5.51, 6.10, 5.43 g/L, respectively.  Conclusion  The yields of ultrasonic method, microwave method or light wave method separately, and soaking yields after the single treatment were compared. It is found that ultrasonic, microwave and light wave method play a leading role in the extraction process. Compared with the solvent method, microwave method and light wave method, Korean pine seed oil extracted by the ultrasonic method has a higher extraction percentage, a higher mass fraction of unsaturated fatty acid, a stronger antioxidant capacity, and can achieve better extraction effect. This method has some advantages in the Korean pine seed oil extraction industry.
Effects of moisture content on curing characteristics of low molecular mass melamine-urea-formaldehyde (MUF) resin by differential scanning calorimetry (DSC) method
Li Zhonghao, Li Xianjun, Zhang Xiaomeng, Lü Jianxiong, Zhou Chuanling, Xu Kang
Corrected proof  doi: 10.12171/j.1000-1522.20200317
[Abstract](66) [FullText HTML](24) [PDF 847KB](27)
Abstract:
  Objective  In order to clarify the resin curing characteristics of the resin impregnated wood in different spatial layers during different drying stages, the effects of moisture content on resin solution curing process were studied.  Method  The melamine-urea-formaldehyde (MUF) resin solution prepared in the laboratory was diluted to 20%, 30%, 40% and 50%, respectively. Then, they were analyzed by differential scanning calorimetry (DSC) method. Without the effect of heating rate, the optimum curing temperature was obtained by extrapolation method to clarify the effect of moisture on MUF resin curing characteristics qualitatively. The apparent activation energy of resin solution, which was diluted to 20%, 30%, 40% and 50%, was calculated by the Kissinger differential method and Flynn-Wall-Ozawa integral method, to quantify the effect of moisture on resin curing process.  Result  The peak temperature (Tp) tended to shift to the higher temperature with the decrease of mass fraction of MUF resin solution. Under the heating rate of 15 and 20 ℃/min, the Tp of 20% resin solution shifted to the lower temperature region. The optimum curing temperatures of 20%, 30%, 40% and 50% MUF resin solution were 93.99, 90.71, 85.46 and 79.71 ℃, respectively. And their apparent activation energies calculated by Kissinger differential method were 92.94, 82.37, 65.93 and 50.68 kJ/mol, respectively, which were similar to those of the Flynn-Wall-Ozawa integral method.  Conclusion  Generally, the moisture hinders the resin solution curing reaction in the absence of heating rate effect, and the blocking effect increases with the increase of moisture content. However, in the condition of higher heating rate (15 and 20 ℃/min), the DSC result of 20% resin solution shows that the moisture promotes the resin curing process, which might due to the drastic molecular movement.
Construction and its function analysis of RNA interference vector of cytochrome cyp-13A11 gene in Bursaphelenchus xylophilus
Sheng Dongping, Zhang Xiaoyang, Feng Mengting, Ye Jianren, Qiu Xiuwen
Corrected proof  doi: 10.12171/j.1000-1522.20200025
[Abstract](135) [FullText HTML](35) [PDF 871KB](19)
Abstract:
  Objective  In order to reveal the function of cyp-13A11 gene in Bursaphelenchus xylophilus, the RNA interference vector was constructed and the function of cyp-13A11 gene of Bursaphelenchus xylophilus was analyzed to provide theoretical basis for biological control of pine wilt diseases.  Method  Specific primers were designed to amplify the cyp-13A11 gene fragment of Bursaphelenchus xylophilus. The products of amplification were constructed into pEASY-T1 interference vector, which was further transferred into Trans1-T1 escherichia coli strain. RNA interference efficiency was determined by qRT-PCR. The feeding reproduction and pathogenicity of pine wood nematodes were investigated after the nematodes soaked in cyp-13A11 dsRNA solution were inoculated on Botrytis cinerea and pine trees, respectively.  Result  Trans1-T1 strain with pEASY-T1 interference vector was successfully constructed and cyp-13A11 dsRNA was synthesized. RNA interference inhibited the expression of cyp-13A11 gene in Bursaphelenchus xylophilus. In addition, the feeding area was less in cyp-13A11 dsRNA treatment than that in ddH2O treatment, as two thirds of the Botrytis cinerea were fed by nematodes in ddH2O treatment on day 3. After 6 days, one third of Botrytis cinerea was fed by nematodes in cyp-13A11 dsRNA treatment, while almost all of the Botrytis cinerea were exhausted by nematodes in ddH2O treatment. The reproduction number of nematodes in ddH2O treatment was 4.28 times higher than that in cyp-13A11 dsRNA treatment. Furthermore, the wilting rates in both ddH2O and cyp-13A11 dsRNA treatments were 22.2% and 5.6% after Bursaphelenchus xylophilus being inoculated on pine trees for 10 days, respectively. The wilting rates of pine trees in both ddH2O and cyp-13A11 dsRNA treatments were 44.4% and 33.3% after 20 days, respectively. Obviously, the wilting rates were 100% in both treatments after 30 days.  Conclusion  The RNA interference vector of cyp-13A11 gene in pine wood nematode was successfully constructed. Silencing of cyp-13A11 gene exhibited an important effect on feeding of Bursaphelenchus xylophilus, as well as reduced the reproduction ability and pathogenicity of Bursaphelenchus xylophilus.
Study on the influence of structure of soil macropores on saturated hydraulic conductivity
Ao Jiakun, Niu Jianzhi, Xie Baoyuan, Luo Ziteng, Lin Xingna, Yang Lan
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190429
[Abstract](28) [FullText HTML](11) [PDF 1270KB](7)
Abstract:
  Objective   To explore the influence of the structure and quantity of macropores with different diameter class on the saturated hydraulic conductivity of soil. To provide a theoretical reference for the study of soil water solute transport law, soil erosion control and soil pollution control in this area.   Method   The study was carried on water conservation forest in wuzuoshan forest farm of Miyun Reservoir in Beijing suburb. Based on the industrial CT scanning technology, the three-dimensional spatial structure of soil macropores in the soil column is reconstructed to explore the influence of structural parameters density and quantity density of macropores with different diameter class on the soil saturated hydraulic conductivity.   Result   (1) When equivalent diameter of macropores is larger, which except equivalent diameter large than 4.30 mm, the quantity density and structural parameters density of macropores is smaller. (2) In three soil layers of six sample plots, the proportion of macropores with an equivalent diameter of 0.31−2.30 mm to all macropores is higher than 95%. (3) The maximum saturated hydraulic conductivity of sample 1, 2, 5 and 6 is 0−10 cm layer, and it decreases with the depth increase, but except of sample 6. The saturated hydraulic conductivity of sample 4 increases with the depth increase. (4) Except of the volume density of macropores with an equivalent diameter greater than 4.30 mm, all the other eigenvalue densities of macropores have a significant positive correlation with the saturated hydraulic conductivity.   Conclusion   (1) In the 0−30 cm soil layer, the saturated hydraulic conductivity of most sample plots decreases with the soil depth increase, but it will also increase with the depth increase. (2) The equivalent diameter of macropores in the soil of forest is mainly concentrated in 0.31−2.30 mm, and its occupancy rate is more than 94%. (3) When equivalent diameter of macropores is smaller, the density of characteristic parameters of structure of macropores is greater except of the volume and the surface area of macropores. (4) There is a significant positive correlation between the characteristic parameters of macropores and the saturated hydraulic conductivity, which except of the volume density of macropores with equivalent diameter greater than 4.30 mm.The influence of the number of macropores on the saturated hydraulic conductivity is significantly greater than structure parameters of macropores.
Branch density model for Pinus koraiensis plantation based on thinning effects
Jiu Weiwei, Luo Tianze, Li Fengri
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200057
[Abstract](38) [FullText HTML](8) [PDF 990KB](12)
Abstract:
  Objective  In order to analyze the influence of thinning on the number of branches for Pinus koraiensis plantation, this study constructed a biological mathematic model based on the thinning effect, and provided a theoretical basis for developing a scientific and reasonable thinning program.   Method  Based on the data of 4 370 branches from 49 sample trees in Pinus koraiensis plantation in Linkou and Dongjingcheng Forestry Bureau of Heilongjiang Province, this study established a single-level nonlinear mixed effect model of branch density with thinning effects using nlme package of R. The converged models were then evaluated by adjusted coefficient of determination (\begin{document}$ {R}_{{\rm{a}}}^{2} $\end{document}), Akaike Information Criterion \begin{document}$ \left({\rm{AIC}}\right) $\end{document}, Bayesian information criterion (\begin{document}$ {\rm{BIC}} $\end{document}), log likelihood (−2Log likelihood) and likelihood ratio test (\begin{document}$ {\rm{LRT}} $\end{document}).  Result  When site index and tree size are similar, branch density increased with the increase of thinning intensity and crown length. When thinning intensity and tree size are similar, branch density increased with the increase of site index and crown length. However, when thinning density and site index are similar, branch density was negatively correlated with diameter at breast height. Nonlinear mixed effect model with plot effect has higher fitting precision than that with tree effect and corresponding fixed effect model. Finally, the nonlinear mixed model with five random coefficients including \begin{document}$ {\rm{DINC}} $\end{document} (depth into crown)、\begin{document}$ {\rm{lnRDINC}} $\end{document} (the natural logarithm of relative depth into crown)、\begin{document}$ {{\rm{RDINC}}}^{2} $\end{document} (the square of relative depth into crown)、\begin{document}$ {\rm{DBH}} $\end{document} (diameter at breast) and \begin{document}$ {\rm{TI}}/{\rm{TA}} $\end{document} (thinning intensity over thinning age) was selected as the most optimized model for predicting branch density, whose \begin{document}$ {R}_{{\rm{a}}}^{2} $\end{document} is 0.826 3 and \begin{document}$ {\rm{RMSE}} $\end{document} is 2.171 4.  Conclusion  The optimal nonlinear mixed effect model with thinning effect not only has higher precision, but also more accurately reflects the effect of thinning on the tree branches than other models.
Responses of leaf photosynthetic characteristics of Cotinus coggygria to combined mineral nitrogen, phosphorus and potassium application
Wu Jiaojiao, Tian Qiuling, Yue Jiaxing, Tan Xing, Zhang Wen, Gao Lan, Li Linke, Liu Yun
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200199
[Abstract](40) [FullText HTML](10) [PDF 994KB](7)
Abstract:
  Objective  Relationships between photosynthetic characteristics and combined application of mineral nitrogen, phosphorus and potassium (N, P and K) have been studied to provide nutrient management strategies of Cotinus coggygria.  Method  Under 10 treatments (see below), the photosynthetic pigment, leaf area, diurnal variation of photosynthetic parameters and light response curve of leaves potted C. coggygria seedlings were measured, and theses generated data were then related to combined application of N, P and K. With a L9 (34) orthogonal design for N (0, 6, 12 g/plant), P (0, 10, 20 g/plant) and K (4, 8, 12 g/plant), these 10 treatments were T1 (N1P1K1), T2 (N1P2K2), T3 (N1P3K3), T4 (N2P1K2), T5 (N2P2K3), T6 (N2P3K1), T7 (N3P1K3), T8 (N3P2K1), T9 (N3P2K1) and T10 (N0P0K0).  Results  Under each treatment the net photosynthetic rate (Pn) and stomatal conductance (Gs) had a “double peak curve” change, while the transpiration rate (Tr) had a “single peak curve” change. The contents of total chlorophyll and carotenoid were higher under T5, T6, T8 and T9 than under other treatments. Except for T2, the daily average value of Pn was significantly higher than that of the control (P < 0.05). Among all the 10 treatments, T9 had the highest performance on all the tested diurnal variation parameters [Gs, Pn, Tr and light energy use efficiency (LUE)], and the daily average values of light response parameters [maximum net photosynthetic rate (Pnmax), light saturation point (LSP), light compensation point (LCP) and dark absorption rate (Rd)]. In addition, the redundancy analysis showed that: The contribution rate of fertilizer was P > N > K, while P had a greater effect on photosynthetic pigments (Chl s and Car) and a positive correlation with Pn, Pnmax and LSP. In contrast, N and K had greater influences on LUE that positively correlated with LCP, Tr and Gs.  Conclusion  Results from this experiment demonstrated that among the tested 10 NPK treatments, T9 (12 g/plant N, 20 g/plant P and 8 g/plant K) was the optimal fertilization to significantly promote leaf photosynthetic capacity of C. coggygria.
Foliar water uptake of four typical plant species and their physiological responses in the Mu Us Desert.
Li Luchen, Gui Ziyang, Qin Shugao, Zhang Yuqin, Liu Liang, Yang Kaijie
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200024
[Abstract](38) [FullText HTML](14) [PDF 1155KB](9)
Abstract:
  Objective  In this study, we examined Agriophyllum squarrosum, Corispermum puberulum, Chenopodium aristatum, and Sophora alopecuroides in the Mu Us Desert, to explore the ability of leaf water absorption and their physiological responses.  Method  We determined whether the dew water can be took up by the leaves of four plant species, and whether the absorbed water can be transported to the root and rhizosphere soil, by dew covered experiments and stable isotope tracer technology to contrast the δ2H values of samples in the leaf, root and rhizosphere soil from the treatment and the control groups; Meanwhile, we measured leaf water potential (ΨL), leaf water content (LWC), and stomatal conductance (Gs) before and after dew treatment by using dew point water potential meter, electronic balance and plant porometer, in order to evaluate the effects of foliar water uptake on the species.  Result  (1) After the deuterium labelled dew treatment, the δ2H values in samples of leaf (20‰ ~ 100‰) in the treatment group of four plant species were significantly higher than the control group (−25‰ ~ −15‰); The δ2H values in samples of root (−45‰ ~ −30‰) and rhizosphere soil (−50‰ ~ −40‰) in the treatment group did not change significantly compared to the control group. 2) After the dew treatment, ΨL, LWC of A. squarrosum increased by 23.81%, 2.49%, and Gs of it decreased by 57.40%, respectively; LWC of C. puberulum increased by 2.45%, but the ΨL and Gs were not change significantly; ΨL of C. aristatum increased by 21.95%, but the LWC and Gs were not change obviously; For S. alopecuroides, there were no significant difference in ΨL, LWC and Gs.  Conclusion  We found that all of the four plant species can absorb dew water through leaves, but the water cannot be transported to the root and the rhizosphere soil. Agriophyllum squarrosum, Corispermum puberulum and Chenopodium aristatum could improve their water physiological state through water absorption. It may be an important water use strategy for them to adapt to drought environment, for this helps the plants to survive. However, Sophora alopecuroides did not significantly respond to foliar water uptake and also could not improve its water physiological state through this process.
Determining modulus of elasticity of full-size plywood panel supported on two opposite sides using a vibration method
Li Huan, Guan Cheng, Zhang Houjiang, Liu Jinhao, Zhou Jianhui, Xin Zhenbo
Corrected proof  doi: 10.13332/j.1000-1522.20200300
[Abstract](83) [FullText HTML](29) [PDF 1386KB](17)
Abstract:
  Objective   To provide a new method for the online non-destructive determination for modulus of elasticity (MOE) in two main directions of a full-size plywood panel, the vibration determination for MOE in two main directions of a full-size plywood panel supported on two opposite sides was studied.   Method   20 pieces of full-size plywood panels with four different thicknesses were used as study objects. The modal sensitivity analysis and experimental modal analysis of full-size plywood panels supported on two opposite sides were performed using finite element software COMSOL Multiphysics and the PULSE vibration test system. The frequencies of the needed modes were obtained by a vibration detection method for MOE of the full-size plywood panel proposed in this study, then incorporated into a vibration detection algorithm of the dynamic MOE in two main directions of a full-size plywood panel. In order to verify the accuracy of the dynamic MOE values measured, the static MOE values in two main directions of a full-size plywood panel were also obtained through three-point bending test.   Result   The frequencies of free vibration modes (2, 0) and (2, 2) as the first and seventh modes in the first nine modes of the full-size plywood panel were conducted for calculation of MOE in the length and width directions of the panels, respectively. The results revealed that thickness variation had no effect on the ordering of the first nine modes for the full-size plywood panels. The dynamic MOE values were greater than the static ones of the full-size plywood panels, and there existed inhomogeneity of mechanical properties for the full-size plywood panels with the same thickness. Dynamic MOE had a strong correlation with static MOE in both length and width directions of the full-size plywood panels (R2 = 0.907 and 0.655, respectively).   Conclusion   It is feasible for determining MOE of a full-size plywood panel based on two-opposite-side vibration and vibration detection algorithm for MOE.
Expansin genes in association with the genome differentiation of Salix matsudana
Yang Ruixia, Yin Peng, Liu Xiao, Wang Yan, Liu Jiafu, Xu Jichen
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200216
[Abstract](44) [FullText HTML](16) [PDF 683KB](9)
Abstract:
  Objective  Expansin, an important gene family in plants, plays a critical role in plant growth and development and resistance to various biotic and abiotic stresses. The purpose of this study was to investigate the variation of the expansin genes in Salix matsudana so as to provide theoretical basis for understanding the AA and BB genomes differentiation in Salix matsudana, and to contribute greatly for molecular design and breeding of Salix.  Method  According to the expansin gene sequences of Populus tomentosa, the expansin family genes in Salix matsudana were individually identified. The characteristics and variations of the expansin genes in AA and BB genome were analyzed and evaluated by the bioinformatics softwares.  Result  A total of 65 expansin genes were identified in allotetraploid Salix matsudana based on the conservation of the sequence and structure of the expansin genes. Both genomes shared 28 genes with 3 genes duplicated. Moreover, 3 expansin genes were missed and 2 genes were with a domain deficient in AA genome, while 3 expansin genes were missed and 1 gene were with a domain deficient in BB genome, respectively. Gene structure analysis showed the considerable changes in the number and cutting sites of intron between the relative gene pairs of both genomes. Besides, AA and BB expansin genes both had 5 high-frequency codons, and separately had 5 and 10 optimal codons. Some codons had significant usage bias such as AGG and UAG. Evaluation of the protein physicochemical properties showed that the AA and BB expansins changed a lot, especially in terms of hydrophilicity and structural stability. Ka/Ks calculation displayed that EXPA23 gene had experienced positive selection during AA and BB genomes differentiation, while the other genes underwent purification selection with Ka/Ks value changed widely.  Conclusion  The report here characterized the composition, structure and expression of the expansin genes in AA and BB genomes, which probably advanced the genome differentiation and further confirmed the important status of expansins in species classification.
Application of the pipe model and the theory of water transpaortation pattern through tree rings in larch productivity productivity estimation
Liu Sheng, Zhang Youxiang, Li Xiang, Tian Jiaxin, Wang Wanru
Accepted Manuscript  doi: 10.13332/j.1000-1522.20200117
[Abstract](44) [FullText HTML](10) [PDF 883KB](11)
Abstract:
  Objective  On the basis of the pipe model and the theory of water transpaortation pattern through tree rings, we investigated the canopy productivity structure of Larix olgensis and leaf biomass models for four larch subspecies in order to provide a theoretical and technological background for evaluating canopy productivity and studying the pattern of water transportation throught tree rings.  Method  We analyzed the canopy productivity structure and fitted leaf biomass models with the data collected from canopy analysis, biomass sampling and dye tracer experiment in tree trunks, as well as comparing the selected predictors and the estimation accuracy of the models for different larch subspecies at different ages.  Result  (1) The sectional area of current-year ring of 11-year-old Larix olgensis at breast height accounted for 19.64% of the total sectional area capable of conducting water but provided the water transportation for 29.8% of the total canopy leaf area, indicating that the water transporation rate of the current-year ring was faster than others. (2) Based on the pipe model and the theory of water transportation pattern through tree rings, both leaf area and leaf biomass were affected to a certain degree by the water transportion capacity and branch mechanical support capacity, which were represented by two types of predictor variables that related to branch weight and water transportation capacity, respectively. (3) the biomass models with the two types of predictor variabels for the four larix subspecies had high estimation accuracy. (4) In order to facilitate the application, models with two predictors were fitted, and predicted values given by these reduced models were highly correlated to leaf biomass observations for the four larix subspeices. (5) We fitted an ANCOVA model of leaf biomass on sectional area of branch at base, with the four larix subspeices incorporated. Statistical tests for testing homogeneous intercept and slope showed that the slope and intercept for Larix gmelinii was significantly different from those for other three subspecies, and so was Larix principis from Larix leptolepis. In comparison, the difference between Larix principis and Larix olgensis was not significant. The results reflectd the differences in the canopy shape of the four larch subspecies.  Conclusion  The pipe model and theory of water trasportation pattern had a wide application prospect in studying tree productivity structure and productivity evaluation. According to this, explanatory variables for leaf biomass can be divided into two categories, related to branch weight and water trasportation capability, respectively. The fitted standard model and reduced models of leaf biomass could produce accurate estimates for the four Larix subspecies.
Expression and function analysis of histidine kinase gene of poplar ‘84K’
Lu Junqian, Wu Shu, Zhong Shanchen, Zhang Weixi, Su Xiaohua, Zhang Bingyu
Corrected proof  doi: 10.12171/j.1000-1522.20200070
[Abstract](63) [FullText HTML](27) [PDF 881KB](11)
Abstract:
  Objective  Abiotic stresses such as drought and salt seriously affect the growth and development of plants. Previous studies showed histidine kinase played important role during the process of plant responsing to abiotic stresses. In this study, we analyzed the expression of histidine kinase gene (PaHK3a) in root, stem and leaf of poplar ‘84K’ (P. alba × P. glandulosa ‘84K’). And the expression of PaHK3a in leaves of in vitro ‘84K’ plants under various plant hormones and abiotic stresses was also detected. Together with the malondialdehyde (MDA) contents, superoxide dismutase (SOD) and peroxidase (POD) activities in leaves of poplar ‘84K’ in green house, the function of PaHK3a was preliminary proposed. The results in this study laid a foundation for molecular breeding of poplar for resistance.  Method  Using in vitro poplar ‘84K’ as materials, the expression of PaHK3a gene in different organs, under plant hormone treatments (10 μM ABA, 10 μM 6-BA, 10 μM IBA, 10 μM GA3, and 10 μM SA) and various abiotic stress conditions (42 ℃, 0 ℃, 200 mmol/L NaCl, and 5% PEG6000), was analyzed by qRT-PCR. Meanwhile, the expression of PaHK3a in leaves of green house grown poplar ‘84K’ plants under drought (6, 8, 10 d) and salt stress (2, 4, 6 d) was also detected, and the MDA contents, SOD and POD activities were measured, and the correlation between expression of PaHK3a gene and physiological indicators was analyzed to determine the function of PaHK3a preliminarily.  Result  The expression of PaHK3a gene was highest in leaves, medium in roots and lowest in stems. The qRT-PCR results showed that the transcriptional levels of PaHK3a gene were about 2.63, 1.49, 1.54, 1.58 times of control, respectively under 42 ℃, 0 ℃, 200 mmol/L NaCl, and 5% PEG treatments. Under IBA treatment, the transcripts of PaHK3a were not significantly different from control. The expression of PaHK3a was down-regulated under the treatments of 6-BA, ABA, GA3 and SA, respectively. At different stress times of drought and salt treatment, the PaHK3a gene in leaves of greenhouse grown ‘84K’ plants increased significantly, with the style of increased first and then decreased; and the MDA content in leaves also had the similar style. SOD and POD activity were measured in drought and high salt, MDA content increased first and then decreased; SOD activity in leaves increased constantly during drought and salt stresses, and POD activity first increased and then decreased under drought stress, while increased constantly during salt stress. The correlation analysis between physiological indexes and PaHK3a gene expression found that under drought and salt stress, the expression of PaHK3a gene was positively correlated with MDA content, SOD and POD activity in leaves.  Conclusion  The PaHK3a was expressed in root, stem and leaf of poplar ‘84K’, with highest expression in leaf. The expression of PaHK3a was down-regulated by exogenous cytokinin (6-BA, GA3) and stress related plant hormones (ABA, SA), and up-regulated by temperature, salt and drought stresses. During the process of drought and salt stresses, the expression of PaHK3a increased significantly, with the increase of MDA content, SOD and POD activities, and it was positively correlated with MDA content, SOD activity and POD activity in leaves. Our results indicate that PaHK3a is involved in the response of poplar to plant hormones and plays an important role in poplar response to abiotic stresses.
Investigating the internal 3D structure changes of wood in compression using X-ray CT
Li Wanzhao, Zhang Zheng, Peng Junyi, Wang Xinzhou, Shi Jiangtao, Mei Changtong
Accepted Manuscript  doi: 10.13332/j.1000-1522.20200290
[Abstract](42) [FullText HTML](9) [PDF 951KB](5)
Abstract:
  Objective  Wood is production flexibility and have high strength/weight ratio. It has been widely applied in the decoration and construction fields in solid wood as well as wood-based panel formats. As bio-based porous materials, the internal structure of wood is prone to change in compression conditions, which has an essential impact on the mechanical performance of wood based materials. Hence, it is important to understand the interaction between loading force and internal structure changes of wood. This shall contribute to better understand and evaluate the mechanical performances of wood.  Methods  In order to investigate the internal structure changes of wood, samples from Douglas fir and poplar based panels were prepared. Douglas fir is a representative species for solid wood products. Poplar is regarded to be a commonly used raw material in wood-based panel industry. Solid wood sample from Douglas fir consists of both earlywood and latewood. Poplar wood based panel was produced by bonding two veneers together, with consistent grain direction, using phenol formaldehyde resin. X-ray computed tomography (X-ray CT) was used to monitor the internal structure of samples when they were compressed by a customized loading cell. The resolution of X-ray images was approximately 12 μm and one single scan consumed nearly 30 min. The compression conditions of customized load cell could be controlled by both loading wedge movement and loading force. In this test, the loading wedge displacement was used to control compression conditions. Specifically, the specimens were scanned when the loading wedge displacement was 0, 0.5, 1.0 and 2.0 mm respectively. The samples were compressed along growth ring directions. Based on the results from X-ray CT and loading cell, the mechanisms of mechanical performance of wood were discussed. The density distribution along samples’ thickness was analyzed. Internal structure of samples was visualized with 2D and 3D views.  Results  The results showed that the stiffness of Douglas fir is much higher than that of poplar. Density increase in Douglas fir sample mainly occurred in earlywood and density increase in latewood was found only at 25.26 MPa. Regional stress accumulation was the main causes of internal structure changes. Structural changes could be re-distributed as increasing the stress. The existence of glue can significantly enhance the stiffness of wood and we found that the morphology of wood vessels adjacent to the glue line was kept well during compression. Large vessels were prone to be collapsed during compression and route of collapsing were parallel to the growth ring. Internal structure changes in latewood mainly occurred as the squeeze of resin canals and the crack of rays.  Conclusion  The results obtained from this study could be used in optimizing the processing technology and application approaches of wood and wood based materials. Combining the X-ray CT and loading cell is a promising way to reveal the mechanisms of wood based materials under loading. In order to further reveal the internal structure changes in wood cell wall, studies with even better resolution are required. Hence, a possible solution is to combine X-ray CT with other techniques that can reach the nano-scale resolutions.
Preliminary analysis on the selection of sleeping sites by Hainan Gibbons (Nomascus hainanus) in Hainan Tropical Rainforest National Park, China
Tang Weilu, Jin Kun
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200185
[Abstract](66) [FullText HTML](23) [PDF 827KB](6)
Abstract:
  Objective  This paper aims to explore the relationship between Hainan gibbons and sleeping sites, understand their selection and utilization of sleeping sites, and provide a scientific basis for the conservation and habitat management of Hainan gibbons.  Method  From July to September 2019, in the area of Bawangling National Nature Reserve in Hainan Tropical Rainforest National Park, four family groups of Hainan gibbons were taken as the research objects to study their selection of sleeping trees and sites. A total of 74 sleeping plots and 515 sleeping trees were investigated using the method of quadrat survey, and the species and ecological factors of sleeping trees were determined. Two independent samples were used for Mann-White U test and stepwise discriminant analysis to determine the key factors influencing the selection of sleeping trees used by Hainan gibbons. The selection index and selection coefficient were used to analyze the preference of Hainan gibbons for ecological factors of sleeping sites.  Result  This study found that there were 83 species of sleeping trees used by Hainan gibbons, belonging to 62 genera and 38 families, all of which were arbors. The largest number of tree species in the sleeping trees were Castanopsis tonkinensis and Lithocarpus amygdalifolius. The largest number of families was Fagaceae, and the largest number of genera were Castanopsis, Cyclobalanopsis and Lithocarpus. Compared with non-sleeping trees, Hainan gibbons preferred to choose sleeping trees with a larger diameter at breast height (DBH), higher height, larger crown and higher height under branch. According to the contribution value, the ecological factors that affected the selection of sleeping trees used by Hainan gibbons were ranked in the order of the tree DBH, crown diameter, height and height under branch. In the selection of sleeping sites by Hainan gibbons, they preferred to sleep in areas with an altitude of 800 ~ 1 000 m, a slope of 15° ~ 30°, a semi-sunny and semi-shady slope, and hillside. Hainan gibbons preferred to sleep at night in the mountain rainforest where the tree density was 60 ~ 90/900 m2, the tree DBH was 20 ~ 30 cm, the tree height was 15 ~ 20 m, the tree height under branch was 5 ~ 15 m, the vine density was ≤ 5/900 m2, the vine DBH was 5 ~ 10 cm, and the canopy density was 50% ~ 75%. Hainan gibbons preferred to sleep at night in habitats 2 ~ 4 km from roads, ≤ 10 km from human settlements and ≤ 500 m from water sources.  Conclusion  Therefore, it can be seen that Hainan gibbons have a certain preference for sleeping trees and sleeping sites. The selection of ecological factors may be related to the stability and comfort of the environment, the availability of food, the reduction of predation risk and thermoregulation.
Soil nutrients and ecological stoichiometry characteristics of different plantations in the alpine region of the Loess Plateau
Liu Ruosha, Wang Dongmei
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200149
[Abstract](45) [FullText HTML](16) [PDF 746KB](11)
Abstract:
  Objective  By analyzing the changes of soil nutrients and ecological stoichiometry in different plantations and different soil layers in the alpine region of the Loess Plateau, the aim is to clarify the soil nutrients and stoichiometry characteristics under different plantations, and to reveal the laws of soil nutrients and stoichiometry changes with soil depth.  Method  In this paper, plantations (including Picea crassifolia, Larix principis-rupprechtii, Populus cathayana, Betula platyphylla) in the alpine region of the Loess Plateau in Qinghai Province were taken as the research objects, and the grassland of natural conversion and cropland were taken as the control. And the C, N and P contents and stoichiometry ratios of six vegetation types in 0 ~ 20 cm, 20 ~ 40 cm and 40 ~ 60 cm soil layers were determined.  Result  It is concluded that: (1) The soil C and N contents of different plantations in the alpine region of the Loess Plateau were significantly different (P < 0.05), and the difference of soil P content was partially significant. The C and N contents in each soil layer of plantations were significantly higher than those of grassland and cropland, and the organic carbon and total nitrogen contents in 0 ~ 20 cm topsoil of Populus cathayana were the highest, which were 25.82 and 2.17 g/kg respectively. (2) The soil ecological stoichiometry of different plantations in the alpine region of the Loess Plateau were significantly different (P < 0.05). The C∶N ratio of plantations in 0 ~ 60 cm soil layer was significantly lower than that of cropland, while the C∶P and N∶P ratios were higher than those of grassland and cropland (P < 0.05). The ecological stoichiometry of Populus cathayana in 0 ~ 20 cm topsoil was higher than that of other plantation types, with C∶N, C∶P and N∶P being 11.99, 43.27 and 3.64 respectively. (3) Correlation analysis showed that the organic carbon in the study area had the closest correlation with total nitrogen (P < 0.01), the total nitrogen had the closest correlation with soil C∶N and N∶P (P < 0.01), and the organic carbon had the closest correlation with soil C∶P (P < 0.01). This indicated that the responses of soil C and N in the study area to different plantations were consistent. The soil C∶N and N∶P ratios were mainly affected by total nitrogen, and the C∶P ratio was mainly affected by organic carbon. (4) In the 0 ~ 60 cm soil layer, the soil C, N and P contents of the different vegetation types decreased with the increase of soil depth in the alpine region of the Loess Plateau. The soil ecological stoichiometry of the vegetation in the study area had no significant change trend except for Populus cathayana which decreased with the increase of soil depth. This indicated that plantations had the best improvement effect on the surface soil nutrients.  Conclusion  Soil nutrients and ecological stoichiometry were significantly different in different plantations, and the nutrient content and stoichiometry of Populus cathayana in topsoil were the highest. Soil nutrients decreased with the increase of soil depth, while soil ecological stoichiometry did not change significantly with soil depth.
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
Accepted Manuscript  doi: 10.12171/j.1000-1522.20170359
[Abstract](1451) [FullText HTML](947) [PDF 1088KB](119)
Abstract:
  Objective  This 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.  Method  Based 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 speed  Conclusion  Based 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.
Comparation in essential oil components of different altitudes and varieties of Paeonia rockii
Wu Yi, Hu Jianzhong, Han Xue, Yin Liqiang, Yuan Weiqiong, Zhao Qianlong, Lv Zhaolin
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190304
[Abstract](0) [PDF 0KB](0)
Abstract:
ObjectiveThe composition of essential oil which was extracted from different altitudes and varieties of Paeonia rockii were studied, and the differences and similarities of the composition of compounds were also explored.MethodIn this experiment, Paeonia rockii essential oils were prepared from different altitudes of the same species and different varieties at same altitudes. The essential oil content and composition of Paeonia rockii were analyzed.ResultThe study has shown that different oils of different varieties of Paeonia rockii essential oil have different oil content, white Paeonia rockii essential oil has the highest oil content, reaching 10.94%, purple Paeonia rockii is the next, which is 10.31%, while the No. 3 pink Paeonia rockii essential oil has the lowest oil content, 7.47%. A total of 70 compounds were detected in three different altitude gradients (1, 2, and 3), and 54 species, 53 species, and 57 compounds were detected in the first, second, and third grounds, respectively. The ingredients were geraniol (5.07%、13.87%、13.74%), tetradecane (5.99%、9.86%、7.25%),7-dodecen-1-ol-acetate (35.16%、29.16%、25.01%), dodecane (7.26%、6.29%、7.32%) and tricosane (8.00%、6.36%、8.11%); A total of 75 compounds were detected in three different varieties (white, pink, purple) of Paeonia rockii essential oil, and 59, 54 and 62 species were detected in white, pink and purple Paeonia rockii. The main components were geraniol (3.91%、5.07%、9.52%), tetradecane (15.93%、5.99%、8.96%), 7-dodecen-1-ol-acetate (19.79%、35.16%、22.91%), dodecane (12.40%、7.26%、6.60%) and tricosane (7.83%、8.00%、6.37%). Although the five kinds of Paeonia rockii essential oils of different varieties at different altitudes are mainly composed of the above five components, the content varies greatly. At the same time, the other components in the essential oils also have large differences in species, quantity and content.ConclusionThis study can provide basic theoretical support for the selection of growth conditions, identification of species and the wide application of essential oil of Paeonia rockii.
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](631) [FullText HTML](298) [PDF 1031KB](42)
Abstract:
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.
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](914) [FullText HTML](542) [PDF 1004KB](67)
Abstract:
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.
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](1110) [FullText HTML](627) [PDF 1799KB](73)
Abstract:
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.
contents
2020, 42(12): 1-2.  
[Abstract](16) [FullText HTML](3) [PDF 319KB](2)
Abstract:
Forest Sciences
Research on stem taper equation of Scots pine based on generalized additive model
He Pei, Xin Shidong, Jiang Lichun
2020, 42(12): 1-8.   doi: 10.12171/j.1000-1522.20200094
[Abstract](90) [FullText HTML](25) [PDF 3341KB](23)
Abstract:
  Objective  Based on the theory of generalized additive model, stem taper equation was constructed for Scots pine (Pinus sylvestris). Accurate variable exponent taper equations such as Zeng et al. (1997), Bi (2000) and Kozak (2004) in forestry were used for comparison.  Method  The generalized additive taper equation was constructed using DBH, tree height, the height at different stem parts, the diameter at different tree heights and their transformation based on taper data of Scots pine. The model was fitted using the gamm function in mgcv library of the R software. Six smooth splines were chosen for fitting process, i.e. B-spline function (BS), cubic regression spline function (CR), Duchon spline function (DS), Gaussian process smooth spline function (GP), P-spline function (PS) and thin plate regression spline function (TP). The models were validated using leave-one-out cross-validation method.  Result  (1) The optimal generalized additive model form of taper equation was constructed by response variable relative diameter and explanation variable square of DBH, total height and the square root of relative height. (2) The fitting results showed that the generalized additive taper equations were similar and better than parametric taper equation except for CR function. (3) The cross validation results showed that the generalized additive models (BS, DS, GP, PS and TP) were basically consistent with the fitting results except for CR, i.e. they were superior to parametric taper equation of Zeng et al. (1997), Bi (2000) and Kozak (2004). The BS model had the highest prediction accuracy in the generalized additive models. Kozak (2004) had the highest prediction accuracy in the variable exponential taper equations. (4) Through the simulation of stem curves of BS and Kozak (2004) models, it was found that Kozak (2004) had a large error in predicting the upper part of the stem of a small tree. However, BS had higher accuracy in simulating small tree and large tree.  Conclusion  The generalized additive model is a nonparametric method for constructing taper equation. The generalized additive taper equation based on BS spline has the highest prediction accuracy. It’s suitable for the prediction of the shape of Scots pine.
General methods for quantitative assessment of in-forest landscape quality of urban forest
Cui Yi, Liu Haixuan, Lü Jiao, Wu Jü, Xu Lijuan, Wei Liuduan, Yu Yulei, Xu Chengyang
2020, 42(12): 9-23.   doi: 10.12171/j.1000-1522.20200064
[Abstract](76) [FullText HTML](29) [PDF 639KB](19)
Abstract:
  Objective  In view of the problems existing in the study of in-forest landscape quality assessment of urban forest, such as many theoretical studies, poor unification in assessment index systems, a regional universal in-forest landscape quality evaluation index system of urban forest was constructed, and the classification standard of in-forest landscape was proposed, which could provide technical support for the optimization of urban forest structure, management and production practice.  Method  Four types of urban forests, including scenic-recreational forest both in urban park and country park, urban forest of residential areas and scenic forest of suburban mountainous areas, were taken as the research objects. The evaluation indicators were selected on the scale of forest stand, the comprehensive quality index of forest structure quality was constructed by factor analysis, and the in-forest landscape quality grade of urban forest was classified by TOPSIS method and cluster analysis.  Result  (1) Fifteen evaluation indices were selected based on four types of urban forest and were used for evaluation of in-forest landscape of urban forest. The in-forest landscape of urban forest was divided into four grades: excellent, high, medium and low. (2) The in-forest landscape quality evaluation index system of urban forest was established, the core indicators including tree species richness (TSR), species richness under canopy (SRC), the forest type (FT), cleanliness of the forest stand (CFS), dispersion of DBH (DDBH), canopy coverage (CC), ornamental organ diversity (OOD), seasonal abundance (SA), breast height basal area per hectare (BAH), ratio of crown width to diameter (RCWD), etc. (3) The index characteristics of the optimal landscape of different types of urban forests were not exactly the same. Scenic-recreational forest of urban park: relative under branch height (RBH) was the smallest, ratio of diameter-height (RDH) was smaller, RCWD was larger, CFS was high. Urban forest of residential areas: BAH was the largest, RBH was the smallest, RCWD was smaller, SA was high. Scenic-recreational forest of country park: BAH, dispersion of tree height (DTH) and RDH were the largest, tree species were the most, with diverse ornamental organs, mostly mixed forest. Scenic forest of suburban mountainous areas: CC was moderate, relative shrub height (RSH) was the lowest, stand vertical stratum (SS) and species under the canopy were richer, CFS was high.  Conclusion  Seen as a whole, forests or landscapes which are of abundant tree species, mixed moderately, neat in-forest condition, both dispersion of DBH and canopy coverage are suitable, and with abundant ornamental organs and seasonal changes are more popular. The optimal range of stand density and RCWD is different for varied types of urban forest. In the management of urban forests, it is suggested to enrich the tree species appropriately, pay attention to the configuration of colored plants and multi-seasonal tree species, adjust the density of the forest properly, timely pruning, cutting and irrigation, remove litter and domestic garbage under the forest, keep the forest tidy, and give different managerial measures timely according to different urban forest types to improve its landscape quality.
Design and application of assistant program for county-level forest management planning
Hu Zhongyang, Liu Ruizhi, Liu Ping
2020, 42(12): 24-31.   doi: 10.12171/j.1000-1522.20200078
[Abstract](66) [FullText HTML](16) [PDF 778KB](16)
Abstract:
  Objective  In order to ensure ecological security at a national scale and improve forest quality, the former National Forestry Administration issued the “Guidelines for the Preparation of County-Level Forest Management Planning” in 2018. All the counties and cities across the country were first time required to complete a county-level forest management planning and to consider the plans as a guideline document for county-level forest management in the next thirty years. Since conducting the county-level forest management planning needs high-level specializations with great amount of work, computer programs are practically significant for effectively completing high-quality plans.  Method  Based on the MATLAB 2014a platform and the “Guidelines for the Preparation of County-Level Forest Management Planning”, a computer program package was developed using MATLAB language to assist in preparing the county-level forest management planning.  Result  The computer program package consists of more than six modules used for data preprocessing, working group of silviculture organization, silvicultural system design, forest management district classification, investment estimation, export of forest management database, etc. The programs were applied to prepare forest management planning of Fengkai County, Haifeng County, Gaozhou City, Huazhou City, Xinyi City, and Shunde District of Foshan, Guangdong Province of southern China. The results show that the computer programs work well in accomplishment of the forest management relevant tasks.  Conclusion  The computer programs have friendly user interfaces and are easy to learn and use with characteristics of reliability and stability and ability of extension. The programs can be utilized to greatly improve the quality and efficiency of conducting forest management planning and also to assist in other relevant forestry survey planning and design.
Spatiotemporal distribution and seed germination characteristics of Betula costata seed rain in the spruce-fir mixed forest
Cheng Fushan, Zhou Mo, Wu Mengjia, Jiang Runhua, Guan Naiqian, Wang Yuwen, Wang Shuo, Xia Fucai
2020, 42(12): 32-39.   doi: 10.12171/j.1000-1522.20200077
[Abstract](150) [FullText HTML](34) [PDF 720KB](29)
Abstract:
  Objective  The population of Betula costata in spruce-fir mixed forest in northeastern China was taken as the research object. The spatiotemporal distribution of Betula costata seed rain and seed germination characteristics were studied to provide theoretical basis for species diversity protection of the forest.  Method  Based on the 9 sample plots, 1 ha (100 m × 100 m) each set in Wangqing Forestry Bureau, Jilin Province of northeastern China, sampling by diagonal five points, we set 5 seed traps in each sample plot, totally 45 in 9 sample plots to collect Betula costata seeds. We used 4 evaluation methods on spatial distribution types to distinguish the spatial distribution state of seed rain, including variance-mean ratio (Cx), negative binomial parameter (K), aggregation index (I), Cassie. R.M. index (CA). In addition, 300 Betula costata seeds collected in September and October were randomly selected from each sample plot for seed germination experiment, and the 1 000-grain mass, germination potential and germination percentage were measured, respectively.  Result  From July to November, 69 100 seeds were collected in total. The peak period of seed falling for Betula costata was October. We found that the seeds of Betula costata presented aggregation distribution at the spatial level based on 4 indexes, i.e. Cx reaching 1 116.30, K reaching 4.75, I reaching 1 115.30, CA reaching 0.41, respectively. The average 1000-grain mass value of Betula costata seeds in September was 0.398 g, which was significantly higher than that in October (0.353 g) (P<0.01). Similarly, the average germination rate in September was (29.84 ± 11.68)%, which was significantly higher than that in October (23.52 ± 8.23)% (P < 0.05).  Conclusion  In spruce-fir coniferous-broadleaved mixed forest, the seeds are small and fruiting for Betula costata and have obvious time distribution characteristics. Because the diffusion of Betula costata seeds is limited, as a result the seeds show an aggregated distribution pattern. In this region, the characteristics of rich provenance and poor germination ability of Betula costata will affect the distribution pattern of Betula costata, thus affect the community structure and species diversity of spruce-fir coniferous-broadleaved mixed forest in this area.
Genetic diversity analysis of Chionanthus retusus natural population based on SRAP molecular markers
Qu Kai, Guo Haoping, Wang Baorui, Zhou Wenling, Hou Lili, Li Qin, Li Jihong, Cheng Tiantian
2020, 42(12): 40-50.   doi: 10.12171/j.1000-1522.20200212
[Abstract](139) [FullText HTML](40) [PDF 893KB](9)
Abstract:
  Objective  This paper aims to reveal the genetic diversity of natural populations of Chionanthus retusus in different regions of China, and to provide a scientific basis for rational protection development and utilization.  Method  The genetic diversity and population genetic structure of 62 samples from 7 Chionanthus retusus natural populations in different regions were studied using sequence related amplified polymorphism (SRAP) molecular marker technique.  Result  Seven natural populations of Chionanthus retusus had higher genetic diversity, and 8 pairs of SRAP primers amplified a total of 1 728 clear bands, of which 1 649 were polymorphic, and the percentage of polymorphic bands (PPB) was 95.43%. The number of effective alleles between populations was 1.213 7, the diversity of Nei’s gene was 0.153 7, and the information diversity index of Shannon’s was 0.268 0. There were higher levels of intra-population genetic variation and lower levels of inter-population genetic variation among natural populations of Chionanthus retusus (Gst = 0.133 6), and higher levels of gene flow among seven natural populations of Chionanthus retusus (Nm = 3.243 7). The genetic similarity coefficient between Chionanthus retusus populations ranged from 0.898 0 to 0.973 6, with an average of 0.934 4. The Mantel test (r = 0.288, P = 0.205) and the clustering among populations proved that there was no significant correlation between genetic distance and geographical distance among populations. The clustering results of 62 primary germplasm showed that most of the germplasms were characterized by the fact that most individuals in the same population came together, and some germplasms had the phenomenon that individuals of different populations gathered together, showing that the genetic variation between populations was relatively stable and the level of genetic variation within the populations was relatively high, which was consistent with the results of genetic diversity analysis.  Conclusion  Comprehensive multi-factor analysis speculated that Taihang Mountain area may be the main producing area of Chinese Chionanthus retusus germplasm resources.
Characteristics of soil microbial biomass C, N and nutrients in young plantations of Parashorea chinensis
Li Wannian, Huang Zeyue, Zhao Chunmei, Yang Mei
2020, 42(12): 51-62.   doi: 10.12171/j.1000-1522.20200191
[Abstract](154) [FullText HTML](35) [PDF 893KB](32)
Abstract:
  Objective  Parashorea chinensis is a tropical rainforest species and a national first class endangered tree species, and the artificial cultivation is an important way to expand its population size. This study analyzed the soil physicochemical properties, soil microbial biomass carbon (SMBC), nitrogen (SMBN) and soil nutrient contents with their stoichiometric characteristics in different stands and soil layers of the young P. chinensis plantation, providing referable evidence for the optimal selection of mixed tree species and soil management.  Method  The standard sites were set up in P. chinensis artificial pure and mixed plantations and the soil samples of different soil layers were collected by diagonal method. The soil pH value, organic matter and nutrient content, SMBC and SMBN content were measured, further it was discussed about the effects of different stands and soil layers on the contents of SMBC and SMBN and the soil quality by ecological stoichiometry and principal component analysis.  Result  (1) The vertical distribution characteristics of SMBC, SMBN and soil nutrient content decreased with the deepening of soil depth, different stand types had no obvious effect on its vertical distribution. (2) The average soil C∶N∶P of P. chinensis plantation was 35∶2∶1, average SMBC∶SMBN was 8∶1. The composition of different tree species significantly affected the changes of soil nutrients, SMBC, SMBN and their stoichiometric ratio, the mixed plantation of P. chinensis and Eucalyptus grandis × E. urophylla could improve the soil microbial activity, soil texture and microenvironment. (3) Correlation and principal component analysis revealed that: the soil microorganism in Parashorea chinensis plantation could maintain a certain internal stability through self-regulation, and SMBC, SMBN might be used as early biological indicators of changes in soil nutrient reserves and C, N sources. The mixed P. chinensis and Eucalyptus grandis × E. urophylla plantation had the most significant effect on soil microecological function, quality and fertility, which suggested that this stand type could be more favorable for the growth of soil microorganism and the development of soil nutrients in young Parashorea chinensis forest land.  Conclusion  The contents of SMBC, SMBN and nutrients with their stoichiometric characteristics of P. chinensis plantation show obvious surface accumulation effect, and the composition of tree species has no obvious effect on its vertical distribution. Compared with the pure plantation, the P. chinensis mixed plantation has more significant effect on soil microbial environment and soil quality. Particularly, the mixed plantation of P. chinensis and Eucalyptus grandis × E. urophylla better improve the function of microorganism and soil structure as well as the activation of nutrients, indicating that this mixed pattern can be selected as the appropriate choice for young P. chinensis plantation and one of the suitable transformation ways for pure Eucalyptus plantation.
Distribution of soil nitrogen components of Wenshan typical subtropical forests along an altitude gradient and its influencing factors in Yunnan Province of southwestern China
Li Cong, Lu Mei, Ren Yulian, Du Fan, Tao Hai, Yang Luoping, Wang Dongxu
2020, 42(12): 63-73.   doi: 10.12171/j.1000-1522.20200252
[Abstract](154) [FullText HTML](40) [PDF 1081KB](66)
Abstract:
  Objective  The paper is aimed to explore the variations in soil nitrogen pools along an altitude gradient and its coupling relationship with environmental factors in the Wenshan Nature Reserve, Yunnan Province of southwestern China, and provide scientific basis and references for the assessment of soil quality in the reserve.  Method  Three typical vegetation types were selected to investigate the variation of soil nitrogen components along the altitude gradient in Wenshan Nature Reserve. The association of soil nitrogen components to environmental factors was analyzed through principal component analysis.  Result  (1) Total nitrogen, hydrolyzable nitrogen, ammonium nitrogen and nitrate nitrogen increased significantly along an altitude gradient (P < 0.05), with the maximum occurred in mid-mountain humid evergreen broadleaved forest. In particular, total nitrogen and hydrolyzable nitrogen increased by 1.17 g/kg and 142.05 mg/kg, respectively. (2) The ratio of soil nitrogen components to total nitrogen pool varied with altitudes. Compared with the subtropical monsoon evergreen broadleaved forest at the lowest altitude, the ratio of hydrolyzable nitrogen and nitrate nitrogen decreased by 9.1% and 0.26%, while that of ammonium nitrogen increased by 0.61% in mid-mountain humid evergreen broadleaved forest at the highest altitude. (3) The environmental factors changed significantly along an altitude gradient. Along the altitude gradient, litter thickness, soil moisture and nutrients (i.e. total organic carbon, available phosphorus and available potassium) increased, while plant diversity and soil temperature decreased. (4) Principal component analysis showed that the increases in litter thickness and soil total organic carbon along the altitude gradient were the main factors determining the accumulation of total nitrogen, while the reduction of plant diversity and soil bulk density contributed mainly to increase in total nitrogen. The increase of soil moisture along the altitude gradient was the main factors for accumulating inorganic nitrogen, whereas the change of soil available phosphorus and potassium had main contribution to accumulating hydrolyzable nitrogen.  Conclusion  Soil nitrogen is sensitive to the changes of environment along an altitude gradient in Wenshan Nature Reserve. Altitude gradient mainly affects litter input, microclimate (hydrothermal conditions), soil firmness (soil bulk density) and soil nutrients (e.g. total organic carbon, available phosphorus and available potassium), and then indirectly or directly regulates the changes of nitrogen composition.
Effects of rhizosphere soil addition of different aged Chinese fir plantation on the mycorrhizal colonization and growth of its seedlings
Xu Xiaochong, Wang Xinjie, Lu Nini, Zhao Yun, Lin Chen, Dong Boyuan, Li Jiani
2020, 42(12): 74-82.   doi: 10.12171/j.1000-1522.20200044
[Abstract](173) [FullText HTML](42) [PDF 682KB](23)
Abstract:
  Objective  This paper aims to study the effects of rhizosphere soil addition of different aged Chinese fir plantation on the growth of aseptic seedlings of it, and to provide a theoretical basis for the mycorrhizal seedlings of Chinese fir.  Method  The aseptic seedlings of 4 months old Chinese fir were transplanted into aseptic substrate soil, and (150 ± 2) g of rhizosphere soil (RS1), middle-aged rhizosphere soil (RS2), near mature rhizosphere soil (RS3), mature rhizosphere soil (RS4) and over mature rhizosphere soil (RS5) were added near the roots of seedlings. The nutrient content, pH and spore density of arbuscular mycorrhizal fungi (AMF) in rhizosphere soil were measured before adding. The AMF colonization rate, nutrient content and pH of substrate soil, morphological index and biomass of Chinese fir seedlings were measured one year after transplanting.  Result  There were differences in nutrient content, pH and AMF spore density in rhizosphere soil of Chinese fir plantation of different ages. The addition of AMF significantly promoted the colonization rate of Chinese fir seedlings. There was a significant positive correlation between AMF infection rate and AMF spore density in rhizosphere soil of the Chinese fir stand. The colonization rate showed the rule of RS5 > RS4 > RS3 > RS1 > RS2 > CK. The addition of rhizosphere soil also promoted the growth of seedlings, such as ground diameter, seedling height, root length, crown width, number of basal branches and biomass accumulation. The addition of RS5 was better than the other four types of rhizosphere soil.  Conclusion  The rhizosphere soil of Chinese fir stand can be used as a fungicide adding to the seedling of Chinese fir, increasing the colonization rate of mycorrhizal roots, and promoting the high-quality growth of seedlings, which has a great practical value to the seedlings of Chinese fir and the application of mycorrhizal fungi in forestry.
Characteristics of Lycium ruthenicum adapting to salinization stress after salt tolerance training
Feng Lei, Xu Wanli, Tang Guangmu, Zhang Yunshu, Gu Meiying
2020, 42(12): 83-90.   doi: 10.12171/j.1000-1522.20200123
[Abstract](89) [FullText HTML](43) [PDF 893KB](18)
Abstract:
  Objective  For soil salinization restoration and sustainability in extreme arid areas, we investigated Lycium ruthenicum adapting to long-term salinization stress.  Method  The K+, Na+ and Ca2+ compartmentalization of organs of L. ruthenicum in low salt stress (MSS), middle salt stress (HSS) and high salt stress (SS) soil were analyzed by regression analysis and principal component analysis, as well as the responses of dry mass and root morphology to salt stresses.  Result  (1) If concentration of NaCl at soil solution was below 183.63 mmol/L, the survival rate of salt-tolerance training plants increased with increasing concentration of NaCl, and all the plants died if concentration of NaCl was above 355.88 mmol/L. With increase of NaCl concentration, the relative growth rate of fruit significantly slowed down from flowering to early fruit, while accelerated from early fruit to full maturity. (2) The root K+ and Na+ treated by HSS were significantly higher than those treated by MSS and SS, and the contents of K+, Na+ and Ca2+ in stems were significantly lower than those treated by MSS and SS. There was significant differences neither K+/Na+ nor Ca2+/Na+ between roots and stems in HSS. The leaf Ca2+ in SS treatment was 5 and 3 folds of MSS and HSS, respectively. There was no significant difference in Na+ content between roots and stems, and no significant difference in Ca2+ content between roots and leaves. The stress increased from MSS to SS, the content of Na+ in the stem increased by 0.78 g/kg on average. (3) PCA analysis showed that principal component 1 (PCA1) and principal component 2 (PCA2) explained 73.9% information of L. ruthenicum under salt stress. PCA1 explained 57.8% of the salt stress of L. ruthenicum. Among them, dry mass of over-ground organs contributed the most to PCA1. According to these contributions to PCA1, leaf dry mass, stem dry mass, root dry mass and taproot diameter were to be top four. PCA1 was negatively correlated with Na+ content both in roots and aboveground organs and lateral root diameter. Plant height, root Ca2+ content, stem diameter, aboveground organ K+/Na+, root dry mass and taproot diameter were positively correlated with PCA1. The content of plant K+/Na+, root K+/Na+, rhizosphere soil K+/Na+, root Ca2+ and aboveground organ Ca2+ could explain 16.1% of PCA2.  Conclusion  With the increase of salt stress, leaves maintained high concentration of Ca2+ to regulate plant K+/Na+, and root and stem enrichment and storage capacity of Na+ were significantly enhanced, which indicate that L. ruthenicum tends to share salt stress cooperatively in different organs to adapt to long-term salt stress after salt tolerance training.
Effects of site conditions on biomass allocation patterns of Caragana korshinskii in arid aeolian sand regions, middle area of Ningxia of northwestern China
Xu Hao, Wu Hongyue, Wang Zhanjun, He Jianlong, Wu Xudong
2020, 42(12): 91-100.   doi: 10.12171/j.1000-1522.20200162
[Abstract](174) [FullText HTML](54) [PDF 812KB](23)
Abstract:
  Objective  This paper aims to recognize the effects of site conditions on the allocation law of Caragana korshinskii biomass in the arid aeolian sand regions, and research the adaptability of Caragana korshinskii in the middle area of Ningxia, northwestern China.  Method  Based on biomass data obtained from 109 Caragana korshinskii shrubs in Baijitan Sand Prevention and Control Forest Farm, site conditions (slope aspect, altitude (1 218−1 476 m) and slope degree) were standardized to zero dimension. Then, permutational multivariate analysis of variances (PERMANOVA) with Euclidean distance and Bray-Curtis distance was used to study the relative impact of site conditions on the shrub biomass allocation patterns (leaf biomass fraction(LMF), stem biomass fraction (SMF), root biomass fraction (RMF) and root shoot ratio (R/S)) and comprehensive characteristics.   Result  (1) Slope aspect had the greatest degree of interpretation on LMF and SMF, and the interpretation degree factor (R2) was 0.144 5 and 0.281 0, respectively; altitude had the greatest degree of interpretation on RMF and R/S, and R2 was 0.296 7 and 0.295 7, respectively. (2) In the interaction of site factors, the interaction of altitude and slope degree had significant influences on RMF and R/S (P < 0.05), while the interaction of slope aspect, altitude and slope degree had significant influences on SMF and R/S. (3) The multivariate analysis of variance based on Euclidean distance and Bray-Curtis distance showed that, the comprehensive impact of slope aspect, aititude, and slope degree on shrub biomass allocation was significant (P < 0.05), among which, the impact of slope aspect (R2 = 0.232 2, 0.235 7) > aititude (R2 = 0.221 3, 0.221 1) > slope degree (R2 = 0.035 8, 0.029 2). In the influence of multi-factor interaction, the two-way interactions of altitude and slope degree and three-way interactions of slope aspect, altitude and slope degree had significant effects on shrub biomass allocation patterns (P<0.05).   Conclusion  Different site conditions showed different influences on shrub biomass allocation patterns. This study establishes the influencing degree of site conditions on shrub biomass allocation patterns for Caragana korshinskii, which provides a scientific basis for further study of shrub carbon sink and the ecological significance of shrubs in the arid aeolian sand regions.
Landscape Architecture
Numerical simulation study on the influence of greening between buildings on sunlight conditions of building in residential area
Liu Fangni, Yin Hao, Zhou Xu
2020, 42(12): 101-114.   doi: 10.12171/j.1000-1522.20200039
[Abstract](60) [FullText HTML](17) [PDF 1807KB](4)
Abstract:
  Objective  Good building lighting condition is an important factor to ensure the hygiene of the room, improve the microclimate and the comfort of the living environment. Studying the impact of greening between buildings on the sunlight conditions of building and analyzing the influencing degree and specific influencing factors can be used to optimize the construction of plant community and improve green space environment and landscape in the residential areas.  Method  Taking the green space between multi-storey residential buildings in Beijing as the object of the study, we used Photoshop, Image-Pro Plus and Rhino to calculate the crown porosity of plants and establish the models of plants and buildings; and Ecotect Analysis to simulate the lighting situation in Beijing. By analyzing the sunlight situation of the buildings on the north side of green space between the buildings in the Great Cold day, the paper explores various factors affecting the lighting of the buildings.  Result  (1) Fifty species of woody plants commonly were used for greening in the study area. The proportion of arbors in the plant structure was high and the growth was at a high level. (2) The influence of building orientation on the lighting conditions was shown as follows: the building oriented south had the best lighting conditions; when the building skew angle was the same, influenced by the longitude and latitude of Beijing area, the building oriented east had better lighting conditions than the building oriented west. With the decrease of distance between buildings and the increase of the length of buildings, the sunshine hours of buildings decreased. (3) The general performance of the survey sample (85%) was that greening had seriously affected building lighting. The light surface of the sample building was generally affected by a large area, and the number of hours of sunlight was significantly reduced. The impact range was mainly concentrated on the 1−4 floor. The inter-building greening, which had a significant impact on building lighting, was mainly characterized by too many evergreen trees, too large plant size, and too close the distance between plants and buildings. When the distance between arbor and building was less than 5 m, it will have a great impact on the daylighting of the building; when it is longer than 5 m, it will still have an effect on the low floors of the building.  Conclusion  (1) The basic characteristics of greening between buildings are that there are a great number of arbor species and small number of evergreen species, and the high-frequency application of small number of evergreen species is an important reason for the adverse effects of building lighting conditions. (2) The layout of the building itself will affect the lighting of the lower floors of the building. (3) The greening between buildings significantly affects the lighting of buildings. The main influencing factors are the plant volume, followed by the distance between plant and building, and the porosity of the plant canopy.
Influence of vegetation and architecture on microclimate based on Envi-met: a case study of Nanjing Agricultural University
Geng Hongkai, Wei Xiao, Zhang Mingjuan, Li Qingwei
2020, 42(12): 115-124.   doi: 10.12171/j.1000-1522.20190418
[Abstract](117) [FullText HTML](34) [PDF 715KB](17)
Abstract:
  Objective  Studying the influence of architecture and vegetation on the site microclimate under the summer thermal environment can provide a basis for the design and planning of dense architectural landscape and surrounding green spaces.  Method  This paper takes three representative buildings of Nanjing Agricultural University as an example, combined with the field measurement and Envi-met simulation, and introduces the consistency index, root mean square error, and average absolute deviation as quantitative evaluation indicators to verify the accuracy of software simulation; selecting 06:00−18:00 time period data, combined with a variety of analysis methods such as mean comparison, correlation test, general linear model, etc., to explore the impact of buildings and vegetation on microclimate.  Result  Vegetation and architecture had an impact on the microclimate, and there was a certain interaction between the above two. In the absence of vegetation, the building orientation had a significant effect on the microclimate. The cooling and humidification effects of the north and west sides of the building were relatively good; the closer the distance of vegetation to the building was, the better the cooling and humidification effect of sample point was; without the influence of architecture, the vegetation had a significant impact on the microclimate, which was manifested by cooling and humidification, making the environment more comfortable. When considering the effects of architecture and vegetation on temperature, there was no significant interaction between each factor of architecture and vegetation; when considering the effects of architecture and vegetation on humidity, there was a significant interaction between each factor of architecture and vegetation; when comprehensively considering the effects of architecture and vegetation on PMV, there was a significant interaction between the relative position of sample points as well as building and the tree coverage. Under the joint action of architecture and vegetation, there was a significant correlation between the relative orientation of sample point and architecture and site humidity as well as PMV; there was a significant correlation between three-dimensional green amount of vegetation and PMV.  Conclusion  Based on the more comfortable microclimate conditions on the north and west sides of architecture, the green space is more suitable as a place for staying and resting. When developing the functions of the east and south sides of the building, appropriate vegetation should be planted to improve the environmental comfort; the micro-climate comfort in the enclosed space formed by the external contour of the building and the terrain and vegetation was higher. Vegetation coverage can effectively improve the microclimate: as the amount of green increases, the thermal comfort of the sample area improves, and different types of plant communities show a significant cooling and humidifying effect compared with the non-greening ground.
Forestry Engineering
Compensation control of woodworking feeding platform based on self-adaptive genetic optimization recurrent neural network
Zhu Li, Ma Jingyao, Meng Zhaoxin, Shi Jinsong, Xing Xin, Jiang Zhongjin
2020, 42(12): 125-134.   doi: 10.12171/j.1000-1522.20200248
[Abstract](91) [FullText HTML](34) [PDF 1440KB](19)
Abstract:
  Objective  In view of the complex structure of new woodworking band saw feeding platform with the parallel multi axis linkage, the processing accuracy is low, the control parameters can not be optimized, and there are many uncertain factors affecting the accuracy, et al. Combined with the advantages of self-adaptive genetic algorithm (GA) and recurrent neural network (RNN), a global optimization control strategy was designed, which combined recurrent neural network and self-adaptive genetic algorithm.  Method  The corresponding error source model was established by analyzing the feeding platform structure and error source. The RNN parameters were optimized in combination with self-adaptive genetic algorithms, and then the PID parameters were optimized. The compensation control strategy was verified by Matlab and Adams joint simulation method, and compared with the traditional PID, genetic algorithm optimization PID parameters and RNN optimization PID parameters. The control parameters, feeding platform displacement and angle change curve were analyzed under different algorithms. Then we set up the actual circuit and controller for experiments.  Result  According to the simulation results, compared with the other three control strategies, the control strategy had the smallest overshoot, the fastest response, reaching stable at about 0.6 second. And it was quicker to reach stable under external interference at about 0.3 second. After the control strategy compensating, the offset error in the Y direction was reduced from 6 to less than 3 mm, the offset error in the X direction was reduced from 6 to 2 mm, the tilt angle error was reduced from 5.5° to 3°, and most of the platform trajectory curve overlapped the target curve fully. When controlled by traditional PID, the offset error of Y direction was 6 mm, the offset error of X direction was 6 mm, the tilt angle error was 5.5°, and the platform trajectory curve deviated greatly from the target curve. When the genetic algorithm optimized the control of PID parameters, the offset error in the Y direction was reduced from 6 to less than 4.8 mm, the offset error in the X direction was reduced from 6 to 5 mm, the tilt angle error was reduced from 5.5° to 4.5°, and part of the platform trajectory curve overlapped the target curve. When the RNN neural network optimized PID parameter control, the offset error in the Y direction was reduced from 6 to less than 4.5 mm, the offset error in the X direction was reduced from 6 to 4.8 mm, and the tilt angle error was reduced from 5.5° to 4° . Part of the platform trajectory curve overlapped the target curve.  Conclusion  Compared with the other three methods, this method has fast response speed, small overshoot, good anti-interference performance and strong robustness. Moreover, it can effectively compensate the error, improve its motion accuracy and meet the driving requirements.
Mechanical properties of wood modified by montmorillonite/poly(ethyl glycol)/hyperbranched polyacrylate emulsion
Liu Ru, Xu Jianfeng, Long Ling
2020, 42(12): 135-141.   doi: 10.12171/j.1000-1522.20200311
[Abstract](103) [FullText HTML](31) [PDF 1372KB](22)
Abstract:
  Objective  Chemical modification of wood was an effective way to improve the mechanical properties, prolong the service life, and broaden the application of fast-growing wood. Wood treated with organo-montmorillonite (OMMT) has a good prospect. However, the difficulty of dispersion of organo-montmorillonite in water as well as the large particle size limited its application. Therefore, improving the dispersion of OMMT in water, simultaneously enlarging its interlayer distance could create conditions for OMMT to enter into the wood cell walls. And also, it was an effective way for wood modification.  Method  In this study, a kind of waterborne poly(ethyl glycol) /hyperbranched polyacrylate (PEG/HBPA) emulsion was used as carrier to enhance the water stability of OMMT. The wood was modified by impregnation and the mechanical properties were tested. Besides, the different ions in the interlayers of OMMT on the modification effects were investigated.  Result  The four kinds of OMMT all can stably dispersed in PEG/HBPA. After 24 hours of rest, no stratification and precipitation occurred, and the particle size and the viscosity did not obviously change. Wood treated with PEG/HBPA showed improvements on the mechanical properties except for the cross hardness. Incorporation of OMMT can further improve the mechanical properties of wood, and the cross hardness was also improved. OMMT containing amino, hydroxyl and carboxyl groups in its interlayers can be better penetrated into the wood cell walls. Among which, OMMT containing amino groups performed the best. The radial compression strength, flexural strength, and the cross hardness of treated wood reached 82.2 MPa, 98.2 MPa and 8920 N, respectively.  Conclusion  Thus, using PEG/HBPA emulsion is an effective way to evenly disperse OMMT. And the OMMT layers can be penetrated into the wood cell walls, improving the mechanical properties, which has a guiding significance on the environmentally friendly and highly-efficient use of fast-growing wood.
Reviews
Research progress on soil erosion mechanism and ecological restoration technology in feldspathic sandstone region
Qin Fucang, Yang Zhenqi, Li Long
2020, 42(12): 142-150.   doi: 10.12171/j.1000-1522.20190430
[Abstract](182) [FullText HTML](64) [PDF 746KB](18)
Abstract:
The ecological protection and high-quality development of the Yellow River Basin are important for the construction of ecological civilization in the new era of China. The feldspathic sandstone region is one of the regions facing the most serious water erosion in the Yellow River Basin. It is also the coarse sand source area of the Yellow River. Great attention was paid to the soil and water erosion control and ecological restoration in feldspathic sandstone region. After persistent efforts through soil and water conservation for years, great achievements had been made, the effect of soil and water erosion control was remarkable and the regional ecological environment was gradually recovering, but the situation of soil erosion in the feldspathic sandstone region remained grim, the ecological environment is still weak in the feldspathic sandstone region. The plantations face the enormous risk of degradation and regeneration of plantation. There are plenty of literatures about the research of soil erosion mechanism of the feldspathic sandstone region. However, the hydrographic underlying surface of this region is complicated and the soil erosion types are diversified. It cannot meet the requirements of development of soil erosion mechanism of feldspathic sandstone region to continue using traditional methods of loess area. This article presents the history of the study on soil erosion mechanism and ecological restoration technology in feldspathic sandstone region, combining the previous research results and the author’s scientific research experiences. Systematic analysis was done on the progresses and shortcomings in the study on soil erosion mechanism and ecological restoration technology from the aspects of internal cause of the erosion in bed rock, soil erosion mechanism, ecological restoration technology, existing problems and development direction. Five directions for future researches on soil erosion mechanism and ecological restoration technology in feldspathic sandstone region were given.

Establishment Time:1979

CN 11-1932/S

ISSN 1000-1522

Supervisor:Sinopec Research Institute of Petroleum Engineering

Sponsors by:

LinksMore+