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Abstract:
  Objective  Based on the Bayesian model averaging method and binomial logistic regression model, this paper constructed a forest fire prediction model in Dali Prefecture, Yunnan Province, so as to improve prediction accuracy of forest fire and provide technical support for forest fire management in the study area.  Method  Using the forest fire data and corresponding meteorological data of Dali Prefecture from 2000 to 2013, the binomial logistic regression model and the Bayesian model averaging method were used to empirically analyze the response of forest fires to meteorological factors in this area. The binomial logistic regression model is a single model. Before modeling, the explanatory variables with significant collinearity were eliminated by multicollinearity test. Then, the final variables were screened by stepwise regression method and the parameters were fitted. The Bayesian average model is a combined model. When modeling based on the Bayesian model averaging method, the Occam’s window method was used to appropriately adjust the model space, and the posterior probabilities of the five optimal models were used as weights for weighted modeling. In this paper, the all samples data was randomly divided into 80% training samples and 20% test samples. A model was built based on the training samples to predict the test samples. The accuracy of the model was calculated by comparing the observations and predictions.  Results  Fitting through the binomial logistic model, the results show that: the model fitting goodness is 0.783, and the prediction accuracy is 0.718; through the Bayesian average model fitting, the results show that: the model fitting goodness is 0.868, and the prediction accuracy is 0.807. The comparison of the prediction results of the two models show that: in the training set, the prediction accuracy of the Bayesian average model is 9.3% higher than that of the binomial logistic regression model; while in the test set, the former is 8.9% higher than the latter.  Conclusion  In the prediction model of forest fire occurrence in Dali Prefecture based on meteorological factors, the goodness of fit and prediction accuracy of Bayesian average model are higher than that of binomial logistic model, indicating that the Bayesian model averaging method has certain practical application significance. It can be used to improve the prediction accuracy of forest fire in the study area, which is beneficial to the decision management of forest fire.
Abstract:
  Objective   Aspartic acid protease belongs to proteolytic enzyme family. In order to further analyze the molecular regulation mechanism of PtoAED3 in plant growth and development, GST-pull down combined mass spectrometry technology was used to identify and analyze the interacting protein of protein PtoAED3 in Populus tomentosa.   Method   The CDS sequence of PtoAED3 was cloned by homologous sequence from P. trichocarpa, and a prokaryotic expression vector pGEX-4T-PtoAED3 containing GST tag was constructed. The GST-PtoAED3 fusion protein was induced by IPTG and purified by GST beads. The purified protein PtoAED3 was co-incubated with the total protein extracted from P. tomentosa, then the candidate interacting proteins of PtoAED3 proteins were obtained by GST-pull down technique and analyzed by mass spectrometry technology.   Results   Through the identification of amino acid sequences of these proteins with mass spectrometry, a total of 128 candidate proteins which could interact with PtoAED3 were screened, which involve multiple biological processes such as cell process, metabolic process, stress response, biological regulation and development process.   Conclusion   The GST-pull down combined mass spectrometry technology was used to screen out candidate proteins that interact with PtoAED3 in P. tomentosa, providing a preliminary direction for studying the interaction of PtoAED3 with substrates or complexes and the molecular regulatory mechanism affecting the growth and development of Poplar.
Abstract:
  Objective   This study aims to investigate the effects of two Arbuscular mycorrhizal fungi, Glomus mosseae (GM) and Glomus intraradices (GI) on the metabolism and chemical defense of Populus alba × P. berolinensis leaves.   Method   In this study, each poplar seedling cut was planted into a pot filled with 1.3 kg sterilized soil mixed with 20 g fungal substrate containing 15 spores/g of either GM or GI. The contents of N, P elements, nutrients and secondary metabolites, as well as the activity of defense proteins in leaves of the poplar seedlings were analyzed 90 days after the planting when the fungal infection rate reached the peak.   Result   Our results showed that the contents of N, P elements and soluble proteins in the poplar leaves from the GM or GI treatment group were significantly higher than those from the control group (P < 0.05), whereas the soluble sugar content was significantly lower (P < 0.05). There were no significant differences in the starch contents between the GM or GI treatment group and the control group (P > 0.05). The contents of secondary metabolites, lignin, flavonoids, total phenols and tannins were significantly higher in the GM or GI treatment group than those in the control group (P < 0.05). The activities of defense proteins, phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), trypsin inhibitor (TI) and chymotrypsin inhibitor (CI) were all significantly higher in the treatment groups than those in the control group (P < 0.05).   Conclusion   The above results indicate that GM and GI might promote the metabolism of Populus alba × P. berolinensis leaves, including increase in the contents of N, P elements and soluble proteins and decrease in the content of soluble sugars, resulting in potential changes in leaf quality, and improvement of leaf tolerance. GM or GI infestation seems to increase the chemical defense ability of the poplar leaves, such as the increase of secondary metabolite contents and activity of defense proteins, thus might affect the resistance of Populus alba × P. berolinensis leaves to pests. However, further research is surely needed to determine whether these two Arbuscular mycorrhizal fungi can significantly enhance the resistance of Populus alba × P. berolinensis to pest insects.
Abstract:
  Objective  To lay the foundation for the genetic improvement of high generation of Picea crassifolia, the genetic variations of growth traits in the half-sib families of Picea crassifolia were studied, and the superior families were screened out.  Method  With 100 Picea crassifolia half-sib families as the research objects, we investigated height(H), increment(I), ground diameter(GD), and crown width(CW) of 15 and 20 year-old offspring, variance and estimation of genetic parameters and parents’ general combining ability of half-sib families were analyzed, and on the basis of comprehensive evaluation on growth traits of parents, superior families were selected.  Result  4 growth traits were all significant differences (P < 0.01) among the half-siblings at the age of 15 and 20. The family heritability range of each trait in different ages was 0.554 − 0.855, and the family variation coefficients of growth traits ranged from 8.33% to 19.49%. The ranges of general combining ability (20-year) of height, ground diameter, increment and crown width were −39.22 − 47.56, −1.19 − 1.05, −5.91 − 6.34 and −21.49 − 25.40. The correlation analysis results showed that there was a significant positive correlation among all growth traits (0.308 − 0.817). The growth traits were used to evaluate 15 and 20 years old half-sib families, 7 families were finally selected, and the average height, increment, ground diameter, east-west crown width and south-north crown width of the selected families in 20 years were 209.40, 20.71, 6.33 and 141.87 cm, and the average genetic gain of each traits was 14.12%, 2.07%, 8.01% and 10.42%.  Conclusion  There are abundant genetic variations among families of Picea crassifolia. Seven families with excellent growth traits were screened out, such as No. 49, No. 51, No. 60, No. 64, No. 108, No. 123 and No. 132. The selected superior families can provide high quality breeding materials for high generation seed orchards.
Abstract:
  Objective  Based on remote sensing data, the characteristics of canopy spectral changes in different succession stages of broad-leaved Korean pine forest in Changbai Mountain were analyzed to provide theoretical basis for revealing the inter species change and the response mechanism of vegetation productivity to climate factors in Changbai Mountain.  Method  Through the Google Earth Engine platform, Landsat and Sentinel series of remote sensing images were used to extract multi-temporal canopy spectrum data for the broad-leaved Korean pine forest (primary forest) and birch-aspen forest (secondary forest), both are in a same succession series, in Changbai Mountain. Analyze the seasonal variation of the canopy spectrum characteristics of the two, the seasonal and inter-annual variation of vegetation greenness, and calculate the Pearson correlation coefficient between the inter-annual vegetation greenness variation and the monthly average temperature of the same period from 1985 to 2019.  Result  (1) For canopy spectral reflectance of the primary forest, the visible light was higher in leaf-off season than in growing season, while the near-infrared reflectance showed an opposite pattern. In the vigorous growth season (from the end of May to the end of October), the canopy reflectivity of the primary forest and the secondary forest is similar in the visible light band, but the near-infrared band is significantly different, and the secondary forest canopy reflectivity is higher. The phenomenon of “red valley”, “green peak”, “blue valley” and “red edge”, the curve form of spectral reflectance, in the two vegetation types were evident, and the interannual fluctuation was weaker than that of the secondary forest. (2) The greenness of primary forest and secondary forest showed the same changing trend. It exhibits growth during leaf development in spring and attenuation during leaf fall in autumn. In the non-growing season, the degree of change in vegetation index of the primary forest was relatively stable and greater than that of the secondary forest, indicating that the understory of the secondary forest had high light transmittance. In vigorous growing season, the EVI and S2REP of the secondary forest were larger than those of the original forest, and the physiological activities of the vegetation canopy were more vigorous. Different satellite image data showed consistent performance, and the EVI peak of the secondary forest appeared slightly earlier than the original forest. (3) During the 35-year period from 1985 to 2019, the temperature in the study region had been on the rise, resulting in the increase in both vegetation greenness and the length of growing season; EVI of the primary forest was increasing, with the rate greater in summer than in other seasons. The interannual difference between spring and autumn for enhanced vegetation index was significant. (4) Compared with the primary forest, the interannual variation in EVI of the secondary forest was more correlated with spring temperature. At the beginning of growing season, both forests presented the same pattern that EVI and temperature were positively correlated. During the entire growing season, EVI increased steadily prior to the period when temperature reached a high level.  Conclusion  Long-term continuous monitoring and analysis of canopy spectrum changes can effectively reflect the difference in vegetation phenology between the primary forest and the secondary forest. Temperature rise may be one of the important factors causing the greenness of the broad-leaved Korean pine forest in Changbai Mountain
Abstract:
  Objective  The changing characteristics and influencing factors of soil saturated hydraulic conductivity in typical plantations were analyzed in South Subtropical Zone, the soil moisture movement law in the soil was studied, which provides basic scientific theoretical support for further study of soil moisture movement law in plantations in this area.  Method  Taking the soils of Pinus massoniana, Cunninghamia lanceolata, Eucalyptus urophylla × E. grandis, Mytilaria laosensis and Castanopsis hystrix located in the state-owned Gaofeng Forest Farm of Guangxi Zhuang Autonomous Region as the research objects, the soil saturated hydraulic conductivity (Ks) of plantations was determined by the constant water head method, and mathematical analysis methods such as correlation analysis and grey correlation analysis were used to explore the characteristics and influencing factors of soil saturated hydraulic conductivity of plantation soils in South Subtropical Zone.  Result  (1) The average saturated hydraulic conductivity of Cunninghamia lanceolata and Pinus massoniana was relatively higher, and the average saturated hydraulic conductivity of Eucalyptus urophylla × E. grandis was lowest. The soil saturated hydraulic conductivity and soil depth of different plantations had the changing rule of decreasing first and then increasing, in which the saturated hydraulic conductivity of the surface soils was significantly higher than that of the deep soils. (2) Correlation analysis result showed that content of organic matter, water stable aggregate content greater than 0.2 mm, total porosity, non-capillary porosity, capillary porosity, saturated water content and content of clay were positively correlated with soil saturated hydraulic conductivity, while soil density was significantly negatively correlated with soil saturated hydraulic conductivity. (3) Grey correlation analysis result showed that content of organic matter, water stable aggregate content greater than 0.2 mm, soil density, total porosity, saturated water content, non-capillary porosity and capillary porosity were important factors, content of sand, content of silt and content of clay were the secondary important factors.  Conclusion  In comparison to Castanopsis hystrix, Eucalyptus urophylla × E. grandis and Mytilaria laosensis, Cunninghamia lanceolata and Pinus massoniana can significantly increase soil saturated hydraulic conductivity, delay the generation of surface runoff and reduce incidence of soil erosion. Scientific management measures should be paid more attention to effectively improve soil water carrying capacity and water storage capacity.
Abstract:
  Objective  Health assessment is one of the important prerequisites for implementing sustainable forest management, however most of the previous studies were carried out only on a single scale, without considering the hierarchical structures of forest ecosystems. Therefore, the present study focused on the canopy characteristics, and studied the method of scale transformation for the forest health assessment by the remote sensing and statistical, where can provide theoretical support and guidance for the forest health management in China.  Method  Based on the datasets of individual-tree health survey from 50 sample plots in Pangu Forest Farm, the health assessment model of individual-tree was constructed using the entropy-AHP comprehensive index method. Five commonly used statistical indicators, namely mean value (Hm), standard deviation (Hstd), coefficient of variation (Hcv), skewness (Hpd) and kurtosis (Hfd), were summarized for each sample plot based on the health assessment results from tree-level. Then, a comprehensive forest health assessment model of regional-level was developed by combining the Landsat TM and topographic data using the nonlinear error-in-variable simultaneous equations model. Finally, the forest health status and their spatial distribution characteristics of Pangu Forest Farm were quantitatively analyzed.  Result  The sample plot survey datasets indicated that the average health score of individual-tree in Pangu Forest Farm was 0.6638 ± 0.0912, belonging to the sub-health level, among which the proportion of sub-healthy trees was the highest (79.43%); the differences of the health grades among different tree species were significant, namely Picea asperata > Betula platyphylla > Larix gmelinii > Populus davidiana > Pinus sylvestris; the statistical values of Hm, Hstd, Hcv, Hpd and Hfd, for the health scores at stand-level were 0.6633, 0.0841, 12.84, −0.6076 and 0.8460, respectively, indicating approximately 78.43% of the total forests had a significant left-pointed normal distribution; the remote sensing inversion results showed that the regional-level health score Hm was about 0.6194 ± 0.0543, in which topographic (DEM), vegetation index (RVI, DVI, EVI and Green) and original bands (B1, B3) were the key driving factors. The estimated accuracy of the constructed NESEM model was all larger than 75%, which could meet the needs of forest health assessment; in addition, a significant pattern that gradually decreased from north to south was observed for the mean forest health scores, in which the higher scores of Hm were usually concentrated in the convenient transportation areas, such as the areas of residential and forest roads.  Conclusion  The forests in study area were mainly sub-health, which may be urgent to carry out scientific health management. Meanwhile, the multi-scale transformation method presented in the study, namely combining the canopy characteristics with the results of forest health assessments by remote sensing and statistical methods, could achieve the scale conversions of forest health assessments among different levels very well.
Abstract:
  Objective  In this study, we explored the responses of leaf functional traits of Pinus tabuliformis to altitude gradients and quantified the contribution of topography and soil to intraspecific trait variation. This work aims to provide a basis for predicting the spatial-temporal variations and its mechanism of leaf functional trait caused by climate change in the future.  Method  Leaves of Pinus tabuliformis on the southern slope of Songshan Mountain area in Beijing at an altitude of 789−1106 m were collected to measure 8 leaf functional traits, including leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), nitrogen concentration per unit mass (MN), phosphorous concentration per unit mass (MP), nitrogen concentration per unit of area (AN), phosphorous concentration per unit of area (AP) and leaf nitrogen to phosphorus ratio (LN:P). Correlation between these traits and its response to altitude gradients were analyzed. The response of these traits to topography and soil were also examined in this study.  Result  (1) LA, SLA and MP showed a decreasing trend with the altitude gradient, while LDMC, MN, AN and LN:P showed an increasing trend along the altitude gradient. AP did not respond to the altitude. The leaf functional traits of Pinus tabuliformis showed significant intraspecific variations and the variation coefficient was between 10.33% and 27.59%. The order of variation was LA > AN > AP > SLA > LN:P > MN > MP > LDMC. (2) A significant synergy or trade-off was observed among some functional traits as the altitude changed, where SLA of Pinus tabuliformis was negatively correlated with LDMC (P < 0.05) and it was extremely negatively correlated with AN and AP (P < 0.001). (3) The variation of leaf functional traits was affected by various environmental factors. We found that LA, SLA and LN:P of Pinus tabuliformis were mainly affected by altitude and soil phosphorus content (TP), while LDMC was mainly affected by soil nitrogen to phosphorus ratio and soil water content. Both MN and AN were mainly affected by soil pH and TP, and MP was mainly affected by altitude and slope. (4) Altitude and soil could only explain 6.28%−41.1% of the variation in leaf functional traits of Pinus tabuliformis.  Conclusion  In the study area, leaf functional traits of Pinus tabuliformis adapt to altitude gradient change by certain character variation and combination, among which the dominant factors and extent of the character variation were different.
Abstract:
  Objective  This paper aims to explain the corresponding relationship between the microclimate elements and street greening layout, guide adaptability design of urban street green space.  Method  Based on field survey, the correlation between microclimate factors and 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 was, the better the reduction efficiency of solar radiation was. The effect was most pronounced when coverage reached more than 90 percent, and the rule characteristics of its cooling effect were more obvious. However, the excessive shade coverage made the street space closed, resulting in a reduced cooling effect. The efficiency of wind speed reduction was 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 was, 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 was 88.78%. The average daily cooling efficiency of the layered vertical structure was 8.69%. In the natural cycle of one day, the weakening efficiency of the wind speed was the best, followed by that of the tree-shrub-grass, the tree-shrub next, tree-grass third, shrub-grass was the last. The average daily wind speed reduction efficiency of the laminated structure was 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 were, the higher the average cooling efficiency was. During the natural cycle of a day, when the ratio of trees and shrubs to grass was close to 1∶1, the better the weakening effect on wind speed was  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 were proposed: (1) to build comfortable street summer microclimate, green shade coverage rate was appropriately maintained 70% − 90% . (2) Shade and ventilation should be increased through a moderate greening cladding structure, but it should be avoided to be 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.
Abstract:
  Objective  It is an important content in the process of forest management to obtain the information of single wood parameters. Oblique photogrammetry has become one of the most efficient methods to obtain single wood information with its multi-angle shooting method.  Method  In this study, taking Chinese pine forest in Wangyedian, Inner Mongolia of northern China as the research object, the tree height, crown width and stem volume were obtained by UAV tilt photography, and the effects of four different photo resolutions (1, 0.5, 0.25, 0.1 m) on the information extraction ability of single tree were investigated. The mean-shift algorithm based on the point cloud data and the watershed algorithm based on CHM were used to segment the single tree crown. Taking the measured single tree parameters of the sample plot and the single tree data extracted by LiDAR as the verification data, the relationship between the resolution of photo and the extraction ability of single tree was explored, and the accuracy and the optimal resolution of the two segmentation methods were compared. The allometric model (\begin{document}${\rm{y}} = 0.000 \; 1{{\rm{x}}^{2.717}}$\end{document}, R2 = 0.571 7) was established to extract tree height and volume with CHM, and the volume distribution map of Chinese pine in the survey area was drawn. According to the experimental results, the key parameters of oblique photogrammetry, such as the reasonable resolution requirements of UAV photos and the flight altitude range, were obtained.  Result  The watershed algorithm and mean-shift algorithm had the best segmentation accuracy at 0.5 m photo resolution, and the canopy extracted by watershed algorithm had less missing points and over segmentation than mean shift algorithm, with f-scores of 0.87 and 0.82, respectively. While, at the resolution of 0.5 m, the crown value extracted by mean-shift algorithm was more accurate. The correlation coefficients between the reference crown and the segmented crown obtained by watershed algorithm and mean-shift algorithm were 0.850 and 0.892, respectively, which were very significant at the level of 0.01. The ability of watershed segmentation algorithm and mean-shift algorithm to extract the height of Chinese pine were similar. The average error of the height of single tree obtained from 0.5 m photo resolution was the smallest and the difference was not big, which were 0.42 and 0.66 m, respectively.  Conclusion  In this study, the key method and the optimum photo resolution parameters for extracting individual Chinese pine by oblique photogrammetry were defined, which improved the investigation efficiency and provided scientific basis for setting reasonable data acquisition parameters of UAV.
Abstract:
  Objective  In view of the waste of processing residues in wood processing industry, Zn2+ doped TiO2 composite photocatalyst with hierarchical porous structure of wood was prepared by impregnation calcination method. Chinese fir was used as template to improve the photocatalytic performance.  Method  Taking methylene blue solution as the target degradation object, the effects of different concentrations of Zn2+ doping on the photocatalytic activity of wood template TiO2 were discussed. The photocatalytic degradation mechanism of wood template TiO2 was analyzed by XRD, SEM, XPS, BET, TEM and UV-Vis.  Result  The Zn2+ doped wood template TiO2 presents good pore structure that hierarches from wood. It is a mixed crystal structure of anatase and rutile TiO2. The average grain size was 22.0 nm. The Zn2+ replaced the lattice position of Ti4+, which made the absorption wavelength of TiO2 presenting red shift in the visible region. Under UV irradiation, the degradation efficiency of methylene blue solution with 1.0% Zn-TiO2 reached 99.31%. Compared with the TiO2 without template, its degradation efficiency increased by 27%. Compared with the templated TiO2, the band gap decreased from 3.08 to 2.41 ev. The degradation efficiency can be retained 90% after five repeated experiments.  Conclusion  Zn2+ doped TiO2 prepared with wood template shows excellent photocatalytic degradation performance and stability. The unique pore structure is conducive to light absorption and mass transfer, and the higher specific surface area provides more active sites for photocatalysis. Due to the difference of radius and valence state between Zn2+ and Ti4+, lattice defects will appear in the lattice, which can inhibit the recombination of photogenerated electrons and holes, increase the carrier transport and improve the photocatalytic performance. Thus, wood residues utilization with functional inorganic materials can present a promising prospect in industrial applicaion.
Abstract:
  Objective  Wind and sand protection is one of the key engineering issues in the construction and maintenance of human infrastructure in arid environment. In order to find out the complex law of wind and sand migration, and to select the appropriate setting parameters of special wind and sand protection system.  Method  Wind tunnel simulation was used to study the variation of wind velocity field, sand flow structure and sand interception ratio/permeability under different wind direction Angle.  Result  (1) The height of the 4x barrier on the windward side model was always the inflection point of the sharp change of the airflow, and did not change with the indicated wind speed, when the indicated wind speed is less than 10 m/s, the leeward area of weak wind or calm wind area increases with the indicated wind speed, and the opposite law is presented when the indicated wind speed is greater than 12 m/s. Under the action of the same indication wind speed, the effective protection range increases gradually with the increase of wind direction angle. (2) The windward sediment mainly concentrates at 0-10 cm near the surface, accounting for 85.31% of the total sediment transport. The leeward sediment transport under different wind direction angle measures mainly concentrated in the range of 20-30 cm height, accounting for 71.25%, 88.75%, 85.25% and 86.00% of the total sediment transport, respectively. (3) Sand interception in leeward layer at 0-10 cm height increased with the increase of indicated wind speed, and reached the maximum at the included angle of 75°, averaging 95.64%. The sand transport in the 10-30 cm height layer has an increasing trend with the increase of indicated wind speed, and the maximum is 81.09% on average when the included angle is 45°.  Conclusion  The variation of indicated wind speed has no significant influence on the variation law of the airflow velocity field of retaining wall, but has a greater influence on the leeward side of the weak wind area or the range of the calm wind area, and the effective protection range is the best at 75°. The sand transport on the windward side gradually decreases with the increase of height, while that on the leeward side climb up and then decline with the increase of height. The wind angle should be set at about 75° as a measure to prevent wind and sand.
Abstract:
  Objective  In order to reveal the phenotypic differentiation and variation pattern of natural Pinus koraiensis populations, 6 natural populations in Jilin Province were taken as the research object.  Method  The 13 phenotypic traits (needles traits and fruit traits) of the Pinus koraiensis population were systematically analyzed and comprehensive assessment by means of variance analysis, principal component analysis, cluster analysis and comprehensive evaluation of multiple traits.  Result  The results showed that: (1) Cone length and ratio of fascicle width to needle thick reached significant levels, and the other traits reached extremely significant differences among populations. (2) The average phenotypic differentiation coefficient of Pinus koraiensis among the populations was 23.30%, and its variation was much smaller than within the population (76.70%). (3) The average phenotypic variation coefficient of the 6 populations was 11.30%, the phenotypic variation coefficient decreased from needle traits (14.56%) to cone traits (10.48%) to seed traits (5.87%). (4) The results of principal component analysis indicated that, the basic source of phenotypic diversity of Pinus koraiensis population was needle traits were greater than seed traits than cone traits. (5) The results of cluster analysis showed that the 6 populations of Pinus koraiensis were divided into 3 groups. (6) Using comprehensive evaluation of multiple traits method, the natural populations were evaluated by fruit traits (seed length, seed diameter, hundred seed mass, cone mass) and needle traits (needle length, needle diameter, needle thick, fascicle width), and 1 population was screened out, respectively.  Conclusion  Pinus koraiensis populations have moderate phenotypic diversity, and there were abundant phenotypic variations between and within groups. The research results can provide a basis for the protection and utilization of Pinus koraiensis germplasm resources, and it can provide materials for the construction of superior populations of Pinus koraiensis.
Abstract:
  Objective  To study the surface fuel load and its influencing factors of typical coniferous forests in Beijing, and to establish a fuel load model, so as to provide research basis for the scientific management of fuel.   Method  Based on stand factors (DBH, tree height, canopy density, crown width, height of the first living branch) and terrain factors (altitude and slope), representative Pinus tabuliformis and Platycladus orientalis forests were selected in 7 districts and counties of Beijing. 42 plots were set for each forest type to investigate and measure the fuel load of two coniferous forests (upper dead leaves, lower dead leaves, shrubs, herbs, 1 hr dead branches, 1 hr dead branches, 1 hr dead leaves, 1 hr dead branches, 1 hr dead leaves, 1 hr dead branches, 1 hr dead leaves, 1 hr dead leaves, 1 hr dead branches, 1 hr dead leaves, 1 hr dead branches, 1 Redundancy analysis (RDA) was used to study the relationship between surface fuel load and stand factors and terrain factors, and the total fuel load model was established by multiple linear regression.   Result  (1) the average total fuel load of Pinus tabuliformis forest and Platycladus orientalis forest was 14.31 t/hm2and 9.78 t/hm2, respectively. The lower dead leaf load accounted for the largest proportion of the total fuel load of the two coniferous forests. (2) Redundancy analysis (RDA) showed that the fuel load of upper dead leaves and shrubs was positively correlated with DBH, and that of lower dead leaves was positively correlated with canopy density and slope. The dead leaf load of upper and lower layers of Platycladus orientalis was positively correlated with tree height and crown width, and negatively correlated with altitude. The fuel load of shrub was positively correlated with tree height and canopy density, and negatively correlated with altitude. The total fuel load, 1 hr, 10 hr dead branch load of the two coniferous forests were positively correlated with DBH, and the herbage fuel load was positively correlated with altitude. (3) The model shows that DBH, tree height and crown width can calculate the total fuel load of Pinus tabuliformis forest, and the first living branch height, crown width and slope can calculate the total fuel load of Platycladus orientalis forest.  Conclusion  Pinus tabuliformis forest has the possibility of developing into a larger forest fire. According to the surface fuel load, we should focus on the management of the forest litter and fuel, timely clean up the fuel under the forest, and reduce the potential forest fire risk. The relationship between the fuel load of different forest types, stand factors and terrain factors is different. In fuel management, we should choose reasonable and appropriate measures according to local conditions.
Abstract:
  Objective  Pectin is a major component and structural polysaccharide of the cell walls of plants. Pectin methylesterase (PME) is a key enzyme that modifies pectin, and thereby regulates cell wall rigidity and elasticity, playing a significant role in the plant development. The purpose of this study was to investigate the basic information and characteristics of ZjPMEs, which could serve as a foundation for further elucidation of the functions of ZjPME genes and screening of genes closely related to fruit texture.  Method  We identified the family genes in the ‘Dongzao’ genome using bioinformatics softwares.The characteristics and expression patterns of the genes were analyzed based on RNA-seq data.  Result  46 PME genes were identified in the jujube genome, including 29 Type-ⅠZjPMEs and 17个Type-ⅡZjPMEs, which were classified into four subfamilies (I-Ⅳ) and unevenly distributed across 10 chromosomes. Within each subfamily, the genes shared conserved gene structure and motif compositions. Expression analysis revealed that most of the genes were expressed highly in flowers, indicating the important function of PME genes in the reproductive developmental process. Furthermore, by analyzing the expression patterns of the ZjPMEs during the fruit development between ‘Dongzao’ (crisp) and ‘P15’ (firm), and between‘Dongzao’(consumed freshly) and ‘Junzao’(consumed as dry fruit), we found ZjPME18 might be closely related to fruit texture. ZjPME18 showed higher expression in ‘Junzao’ and ‘P15’.  Conclusion  The ZjPMEs have specific structure characteristics and expression patterns, and the expression and regulation of ZjPME18 may be closely related to the fruit texture.
Abstract:
  Objective  The aim of this study was to investigate the response of root architecture and nutrient absorption capacity of one-year-old Pinus sylvestris var. mongolica to nitrogen addition and inoculation of ectomycorrhizal fungi.  Method  The one-year-old mycorrhizal (mixed inoculated with 8 ectomycorrhizal fungi, HJ) and non-mycorrhizal (no inoculation, WJ) seedlings of P. sylvestris var. mongolica were selected. Four nitrogen addition treatments were set, including no nitrogen (CK, 0 kg/(ha·year)), low nitrogen (LN, 15 kg/(ha·year)), middle nitrogen (MN, 30 kg/(ha·year)) and high nitrogen (HN, 60 kg/(ha·year)) treatments. The root morphology (including the total root length, surface area, volume, bifurcations, tips, average diameter) and nutrient content of the seedlings were measured.  Result  (1) There were significant differences between the seedling biomass of the two inoculation treatments under CK, MN and HN treatments. Under the CK treatment, the biomass of mycorrhizal seedlings was increased by 54.3% than that of the non-mycorrhizal seedlings. Under the MN and HN treatments, the biomass of mycorrhizal seedlings was decreased by 17.8% and 23.7% than that of the non-mycorrhizal seedlings, respectively. (2) The total root length, surface area, number of tips of one-year-old P. sylvestris var. mongolica seedlings with diameter of 0−0. 5 mm were affected significantly by the nitrogen addition and inoculation treatments. Increasing of nitrogen addition, the root morphological indexes of non-mycorrhizal seedlings showed a tendency of first increased and then decreased, but that of mycorrhizal seedlings showed a decreasing tendency. (3) Compared with CK, the nitrogen and phosphorus contents of the non-mycorrhizal seedlings were significantly increased by nitrogen addition treatments, but that of the mycorrhizal seedlings were promoted by LN treatment and inhibited by HN treatment.  Conclusion  There was a synergistic effect of the low nitrogen addition and inoculation treatments on the root morphology and nutrient content of the seedlings. The effect of inoculation on root morphology and nutrient content of seedlings was weakened by high nitrogen addition.
Abstract:
As the most abundant natural and renewable aromatic compounds, lignin has been recognized as a raw material for producing biofuels and chemicals. The commercial lignin is mostly obtained by pulping processes, such as soda lignin and lignosulfonates, which are operated at harsh conditions and cause high energy consumption and sever water pollution. The commercial lignin has low purity and inhomogeneous structure, which hinder its valorization. Therefore, it is urgent to find a facile, efficient, and environmentally friendly method for lignin fractionation to reduce energy consumption and pollution. As a promising and green solvent, deep eutectic solvent (DES) consists of hydrogen bond donor and hydrogen bond acceptor counterpart in a certain molar ratio that result in the formation of eutectic mixture, showing an unusually low freezing point. DES has the characteristics of simple preparation, high stability, fine biocompatibility, high selectivity and recyclability. In recent years, DES has been widely used in the field of biomass treatment due to the excellent delignification. The fractionation abilities for lignin by different types of DES are quite different. Generally speaking, the fractionation ability for lignin by carboxylic-based DES is stronger than that by amide-based DES. The lignin fractionated by DES has the characteristics of high purity, low molecular mass, and polydispersity, which has an application potential compared with commercial lignin. In this review, it begined with the effect of DES types on the lignin fractionation efficiency followed by the influencing factors (composition of DES, reaction temperature, time, and solid-liquor ratio) on the fractionation efficiency and lignin structure. Additionally, the recycling experiments of DES were introduced. According to the existing challenges in the lignin fractionation with DES, it covers the selection of DES, the combination of other pretreatment methods, optimization of reaction conditions, the recycling of DES, and the valorization of lignin to provide some references for the clean and efficient fractionation of lignin.
Abstract:
Regulators of G-protein signaling are important negative regulatory factors in G protein signaling pathway, which plays an important role in the realization of mycelial development, sporulation, secondary metabolites, pigment synthesis, pathogenicity and sexual reproduction regulation of fungi. In recent years, with the deepening of research on RGS of plant pathogenic filamentous fungi, a large number of academic reports have been produced, however, systematic comparative analysis of RGS in model fungi and phytopathogenic filamentous fungi has not been reported. In this study, the structure, classification and function of RGS of model fungi and plant pathogenic filamentous fungi were compared and analyzed. At the same time, through SMART conservative domain, secondary structure composition and genetic relationship analysis, RGS proteins in plant pathogenic filamentous fungi and model fungi were confirmed to have conservative RGS domain and similar secondary structure composition, also RGS proteins were divided into 6 categories according to sequence homology, and RGS proteins with different domains were clustered respectively, the results showed that RGS proteins had certain conservativeness in functional performance in different fungi. In addition, the number and types of RGS in plant pathogenic filamentous fungi were found to be more than that of model organisms. The results show that RGS proteins have certain uniqueness in the functions in different fungi. The above research provides an important theoretical basis for further research on the mechanism of RGS in plant pathogenic filamentous fungi and the relationship between RGS in plant pathogenic filamentous fungi and other model organisms.
Abstract:
  Objectives  In order to explore the leachability of iodopropynyl butylcarbamate (IPBC) formulations, an analytical method of IPBC by high performance liquid chromatography (HPLC) was established and used for the determination of IPBC leaching rate of treated wood and bamboo, aiming to determine an analytical method of IPBC by HPLC and the leachability of IPBC.  Method  UV detector and C18 column (150 mm × 4.6 mm (inner diameter), 5 μm) were used for detection. The chromatographic conditions, such as detection wavelength, mobile phase composition and ratio, column temperature and mobile phase flow rate were investigated and discussed, so as to optimize the chromatographic conditions suitable for the analysis of IPBC. The IPBC standard solution was detected by external standard method. The standard curve, precision and accuracy were evaluated. The leaching procedure was adopted according to the Chinese standard method. The IPBC leachability rate was tested in treated wood and bamboo by the established analytical method.  Result  The chromatographic conditions for the determination of IPBC content by HPLC were as follows: flow phase acetonitrile-water (60:40), flow rate 1.0 mL/min, UV detection wavelength 200 nm. There was a good linear relationship between IPBC concentration and chromatographic peak area in the range of 5 ~ 80 mg/L for IPBC standard solution. The correlation coefficient was r2 = 0.999 4. The standard deviation and coefficient of variation were 0.05% and 0.50%, respectively. The recovery rates were 99.5% ~ 100.4%. The leaching rate of IPBC in masson pine and radiation pine decreased with the increase of IPBC concentration, the leaching rate of masson pine was from 0.11% to 1.99%, the leaching rate of radiation pine was from 0.10% to 0.48%. In bamboo, the leaching rate of IPBC increased with the increase of IPBC concentration, with the leaching rate from 3.11% to 7.08%. The average leaching rate of IPBC treated bamboo higher than IPBC/PPZ-TEB. The leaching rate of IPBC micro emulsion in treated wood was higher than that dissolved with ethanol. The leaching rate of IPBC with surface coating of hard wax oil in treated wood was lower than that without surface coating.  Conclusion  The determination method of IPBC content by HPLC with good correlation, high precision and recovery rate could be used for the analysis of IPBC content. The leaching rates of IPBC treated masson pine, radiant pine and bamboo were very low as less than 7.1%. The leaching rate of IPBC could be decreased by mixing with other agents or surface coating with hard wax oil.
Abstract:
  Objective  The wall wood columns of ancient building are partly or completely wrapped by the wall. It is easy to decay for the contact part between the wood column and the wall, and the detection operation space is narrow. Through the study on the nondestructive testing for defect status of the wall wood columns in Yangxin Hall of the Palace Museum of Beijing, the nondestructive testing method of the defect status and the existence law of the decay for the wall wood columns were explored and revealed, respectively, which provides the basis for the repair work of the wall wood columns in Yangxin Hall, and also provides reference for the nondestructive testing and defect evaluation for the wall wood columns in other ancient wooden buildings.  Method  68 wall wood columns in the Main Hall, Meiwu Hall, East Hall and West Hall of Yangxin Hall were used as the research objects. First of all, the exposed face, air vent and opening of wood columns were used for field detection, including external defect detection, knocking detection, internal defect detection, moisture content detection and tree species sampling. Then, the data of wood column size, surface defect types and size, micro drill resistance curve and so on were collected and analyzed to evaluate the defects status of each wood column tested, and the decay distribution law of the wall wood columns was summed.  Result  The wall wood columns in Yangxin Hall were relatively complete. The results showed that there were different forms for the external and internal defects of the wall wood columns in Yangxin Hall. The main forms of external defects were external decay and material missing, and the main forms of internal defects were internal decay and cavity, and the secondary forms of these two main defects were cracks. For a single wood column, the decay mainly occurred in the area where the wood columns were in contact with the wall at the cross section. In the longitudinal, decay mainly occurred in the bottom of wood column, and the decay decreased with the height. The probability of decay for two-sided exposed wood columns was the lowest and followed by the single-sided exposed wood columns, and the completely wrapped wood columns were the highest.  Conclusion  The method used in this study is feasible for nondestructive testing and evaluation for defect status of the wall wood columns, and the position, wrapping degree and tree species of wall wood columns have influence on their defect status.
Abstract:
  Objective  This study analyzed the evolution of ecosystem pattern in the Kubuqi Desert of northern China and its driving forces, clarified the degree of influence of different driving factors on the changes of the ecosystem pattern, and then proposed targeted improvement measures. The research results can provide scientific basis and decision support for the ecological protection and high-quality development of the Kubuqi Desert.  Method  In this paper, ecosystem change amplitude, annual change rate, dynamic degree and landscape pattern index were used to analyze the changes of ecosystem pattern, evolution characteristics and the contribution of main driving forces to ecosystem changes of Kubuqi Desert Area from 2000 to 2018.  Result  (1) Grassland, bare land and farmland were the main ecosystems of Kubuqi Desert Area, accounting for 91.46% of the total area, while water area, construction land and forest land accounted for a small proportion. (2) During the study period, the area of farmland, grassland and construction land in Kubuqi Desert increased, while the area of woodland, water area and bare land decreased. The transformation and change of ecosystem was mainly from bare land to grassland, and grassland to bare land was also obvious. (3) The degree of landscape fragmentation and landscape diversity index increased during the study period. (4) Ecological protection and restoration was the primary driving force of ecosystem pattern evolution, with the contribution rate of 44.53%; land degradation was the second driving force of ecosystem change, with the contribution rate of 23.87%; the contribution rates of farmland expansion, urbanization construction and water resources development were 17.72%, 8.51% and 5.37% respectively.  Conclusion  In order to ensure the sustainable development of ecosystem in the Kubuqi Desert, ecological protection and restoration projects should be implemented scientifically. This requires the overall promotion of comprehensive management, systematic management and source management of “landscapes, forests, fields, lakes, and sands”. The prevention of land degradation is the focus, and the development and utilization of cultivated land must be reasonable. By promoting a virtuous cycle of the ecosystem, regional ecological security can be maintained.
Abstract:
  Objective  In most areas of China, Lycium chinense is in a wild state and its application is limited. In the context of global climate change, the prediction of the current and future suitable distribution areas of L. chinense is of great significance for the protection of its germplasm resources, rational introduction and cultivation, and large-scale promotion.  Method  Based on ArcGIS and MaxEnt models, we used 124 distribution data of L. chinense and 8 climatic variables to evaluate the main climatic factors restricting its geographical distribution and discuss its current and future potential distribution areas.  Result  At present, the total suitable area of L. chinense occupies about 36.73% of the national land area, and the horizontal distribution interval is about 18° ~ 45°N and 90° ~ 123°E. Core suitable areas are mainly located in the Qinling Mountains, Taihang Mountains and Zhejiang, Jiangsu and Anhui in East China; Yunnan, Guizhou, Chongqing and Sichuan in the Southwest; Gansu, Ningxia in the northwest and their neighboring areas. The main climatic factors affecting its distribution are the Min Temperature of the Coldest Month, the Precipitation of the Wettest Month, the Precipitation of the Driest Month, and the Max Temperature of the Warmest Month. With the future climate warming, the total suitable area of L. chinense is not much different from the current one, but its main core suitable area tends to “expansion at high altitudes”, “migration in coastal areas” and “central gathering”. The specific manifestation is the expansion to high-altitude areas in Shaanxi, Gansu and other Qinling areas; the eastern coastal areas gradually formed a narrow strip core suitable area; the central Hunan and Hubei areas gradually formed a large area of flaky core suitable area.  Conclusion  The suitable areas of L. chinense is mainly wide and continuous, while core suitable area is narrow and discontinuous. The climatic factors affecting its geographical distribution are mainly temperature and rainfall, and the Min Temperature of the Coldest Month is the most important climatic factor limiting its distribution. In the future, the eastern coastal areas of China, Dabie Mountains, Qinling Mountains and Daba Mountains in central China, southwestern regions such as Sichuan, Chongqing and their adjacent areas are suitable for the introduction, cultivation and promotion of L. chinense.
Abstract:
  Objective   The boring vibration recognition model based on deep learning combined with edge computing can realize the long-term monitoring and real-time warning of the boring vibration of forest stem borers, but it needs to greatly reduce the parameters and computation of the intelligent recognition model. In this study, the deep learning model compression algorithms are adopted to compress the existing boring vibration recognition model without losing accuracy, so as to reduce the volume of the model and improve the recognition speed of the model in the embedded platform.   Method   Firstly, two kinds of signals, i.e. the boring vibration of Semanotus bifasciatus and the background noise, were collected, and used to train five-layer convolution neural network BoringNet to obtain the boring vibration recognition model. Then, the convolution kernel pruning with different rates, model quantization and multi-target knowledge distillation were used to compress the boring vibration recognition model. Finally, the combination strategies of the above-mentioned compression algorithms were designed and three algorithms are combined to compress the boring vibration recognition model to explore the models compression effect of various combinations.   Results   When the clipping rate was 60%, the model was the best. At this time, the amount of calculation and parameters of the model were reduced from 18.06 M and 0.54 M to 3.01 M and 0.09 M, respectively. The volume of the model was compressed from 2200 kB to 134.9 kB. The recognition time of raspberry pie 3B + was reduced from 9.04 ms to 1.65 ms, and the accuracy of the model was still 99.29%, which was improved by 0.5%.   Conclusion   The deep learning model compression method in this study can greatly compress the model parameters and computation for the boring vibration interception scene, realize the real-time recognition of the embedded platform on the premise of ensuring the accuracy, promote the transformation of boring vibration recognition model from workstation test to field deployment, and lay the foundation for the edge computing of boring vibration recognition.
Abstract:
  Objective  In order to improve the utilization rate of tending residues of Larix principis-rupprechtii, explore the influence of different treatment methods on the decomposition rate of tending residues, accelerate the decomposition rate of tending residues, restore the land fertility of Larix principis-rupprechtii plantations, and maintain long-term high productivity.  Method  In this study, tending and thinning residue of Larix principis-rupprechtii Mayr plantation was used as research subject. And 4 treatment methods, including smashing residue, adding urea, EM and wood vinegar, were used to design a 4 factors and 5 levels orthogonal experiment.  Result  The effects on decomposition of Larix principis-rupprechtii tending residue through 25 treatments were studied and the optimum level of the 4 factors which is conducive to the decomposition of residues was obtained: particle diameter (0.3 ~ 0.5 cm), urea solution (3 ~ 9 kg/m3), volume ratio of EM (500) and stock solution of wood vinegar (600 to 800 times).  Conclusion  The result of the determination were analyzed, Among them, particle diameter was the most influential factor on the decomposition rate of the residue., and the interaction of the 4 factors is generally greater than that of unitary urea solution, EM or wood vinegar. According to the decomposition rate from big to small. The decomposition rate of NO.9 treatment was the highest, and levels of each factor were: particle diameter (0.3−0.5 cm), urea solution (9 kg/m3), volume ratio of EM (1 000) and stock solution of wood vinegar (0 times). The decomposition rate of NO.9 is 2.04 times than the lowest decomposition rate. It can be seen from the optimal processing combination of NO.9 that the level of each factor is not necessarily in the best level, and we could speculate that there might be an interactive effect, but it still needs to be proved.
Abstract:
  Objective   Chromosome karyotype information is an important basis for plant genetics and breeding research. The inter-subsectional distant hybridization is a significant direction in modern tree peony breeding. Because of the high morphological similarity of chromosomes in Paeonia sect. Moutan, the karyotype analysis of distant hybrids requires a large number of high-quality chromosome preparations. Pretreatment is a key link that affects the quality of chromosome preparation. It is of great significance to obtain the accurate karyotype and study the genetic law of distant hybridization of tree peony by improving the quality and efficiency of chromosome preparation with the promoted pretreatment method.   Method   In this study, we used the pistils from the young flower buds of Paeonia × lemoinei ‘High Noon’ to quantify the influence of different pretreatment solutions and pretreatment time on the degree of chromosome contraction and dispersion at 4 ℃, and to analyze the differences of karyotype under diverse pretreatment effects.   Result   Pretreatment with p-dichlorobenzene or p-dichlorobenzene-α-bromonaphthalene could get excellent chromosome preparation. After being pretreated with p-dichlorobenzene for 36 ~ 72 h or p-dichlorobenzene-α-bromonaphthalene for 24 ~ 48 h at 4 °C, a large number of chromosomes with moderate contraction and good dispersion could be stably obtained. More karyotype information of P. × lemoinei ‘High Noon’ was obtained by using a large number of high-quality chromosome preparations. The karyotype formula was 2n = 2x = 10 = 8m (2SAT) + 2st (2SAT), and the satellites were located on the short arm of chromosome 4, 8, 9 and 10, among which the satellites on the chromosome 9 and 10 were more easily observed than those on the chromosome 4 and 8.   Conclusion   Improving the pretreatment effect could effectively promote the quality and efficiency of chromosome preparation of P. × lemoinei ‘High Noon’, and obtain more abundant and accurate karyotype information. The quantitative method used in this study could effectively evaluate the quality of chromosome preparation from the two aspects of chromosome contraction and dispersion. The selected pretreatment method was stable and efficient, which laid a favorable foundation for karyotype analysis and further genetic research of distant hybrid of tree peony.
Abstract:
  Objective  The bacterial canker of Populus euramericana is caused by the Gram-negative bacterium Lonsdalea populi. The rapid spread of the disease has seriously threatened the growth and development of P. euramericana and has caused great economic losses to the plantation. Two-component system (TCS) is the important signal transduction mechanism of the Lonsdalea populi. Now, how the two-component system of poplar bacterial canker regulates the pathogenic process is still lack of systematic research. Therefore, the large-scale deletion mutation and mutant phenotype analysis of TCS in this study will provide genetic materials for further study on the pathogenic mechanism of poplar bacterial canker.  Method  In this study, 28 two-component gene deletion mutants of poplar canker pathogen strain L. populi N-5-1 were constructed by parental association, the differences in pathogenicity, growth, mMswimming, biofilm formation and resistance of these mutants were analyzed by phenotypic analysis, and the regulation of two-component system coding genes on the pathogenicity of these mutants was studied.  Result  In this study, 36 recombinant vectors of two-component coding genes were constructed and 28 deletion mutants were obtained. Phenotypic analysis showed that 18 genes encoding TCS were involved in virulence of L. populi N-5-1. Among them, the pathogenicity of 8 mutants has obviously disappeared. In addition, the deletion mutants that regulate motility and biofilm-forming ability and those that are deficient in stress response (metal ions, salt ions, antibiotic stress, etc.) were also screened.  Conclusion  In this study, five two-component genes that significantly affect the pathogenicity of L. populi were obtained, providing genetic material for future studies on the pathogenic mechanism of L. populi.
Abstract:
  Objective  Studying the coupling and coordination relationship between vegetation and soil in the early stage of restoration in different climate regions of the Wenchuan earthquake-affected areas can provide a basis for promoting the ecological restoration and the coordinated development of vegetation-soil system in the disaster disturbed area.  Method  In this study, the treated area and undestroyed area of the arid-valley climate region and the subtropical monsoon climate region (AT and AU, ST and SU) were selected as the research objects. We measured twenty-one indexes covering plant and soil, analyzed the main influencing factors and the weights of twenty-one indicators of the four ecosystems in the two climate regions by principal component analysis, and constructed the corresponding model of vegetation-soil coupling coordination degree.  Result  SU’s D, comprehensive indexes of vegetation and soil were all significantly higher than the other three vegetation-soil systems. AT and ST were both soil lagging development type of primary coordinated development, AU and SU were synchronous development type of vegetation and soil of primary and intermediate-level coordinated development respectively. The influencing factors of the arid-valley climate region were relatively simple: the main influencing factors of AT were soil organic carbon, total nitrogen, available nitrogen and available phosphorus, and those of AU were plant carbon, nitrogen, potassium and magnesium. The influencing factors of the subtropical monsoon climate region were vegetation-soil influencing factors coexisting: the main influencing factors of ST were species richness, biomass, soil total nitrogen and available nitrogen, and those of SU were vegetation coverage, plant phosphorus, soil available potassium and bacteria.  Conclusion  The climate and type of ecological restoration had certain influence on the coupling status of vegetation and soil. The coupling status of vegetation-soil in SU was significantly better than the other three ecosystems. The soil environments of AT and ST were both poor, indicating that nutrient condition of treated areas did not recovered to the pre-earthquake level after treatment for seven years.
Abstract:
  Objectives  Improve the breeding efficiency of chestnut varieties by studying the genetic tendency and genetic differences of chestnut hybrid offspring  Methods  Using ‘Yanshanzaofeng’ and ‘Yanjing’ as the parental crosses, 259 F1 individuals were produced as test materials. Measured 13 traits of chestnut in 2016 and 2017, including nut-related traits, bur-related traits, amylose content, amylopectin content, total starch content, and soluble sugar content, and conduct genetic tendency research.  Result  Research on nut-related traits shows that the traits such as single nut weight, nut thickness, nut height and nut width showed a normal distribution trend, and the average value of offspring was greater than the mid-parent value, indicating an additive effect in 2016 and 2017. The coefficient of variation of the single-nut weight traits of the offspring of reciprocal crosses for two consecutive years is 18.5%−20.19%. The offspring are widely separated and have high genetic diversity. It is possible to breed chestnut varieties with larger single-nut weight. The coefficient of variation of nut width, thickness and height traits are all less than 20%, and genetic transmitting ability is between 98.54%−106.55%, indicating that nut traits are less affected by the environment. The research on the bur-related traits showed that the average value of the bur weight of the progeny of reciprocal crosses is higher than mid-parent value for two consecutive years,, the coefficient of variation of the reciprocal crosses is greater than 20%, and the genetic transmitting ability is between 112.0%−117.44%. It can be inherited stably and is less affected by the environment. For two consecutive years, the ultra-high parent rate of the bur width in the offspring of reciprocal crosses reached 37.50% and 23.96%, and the genetic transmitting ability was 112.50% and 113.93%, respectively. In 2016, the average value of the progeny and the 2017 orthogonal progeny of the prickle length was less than mid-parent value, and the genetic transmitting ability was 90.25%, 90.83% and 93.66%. The ultra-low parent rate in 2016 was 27.08% and 18.9%, respectively. Prickle length tend to become shorter. Research on fruit quality-related traits shows that the range of the coefficient of variation of starch-related traits in the offspring of reciprocal crosses for two consecutive years was 7.82%−17.66%, and the genetic transmitting ability of amylopectin content was between 101.11% and 108.22%. The ultra-high affinity rate of the offspring of reciprocal crosses in 2016 was higher than that in 2017, which were 34.38% and 30.09% respectively. Tending to increase the content of amylopectin. Compared with 2017, the genetic transmitting ability of soluble sugar content in the offspring of reciprocal crosses in 2016 was lower, at 64.1% and 59.94%, respectively, indicating genetic instability and greater environmental impact.  Conclusion  Through the study of the genetic tendency and segregation characteristics of these traits, it is concluded that nut-related traits can be inherited stably, and fruit quality traits are genetically unstable and are greatly affected by the environment. This research provides reference for the screening of the offspring of chestnut cross breeding and the prediction of target traits in the future.
Abstract:
  Objective  In the process of tree pruning, pole chain saw as an efficient and convenient tool effectively reduces the risk of climbing trees for forest workers. In this work, the ergonomic evaluation of typical electric pole saws in the market was carried out, and an improvement scheme with movable handle was proposed for its defects. The effectiveness of the modified scheme was proved by comparative experiments, which provided an improvement idea for the same type of tools.  Methods  The movable handle can be used to adjust the fatigue load of the tool on the arm and the whole body by changing the distance between the holding point and the center of gravity. Seventeen males were selected to perform the experiment, during which their heart ratio, surface electromyography signals of biceps brachii and palmar longus, grip distance and subjective assessment were measured during the operation of the original electric pole saw. And to select improvements based on these data.The improvement effect is evaluated by comparing the improved experimental data with that of the control group.  Results  Before the improvement, the increase ratio of heart rate of the subjects was greater than 18%, indicating that the whole body fatigue load was too large. Besides, the normalized surface electromyographic signals of biceps brachii and palmar longus were higher than 20% and 30%, respectively, which revealed excessive local fatigue. By paired sample T test method, the increasing ratio of heart rate, the normalized surface electromyographic signals of biceps brachii and palmar longus, subjective assessment, and grip distance were significantly different before and after the improvement (P < 0.05).  Conclusion  The overall evaluation results show that the modified electric pole chain which allows the operator to adjust the grip distance between the hands freely by using the movable handle can effectively reduce the fatigue load of the arm and the whole body, and finally improve the operation comfort. Moreover, the additional cost of the modification is controlled below 100 yuan, which increases the feasibility of universal promotion.
Abstract:
  Objective   In order to clarify the changing trend of heartwood and sapwood amount during the development of Eucalyptus cloeziana heartwood, and to provide scientific basis for the cultivation of large-diameter E. cloeziana and efficient use of wood, the variation of heartwood and sapwood, stem cross-sectional peeling diameter and height of E. cloeziana at different-aged was investigated.   Method   5, 17, 29 and 35-year-old E. cloeziana were used to determine the stem cross-sectional peeling diameter, peeling radius, heartwood radius and sapwood width in four directions of east, west, south, north. Besides, the regression equation of heartwood and sapwood amount and tree age, stem cross-sectional peeling diameter, tree height was established to analyze the axial and radial variation patterns of heartwood and sapwood E. cloeziana.   Result   The heartwood radius and heartwood area increased with the tree age, while the width of sapwood varied greatly between 5 and 29 years, but the sapwood area didn,t change significantly with tree age. There was no significant difference in the area of sapwood between different tree ages (P > 0.05), and there were differences in the radius of heartwood, the area of heartwood and the width of sapwood (P < 0.05). The amount of stem cross-sectional heartwood increased with the increase of stem cross-sectional peeling diameter, but the amount of stem cross-sectional sapwood was weakly correlated with stem cross-sectional peeling diameter. When the stem cross-sectional peeling diameter was about 4.66 cm, E. cloeziana began to form heartwood, and then the diameter of trunk stem cross section grew by 1 cm, the heartwood radius increased by about 0.52 cm. The heartwood radius, heartwood area and sapwood area of E. cloeziana of each tree age decreased with the increase of tree height, the largest at the base of the tree, and the sapwood width decreased when the tree height was 1 − 5.3 m. There was a certain fluctuation, which was relatively constant above the height of 5.3 m.   Conclusion   The amount of heartwood is significantly positively correlated with tree age and stem cross-sectional peeling diameter, and negatively correlated with tree height. The study suggests that the 35-year-old E. cloeziana still has great growth potential and can be further cultivated for the large-diameter E. cloeziana.
Abstract:
  Objective  Niche and interspecific association are the basis and main method to study community structure. The purpose of this paper was to study the structural characteristics and dynamic changes in herb layer of burned Pinus tabuliformis forest in the southern Taihang Mountains the different restoration stages.  Method  We focus on the niche characteristics and interspecific associations of the dominant species of herb layer plants in four burned areas of 13 years (S1), 7 years (S2), 6 years (S3) and 1 year (S4). Then we calculated the niche width and niche overlap, and studied the interspecific association through the overall association test, χ2 test and spearman rank correlation test. Then divide the ecological species groups.  Result  The results showed that the dominance, niche width, and niche overlap with other dominant species of Carex lanceolata, Chrysanthemum chanetii and Artemisia stechmanniana were larger in different restoration periods. The overall association test shows that S1 was a significant positive association, S2 and S4 were a significant negative association, and S3 was an insignificant positive association. The χ2 test showed that the positive and negative association ratios of S1, S2, S3 and S4 were 2.33, 0.69, 0.84 and 0.63. Spearman rank correlation test showed that the number of positive association pairs in S1 is greater than that of negative association pairs, while the number of positive association pairs in S2, S3 and S4 is less than the number of negative association pairs. The dominant species in S1, S2 and S3 can be divided into three ecological species groups represented by Carex lanceolate + Chrysanthemum chanetii, Artemisia stechmanniana and other dominant species. And the 10 dominant species in S4 can be divided into three ecological species groups represented by Carex lanceolata, Chrysanthemum chanetii and Artemisia stechmanniana.  Conclusion  Studies had shown that the plant community in the burned area of the southern Taihang Mountain reached a stable state after 13 years of restoration. The niche and interspecific association may illuminate how interaction mechanisms such as species coexistence, distribution, structure changes in burned area. Which could provide theoretical support in burned area management and plant distribution.
Abstract:
  Objective  Solar radiation is the main source of energy, and also one of the most important influencing factors affecting the local and regional climate and environment of forest ecosystem. However, long-term changes of radiation data are needed to focus on climate change research. Exploring the long-term characteristics of solar radiation of forest is very important to establish a research foundation for climate change, tropical forest productivity, radiation energy balance, and the establishment and verification of radiation models. In order to explore the long-term changes of the radiation characteristics of the tropical seasonal rainforest in Xishuangbanna, the observation of the ground based long-term radiation had been conducted.  Method  The characteristics of and the ratio of various components to solar radiation had been explored in a tropical seasonal rainforest in Xishuangbanna on different time scales from 2003 to 2016.  Results  The results showed that the multi-year mean annual values of total radiation, net radiation, reflected radiation, atmospheric invers-radiation and upward canopy long-wave radiation were: 5 268.8, 3 151.5, 513.8, 12 468.6, 13 299.3 MJ/m2, respectively. The inter-annual variation of total radiation showed a fluctuating upward trend, whereas the net radiation fluctuates showed a downward trend, and a significant decrease in the proportion of total radiation. The inter-annual variability of atmospheric invers-radiation was higher due to the different atmospheric conditions were mainly affected, which resulting to a large inter-annual variability of the effective radiation. Whereas the inter-annual variability of upward canopy long-wave radiation was lower, which indicating the canopy long-wave radiation of tropical seasonal rainforest was not changed too much. The diurnal variation curve of atmospheric inverse-radiation was bimodal in the dry season and unimodal in the rainy season. On different time scales, the upward long-wave radiation from the forest canopy was higher than the atmospheric inverse-radiation, indicating that the tropical seasonal rainforest canopy was a heat source for the atmosphere. The ratio of net radiation to total annual radiation was about 60%, and the inter-annual variation showed a significant downward trend. The ratio of reflected radiation and effective radiation to total annual radiation were relatively stable. The ratio of net radiation to total radiation was high during the daytime but low at dawn and dusk, which showed an inverted U-shaped curve. The ratio of reflected radiation and effective radiation to total radiation were lower during the daytime and higher at dawn and dusk, which showed U-shaped curves.  Conclusion  In addition to being affected by general factors such as solar activity, cloud cover and water vapor, the radiation of Xishuangbanna tropical rainforest is also affected by regional climates, such as seasonal defoliation and seasonal fog weather. The study of long-term changes in forest radiation characteristics is of great significance for climate change research, climate model verification and forest productivity research.
Abstract:
Pine wilt disease was caused by Bursaphelenchus xyluphilus, which was the most serious and dangerous major forestry disaster in China in recent years. At present, the disease has caused a large area of pine tree death in 18 provinces and regions of China. Because of the difference of natural environment, the occurrence of pine wood nematode in different epidemic areas is different, especially in Liaoning epidemic area, where the average annual temperature is below 10 ℃. Compared with other epidemic areas, the cold tolerance of pine wood nematode was stronger in Liaoning epidemic area. In addition, there are new host species in Liaoning epidemic area, such as P. koraiensis, P. sylvestris var. mongolica, Larix olgensis, L. kaempferi, L. principis-rupprechtii, as well as new vector insect M. saltuarius. These differences not only brought more challenges to the control of pine wood nematode disease in Liaoning epidemic area, but also increased the risk of the epidemic situation continuing to spread to the northern region. It will contribute to the research of pine wood nematode in Liaoning epidemic area, and provide a theoretical basis for determining a set of effective control management in accordance with the the occurrence characteristics of pine wood nematode disease in Liaoning.
Abstract:
  Objective  To provide a theoretical basis for optimizing the intensive management technology in Populus tomentosa–Wheat agroforestry system under wide- and narrow-row spacing planting schemes, the distribution and morphological characteristics of fine root length density (FRLD) in this system were studied.  Method  In a four-year-old triploid P. tomentosa–Wheat agroforestry system under wide- and narrow-row spacing planting schemes, a soil coring method was adopted for roots sampling around three average standard trees after wheat harvest. The sampling locations were 75 cm away from tree lines for narrow row and 75 cm away from trees for tree row, while 100, 200, 300, and 400 cm away from tree lines for the wide row, sampling depth was 80 cm. A total of 288 root samples were obtained. All fine root samples were scanned, dried and weighed to obtain the distribution and morphological data in different depths and horizontal distances.  Result  Vertically, the fine roots of P. tomentosa and wheat were mainly concentrated in the shallow soil layer. The FRLD in 0–20 cm soil layer accounted for 68% and 45% of the total FRLD, respectively. The FRLD of decreased exponentially with depth for both P. tomentosa (R2 = 0.679 3, P < 0.05) and wheat (R2 = 0.922 9, P < 0.05). There was no significant difference in FRLD between the two species in the shallow soil layer (P > 0.05). However, in the deep soil layer, the FRLD of wheat was significantly higher than that of P. tomentosa (P < 0.05). Horizontally, Fine roots of P. tomentosa were mainly concentrated in narrow row and tree row, while fine roots of wheat were widely distributed in wide row. On a two–dimensional scale, two species had their own dense distribution zones of fine roots and did not interfere with each other. The fine root diameter of P. tomentosa was significantly higher than that of wheat, while its specific root length was significantly lower than that of wheat (P < 0.05).  Conclusion  In P. tomentosa–Wheat agroforestry system under wide- and narrow-row spacing planting schemes, the spatial distribution of the fine roots of P. tomentosa and wheat was separated, and the dense distribution area overlapped less. Also, in order to absorb soil resources more effectively and occupy a competitive advantage, wheat would produce more fine roots with higher absorption efficiency. The results can provide a theoretical basis for optimizing the intensive management technology in agroforestry system under this planting schemes.
Abstract:
  Objective  Analyze the potential distribution areas of extremely small population of endangered Acer catalpifolium in China today and in the future, reveal the distribution dynamics of Acer catalpifolium under future climate change.  Method  Taking Acer catalpifolium as the research object, based on the existing Acer catalpifolium distribution sites, climate data and altitude data, using the MaxEnt model and GIS technology to simulate the current, future 50s (2040—2060) and 90s (2080—2100) (SSP126, SSP245, SSP370 and SSP585) the distribution pattern of Acer catalpifolium under climate scenarios、classify the fitness level and use the area under the receiver operating curve (ROC) (AUC) to evaluate the accuracy of the simulation. Analyze the contribution rate of climate variables with the knife-cut method to find out the dominant climate variables that restrict the distribution of Acer catalpifolium; compare the geographic distribution of Acer catalpifolium under different climatic conditions based on the distribution area ratio (Na) and the degree of habitat change (Ne) dynamic.  Result  The main suitable areas for Acer catalpifolium are distributed in southwest China. The AUC values of the training set and the test set under the nine climatic scenarios are both greater than 0.995, indicating that the model simulation accuracy is extremely high; the warmest season rainfall, temperature seasonal variation standard deviation, altitude The equal contribution rate is the highest, 56.1%, 18.2% and 10.9% respectively.  Conclusion  Under the background of climate change, Acer catalpifolium will lose a large number of highly suitable areas, and the habitat fragmentation will be more serious than the trend. The medium-to-high intensity emission scenario SSP370 has little impact on the potential distribution area of Acer catalpifolium. This study can provide a basis for the in-situ and ex-situ conservation of the endangered species of Acer catalpifolium.
Abstract:
  Objective  taking the Larix gmelinii plantation in Xiaoxing’an Mountains as the research object, based on the spatial structure parameters and management density table of the stand, the cutting intensity and logging were determined, and the spatial structure of the stand was optimized, and the effect of optimization was analyzed to provide theoretical basis for the optimization of the spatial structure of the plantation.  Method  In Nancha County, Yichun City, Heilongjiang Province, four fixed plots of Larix gmelinii plantation with an area of 0.2 hm2 were set up. The angle scale, size ratio, competition index and opening ratio of the commonly used stand spatial structure parameters were selected, and the spatial structure evaluation index was constructed. The cutting intensity and cutting wood were determined by combining the management density table of Larix gmelinii, and the spatial structure changes before and after thinning were analyzed Turn.  Results  The results show that the forest trees in the sample plot belong to the cluster distribution, random distribution and uniform distribution. There are many medium and small diameter trees, which are in a disadvantaged state. The growth space of the trees is in a serious and insufficient state, and the forest competition pressure is relatively high. The evaluation grades are all level 2. According to the management density table, the monitoring sample plot 2 and monitoring sample plot 4 were harvested. The harvesting plant number intensity was 20.7% and 12.7%, respectively. After harvesting, the angular scale decreased by 3.9% and increased by 3.8%, and the size ratio decreased by 0.5% and 0.4, respectively. %, the competition index decreased by 16.8% and 5.2%, the openness ratio increased by 24.5% and 4.2%, and the spatial structure evaluation index increased by 27.8% and 7.2%.  Conclusion  Using stand spatial structure parameters combined with management density table for thinning can effectively improve stand spatial structure, improve the growth space and dominant degree of trees, and reduce the competitive pressure.
Abstract:
  Objective  This paper aims to optimize the spatial structure of stand, improve the quality of existing forests and protect the habitat of wild animals, so as to provide a theoretical basis for forest management in Maoershan Mountain of northeastern China.  Method  Taking Maoershan Mountains forest farm as the study area. According to the four spatial structure indices of complete mingling, uniform angle index, competition index, stand layer index and habitat suitability index, a comprehensive spatial structure model is constructed by using the idea of multiplication and division. The habitat suitability index is calculating based on the 2016 survey data of the Maoershan Mountains. Taking the Great Spotted Woodpecker as an example, we using the R to compile the stand optimization simulation. Compare the changes of stand structure and habitat suitability index under the different thinning intensities, and analyze the feasibility of integrating the habitat suitability index into the optimization model.  Result  Compare the changes of each index and optimization function Q-value under different tending intensities (10%, 20% and 30% respectively), the optimal tending intensity is 20%, the maximum Q-value is 73.28, the average Q-value is 49.59, the canopy density is 0.62 and the cutting trees are mainly located in dense forest areas which a total of 133 trees. After stand optimization, the complete mingling and stand layer index increased, the competition index decreased, the uniform angle index is between [0.475, 0.517] which is in a randomly distributed state; and the habitat suitability index increased to 0.57.  Conclusion  It shows that this optimization simulation optimizes the spatial structure of the stand while improves the habitat suitability index. The conclusion of this study can provide a scientific basis for optimization of the spatial structure and protection for the living environment of wild animals.
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.
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.
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.
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.
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2021, 43(3): 1-2.  
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Abstract:
Forest Sciences
Abstract:
  Objective  Stand-level volume, biomass and carbon stock models or tables are necessary quantitative tools for implementing forest management inventory. Developing stand volume, biomass and carbon stock models for ten major forest types in forest region of northeastern China is not only an exploration of methodology, but also provides reference results for practice.  Method  Based on the field measurement data of 2 000 sample plots distributed in 10 forest types in northeastern China, i.e. spruce & fir (Picea spp. & Abies spp.), larch (Larix spp.), Mongolian scotch pine (Pinus sylvestris var. mongolica), Korean pine (Pinus koraiensis), oak (Quercus spp.), birch (Betula spp.), poplar (Populus spp.), elm (Ulmus spp.), linden (Tilia spp.), and other three precious broadleaved species (Fraxinus mandshurica, Juglans mandshurica & Phellodendron amurense), the stand-level volume, biomass and carbon stock models were developed through independent nonlinear regression (INR), simultaneous error-in-variable equations (SEIVE), and SEIVE with dummy variable modeling approach.  Result  The coefficients of determination (R2) of the population-averaged stand-level volume, biomass and carbon stock models based on all sample plots were 0.945, 0.805 and 0.839, respectively; and those of tthe models with type-specific parameters were 0.959, 0.949 and 0.951, respectively. The R2 values of stand-level volume, biomass and carbon stock models for 10 forest types were all more than 0.86, the mean prediction errors (MPE) were all less than 3%, and the mean percent standard errors (MPSE) were almost less than 10%. For the volume stock models, the R2 values were between 0.876−0.980, MPE were between 0.90%−1.95%, and MPSE were between 5.14%−11.89%; for the biomass stock models, the R2 values were between 0.864−0.988, MPE were between 0.66%−2.07%, and MPSE were between 3.61%−11.60%; and for carbon stock models, the R2 values were between 0.866−0.988, MPE were between 0.67%−1.96%, and MPSE were between 3.65%−11.57%.  Conclusion  The volume stock per hectare of different forest types mainly depends upon basal area and mean tree height of forest stands, and the biomass stock mainly relates to volume stock and mean tree height. The SEIVE with dummy variable modeling approach is a feasible method for developing stand-level stock models. The developed volume, biomass and carbon stock models for 10 major forest types in northeastern China in this study meet the need of precision requirements to the regulation on forest management inventory, indicating that the models can be applied in practice.
Abstract:
  Objective  Quantile regression and quantile groups were used in this article to model and predict height to crown base, which provided new ideas and methods for the construction of height to crown base models.  Method  The data were collected from the measured data of natural forests of Larix gmelinii in 4 forest farms of Xinlin in Daxing’ anling of northeastern China. Nonlinear regression was used to build the basic and generalized models of the height to crown base and then extended to quantile regression. Four types of sampling designs (the largest DBH tree sampling, the smallest DBH tree sampling, the mean DBH tree sampling and random sampling) and three quantile group (\begin{document}$\tau {\text{ = }}$\end{document} 0.1, 0.5, 0.9), five quantile group (\begin{document}$\tau {\text{ = }}$\end{document} 0.1, 0.3, 0.5, 0.7, 0.9), nine quantile group (\begin{document}$\tau {\text{ = }}$\end{document} 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9) were used to predict height to crown base. The prediction effects of different quantile groups were compared as well as the impact of different sampling designs. Two-fold evaluation was used to compare the prediction effects of nonlinear regression, optimal quantile regression and optimal quantile group. Model evaluation criteria included mean absolute error (MAE), root mean square error (RMSE), mean percentage of error (MPE) and adjustment determination coefficient (\begin{document}${{R}}_{{\rm{adj}}}^2$\end{document}).  Result  (1)Whether it is nonlinear regression or quantile regression, the fitting MAE of generalized models can be reduced by 6% to 12%, RMSE can be reduced by 6% to 10% compared with basic models. And the validation effects of generalized models were also better than basic models. There was a negative correlation between height to crown base and DBH, and a positive correlation between height to crown base and HDOM and BA. (2) Median regression had the best fitting ability among all quantiles, and the effects of median regression were similar to that of nonlinear regression. Quantile regression can describe the distribution of height to crown base. (3) All three quantile groups can predict height to crown base and the effect was not much different. The three quantile group was sufficient to predict height to crown base. The results of two-fold evaluation for median regression were similar to that of nonlinear regression, while three quantile group’s prediction ability was the best. Compared with nonlinear regression and median regression, the MAE and MPE of three quantile group decreased about 20% and 4% respectively, \begin{document}${{R}}_{{\rm{adj}}}^2$\end{document} increased about 16%. (4) The optimal sampling designs for basic and generalized quantile groups were five mean DBH trees and seven largest trees, respectively.  Conclusion  The height to crown base models based on three quantile group (\begin{document}$\tau {\text{ = }}$\end{document} 0.1, 0.5, 0.9) in this study can improve the prediction accuracy. The optimal sampling design of the basic and generalized quantile groups is 5 mean DBH tree sampling and 7 largest DBH tree sampling, respectively. Considering the accuracy of prediction and the cost of investigation, it is recommended to select 5 medium trees from the sample plot to predict the height to crown base when quantile groups are applied in practice.
Abstract:
  Objective  On the basis of pipe model and the theory of water transportation pattern through tree rings, we investigated the canopy productivity structure of Larix olgensis and leaf biomass models for four larch subspecies to provide a theoretical and technological background for evaluating canopy productivity and studying the pattern of water transportation through 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 varied 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 transportation rate of current-year ring was faster than others. (2) Based on 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 transportation capacity and branch mechanical support capacity, which were represented by two types of predictor variables relating to branch mass and water transportation capacity, respectively. (3) The biomass models with 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 were 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 have 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 mass and water trasportation capability, respectively. The fitted standard model and reduced models of leaf biomass could produce accurate estimates for the four Larix subspecies.
Abstract:
  Objective  Chalcone synthase (CHS) is one of the rate-limiting enzymes of phenylpropanoid pathway which plays superior roles in the production of secondary metabolites. In this study, by cloning and bioinformatics analysis of CHS gene and analyzing the relationship between CHS gene expression and flavonoid synthesis of Koelreuteria paniculata, we hope to provide reference for further study of flavonoid biosynthesis pathway related genes, evolution of CHS gene family and coloration mechanism of Koelreuteria paniculata ‘Jinye’.  Method  CHS genes were isolated and characterized by RT-PCR from Koelreuteria paniculata. And the expression patterns of CHS gene in different tissues of Koelreuteria paniculata and in the leaves of Koelreuteria paniculata and Koelreuteria paniculata ‘Jinye’ in May, July and September were analyzed by qRT-PCR; the differential flavonoid metabolism between Koelreuteria paniculata and Koelreuteria paniculata ‘Jinye’ was screeidues ether.  Result  Two full-length DNA of CHS genes were cloned named KpCHS1 and KpCHS2 . The KpCHS1 gene sequence was found to be 2 492 bp and comprised an open reading frame of 1 173 bp, encoding for 390 amino acid residues, the KpCHS2 gene sequence was found to be 1 321 bp and comprised an open reading frame of 1 182 bp, encoding for 393 amino acid residues ether. Alignment of the predicted amino acid sequence of KpCHS2 had been shown to have high sequence similarity with KpCHS1, with four CHS specific conserved motifs and one chalcone synthase active site. Furthermore, KpCHS1 and KpCHS2 were generally expressed in roots, stems, leaves and seeds of Koelreuteria paniculata. Among them, the expression of KpCHS2 was the highest in seeds, while that of KpCHS1 was higher in leaves. In roots and stems, the expression levels of the two genes were similar and lower. The expression pattern analysis showed that in Koelreuteria paniculata and Koelreuteria paniculata Jinye’, the expression of KpCHS1 decreased with the increase of months, while the expression of KpCHS2 did not show obvious regularity. In the July plant samples, the expression of KpCHS1 gene in Koelreuteria paniculata ‘Jinye’ was higher than that in Koelreuteria paniculata. Besides, we analyzed the metabonomics of Koelreuteria paniculata and Koelreuteria paniculata ‘Jinye’ leaves in July, and screened out the different flavonoids. It was found that kaempferol-7-o-glucoside, 7-hydroxycoumarin, quercetin-3β-D-glucoside, and kaempferol, naringin, which were important intermediate products in flavonoid biosynthesis, were significantly increased in Koelreuteria paniculata ‘Jinye’ leaves.  Conclusion  KpCHS1 and KpCHS2 belong to the chalcone synthase family of Koelreuteria paniculata and are highly homologous, but they are distributed in far branches of the phylogenetic tree. It is speculated that the two proteins may have great differences in the catalytic function of amino acid activity. KpCHS1 and KpCHS2 are expressed in roots, stems, leaves and seeds, and higher in leaves and seeds of Koelreuteria paniculata. Our results indicate that the expression of KpCHS1 gene is highly related to the synthesis of flavonoids in Koelreuteria paniculata.
Abstract:
  Objective  Long non-coding RNA (lncRNA) is a class of transcripts, which are larger than 200 nt in length and have extremely low protein-coding ability or without protein-coding ability. LncRNA is one of the key regulators of plant stress response. In this study, we studied the salt-tolerant physiological indexes under the salt stress of transiently overexpressing lncRNA of Tamarix hispida, and analyzed whether it had the ability to improve the salt tolerance and enrich the molecular mechanism of woody plant lncRNA in response to stress. It laid a foundation for the molecular regulation mechanism of lncRNA in T. hispida in response to salt stress.  Method  In this study, a differential expression lncRNA-224223.1 was selected and named ThSAIR6 from transcriptomes of T. hispida under salt stress. The quantitative real-time PCR (qRT-PCR) was used to analyze the expression pattern of ThSAIR6 in leaf tissues of wild type T. hispida under salt stress. It could initially identify whether it responded to salt stress or not. Overexpression vectors (pROKII-ThSAIR6) were constructed in order to further study the stress tolerance. Overexpression (OE) and control T. hispida plants were obtained by agrobacterium-mediated high-efficient transient transformation system. Physiologic indexes related to salt tolerance of OE and control T. hispida plants under salt stress were measured in order to judge whether it could improve the salt tolerance of T. hispida plants.  Result  The results of qRT-PCR showed that the expression quantity of ThSAIR6 in wild type plants significantly increased after salt stress for 24 h (P < 0.05), indicating that it could response to salt stress. The results showed that overexpression of ThSAIR6 in T. hispida plants significantly decreased the contents of H2O2 and \begin{document}$ {\rm{O}}_{\rm{2}}^{ {-} {\text{•}}} $\end{document} (P < 0.05), enhanced the POD and SOD activities (P < 0.05), and lowered the amount of dead cells, the electrolyte leakage and water loss rate of T. hispida tissues at the same time.  Conclusion  In conclusion, lncRNA ThSAIR6 of T. hispida can response to salt stress. Overexpression of ThSAIR6 in plants significantly decreases the contents of H2O2 and \begin{document}$ {\rm{O}}_{\rm{2}}^{ {-} {\text{•}}} $\end{document}, enhances the POD and SOD activities, improves ROS scavenging, and reduces cell damage of plant tissues under salt stress, thus effectively improves its salt tolerance.
Abstract:
  Objective  Due to the water scarcity and the improvement in urban greening, the tension has grown from the struggles for water between industries, urban life, and urban afforestation in Beijing. Thus, it is the top priority to explore the response mechanism of urban greening tree species to arid habitats and to screen the low-water consumption and high-water utilization landscaping tree species for high-quality urban forest landscape.  Method  Typical greening tree species including Ginkgo biloba, Koelreuteria paniculata, Sophora japonica, Platycladus orientalis, Pinus tabuliformis, and Pinus bungeana in Beijing were selected and subjected to three groups of soil water stresses such as slight drought (SLD, 50%−70% field capacity (FC)), moderate drought (MD, 30%−50% FC) and extreme drought (ED, lower than 30% FC). The interspecific differences in the instantaneous water use efficiency (WUEi) and mean water use efficiency (WUEL) of these tree species under water stresses and their relationship to eco-physiological factors were investigated based on the stable isotope technology and the observations on tree physiological traits.  Result  The photosynthetic capacities and WUEi in G. biloba, K. paniculata, S. japonica and P. orientalis decreased significantly compared with control (CK, 90%−100% FC) when potted soil volumetric water content (SWC) was less than 70% (P < 0.05), whereas there was no significant difference in WUEi of P. tabuliformis and P. bungeana subjected to continuous drought (P > 0.05). The WUELs of evergreen tree species were significantly higher than those of deciduous tree species under MD and ED (P < 0.05). The WUELs of three deciduous tree species differed in response to extreme drought (P < 0.05), and the sequence of WUELs in three deciduous tree species was S. japonica > K. paniculata > G. biloba. The WUELs of G. biloba and K. paniculata in SLD, and P. orientalis and P. tabuliformis in MD reached their respective peaks and then decreased along with the increases in soil water stress; while those of S. japonica and P. bungeana increased with potted soil drying, and were 44.19% and 30.35% higher than control, respectively at severe drought condition (P < 0.05). Comparing the correlations between photosynthetic parameters, WUEi and WUEL of different tree species, it was found that the stomatal conductance (gs) of G. biloba, K. paniculata and S. japonica significantly affected its photosynthesis and transpiration processes (P < 0.01) and hence exerted a strong influence on WUEi, while those in evergreen tree species such as P. orientalis, P. tabuliformis, and P. bungeana were insensitive to the variation in soil moisture and had little impact on WUEi (P > 0.05). The WUEL of evergreen tree species was higher than that of deciduous ones under moderate and extreme water stress.  Conclusion  Therefore, considering the limited water resources of Beijing, evergreen tree species have stronger abilities to conserve water content and optimize photosynthetic performance to improve their water use efficiency, to adapt to arid habitats than those of deciduous trees in Beijing.
Abstract:
  Objective  In order to study the effects of understory vegetation and litter on soil CO2 flux in cold temperate natural forests in China, we analyzed and explored the characteristics of CO2 flux emission under different treatments, to provide reference for the management of forest ecosystem and the study of soil greenhouse gases in Daxing’an Mountains region and theoretical reference.  Method  In the period from May to September in 2019, the method of static box-gas chromatography was used to study soil CO2 flux emission characteristics in four main forest types (Betula platyphylla forest, Populus davidiana forest, Pinus sylvestris var. mongolica forest and Larix gmelinii forest) in the north of Daxing’an Mountains.  Result  The soil CO2 flux of the four forest types under different treatments all showed a single-peak curve changing trend, and the peak appeared in July or August. The removal of litter increased the soil respiration of broadleaved forests and decreased the soil respiration of coniferous forests. However, the changes did not reach a significant level (P > 0.05). Compared with the natural state, the removal of understory vegetation significantly (P < 0.05) increased the average CO2 flux of Betula platyphylla forest, Populus davidiana forest and Larix gmelinii forest by 27.57%, 15.84% and 24.13%, respectively, but decreased it in Pinus sylvestris var. mongolica forest by 0.68% (P > 0.05). With the simultaneous removal of understory vegetation and litter, the average CO2 fluxes of Betula platyphylla forest, Populus davidiana forest and Larix gmelinii forest increased by 20.05%−25.34%, but the Pinus sylvestris var. mongolica forest decreased by 12.36%. The average flux of broadleaved forest was significantly larger than that of coniferous forest (P < 0.05) when the understory vegetation and litter were both removed.  Conclusion  The existence or non-existence of litter and understory vegetation would have different effects on soil CO2 flux. Also, the impact on different forest types also varies. Scientific and reasonable understory management strategy plays a key role in regulating carbon dioxide emissions and the protection of ecological environment.
Abstract:
  Objective  The combustion of underground fire is a slow, flameless, long duration smoldering, which does great harm to forest. Daxing’anling region is a frequent area of forest underground fire in northeastern China. This paper aims to study the effects of different heating times and humus particle sizes on the vertical combustion of underground fires, aiming to provide a reference for the prevention, monitoring and suppression of underground fires in the area.  Method  Taking the typical forest type in the Daxing’an Mountains, i.e. Larix gmelinii forest as the research object, according to the indoor control simulation of scorching experiment data, SPSS was used to perform two-factor analysis of variance, and the Origin software was used to draw. The effects of three heating times and five humus particle sizes on the spreading speed and the highest temperature at different depths during the vertical combustion of underground fire were studied.  Result  During the vertical burning process of the forest underground fire, the temperature of the highest burning at a depth of 3 cm was only affected by the heating time and the difference was significant (P < 0.05), but the effects of humus particle size on the difference were not significant (P > 0.05). The highest temperature of combustion at a depth of 6 cm was affected by the heating time (P < 0.05) and the particle size of humus (P < 0.05). When the depth was greater than 6 cm, the maximum combustion temperature was only affected by the humus particle size and the difference was significant (P < 0.05). The spread rate during the vertical combustion of forest underground fires was only affected by the humus particle size. There were significant differences between the spreading speeds (P < 0.05).  Conclusion  The highest temperature of underground forest fires burning at 3 cm and 6 cm depth rises with the increase of heating time, and the burning temperature is the highest when heated for 2 h. When the vertical combustion depth is 9−21 cm, the humus particle size is 40 mesh, the burning temperature is the highest. Among the effects of humus particle size on the spread speed of forest underground fires, the spread speed of humus particle size 20 mesh is the fastest; when the humus particle size is 60 mesh, it is the criticality in the process of underground fire combustion. The highest combustion temperature and spread speed are lower.
Abstract:
  Objective  Litter layer is an important component of forest ecosystem, and it is of unique and key significance to study the spatial distribution characteristics of nutrients for maintaining forest ecological environment and sustainable management.  Method  To investigate the spatial heterogeneity of litter nutrients at different decomposition stages, we established four 1 ha permanent sample plots in temperate spruce-fir mixed forests. Litter collection and stand survey were conducted using an equidistant grid point sampling method. Litter samples in semi-decomposed (F) horizon and completely decomposed (H) horizon were determined to analyze the spatial variations of litter nutrient concentrations using statistical analysis and kriging interpolation.  Result  (1) In the F horizon, concentrations of litter organic carbon (OC), total nitrogen (TN) and total phosphorus (TP) were 421.68, 18.86 and 1.26 g/kg, respectively, and they were 350.78, 17.80 and 2.68 g/kg in the H horizon. Litter OC and TN decreased but TP increased with the increase of decomposition degree. The coefficients of variation of litter OC, TN and TP in the F and H horizons varied in the four sample plots with a range of 10.94%−65.63%. The spatial variation degrees of litter OC and TP in the F horizon were smaller than those in the H horizon. (2) Litter OC, TN and TP concentrations showed higher spatial autocorrelation, primarily resulting from the structure factors at the forest community scale. Litter nutrient concentrations in the four sample plots showed a strip and patch gradient distribution. Litter OC in the F horizon had similar spatial distribution pattern to the H horizon. However, the high-value centres of TN and TP in the F horizon were generally lower in the H horizon. The fractal dimension of litter OC and TP concentrations in the F horizon was higher than that in the H horizon. This indicated that the F horizon exhibited a more complex spatial pattern, whereas litter TN had a better structure and stronger spatial dependence in the F horizon than that in the H horizon. (3) Litter OC and TN in the H horizon had a significant negative correlation (P < 0.05) with the standing crop of litter but the TP concentration with an opposite relationship. Litter OC and TN in the H horizon were significantly affected by water holding capacity. In addition, litter OC, TN, TP and their stoichiometric ratios were significantly correlated. Litter TN and TP in the F horizon were significantly affected by biodiversity indices and species number, while those in the H horizon were mainly affected by the proportion of conifer species and stems. However, litter TN and TP were more strongly related with stand characteristics in comparison with OC.  Conclusion  The spatial distribution characteristics of nutrients in litter layer over temperate natural spruce-fir mixed forest are affected by litter properties (e.g. the degree of decomposition and water holding capacity.) and stand structure (e.g. tree species and stand density.).
Abstract:
  Objective   In order to provide the basis for the optimal allocation of vegetation patterns for soil and water conservation in the Loess Plateau and other water resource deficient areas, the effects of different vegetation patterns and fragmentation on runoff and sediment yield were studied.   Method   To explore the impacts of different vegetation patterns on runoff, sediment, and infiltration in this research, we measured the characteristics of runoff, sediment, and soil infiltration of five vegetation patterns (block-shaped mosaic pattern plots SP1, SP2, horizontal strip pattern plot BP, slope band pattern plot LP, and bare land pattern plot CK, respectively) by field simulated rainfall tests.   Result   (1) In general, vegetation had relatively good capacity in sediment reduction and water storage. The sediment reduction efficiency reached 47.44%−91.67%, and the water storage efficiency reached 25.67%−62.94%. Therefore, the sediment reduction capacity of vegetation was stronger than the water storage capacity. (2) The vegetation patterns had statistically significant effects on the runoff and sediment yield on the slope (P < 0.05). The order of the highest to lowest storage and sediment reduction effects of vegetation patterns were block-shaped mosaic pattern, horizontal strip pattern, followed by the slope band pattern. Thus, the block-shaped mosaic pattern had the best soil and water conservation effect. (3) The process for the runoff occurrence of different vegetation patterns showed a trend of “a rapid-rise phase followed by a relative stable phase”. The vegetation patterns helped to delay the occurrence of the runoff peaks. (4) The fragmentation index of vegetation patches was inversely proportional to the erosion and sediment production. The higher the degree of fragmentation of vegetation patches was, the lower the sediment yield and the better the efficiency of water storage and sediment reduction were. (5) The infiltration coefficient of different vegetation patterns was in the following order: the block-shaped mosaic pattern > horizontal strip pattern > slope band pattern > bare land pattern. Further, the Horton model exhibited a good fitting behavior on soil infiltration of different vegetation patterns.   Conclusion   Through the above research, it is found that vegetation and bare land mosaic pattern are significantly better than that of bare land and long strip slope pattern in water storage and sediment reduction. Therefore, in the loess area with limited water resources, vegetation can be planted in the way of alternate distribution of vegetation and bare land to maximize the benefits of water storage and sediment reduction.
Abstract:
  Objective  The study on the coupling and coordination relationship between ecological environment and industrial development can help planners obtain the coordinated development trend of Beijing-Tianjin-Hebei region, northern China from an ecological perspective, and provide scientific basis for planning and management.  Method  Based on the MSPA and InVEST models, this study firstly explored the changes of ecological infrastructure, habitat quality and economic development in the Beijing-Tianjin-Hebei region from 2000 to 2017, and then applied the coupling coordination model to comprehensively analyze the coupling coordination of the above three in the region. Finally, the coupling coordination degree of different regions in Beijing-Tianjin-Hebei region in the next five years was predicted by the gray prediction model.  Result  (1) The overall ecological infrastructure in the Beijing-Tianjin-Hebei region was in the low level, and the landscape connectivity was poor. The spatial variation of the habitat quality was significant, with an average habitat quality of 0.450, which was not high. (2) The development of agriculture, forestry, animal husbandry and fishery in the northwestern ecological conservation area was stable, while the secondary industry in Tianjin-Hebei region was in a dominant position. As for the transportation, warehousing and postal industries in the eastern coastal development area and the financial industry in Beijing-Tianjin region, they were well developed. (3) The coupling coordination degree in Beijing-Tianjin-Hebei region was ranked from a mild disorder state to a primary coordination state, the regional variations of the coupling coordination levels were significant. Among them, the southern functional expansion area had the highest coupling coordination degree, while it was lowest in the northwestern ecological conservation area. (4) In the next 5 years, the coupling coordination degree in the Beijing-Tianjin-Hebei region will be improved, but the central core functional area will remain on the verge of imbalance, Beijing and the eastern coastal development area will remain in a barely coordinated state, which are key areas need to be optimized in the future. The coupling coordination degree in Tianjin will change from barely coordination to primary coordination, and the northwestern ecological conservation area will change from being on the verge of imbalance to primary coordination, which are the potential areas for coordinated development. The coupling coordination degree of the southern functional expansion area will be transformed into middle-level coordination, which is the fastest development area.  Conclusion  This study evaluated the coupling and coordination of the ecological infrastructure-habitat quality-industrial development in Beijing-Tianjin-Hebei region, and predicted the critical areas with the potential for synergistic development. All of the conclusion can provide a basis for the future coordinated development of Beijing-Tianjin-Hebei region and offer an important reference for ecological construction and industrial development evaluation within other urban agglomerations.
Landscape Architecture
Abstract:
  Objective  The quantitative evaluation of the value of green space ecosystem services in urban areas is an important work basis for land space planning. The prediction of its evolution based on the value measurement is more helpful for the planners to understand and measure the existing ecological stock, future development trend and potential problems within the urban area, so as to plan and respond in advance.  Method  In order to clarify the impact of evolution of land space utilization on the service value of regional ecosystem in Chengde City, Hebei Province of northern China, this paper combines RS and GIS technology to analyze the evolution characteristics of land use/land cover change (LUCC) space utilization in Chengde City. At the same time, the value equivalent factor per unit area was used to calculate the value of ecosystem services in Chengde City. On this basis, MARKOV model was used in this paper to predict the evolution trend of land use in Chengde City in 2026 and the changes of ecological space stock and ecosystem service value.  Result  The overall ecosystem service value of Chengde City showed an obvious downward trend. From 1995 to 2015 (totally 5 periods, i.e. 1995, 2000, 2005, 2010, 2015), the total values of ecosystem services in Chengde City were 103.851 billion CNY, 103.593 billion CNY, 103.609 billion CNY, 100.971 billion CNY and 99.936 billion CNY, respectively. At the same time, the evolution simulation results showed that the overall service value of Chengde City will still be in a downward trend in 2026, with a value decline of about 997 million CNY.  Conclusion  The spatial dimension of ecosystem service value in Chengde City presents an obvious patch distribution. The core service value is concentrated in the northwestern and southern forest land area, and the time dimension has a significant function reduction. The core reduction area is concentrated in the edge areas of the built-up areas in cities and counties. This study summarized the evolution of ecological service value and spatial change rule of Chengde City from spatial distribution, time evolution and development prediction, so as to provide basis for the development planning and control strategy of the subsequent land space of Chengde City.
Abstract:
  Objective  Based on the study of granite and dolomite mountain in Beijing, this study explored the differences of plant communities under different bedrock conditions, and provided scientific basis for vegetation restoration of granite and dolomite mountain in Beijing.  Method  Three granite and dolomite mountains were selected in the experiment. Through the sample survey, the plant community characteristics of two different kinds of bedrock were analyzed from the aspects of species composition, biodiversity, altitude gradient characteristics, similarity coefficient, etc.  Result  The results showed that: (1) there were 188 kinds of vegetation in granite mountain, belonging to 148 genera of 61 families; 95 kinds of vegetation in dolomite mountain, belonging to 80 genera of 38 families; all of them were dominated by Compistae, Fabaceae and Gramineae, which were the important resources of plant restoration and planting in two kinds of bedrock mountain. (2) By measuring different life styles, the dominant species of tree layer, shrub layer and herb layer between two kinds of bedrock mountain vegetation in Beijing can be used as important materials for mountain restoration. (3) Compared with the characteristics of plant community in granite mountain, it was found that there was no consistency between them; compared with the characteristics of plant community in dolomite mountain, it was found that there was a high consistency.  Conclusion  The plant community species of different granite and dolomite mountain are consistent in dominant families and genera, which are important plant resources for ecological restoration of granite and dolomite mountain. By comparing the similarity between different mountains, we can not generalize the phytoremediation of granite mountain. We should pay attention to distinguish different site conditions. For the dolomite mountain, we can use similar methods and plant species to repair.
Forestry Engineering
Abstract:
  Objective  Wood preservative treatment is an effective way to prolong the lifespan of wood, reduce deforestation and further improve the ecological environment. In this study, in order to provide a basis for the development of eco-friendly wood preservatives and enrich the wood preservative system, the decay performance of a series of methoxyacrylate fungicides, iodopropynyl butyl carbamate (IPBC) and 4, 5-dichloro-N-octyl-4-isothiazolin-3-one (DCOIT) has been systematically screened.  Method  In order to discover novel agents with high-activity to control wood rot fungus, the inhibition zone method was used to test the antifungal activity of 5 candidate agents (azoxystrobin, kresoxim-methyl, pyraclostrobin, IPBC and DCOIT) against wood rot fungus. Then the high-activity agents were prepared into water-based formulations, and the method for lab sand block test was used to evaluate interior decay resistance of treated materials at different levels of drug retention.  Result  The inhibition zone results indicated that azoxystrobin, pyraclostrobin, DCOIT and IPBC showed good inhibitory effects on brown rot fungi and white rot fungi. Especially, pyraclostrobin and IPBC exhibited high antibacterial effects, which were higher than the control agent propiconazole. For the preservative treated radiata pine material under the chemical retention of about 0.21−0.46 kg/m3, the mass loss rates of treatment material by azoxystrobin and pyraclostrobin for white rot fungi and brown rot fungi were 3.1%−7.9% and 3.5%−7.8%, respectively. Moreover, the mass loss rate of IPBC treatment radiata pine material was 0.9%−5.6% under the chemical retention of about 0.2 kg/m3. The lab sand block test of the preservative treated Populus tomentosa results showed that the decay resistance of all the treated samples at different chemical retention levels was much better than that of the untreated samples. However, their mass loss rate was still large. It is not recommended to use this kind of fungicides for the preservative treatment of Populus tomentosa.  Conclusion  In this study, the antifungal activity of pyraclostrobin and azoxystrobin formulations is equivalent to the control agent propiconazole, and antifungal effect of IPBC is better than propiconazole. So they could be further developed and utilized as a novel wood preservative.
Abstract:
  Objective  The objective of this study is to investigate the effects of brown-rot decay on color, microstructure, and chemical components of wood at the early stage of decay test, as well as provide a theoretical basis for the further explanation of wood degradation mechanism.  Method  The sapwood of southern pine was decayed by Gloeophyllum trabeum for different durations. The microstructure of decayed wood was characterized by field emission scanning electron microscopy (FE-SEM), in order to elucidate the access pathways of brown-rot fungi into wood. Meanwhile, colorimetry, Fourier transform infrared spectroscopy and X-ray diffraction were used to characterize the mass loss, color change, chemical component, functional group change, and crystallinity change of wood after different decay stages.  Result  The lightness of wood decreased and the total color difference increased during the decay test, with a trend toward rufous surface color. Mycelium entered into the wood through cell structures such as ray parenchyma cells, pits and tracheids, and basically completed the initial colonization after 20 d. The mass loss of wood at the early stage of brown-rot decay was mainly caused by the degradation of hemicellulose, while the degradation of cellulose was less pronounced. At the same time, the distance between crystal planes of cellulose decreased to the minimum value (3.962 Å) while the relative crystallinity increased significantly (47.02%), which prohibited the degradation of cellulose. Therefore, the mass loss rate of wood slowed down after that.  Conclusion  At the early stage of brown-rot decay on southern pine wood, hyphae entered into wood by pits, ray parenchyma cells and tracheids. Hemicellulose in cell wall was preferentially degraded and the lattice distance of crystalline cellulose reduced while the relative crystallinity increased. This research could provide a theoretical basis for the further exploration of brown-rot degradation mechanism of wood, as well as wood preservation.
Abstract:
  Objective  The determination of dimensions of mortise and tenon joint is the premise of editing NC(numerical control) codes of mortise and tenon joint. It is also the foundation of realizing CNC (computer numerical control) 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, which 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 takes 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 parametric design ideas. Secondly, the correlation functions between dimension parameters of lattice tenon were established based on assembly constraints, which included 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 included 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 of mortise and tenon joints, even solid wood furniture processing.

Establishment Time:1979

CN 11-1932/S

ISSN 1000-1522

Supervisor:Sinopec Research Institute of Petroleum Engineering

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