Objective: The relationship between radial growth of Pinus yunnanensis and climatic factors and growth dynamics under the extreme drought events at different altitudes were studied to explore the ecological resilience and growth degradation history of P. yunnanensis, which could provide a basis for predicting the future effects of extreme disturbance on the growth dynamics of P. yunnanensis and provide theoretical support to forest protection in this area. Method: Increment cores of P. yunnanensis at different altitudes in Yongren County, Jinsha River basin were collected by increment borer and established chronologies. Percentage changes of radial growth were used to evaluate the growth degradation. Resistance and resilience were used to assess the ecological resilience of P. yunnanensis. Response analysis and redundancy analysis were used to study the relationship between growth and climate factors of P. yunnanensis at different altitudes. Result: The main limiting factors for the radial growth of P. yunnanensis at low (1 845 m) and medium (2 340 m) altitudes are the monthly mean air temperature, precipitation and drought intensity of initial growing season from March to May, and the monthly precipitation and drought intensity of growing season from June to August. Monthly air temperature of July during growing season and drought intensity of the initial growing season are the main limiting factors for the radial growth of P. yunnanensis at high altitude (2 740 m); In the past 150 years, growth of P. yunnanensis degraded during the period of 1884-1886, 1897-1900, 1903-1906, 1947-1949, and 2009-2011. The radial growth degradation of P. yunnanensis was most obvious in low-altitude area, followed by high-altitude area, and the degradation in the middle-altitude area was weaker. The ecological resilience of P. yunnanensis to the same extreme drought events varies among different altitudes. The drought resistance of P. yunnanensis is in an order of medium altitude > high-altitude > low-altitude. The resilience to extreme drought is just in an opposite order. With the increase of age, the drought resistance has enhanced at low-altitudes, while the resilience has weakened. The resistance of P. yunnanensis at the middle-altitudes is stable, the resistance and resilience at the high-altitudes are stable. Conclusion: Trees growing in the marginal distribution of P. yunnanensis are more prone to growth degradation, trees under favorable hydrothermal conditions are more resistant to the interference of extreme events, and trees near the limit environments of P. yunnanensis are more resilient to disturbances.

Objective: The aim of this study is to quantify the particulate matters (PM) retained per unit leaf area by different tree species and its spatio-temporal variation in Guiyang City, in order to provide a scientific basis for the rational selection of landscaping tree species with higher capacity of retaining PMs. Method: Fourteen commonly used landscaping tree species growing at 4 sites, urban square, urban park, suburban green area, and suburban forest, in Guiyang City each with different levels of pollution. Leaf samples were collected regularly from 3 trees of each species (some species are not present at certain sites) at the same time. The aerosol re-suspension method based on the wind erosion principle was applied to measure the retained PM quantity per unit leaf area (M). The micro-morphological and structural characteristics (stomata density, stoma size, stomata opening size, roughness, vein density, groove width, wax coverage index, epidermal hair length, epidermal hair density, etc.) of leaves were quantitatively analyzed using image analysis software. The influence of leaf morphology and structure characteristics on the leaf retained PM was analyzed by means of path analysis. Result: It showed that the site means of M_TSP of all studied tree species varied within a range of 1.56-11.14 μg·cm^-2, with non-significant difference between trees and shrubs, but a significant difference among tree species. The tree species of Loropetalum chinense var. rubrum showed the highest quantity of PM retention, followed by Cedrus deodara, Osmanthus fragrans, Rhododendron simsii, Bambusa multiplex, Ligustrum lucidum, and Magnolia denudata, while other tree species showed a weak capacity of PM retention. Among the structural morphological characteristics, the leaf surface roughness, the epidermal hair density, and epidermal hair length were the major factors affecting PM retention compared to other ones. Therefore, the leaves with higher epidermal hair density, bigger epidermal hair length, and rougher leaf surface presented a higher PM retention. The weight ratios of different PMs retained by leaves were not the same as that in the ambient air. The weight ratio of retained coarse and large PMs was 97.36%, while it was 80.29% in the ambient air, indicating that leaves tend to retain more PMs with bigger diameters (such as PM_2.5-100) but less fine PMs (such as PM_1-2.5 and PM₁). Most tree species showed a higher PM retention in winter and spring than in summer and autumn. For the same tree species, the PM retention in urban sites was higher than that in suburban sites. Among the 2 urban sites with a high air PM density, the PM retention quantity was higher in urban park than in urban square, probably due to the more concentrated distribution of trees in the urban parks which leads to a more favorable microclimate to capture more PM on leaf surface, i.e., an agglomeration effect. Conclusion: A significant difference in the PM retaining capacity exists among tree species. The main factors affecting the leaf PM retaining capacity are the leaf surface roughness and the epidermal hair density. The leaves tend to retain more large and coarse PM but less fine and ultra fine PM. The quantity of retained PM by leaves at more polluted sites is higher than that at less polluted sites. The micro-morphological and structural characteristics of leaves can be used as evaluation indicators for selecting tree species with high PM retention capacity. L. chinense var. rubrum, C. deodara, and O. fragrans can be used in urban greening for mitigating the PM pollution because of their high PM retention capacity.

Objective: The differences of mass and particle size distribution of the easy-or difficult-removable particulate matter (PM) retained by the leaves among 4 willow species were compared to assess the characteristics of particle retention in willows, further to lay a scientific foundation to improve the quantitative assessment accuracy of atmospheric PM and rational use of willow trees in urban greening. Method: Three years old clones of Salix matsudana, S. matsudana f. tortuosa, S. babylonica, and S. viminalis grown in the nursery were investigated, leaf samples were collected 7 days after rain (rainfall=36 mm). Subsequently the easy removal particle matter (ERP) retained on the leaves were obtained by washing, then the washed leaves were furhter brushed and ultrasonic cleaned to acquire the difficult removable particle matter (DRP). Accordingly, the dry mass of these two types of PM was measured, and the corresponding particle size distribution was determined. Based on these data, the mass and retaining efficiency of the diameter-specific particles in ERP, DRP, and total removable particulate matter (TRP) were calculaed. Result: The differences in elution mass of TRP and ERP among willow species were significant, and the proportion of ERP to TRP ranged from 30% to 50%. Among species, S. matsudana f. tortuosa had the highest retention mass of ERP, while S. viminalis could retain the highest mass of TRP and DRP. On the aspects of the proportions of the diameter-specific particles in both ERP and DRP, S. matsudana displayed the highest proportion of PM₁₀, and S. viminalis displayed the highest PM_10-100. The average diameter of ERP changed as S. viminalis (34.98 μm) > S. matsudana f. tortuosa (33.89 μm) > S. babylonica (31.52 μm) > S. matsudana (27.81 μm), while the situation for DRP was S. matsudana f. tortuosa (40.18 μm) > S. viminalis (35.34 μm) > S. babylonica (29.27 μm) > S. matsudana (28.25 μm). For the absolute retention mass of the diameter-specific particles, S. matsudana f. tortuosa exhibited the largest values for each diameter gradient in ERP, and S. viminalis displayed the largest value for particles larger than 10 μm in DRP, while the largest values for the particles less than 10 μm in DRP were found in S. matsudana. S. viminalis exhibited the highest retaining efficiency (RE) for the TRP and DRP larger than 10 μm, and S. matsudana exhibited the highest RE for the TRP and DRP less than 10 μm. Comparing with the above two species, S.matsudana f. tortuosa had the highest RE of ERP. Conclusion: DRP retained by leaves of four willow species was accounted for 50% of TRP. The retention capacity of S. matsudana f. tortuosa updated rapidly, while S. matsudana and S. babylonica were able to fix the absorbed small-sized PM (d ≤ 10 μm) more persistently, on the contrary, S. viminalis had the strongest capacity of retaining the large-sized PM (d> 10 μm).

Objective: Using single polarization TanDEM-X InSAR data, we studied the forest height estimation method with InSAR coherence amplitude, and analyzed the effects of different DEMs spatial resolutions (one is LiDAR DEM of 5 m resolution and the other is SRTM DEM of 30 m resolution) on forest height estimation accuracy. Method: First, non-volumetric decorrelation was corrected from the observed coherence in order to obtain the volumetric decorrelation (γ_Vol), and then based on the SINC model, the amplitude of γ_Vol was used to estimate forest height. Then forest height inversion results were validated against LiDAR CHM data and compared with the method based on phase difference. Plot sizes of 15 m×15 m, 30 m×30 m, 50 m×50 m and 100 m×100 m were selected to analyze the effects of spatial interpolation. Result: The effects of DEMs in two kinds of resolutions (5 m×5 m, 30 m×30 m) on inversion accuracy are small, when plot size is 100 m×100 m, the R² are 0.54 and 0.51, the RMSEs are 2.38 m and 2.51 m, and the overall accuracies are 77.19% and 75.99%, respectively. Although the method based on phase difference has a better performance than the SINC model over different plot sizes, its results are obviously underestimated and should be calibrated with some known forest height samples. If the plot size is set as 100 m×100 m, the R² is 0.79, the RMSEs before and after calibration are 2.57 m and 1.63 m, the overall accuracies are 75.44% and 84.41%, respectively. Conclusion: The forest height estimation method using SINC model with the TanDEM-X InSAR coherence amplitude can obtain a good performance even if using a low spatial resolution DEM, such as SRTM DEM of 30 m resolution for terrain compensation and geo-coding. Although the accuracy of SINC model is less accurate than that of phase difference method, it requires neither plot measurements for model calibration nor high-resolution DEM for terrain compensation and geo-coding, so it has the potential for large-scale forest height mapping and higher value for practical applications.

Objective: In this paper, the expression dynamics of key genes in salicylic acid and jasmonic acid/ethylene signaling pathway in rosa were monitored in order to clarify the roles and regulatory mechanisms of salicylic acid and jasmonic acid/ethylene signaling pathways in rose in response to Diplocarpon rosae. Method: The detached leaves of cultivar Rosa 'MEIbil' compatible with D. rosae(cfcc87205) was used as the test materials, and five treatments, including inoculation with D. rosae (CK+IN), 2 mmol·L^-1 SA-induced for 2 h and non-inoculation(SA+NO), 2 mmol·L^-1 SA-induced for 2 h and inoculation(SA+IN), 0.2 mmol·L^-1MeJA-induced for 2 h and non-inoculation(JA+NO), 0.2 mmol·L^-1MeJA-induced for 2 h and inoculation(JA+IN), and blank control(CK), were set. The leaves were sampled from 16-144 h post-treatments and the expressions of ICS, NPR1 and PR1 in salicylic acid signaling pathway and the expressions of AOS, JAR, COI1 and MYC2 related with jasmonic acid signaling pathway were detected through RT-qPCR analysis technique. The difference of expression amount of each gene at the same time point over different treatments and the expression dynamics of each gene under the same treatments were analyzed comprehensively. Result: In CK+IN treatment, ICS was down-regulated (P ≤ 0.05), NPR1 was up-regulated at 16 h and down-regulated continuously from 48-144 h post-inoculated(P ≤ 0.05), PR1 and JAR1 were down-regulated at 48 and 16 h post-inoculated (P ≤ 0.05), respectively, but there were no significant differences with CK in other time points. AOS was up-regulated at 16 h, down-regulated at 72 h, and there was no significant difference with CK treatment at 24, 48 and 144 h post-inoculated(P ≤ 0.05). COI1 was up-regulated from 24 to 72 h post-inoculated (P ≤ 0.05). MYC2 was up-regulated at 16 h, and down-regulated at 24, 72 and 144 h post-inoculated (P ≤ 0.05), however there was no significant difference with CK treatment at 48 h. In SA+IN treatment, ICS, NPR1, PR1 and AOS were up-regulated (P ≤ 0.05), there was no significant difference in JAR1 expression between SA+IN and CK+IN treatment(P ≤ 0.05), COI1 was down-regulated from 24 to 144 h post-inoculated(P ≤ 0.05), MYC2 was up-regulated at all time points except at 16 and 48 h post-inoculated(P ≤ 0.05) at which there had no significant difference with CK+IN treatment. In JA+IN treatment, the expression of ICS was up-regulated at all time points except at 16 h post-inoculated(P ≤ 0.05) at which the expression was down-regulated. The expression of PR1 had no significant difference from that in CK+IN treatment before 48 h, and then up-regulated (P ≤ 0.05), while the expressions of AOS and MYC2 were up-regulated especially before 48 h post-inoculated(P ≤ 0.05), and JAR1 had no significant difference from that in CK+IN treatment except up-regulated at 24 h. In addition, the expression variation trends of NPR1 and COI1 were consistent with those in SA+IN treatment. The results showed that D. rosae inhibited the synthesis of salicylic acid and the active jasmonic acid. SA+IN treatment was able to increase the expressions of genes in salicylic acid signaling pathway and promote the synthesis of jasmonic acid, but had little effect on the synthesis of active jasmonic acid. Meanwhile SA+IN treatment weakened the induction effect of D. rosae on MYC2 before 48 h post-inoculation, while the treatment increased the expressions of both ICS and PR1 as well as the expression of MYC2 after 48 h post-inoculated. JA+IN treatment not only promoted synthesis of active jasmonic acid and the expression PR1 but also increased the expression of MYC2. In addition, this study also found that in the SA+NO and JA+NO treatments, the expression levels of 7 genes changed to different degrees compared with that in CK treatments, but the change trends were inconsistent with the corresponding SA+IN and JA+IN treatments, indicating that D. rosae affected the induced expression of genes of the host by exogenous salicylic acid and jasmonic acid on the corresponding signaling pathway. Conclusion: In conclusions, D. rosae has a strong inhibitory effect on the salicylic acid and jasmonic acid/ethylene signaling pathways of rose, and mainly inhibits salicylic acid signaling pathway before 48 h post-inoculation, and mainly inhibits the jasmonic acid/ethylene signaling pathway after 48 h post-inoculated. The pathogen, D. rosae, may realize dual inhibition of salicylic acid and jasmonic acid/ethylene signaling pathways of rose by enhancing the expression of MYC2 in roses.

Objective: In this study, the antifungal activity of essential oils (EOs) of cinnamon(Cinnamomum cassia), citronella(Cymbopogon nardus var. lenabatu), garlic(Allium sativum) and tea tree(Melaleuca alternifolia) against 12 kinds of pathogenic fungi of bamboo was investigated, and the effective antibacterial components of the four kinds of essential oils were compared. The purpose of this study are to make a good use of EOs in preventing and controlling bamboo forest diseases and developing an efficient, economical and pollution-free biological pesticide for bamboo. Method: Four essential oils of cinnamon, citronella, garlic and tea were emulsified with 3% polyvinyl alcohol, and PDA medium containing essential oils of different concentrations (0.005%-2.0%) was used to test the effects of four essential oils on 12 kinds of pathogenic fungi. MIC (minimum inhibitory concentration) and MFC (minimal fungicidal concentration) of 4 EOs to 12 bamboo pathogenic fungi (Schizophyllum commune, Arthrinium phaeospermum, Rhizoctonia sp., Helminthosporium sp., Fusarium oxysporum, Cladosporium oxysporium, Fusarium solani, Alternaria alternate, Aureobasidium pullulans, Epicoccum nigrum, Aciculosporium take, Shiraia bambusicola) were detected. According to the result of MIC and MFC, different concentrations of essential oil were selected:0.01% cinnamon (0.02% cinnamon for Epicoccum nigrum and Aciculosporium take), 0.05% garlic, 0.1% citronella (0.03% citronella for Alternaria alternate used), 0.1% tea tree for Cladosporium oxysporium, Alternaria alternate, Aureobasidium pullulans, Epicoccum nigrum and Aciculosporium take and 0.5% tea tree for other 7 kinds of fungi. The concentration of trans-cinnamaldehyde, diallyl disulfide, diallyl sulfide, citronellal and terpine-4-ol was the same as the corresponding EOs, and the concentration of citronellol and geraniol was 25% of citronella EO. The antifungal ability was evaluated by continuously recording the growth diameter of the fungus. Result: The EOs of cinnamon, citronella, garlic and tea tree all had to different degrees inhibitory effects on 12 tested pathogens. MIC of cinnamon EO was mainly 0.005% to 10 fungi (0.010% to 2 pathogen fungi), and the MFC was 0.01%-0.10%. MIC of garlic EO was 0.005%-0.010% to 11 fungi (0.200% to 1 pathogen fungus), and the MFC was 0.1% -1.5% (2 fungi exceeded the test concentration by 2.0%). MIC of citronella EO was 0.005%-0.030%, and the MFC is 0.04%-0.50%. MIC of tea tree EO was 0.03%-0.20%, and MFC is 0.2%-1.5%. According to the analysis of drug resistance (MFC/MIC), cinnamon and tea tree EOs had better drug resistance, followed by citronella EO, and garlic EO was the worst. In addition, it has been verified that the effective antifungal components of cinnamon, citronella, tea tree and garlic EOs were trans-cinnamaldehyde, citronella and geraniol, terpine-4-alcohol, and diallyl sulfide, respectively. Conclusion: Cinnamon, citronella, tea tree and garlic EOs have antifungal effect of pathogenic fungi from bamboo. Comprehensive assessment of 4 EOs, cinnamon EO is the best; citronella and tea tree EOs followed, but tea tree EO has low economic value for biological pesticide due to its expensive price; garlic EO is not suitable for development and utilization due to its high MFC and drug resistance.

Objective: In this paper, we studied the population dynamics of the dominant hard tick (Haemaphysalis longicornis) in the forest environment in the western mountainous areas of Beijing, and investigated the influence of the weather factors on questing activity of H. longicornis, in order to protect tourists and forest workers from their bites. Method: Three experimental sites in the western mountainous scenic area of Beijing were selected, and the tick population in the sites was sampled every two weeks from 2017 to 2018, and the dragging method was used to investigate tick population for 3 hours in each site. During investigation, 9 weather factor data, such as temperature, relative humidity, dew-point temperature and solar radiation, were collected by hygrothermograph and automatic weather station. The principal component analysis, T-test and Pearson correlation coefficient were used to analyze the difference in the number of ticks between different sites and the effects of weather factors on questing activity of H. longicornis. Result: The results showed that:1) The annual population dynamics of the H. longicornis presented a bimodal pattern with the peaks occurred in May and September, respectively, and the number of peaks in May was 13.9 times of that in September. 2) There was a difference in the number of ticks among different sites. The average number of ticks collected in Tangjiachang, where animal husbandry was the main activity, was significantly greater than that collected in Donggou (t=-3.38, P < 0.01) with a small amount of agricultural activity, and also significantly greater than that collected in Beigou (t=-3.00, P < 0.01) with fewer human activity. However there was no difference in the number of ticks between Donggou and Beigou (t=-0.77, P>0.05). 3) The solar radiation, saturation difference and evaporation were positively correlated with questing activity of H. longicornis, while relative humidity, leaf-litter layer relative humidity and the dew-point temperature were negatively correlated to questing activity of H. longicorni. 4) Principal component analysis method was used to reduce the dimension of 9 weather factors, and 2 principal components were extracted, and their cumulative contribution rate was 78.32%. The first principal component was defined as the temperature factor, with the maximum contribution of sampling temperature, saturation difference, solar radiation and evaporation, reaching 42.39%; the second principal component was defined as the humidity factor, which contributed the most to the relative humidity, the leaf-litter layer relative humidity and the dew-point temperature, with 35.93%. Conclusion: The adult ticks of H. longicornis have two peak periods in spring and autumn, especially in spring when ticks are more active in warm and dry weather and its population is higher than that in autumn. The coupling of the two attributes makes spring a high incidence of invasion and bites of H. longicornis in northern China. In the livestock area, due to the large number of hosts, the population of H. longicornis significantly increases and therefore, the supervision of tick-borne diseases should be strengthened in the above-mentioned region and weather conditions, especially in spring.

Objective: The effects of drying schedule, pretreatment condition, moisture content on wood drying stress and its distribution from pith to bark were investigated in this study to achieve the simulation and prediction of drying strain. Methods: The data sets of elastic strain and mechano-sorptive creep obtained with image analysis method were analyzed. The elastic strain and mechano-sorptive creep were modelled by artificial neural network, for the model of elastic strain with four inputs, i.e., drying temperatures, wood moisture content, relative humidity and the distance from pith, and for mechano-sorptive creep added pre-steaming temperature as an additional input. According to the training and validation processes, two reasonable prediction models were obtained, and then the predictive ability of the models were discussed with testing processes. Results: In elastic strain model, there were significant correlations between experimental and predicted values in all date sets. The R-values for training, validation and test sets were 0.988, 0.983 and 0.978, respectively. The R² values were greater than 0.95 in all data sets, and the best validation performance of the mean square error was 1.21×10^-6. In mechano-sorptive creep model, the R-values for training and validation sets were 0.981 and 0.977 with the data sets at moisture content of 28% and 12%, respectively. The best validation performance of the mean square error was 1.26×10^-6. The R-value for test set was 0.969 with the data set at moisture content of 20%. Furthermore, the R² values were greater than 0.94 in all data sets, indicating that the network model was capable to explain more than 94% experimental values. Conclusion: In the two established models, the predicted values were in good agreement with the experimental values, showing a high prediction accuracy, which provided a feasible basis for the application of artificial neural network in exploring drying stress and strain.

Objective: The lifting system of the continuous flat press has such characteristics as multiple controlled objects, nonlinear, strong coupling. In order to reduce the synchronous motion error of multiple hydraulic cylinders, ensure the hot platen be kept at the same level during the lifting and descending period respectively, and reduce the damage to hot platen and related components caused by non-synchronization, a ring coupling synchronization control method based on generalized predictive control(GPC)was proposed in this paper. Methods: Firstly, the synchronous control model of the hot platen lifting system was established, and the generalized predictive control algorithm was used to optimize the control parameters of each cylinder. The optimal performance index function influenced by the synchronization error of the hot platen lifting system was established, and the ring coupling synchronization control law based on predictive control was derived for each subsystem. To reduce computational complexity, the optimal index function was decomposed, the synchronization error between the hydraulic cylinder and its adjacent one was added in each hydraulic cylinder's optimal control index function, and the disturbance and random noise were suppressed by on-line rolling optimization of control parameters, then a ring coupling control method was adopted to achieve the synchronization control for all hydraulic cylinders. Moreover, based on the established system control model, a simulation experiment was carried out using Matlab. The position tracking, synchronization error and anti-disturbance ability were compared between the PID based master-slave control method and our proposed method. Results: The ring coupling synchronization control method proposed in this paper could ensure the tracking accuracy of each cylinder. Meanwhile, the synchronization error between the adjacent subsystems could converge to zero, hence the synchronization control of multi-channel hydraulic cylinder was achieved. The results of the Matlab simulation showed that the ring coupling synchronization control based on predictive control method resulted in a better position tracking accuracy, synchronization performance, anti-disturbance ability and response speed compared with the conventional master-slave control method. For the system disturbance and sudden changes of parameters during the lifting processes, the system could recover stability quickly, which reflected the robustness and adaptability of the control algorithm proposed in this paper. Conclusion: Ring coupling control mode was much more suitable for the multi-objects controlled system, and the system complexity would not increase along with the number of the controlled objects. By combining the prediction control algorithm with ring coupling synchronization control strategy, the desirable position tracking precision and synchronization accuracy of the hot platen in continuous flat press could be obtained. Meanwhile, the damage to the equipment caused by non-synchronous hydraulic cylinders could be reduced.

Objective: A triangular crawler wheel system was designed for log skidders in place of the traditional tire, in order to improve the trafficability and to increase the tractive force and climbing ability of the vehicle. Methods: The technology solution, with the starting point of modifying the basic parameters of wheeled skidders to better adapt to the working conditions, selected the key parameters of the triangular pedrail wheel through the analysis of its structure composition and layout characteristics. Overall, the main parameters were theoretically calculated and determined by combining the driving theory, working efficiency and spatial layout relation, etc. More specifically, a mathematical model of the key parameters was established by introducing the driving efficiency theory on triangular crawler wheel system. Besides, a function for nonlinear constrained optimization, fmincon was implemented to obtain the optimal combination of the parameters, with the calculation achieved by MATLAB optimization toolbox. Results: Exitflag=1 is obtained from the output calculation results, indicating that the first-order optimality condition of this optimization meets the allowable range, and the analysis results are relatively ideal. According to the optimization results, the geometric layout plan of the triangular track wheel is drawn. In the layout plan, there is no interference between each part of the triangular track wheel. Conclusion: 1) Through the analysis of the composition and function of the triangular track wheel, combined with the working conditions in the forest, the overall arrangement scheme of the triangular track wheel suitable for the material gathering machine is proposed. 2) The key parameters of triangular track wheel were proposed, and the selection principles and methods of key parameters based on the practical investigation and comprehensive consideration of work efficiency, running stability and structural characteristics of triangular track wheel were determined. 3) Based on triangular crawler drive efficiency of the optimal principle, the crawler drive section of the drive power loss was analyzed. A mathematic model of the track driving efficiency was established to optimize the objective function, and with the help of MATLAB software in the optimization module, the key parameters for triangular pedrail wheel is optimized and the key optimized parameter values were finally obtained.

As a disturbance to soil ecosystem, organic mulching has a significant impact on soil structure and function, which plays an important role in urban soil conservation and urban soil restoration. The effects of organic mulching on soil environment were discussed, and its mechanisms were further clarified based on a literature review from Web of Science, CNKI, and other databases. It is important to further exploring the substance cycling process of soil ecosystem and improving the technical system of application of organic mulch, as well as strengthening the effects of urban soil conservation and restoration. Most studies illustrated that organic mulching could alleviate evaporation of surface water and direct infiltration of rainwater, promote soil aggregate structure, improve soil water retention, help to stabilize soil moisture and slow down soil erosion. Organic mulching cools the soil at high temperatures but keeps it warm at lower temperatures, which improves the conditions of plant growth. The greenhouse gas emission is uncertain because of the influences of soil conditions, mulching amount, mulching materials, and other factors. Due to the changes of soil water, air and heat, the activity, species and diversity of soil microorganisms after organic mulching are affected, and the activities of soil animals are also stimulated, which improves the soil structure and quality. The improvement of soil physical and chemical properties, the increase of nutrients and the changes of microbial community structure and function further enhance soil enzyme activity and accelerate the transformation rate of carbon and nitrogen in soil. Affected by the soil environment, the structure of plant root system was changed, fine root turnover was strengthened and rhizodeposition was increased. Additionally, the organic mulch itself provides the soil with carbon source, the substance cycle of soil ecosystem is accelerated, which causes the increasing sequestration of soil organic carbon, while the changes of soil carbon fractions remain contested. The decomposition of organic mulch increase soil organic matter and nutrient content, improve soil nutrition and increase soil fertility to varying degrees. At present, there are more and more studies on organic mulching on soil environment, however, the results have not been uniform, there is a lack of long-term in situ monitoring data, its mechanism has not been clearly understood, and the technical system in production practice still needs to be improved. Therefore, suggestions are put forward for future studies:1) Long-term dynamic monitoring and experimental studies should be carried out to clarify the changes of soil environment after organic mulching. 2) Comprehensively explore the effects of organic mulching on the transportation process of substance and energy in soil ecosystem, and deepen the understanding of the mechanism of the impacts. 3) Establish a sound technical system for organic mulch application to improve soil conservation and soil remediation effects.

The lack of efficient phenotyping capability has become a bottleneck to the studies of forest tree breeding, and the key difficulty of phenotyping is to capture accurate phenotypic data so that the results acquired can be correctly explained. The central challenge of precision forestry is automatic, large-scale and real-time analysis of phenotypic traits. Conventionally, evaluation of tree phenotypic traits is manually-performed, subjective, inefficient, destructive and error-prone. The manual analysis is unable to meet the needs of exploring the internal relationships among "genotype-phenotype-environment" and unraveling the formation mechanism of specific biological traits in a comprehensive manner. Modern phenotyping technology uses a system equipped with various types of imaging sensors to automatically collect a large number of phenotypic data, such as forest morphology, structure, physiology and biochemistry, so as to monitor the growth of individual trees. In addition, the nondestructive measurements enable continuous monitoring of the same individual trees to obtain the phenotypic traits related to growth and development. For example, in stress studies, phenotyping technology can clarify the model of response and resistance of the trees to the stress. Effective implementation of remote sensing to phenotype trees that facilitates accurate, high-throughput, automatic and non-destructive screening of trees in genetic tests is critical for accelerating tree improvement and breeding strategies for higher yield and stress-resistance in precision forestry. We present a review of recent advances in forestry phenotyping and an introduction of individual-based and stand-based forestry phenotyping. Thus, various techniques for tree phenotyping were presented together with applications of these techniques. The measured parameters, spectral range, imaging principle, advantages and disadvantages of visible camera, fluorescence imaging sensor, near-infrared camera, hyperspectral imaging sensor, thermal infrared imaging sensor, and LiDAR scanner, as well as the development of tree phenotype information collection were analyzed. Furthermore, faster and higher-resolution tree data collection would lead to the improvement of precision-forestry practices. Future application of phenotyping platforms requires:1) establishing new platforms to obtain the key phenotypic traits of stands and individuals so as to improve the accuracy and throughput; 2) using environmental monitoring techniques to analyze the phenotypic responses of trees under abiotic stress so as to carry out breeding for high resistance varieties; 3) using the phenotypic changes under biological stress to promote the accurate monitoring, classification, identification and control of pests and diseases; 4) using high throughput phenotyping technology to combine with genome wide selection, quantitative trait loci and genome wide association study to identify the function of genes. In this paper, it was described that advances in phenotyping technologies lead to real-time, high-quality and high-throughput data on trees to accelerate tree improvement through breeding and to optimize precision forestry practices.

The European woodwasp (Sirex noctilio) (Hymenoptera:Siricidae), originated from Europe, Asia (Republic of Georgia, and Mongolia) and North Africa, is a major forestry invasive pest in the world. It has been introduced to many countries, causing great economic losses to their pine resources. In 2013, it was first found that the woodwasp invaded China and settled in northeast of China on Pinus sylvestris var. mongolica. Therefore the monitoring techniques are urgently needed to monitor the population transmission situation, in order to control the invasive pest. In this paper, we summarize the reproductive behavior and chemical ecology regulation in S. noctilio. As to reproductive behavior, males emerge a few days to weeks earlier than females and male's population is more abundant than female's. Its eclosion is affected by climate and the height of the eclosion hole on the trunk. Males aggregate in the upper tree branches for brighter light there. Courtship behavior is regulated by physical factors (light and sound) and chemical factors (host plant volatiles and pheromone). Sirex adults are sexually mature at emergence. Both parthenogenesis and hermaphroditism can be carried out in this insect. If females are parthenogenetic, unmated females oviposit only unfertilized eggs, which develop into males. Once mating happen, mated females can oviposit both fertilized and unfertilized eggs, fertilized eggs develop into females, while unfertilized eggs develop into males. The female can lay eggs after eclosion, and some of them can lay eggs after mating. The amount of laying eggs is affected by temperature and humidity, the shape of female and the symbiotic fungus in the trunk. As to chemical ecological regulation, pheromones from female's cuticle are attractive to males, while pheromones released by males are attractive to either males or virgin females. The release of pheromone is consistent with the mating rhythm. Health and damaged host plant volatile, physiologically stressed trees (pesticide injection and circumcision) in particular, are attractive to S. noctilio, including monoterpenes, sesquiterpenes, aromatic compounds, green leaf volatiles, carbohydrates and so on. There is a dynamic releasing rhythm in volatiles from physiologically stressed hosts. The wasp can carry symbiotic fungus. Volatiles of fungi are composed of monoterpenes, aldehydes, esters and ketones, which can trigger behavioral responses of both wasps and their parasitoids. It is indicated that parasitoids locate the larvae and eggs by symbiotic fungi volatiles. Finally, forest structure improvement, natural enemies and nematode control, satellite remote sensing monitoring, inspection and quarantine are commonly used for monitoring and controlling S. noctilio in forests.

Objective: The aims of this study are to verify whether there are significant spatial correlation effects, spatial agglomeration effects and spatial spillover effects in the process of forestry economic growth, and to analyze the inner relationship between factor inputs, industrial structure upgrading and forestry economic growth. Methods: By taking 40 key state-owned forestry bureaus in Heilongjiang Province as an example, global Moran index was used to verify whether there is spatial auto-correlation effect for forestry economic growth, and whether there are spatial cross-correlation effects with labor, capital, forest management and industrial structure; Local Moran indices were used to test the existence of spatial agglomeration effects for forestry economic growth; Spatial regression models were used to test whether there are spatial spillover effects for forestry economic growth, and the manifestations were discussed. Results: The results showed that global Moran index mean value for labor input growth and forestry gross output growth is negative while the others are positive at 0.10 significance level in general; only 8 forestry bureaus such as Suiling have high growth agglomeration characteristics for local Moran indices at 0.10 significant level; Labor input has significant negative spatial spillover effect, while forestry gross output, capital investment, forest management and industrial structure upgrading have significant positive effects, and the spillover effects are greater than local effects for fixed effect of SDM(spatial Durbin model). Conclusion: Our results demonstrated that there are significant spatial correlation effects between factor inputs, industrial structure upgrading and forestry economic growth, while the spatial agglomeration effects are gradually forming; The marginal effects of factor inputs driving and industrial structure upgrading are mainly manifested through spatial spillover effects. The spatial spillover effects of forestry economic growth in Heilongjiang key state-owned forest areas are essentially knowledge spillover effects, which are embodied in three aspects:assimilation of production contents and management models, convergence of element allocation structure, and synchronization of industrial structure upgrading.

Objective: From the perspective of industrial organization,this paper analyzes the behavioral mechanism of ecological management adopted by farmer households and uses the survey data of economic forest growers in Zhejiang Province to empirically test the effect of different organization models on the whole process's ecological management of economic forest planting. Method: Typical sampling and random sampling were used to conduct field survey on economic forest growers in Zhejiang Province in 2018, and obtained 429 valid samples. The impact of industrial organization model on ecological management is preliminarily analyzed by using Order-Probit model and Probit model as the benchmark model,and then uses Propensity Score Matching (PSM) model to eliminate selective bias. Result: The average treatment effect on the treated (ATT) estimation of PSM showed that:1) Farmers' cooperative model increases the overall score of farmers' ecological management by 0.557 4 on average,significant at the level of 1%. Farmers' cooperative model increases the probability of adopting interplanting,artificial weeding,soil testing formula fertilization,reducing the intensity of fertilization,green fruit treatment and exocarp treatment by 14.95%,19.9%,33.66%,17.18%,26.38%,and 22.06%,all significant at the level of 5% at least. 2) Company & farmer cooperative model (the companies and farmers establish a stable cooperative relationship in the production and marketing links) increases the overall score of farmer's ecological management by 0.388 2 on average,significant at the level of 5%. Company & farmer cooperative model has no significant effect on reducing the intensity of pesticide application,but it makes the probability of adopting interplanting,artificial weeding,soil testing formula fertilization,green fruit treatment,exocarp treatment technology increased by 12.94%,9.82%,17.65%,16.18% and 16.83% respectively,all significant at the level of 10% at least. 3) Market contract model (the dealers and farmers establish a stable supply and marketing relationship) can not significantly improve the overall score of ecological management. Market contract model only increases the probability of adopting exocarp treatment technology by 11.88% at a significant level of 10%. The ATT estimations for other ecological technologies are not significant. The average treatment effect on the untreated (ATU) estimation of PSM showed that:1) If farmers who do not join farmers' cooperative join the farmers' cooperative,the overall score of ecological management will increase by 0.550 9 on average; 2) If farmers who do not join company & farmer cooperative join the company & farmer cooperative,the overall score of ecological management will increase by 0.465 6 on average; 3) If farmers who do not join market contract model join market contract model,the overall score of ecological management increased by 0.210 6 on average. Conclusion: 1) The level of ecological management of economic forest planting during the whole production process is generally low,correspondingly,the adoption rate of each single ecological technology is low. 2) The promotion effect of market contract organization model on ecological management of economic forest planting during the whole production process is not significant. Farmers' cooperative model has a greater effect on promoting the ecological management of economic forest planting than the company & farmer cooperative model. 3) On the situation of improving the level of production organization in the future,the ecological management during the whole process of economic forest planting still has the potential to improve. Comparing the potential of ecological management of economic forest planting under different organization models,they ranked in the following order:farmers' cooperative model > company & farmer cooperative model > market contract model. 4) Male householder,education and technical training can significantly promote the whole process of eco-management of economic forest planting,and the increase in non-agricultural employment will significantly inhibit economic forest growers to adopt the whole process of ecological management.

Objective: This paper aimed to study the differences and causes of the economic development level of communities within and nearby the nature reserve,and then testified whether the establishment of the nature reserve would inevitably lead to low household income,so as to provide countermeasures and suggestions for improving the community policies of the nature reserve. Method: According to the principle of stratified random sampling,30 natural villages (12 within and 18 outside the area) were selected from the communities within and outside Fujian Wuyishan National Nature Reserve,and 174 rural households were randomly selected as the research objects. In 2011,2014 and 2015, we obtained the first hand data,and the descriptive statistical analysis method was used to present the income level,income structure and income dynamic changes of households. Based on the theoretical framework of sustainable livelihood framework(SLF),a theoretical analysis model to explore the cause of households' income differences within and nearby the nature reserve is constructed,and the 2SLS with tool variable model was used for the causable. Result: The results showed that the income of households within the nature reserve was significantly higher than that of households nearby the natural reserve at three study time nodes,which means,the establishment of nature reserve would not lead to low income. The livelihood level of households within the area was superior to that nearby the area,which depended on the joint influence of natural capital,human capital,social capital,material capital and financial capital. Natural capital and human capital were the main factors influencing the income of households within the region higher than that of households nearby the region. Conclusion: This paper shows that the construction of nature reserves within the regions with higher economic development level would not necessarily lead to low household income and would be conducive to the growth of household income and promotes harmonious relations between nature reserves and communities. In order to improve the income of households,it is suggested to expand the policy influence,and strengthen the household ability to respond to risks,thus the synergistic effects achieved in ecological protection and economic development.

Objective: In this paper,the adaptability of Granier's original formula in estimating the sap flow of Ulmus pumila trunk was verified and the possible error was analyzed,so as to improve the accuracy of estimating the transpiration rate of U. pumila by correcting the Granier's formula. Method: U. pumila was selected as a research object in this paper. The temperature differences of the trunk of U. pumila were measured by thermal diffusion probe method (TDP),and the sap flow velocity was calculated by Granier's original formula. The whole tree container weighing method was used as the verification benchmark. The transpiration rate determined by the weighing method was used as the dependent variable,and the temperature difference coefficient K determined by the thermal diffusion probe method was used as the independent variable. Curve fitting was performed with the data to obtain the Granier correction formula. Result: The daily variation of the flow rate calculated by Granier's original formula was consistent with the measured value of the whole tree container weighing method,showing a "single peak" curve. However,the sap flow rate calculated by the Granier formula was more than 80% lower than the measured value of the weighing method. After the correction of Granier original formula (F_d=0.059 6K^{0.916 4},R²=0.704 9; K is referred to the temperature difference coefficient determined by the thermal diffusion probe method),the difference between the calculated flow rate (F_d) and the gravimetric method was basically maintained between -30% and 30%. The residuals of the U. pumila Granier correction formula were between -2 and +2,indicating that this fitting equation was valid. Conclusion: The sap flow rate of U. pumila calculated by the original formula is significantly lower than the true value of transpiration rate measured by weighing,and thus it cannot accurately express the true transpiration rate and cause a large errors. However,the corrected Granier formula can estimate the true sap flow. Therefore,the corrected Granier original formula should be used to accurately estimate the true sap flow rate of U. pumila.

Objective: Under the background of increasing nitrogen deposition,the effects of nitrogen deposition on carbon,nitrogen and phosphorus accumulation of endangered Ulmus elongata and their quantitative relationship and non-structural carbohydrate content were studied by adding exogenous nitrogen,so as to provide reference for the protection of this minimal population. Method: The accumulations of total carbon,nitrogen and phosphorus in roots,stems and leaves of U. elongata and their quantitative relationships between those nutrients and changes of non-structural carbohydrate contents were analyzed by applying different concentrations of nitrogen to the annual seedlings of U. elongata. Result: The leaf biomass was significantly reduced with the addition of high nitrogen (N:262.3 mg·L^-1),but the root or stem biomass was not significantly affected. Both low nitrogen (N:52.46 mg·L^-1) and high nitrogen treatment increased the total carbon content in roots,but significantly decreased the total carbon content in leaves. Under high nitrogen treatment,the total nitrogen content in roots,stems and leaves increased significantly,while the total phosphorus content decreased significantly with the increase of nitrogen application level. Both low and high nitrogen treatments reduced the C:N value in the plant,however C:P and N:P were the highest under high nitrogen treatment. The soluble polysaccharides and starch contents in roots and stems were increased under both low and high nitrogen treatments. The content of soluble polysaccharide and starch in leaves was significantly decreased by high nitrogen treatment. The content of non-structural carbohydrates (NSC) first decreased and then increased in roots and stems,and in leaves NSC was contrary to roots and stems with the increase of nitrogen application level. High nitrogen treatment led to the decrease of P_n,G_s,Tr,WUE and L_s in varying degrees,but the increase of C_i concentration. Conclusion: High nitrogen treatment increases N content in Ulmus elongates,and however inhibits the leaf photosynthesis,reduces the carbon accumulation and increases the phosphorus limitation,which increases the risk of endangerment. At the same time,U. elongata copes with the adverse effects of high nitrogen by accumulating more NSC in roots.

Objective: In this study,the effect of different concentrations of cadmium pollution on physiological and biochemical characteristics of Cinnamomum camphora seedlings was investigated,which aims to reveal the response mechanism of photosynthetic and other physiological characteristics of C. camphora under cadmium stress,so as to provide data accumulation and scientific basis for the remediation of contaminated soil. Method: In this study,an indoor pot experiment was conducted with one-year-old C. camphora seedlings that were subjected to 4 treatments of different contents of cadmium in contaminated soil,including 0 mg·kg^-1 (CK),1 mg·kg^-1 (Cd1),10 mg·kg^-1 (Cd2) and 30 mg·kg^-1 (Cd3),and each treatment had 5 replicates. Samples were collected and analyzed on days 0,15,30,and 60. The photosynthetic characteristics parameters,the contents of chlorophyll,proline,soluble sugar,soluble protein,malondialdehyde (MDA),and the activities of superoxide dismutase (SOD) and peroxidase (POD) of C. camphora seedlings were tested to explore the tolerance of C. camphora to cadmium and its potential and feasibility for phytoremediation. Result: The net photosynthetic rate (P_n) of C. camphora leaves did not change significantly under different concentrations of cadmium pollution in 0-15 days. P_n of the seedlings treated with contaminated soil for 30 days and 60 days was lower than that of the control,and P_n of seedlings treated with high Cd²⁺concentration (Cd3) was the lowest with an average deceases of approximate 22.33% compared with that of the control. In addition,the content of chlorophyll in C. camphora under different concentrations of cadmium contaminated soils decreased,and chlorophyll in medium and high concentrations of cadmium (Cd2 and Cd3) significantly reduced. The content of proline (Pro),soluble sugar and soluble protein in C. camphora leaves was increased by cadmium pollution of different concentrations,and the content was the highest under high concentration Cd²⁺ stress (Cd3). After 30 days and 60 days,the activity of SOD in medium and high concentration cadmium treatment (Cd2 and Cd3) was significantly higher than that in the control as well as low concentration cadmium stress. During the whole treatment period,POD activity increased with the pollution time and the cadmium concentration. However,the medium and high concentration cadmium stress had a significant effect on the increase of MDA content. Conclusion: The results suggest physiological and biochemical indexes of C. camphora,such as the photosynthesis parameters,osmotic adjustment substances and antioxidant protective enzymes,are closely related to stress time and pollution concentration. But,C. camphora seedlings grow well under different concentrations of cadmium stress,reflecting that C. camphora has strong cadmium tolerance and thus has potential value for remediation of heavy metal contaminated soil.

Objective: Rainfall is one of the important causes of slope instability. It is generally believed that plant roots can effectively reinforce soil and increase slope stability. In general,shallow landslides occur during and shortly after precipitation events. The function of soil reinforcement and its change dependent upon the soil volumetric water contents remain poorly studied because of the complex root-soil interactions and difficulty of the underground observations. This study investigated the influence of soil moisture on soil cohesion and internal friction angle,and identified the root failure mode under different soil moisture,which aims to expand our knowledge about the dynamics of slope stability during rainfall. Method: In this study,a common shrub species (Vitex negundo) in north China was selected. In different periods after rainfall,the undisturbed root-soil composite samples and plain soil samples without roots were collected from soil profiles. The shear strength of the undisturbed root-soil composite and plain soil samples were measured for calculating the cohesion (c) and internal friction angle (φ). Here,remolded samples of root-soil composite and plain soil were also tested for comparison. Result: 1) The increase of root pullout strength of V. negundo exhibited a single peak curve with the soil volume water content,and the strength reached the maximum value when the soil volume water content was about 18%. 2) Plant roots were able to significantly reinforce the soil. Compared with root free soil,the cohesion of the undisturbed and remolded root soil composite increased by 15.8 and 7.5 kPa,and the internal friction angle increased by 3.1° and 1.1°,respectively. 3) The cohesion and friction angle of rooted soil were negatively correlated with soil water content,generally. With the increase of soil moisture from 13% to 40%,the additional cohesion of undisturbed and remold samples decreased to 5.9 and 2.6 kPa,respectively. Additional internal friction angle of the undisturbed samples decreased to 0.1°,while that of remold samples increased to 1.8°. Conclusion: Plant roots can play an important role on both cohesion and internal friction angle,however,the reinforcement provided by roots would be decrease significantly with precipitation-driven water content increase. Thus,it is suggested that in the area or season with heavy rainfall,the additional cohesion provided by roots should be evaluated more conservatively. This study provides a theoretical basis for establishing a dynamic root reinforcement model considering soil moisture.