Objective: In response to the lack of automatic picking, bagging, and substrate filling functions for non-woven fabric seedling containers in current Camellia oleifera seedling equipment, this study analyzes the bagging conditions and mechanical tests of non-woven fabric seedling containers suitable for C. oleifera grafting seedlings, and provides theoretical basis for the development of related containerization equipment. Method: A literature review was conducted on the non-woven fabric seedling cultivation technology of C. oleifera grafted seedlings. Based on the requirements of automatic bag filling, an M bag non-woven fabric seedling bag with a size and bag type of 100 mm×120 mm was selected. The grabbing experiment of the non-woven fabric seedling bag was carried out, and the needle suction cup was determined as the key component for opening the bag according to the grabbing effect. Based on the integrity of the opening contour of non-woven seedling bags, the opening mechanism analysis is carried out, and the reasonable range of the distance between the suction cup and the bag top and the opening distance is obtained through experiments. Based on the analysis of the force on the suction cup after filling the non-woven seedling bag substrate, a non-woven seedling bag detachment force test platform was built. The bag opening distance, suction cup to bag top distance, and seedling bag specifications were used as experimental factors, and the non-woven seedling bag detachment force was used as the experimental indicator. A multi factor orthogonal experiment was designed, and variance analysis and response surface analysis were conducted using Design-Expert 13 software to explore the optimal combination parameters of factors. Result: During the process of reducing the bag opening distance from 100 mm to 80 mm, the smaller the distance between the suction cup and the bag top, the greater the detachment force of the seedling bag. During the process of increasing the spacing between bag openings from 80 mm to 100 mm, the larger the distance between the suction cup and the top of the bag, the greater the detachment force of the seedling bag. During the process of reducing the spacing between bag openings from 100 mm to 80 mm, the greater the weight of the seedling bag, the greater the detachment force of the seedling bag. During the process of increasing the spacing between opening bags from 80 mm to 100 mm, the smaller the weight of the seedling bag, the smaller the detachment force of the seedling bag. The distance between the suction cup and the top of the bag within the range of 10?20 mm does not significantly affect the detachment force of the seedling bag, while the greater the weight of the seedling bag, the greater the detachment force of the seedling bag. The optimal parameter combination was obtained through optimization using Design-Expert 13 software: bag opening spacing of 80 mm, suction cup to bag top spacing of 15 mm, and seedling bag specification thickness of 35 g·m^?2 (M bag type 100 mm×120 mm non-woven seedling container). Under this combination, the non-woven seedling bag has a maximum detachment force of 97.7 N on the needle suction cup. Conclusion: The greater the detachment force between the non-woven seedling bag and the needle suction cup, the more stable the bag opening effect. According to the experimental results, the maximum detachment force of the seedling bag is obtained when the opening distance is 80 mm, the distance between the suction cup and the bag top is 15 mm, and the size of the seedling bag is 35 g·m^?2 (M bag type 100 mm×120 mm non-woven seedling container). At the same time, the opening contour of the bag is the most complete under this combination. The maximum detachment force of the non-woven seedling bag on the needle suction cup is 97.7 N, which is slightly different from the maximum detachment force of 97.4 N obtained from the verification experiment.

Objective: To solve the problems of difficult harvesting, low efficiency, and high cost existing in the traditional manual harvesting method of walnuts. According to the development trend of walnut planting areas in China towards standardized orchards, a walnut vibration harvesting control system based onprogrammable logic controller (PLC) is designed. And the feasibility of the walnut vibration harvesting control system is verified through simulation tests, so as to improve the automation level of walnut vibration harvesting, reduce the difficulty of manual harvesting, and increase the harvesting efficiency. Method: The trunk point cloud is collected by a LiDAR. The data is preprocessed in the Visual Studio 2017 environment, and the trunk information at the optimal point cloud intensity is segmented. The trunk diameter is extracted by using the least square circle fitting method. A fuzzy PID controller is designed by applying the MATLAB software. The system block diagram is built by Simulink to find the optimal parameters of the controller, so as to improve the feasibility of the walnut vibration harvesting control system. The PLC program is designed by using the TIA Portal software to realize the functions of the telescopic vibration arm, clamping function, and vibration function. The human-machine interface is designed by using the Kingview software, and the communication between the PLC and the human-machine interface is realized through ethernet to achieve real-time monitoring after the system runs. The feasibility of the walnut vibration harvesting control system is verified through simulation and physical experiments. Result: By applying the MATLAB software, the optimal parameters of the controller are obtained as K_p = 7.682, K_i = 5.675, and K_d = 1.675. The simulation verification results of the clamping force and vibration frequency under different moving distances and trunk diameters show that when the telescopic distance is between 20 and 100 cm, the error is between 0.02% and 0.15%; when the trunk diameter is between 15 and 20 cm, the clamping force error is stable between 1.20% and 2.72%; and the vibration frequency error is between 0.67% and 3.00%. Through the verification of actual harvesting, the control system can accurately control the movement, clamping, and vibration of the vibration arm. The harvesting efficiency is more than 7 times that of manual harvesting, and the harvesting completion rate is above 81%. Conclusion: In this study, a walnut vibration harvesting control system based on PLC is proposed and designed, and the feasibility of the system is verified through simulation tests. This vibration harvesting control system is suitable for walnut harvesting in standardized orchards, provides a scientific basis and practical guidance for the intelligentization of walnut vibration harvesting, and effectively improves the walnut harvesting efficiency.

Objective: To achieve efficient and low-damage vibration harvesting of wolfberries, this study investigates the vibration response in fruit-bearing branches of wolfberry. Method: By establishing a dynamic model of wolfberry-bearing branches, the acceleration decay curve and biomechanical characteristic parameters of the branches in a free vibration state were measured. The equivalent stiffness coefficient, equivalent damping coefficient, and equivalent mass of the branch dynamic model were calculated. The vibration characteristics of external forces at different positions on the branches were studied to determine the optimal vibration position. Matlab software was used to simulate the dynamic response of the branches, and corresponding field vibration tests were conducted for validation. Result: During the vibration process, the kinetic energy variation of branches reflects their motion velocity changes. The magnitude of kinetic energy is positively correlated with the vibration harvesting effect, and the branch kinetic energy can serve as an evaluation index for the response effect of vibration positions. Simulation results demonstrate that vibrating at different branch positions leads to significant differences in corresponding kinetic energy changes. When the excitation point is located at the middle-rear position of the branch, the maximum kinetic energy of the branch reaches 27.06 J, corresponding to a ripe fruit harvest rate of 92.17%, indicating the optimal vibration effect. Field trials are largely consistent with the simulation results, confirming the optimal vibration position for fruiting wolfberry branches. Conclusion: Kinetic energy is an effective indicator for evaluating the vibration effect of branches. The vibration effect is optimal when the excitation point is located at the middle to rear part of the branches. This study provides a basis and reference for precise multi-point vibration.

Objective: By combining ground penetrating radar (GPR) and dye-tracing techniques, this study analyzes the spatiotemporal characteristics of soil preferential flow under different rainfall intensities and reveals the regulatory mechanisms of rainfall heterogeneity on preferential flow development. Additionally, we attempt to establish relationships between GPR characteristic parameters and preferential flow indices, clarify the applicability and limitations of GPR technology in identifying preferential flow, and provide insights for non-destructive monitoring of subsurface hydrological processes. Method: Focusing on a natural secondary forest dominated by Quercus mongolica, Acer pictum, and Populus davidiana in the Laotudingzi National Nature Reserve, Liaoning Province, dye-tracing experiments were conducted under heavy rain (35 mm) and torrential rain (60 mm) conditions. Stained profiles were excavated to visually analyze preferential flow characteristics, and preferential flow indices were used to comprehensively evaluate flow development. By analyzing four GPR waveform parameters: maximum amplitude (A_max), maximum amplitude area (S_max), total amplitude area (ΣS), and maximum time interval (T_max), combined with the dye coverage ratio (DC) of soil profiles, the vertical variation of preferential flow was explored. Three-dimensional maps of A_max changes before and after dye tracing were constructed to investigate variations in GPR parameters over time (pre-dye, 30 min, 1 h, and 24 h post-dye) and water transport processes. Result: 1) Preferential flow in the study area predominantly exhibited funnel and finger flow patterns with lateral flow characteristics. Heterogeneity exists in the water infiltration process,and DC exhibits a nonlinear decline as a whole with the deepening of the soil layer. As infiltration increased, the preferential flow index decreased (0.47→0.42), spatial heterogeneity declined (coefficient of variation: 0.66→0.28), and distribution expanded (DC: 48.78%→74.36%). 2) GPR parameters significantly correlated with DC. Post-dye A_max, S_max, and ΣS showed highly significant positive correlations (P≤0.01), while post-dye T_max showed a significant negative correlation (P≤0.05), confirming GPR’s effectiveness in quantifying preferential flow. 3) Post-dye A_max peaked at 10 cm depth, indicating intense water dynamics and highest preferential flow activity, with amplitude decreasing and flow weakening at greater depths. 4) The increase in infiltration water volume accelerated the maximum value of A_max from 1 hour to 30 minutes after staining during the observation period, indicating that the augmentation of infiltration water volume could accelerate water infiltration and expedite the development of preferential flow. Conclusion: This study elucidates the characteristics and dynamics of soil preferential flow in Laotudingzi National Nature Reserve under varying rainfall conditions. These findings indicate that an increase in infiltrated water volume accelerates the development of soil preferential flow, enabling it to reach its peak intensity within a shorter timeframe, yet paradoxically suppresses the overall extent or magnitude of preferential flow development. GPR technology effectively identifies preferential flow and correlates with its intensity, offering quantitative support for dye-tracing results, thereby aiding non-destructive monitoring of hydrological processes.

Objective: This study aimed to understand the fine root decomposition characteristics, nutrient dynamics, and main influencing factors during the expansion of Phyllostachys edulis into Cunninghamia lanceolata forest and broad-leaved forest. The goal was to reveal the mechanisms underlying the effects of bamboo expansion on belowground carbon turnover and nutrient cycling in forest. Method: Utilizing continuous ecological interfaces formed by P. edulis expansion into C. lanceolata forest (C. lanceolata forest → bamboo and fir mixed forest → P. edulis forest) and broad-leaved forest (broad-leaved forest → bamboo and broad-leaved mixed forest → P. edulis forest) in the Mufu Mountain area, we combined in-situ and ex-situ decomposition methods to investigate the dry mass residual rate and the dynamics of carbon (C), nitrogen (N), and phosphorus (P) content in the fine roots of C. lanceolata, Camptotheca acuminata, and P. edulis along these two expansion sequences. Result: The initial C content, C/N ratio, C/P ratio and N/P ratio of C. acuminata fine roots were significantly lower than those of C. lanceolata and P. edulis (P<0.05). Conversely, its initial N content and P contents were significantly higher than those of them(P<0.05). However, there were no significant differences in these initial elemental traits between P. edulis and C. lanceolata. In the sequence of the expansion of P. edulis into C. lanceolata forest, the decomposition rate of P. edulis fine roots and their C, N and P release rates were significantly higher than those of C. lanceolata (P<0.05). The decomposition rates of fine roots for both species did not change significantly with increasing bamboo expansion intensity. The phased dry mass loss rate of the moso bamboo fine root was positively correlated with soil temperature. In the sequence of the expansion of P. edulis into broad-leaved forest, the decomposition rate and C, N, P release rates of C. acuminata fine roots were significantly higher than those of P. edulis (P<0.05). P. edulis fine roots decomposition accelerated with increasing expansion intensity, exhibiting a home-field advantage. C. acuminata roots released C faster but N more slowly than P. edulis roots, while P release showed no significant difference between the two species. Conclusion: P. edulis expansion enhanced the fine root decomposition of C. lanceolata and C. acuminata to some extent. However, the patterns of nutrient release from fine roots varied significantly between the two expanded forest types. Initial fine root chemical traits were identified as the primary factor regulating fine root decomposition and nutrient release during bamboo expansion into both C. lanceolata forest and broad-leaved forest. Notably, P. edulis fine roots exhibited a distinct home-field advantage effect along the expansion sequence into broad-leaved forest.

Objective: To investigate the relationship between the color Lab characteristic values and pigment content, as well as the microscopic and ultrastructure of mesophyll cells in Euonymus maackii leaves, and to clarify the color pattern of the leaves, thereby providing a theoretical and scientific basis for the phenological management and breeding of colored-leaf varieties of E. maackii. Method: This study employed an improved leaf color acquisition method to collect the Lab characteristic values of E. maackii leaves with different colors. The contents of chlorophyll, carotenoids, anthocyanins, and soluble sugars in leaves of E. maackii with different colors were determined. The microscopic structure and tissue hierarchy of E. maackii leaf paraffin sections were observed. The ultrastructure of mesophyll cells in E. maackii leaves, including chloroplasts, central vacuoles, and plastoglobules, was observed using transmission electron microscopy. Result: The leaves of E. maackii can be categorized into three color series: green, yellow, and red. There are significant differences in pigment content, microscopic, and ultrastructure among leaves of different colors. Leaves in the yellow series have higher brightness (L^* value) and chroma (C^* value). The degradation of chlorophyll and the accumulation differences of anthocyanins and carotenoids are the main reasons for the color differences in leaves. The study found that the contents of chlorophyll and carotenoids in green series leaves were significantly higher than those in yellow and red series leaves. The contents of soluble sugar and anthocyanins in red series leaves were significantly higher than those in yellow and green series leaves, which are the main reasons for the color differences. Comparative analysis of anatomical structures revealed significant differences in the thickness of palisade and spongy tissues among different leaves. The palisade-sponge ratio, by affecting the size of the pigment attachment surface, led to differences in pigment accumulation. Ultrastructural analysis of leaves showed that the organelle structures of mesophyll cells in red series leaves were relatively intact, while those in yellow series leaves were damaged. The disintegration of chloroplasts and vacuoles accelerated the degradation of chlorophyll. Through path analysis, the direct and indirect pathways affecting leaf color were further clarified: the brightness (L^* value) and chroma (C^* value) of leaves are directly or indirectly closely related to parameters such as chlorophyll b, leaf thickness, and spongy tissue thickness. The red-green hue value (a^* value) and yellow-blue hue value (b^* value) of leaves directly reflect the red and yellow colors of leaves. The main factors affecting the a^* and b^* values of leaves are the content of chlorophyll a, upper epidermis thickness, and spongy tissue thickness. Conclusion: The autumnal red and yellow color changes in the leaves of E. maackii are primarily determined by pigment regulation mechanisms and are also influenced by leaf structure. The increase in the brightness (L^* value) and chroma (C^* value) of leaves with different colors is mainly regulated by the reduction in chlorophyll b content and the increase in carotenoid content. Under the stress of low autumn temperatures, the diversity of E. maackii leaf structure leads to a variety of leaf colors. Leaves with restricted material synthesis, in order to preserve the plant’s nutrient reserves, gradually disintegrate their organelles and break down the contained pigments, causing nutrient reflux and thus lack anthocyanins, appearing yellow. On the other hand, leaves that are in good growth condition and still have strong material synthesis capabilities under low-temperature stress synthesize a large amount of anthocyanins, thereby appearing red.

Objective: This study explored the effect of nitrogen addition on the content of osmoregulatory substances in a typical tree species, Pinus tabuliformis, in the Loess Plateau region, for revealing the mechanism by which nitrogen addition alleviates drought stress by maintaining hydraulic function, and thereby exploring the response of forest ecosystems in the region to global change. This research aimed to provide a scientific basis for managing P. tabuliformis plantations in the Loess Plateau region. Method: Two-year-old P. tabuliformis seedlings were used as the research object, and four levels of drought stress treatments (control CK, mild stress RE₂₅, moderate stress RE₅₀, and severe stress RE₇₅) and three nitrogen addition levels (N₀, N₃, N₆ with concentrations of 0, 3, 6 g·m^–2a^–1, respectively) were set up to analyze the changes in physiological growth characteristics, osmoregulatory substances, and hydraulic function of the seedlings under the interactive effects of nitrogen addition and drought stress, along with their interrelationships. Result: 1） Under CK treatment, the total biomass at N₃ and N₆ levels significantly increased by 3.69% and 10.56% (P<0.05) compared to the N0 level, and the net photosynthetic rate increased by 22.16% and 79.61% (P<0.05). At the N₀ level, the root-to-shoot ratio under RE₇₅ treatment significantly increased by 54.9% (P<0.05) compared to the CK group. 2） Correlation analysis proved that high-concentration nitrogen application significantly increased the proline content in new branches under CK treatment, mild and moderate drought stress; nitrogen application significantly increased the content of non-structural carbohydrates under each drought treatment but had no significant effect on the content of potassium ions. The effect of nitrogen application on osmotic regulation of new branches of P. tabuliformis seedlings was greater than that of drought. 3） Under nitrogen application conditions, the total amount of soluble sugars and non-structural carbohydrates showed a significant positive correlation with net photosynthetic rate, biomass, hydraulic conductivity, and water use efficiency, indicating that nitrogen application increased the formation of soluble substances and non-structural carbohydrates by enhancing the net photosynthetic rate above ground, promoting biomass accumulation, and maintaining hydraulic function through osmotic regulation by soluble sugars, thereby improving the water use efficiency of P. tabuliformis. 4） Redundancy analysis showed that proline (P<0.05) and soluble sugar (P<0.05) had significant effects on hydraulic function under the coupled effects of nitrogen addition and drought stress, with an explanation rate of 38.5% and 12.9%, respectively. Conclusion: New branches are the most vulnerable organs under drought stress. Among nitrogen addition levels, the concentration of 6 g·m^?2a^?1 is the optimal nitrogen addition level for alleviating mild drought stress in P. tabuliformis seedlings.

Objective: This study aims to provide a theoretical basis for the exploitation and utilization of Eucalyptus cloeziana leaves by isolating, and identifying the leaf flavonoids and determining their activity. Method: In this study, the eight different macroporous resins were used to purify flavonoids from E. cloeziana leaves, and their adsorption/desorption characteristics of total flavonoids in E. cloeziana leaves were compared to select a macroporous resin suitable for purifying flavonoids from E. cloeziana leaves, and optimize the purification parameters. The structure and content of flavonoids were investigated with infrared spectroscopy and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). In addition, the antimicrobial activity of flavonoids before and after purification against four bacterial strains of Staphylococcus aureus, Staphylococcus aureus, Bacillus subtilis, and Erwinia carotovora was investigated. At the same time, the in vitro antioxidant activity [such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging rate, 2,2-diazo-bis (3-ethyl-benzothiazole-6-sulfonic acid) diammonium (ABTS) free radical scavenging rate and total reducting capacity] and enzyme inhibitory activity (acetylcholinesterase, α-glucosidase) were also determined. Result: The ADS-17 resin was identified as the optimum choice for its exceptional adsorption and desorption properties, and the optimal purification process conditions were as follows: pH value of 3, eluent ethanol volume fraction of 50%, concentration of flavonoids in the sample solution of 0.9 mg·mL^–1, adsorption rate of 2.0 mL·min^?1, elution rate of 1.0 mL·min^–1 and eluent dosage of 65 mL. Under these conditions, the purity of the total flavonoid extract was increased from 20.03 mg·g^–1 to 36.31 mg·g^–1. Through infrared spectroscopy scanning, it was shown that the extract contained characteristic absorption peaks of flavonoids. And then, a total of 13 flavonoids were identified by UHPLC-MS. Compared to the crude extract, the flavonoids peaks of the purified extract were more prominent, among which myricetin, myricitrin and quercetin were 1.67, 1.64 and 3.57 times higher than before purification, respectively. The antioxidant capacity of purified flavonoids from E. cloeziana leaves was superior to that of the crude extract. And the half inhibitory concentration (IC₅₀) values of the purified DPPH and ABTS were lower than those of the crude extract by 0.77 and 11.31 μg·mL^–1, respectively, and the difference in IC₅₀ value with VC was not significant (P>0.05). In addition, the purified extracts showed significantly higher inhibitory ability on acetylcholinesterase and α-glucosidase activities, and their IC₅₀ values were 45.26 and 1.60 μg·mL^–1 lower than those of crude extracts, respectively. The antibacterial experiment also showed that purified extract was more effective than crude extracts, with the minimum inhibitory concentrations of the crude extracts against Escherichia coli, Staphylococcus aureus, Erwinia carotovora, and Bacillus subtilis ranging from 12.50 to 25.00 mg·mL^–1, while the minimum inhibitory concentrations of the purified extracts against the above species were less than 6.25 mg·mL^–1. Conclusion: ADS-17 macroporous resin can effectively enrich the flavonoids in E. cloeziana leaves, and the purified flavonoids have good antioxidant, enzyme inhibition and bacteriostatic activities.

Objective: In this study, the variation patterns of biomass and nitrogen utilization efficiency (NUE) of Catalpa bungei clones were investigated at different soil nitrogen content sites, and the interaction effects between clones and environment were analyzed to screen elite clones with high productivity and high nitrogen use efficiency. The objective is to screen superior clones with high productivity and NUE, and to provide theoretical basis for the breeding of C. bungei clones. Method: Thirteen 6-year-old C. bungei clones from three experimental sites were selected as the research materials. The biomass was calculated using an allometric growth model. Subsequently, the nitrogen content was measured, with which NUE was calculated. The ASReml-R package was used to fit a mixed effect model. The BLUP data of biomass and NUE of thirteen C. bungei clones from three experimental sites was obtained, and the visual BLUP-GGE biplots were used to analyze the adaptability and stability of these clones. Result: There was a significant (P<0.05) difference in soil nitrogen content among the three experimental sites, with a descending order of Caoxian, Yongcheng, and Mudanqu. The statistical analysis showed that there were significant (P<0.01) differences in biomass and nitrogen use efficiency among different clones at the same site, and significant (P<0.01) differences in biomass and nitrogen use efficiency of the same clone among different sites. Through sorting the two indicators separately, it was found that biomass of clones 6-7, 008-1, 1-3, and 2-8 was higher than that of the other clones in all sites, and the NUE of clones 8401, 6-7, 2-8, and 20-01 was higher than that of the other clones in all sites. The adaptability analysis of different clones showed that clone 2-8 had the strongest adaptability in the Mudanqu and Caoxian, while clone 1-3 had the strongest adaptability in Yongcheng. Clone 6-7 and clone 2-8 were superior clones with high biomass and NUE, and their performance was suitable at the three experimental sites. Clone 1-3 had relatively higher biomass and NUE, but its NUE was not high. Clone 008-1 had high biomass, but its NUE was low with low stability. Conclusion: Based on the ranking of biomass and NUE of the thirteen clones under different soil nitrogen contents, and combined with analysis of adaptability, high productivity, and stability in the BULP-GGE biplots, it is found that clone 6-7 and clone 2-8 are elite clones with high biomass and NUE, and they have good growth performance at all three sites. The clone 1-3 is a clone with high biomass and NUE at low nitrogen site, and it is suitable to be planted in Mudanqu and other sites with low soil nitrogen content. The clone 008-1 is a clone with high biomass and NUE at high nitrogen site, and it is suitable to be planted in Caoxian and other sites with high soil nitrogen content.

Objective: The tissue culture seedlings of Populus alba × P. glandulosa (84K poplar) that have been preserved through long-term subculture are prone to bacterial infection, leading to problems such as slow growth and low genetic transformation efficiency. However, there has been no report on rapid bacteria elimination technology. This study aims to isolate and identify the bacteria in the tissue culture seedlings of 84K poplar that are infected with bacteria, and to explore an efficient and convenient technology for eliminating bacteria from the tissue culture seedlings, so as to provide technolical reference for the multiplication of tissue culture seedlings of woody plants, their long-term subculture preservation, stress resistance, growth vitality, and the maintenance of an efficient and stable transgenic transformation system. Method: In this study, the tissue culture seedlings of 84K poplar infected with bacteria were used as materials. The strains were isolated and further identified by using 16S rDNA sequencing combined with NCBI-BLAST search. Treatments such as 0.1% mercury chloride, aseptic hydroponics, darkness, and darkness with variable temperature were compared, and in combination with the method of shoot tip culture, the tissue culture seedlings of 84K poplar infected with bacteria were subjected to bacteria elimination treatment. Furthermore, the experiment of callus induction to buds before and after bacteria elimination was compared to evaluate the effect of bacteria elimination. Result: There were three kinds of bacteria (84K-01, 84K-02, 84K-03) in the tissue-cultured seedlings of 84K poplar that were infected by bacteria. Among them, the similarity between 84K-01 and a species of the genus Curtobacterium (CP066341.1) was as high as 99.79%, the similarity between 84K-02 and a species of the genus Williamsia (JQ660098.1) was as high as 99.93%, and the similarity between 84K-03 and a species of the genus Luteibacter (CP077072.1) was as high as 99.86%. The treatments with 0.1% mercury chloride, darkness for 21 days, and darkness at variable temperatures for 21 days, combined with the method of shoot tip culture all had significant effects on eliminating the three types of bacteria in the tissue culture seedlings of 84K poplar (P<0.05). The treatment of darkness at variable temperatures for 21 days combined with the method of shoot tip culture had the best comprehensive effect, with the sterile rate of 51.85%. Further analysis of the callus induction and bud formation ability of the bacteria-eliminated 84K poplar showed that the callus induced from the leaves of the bacteria-eliminated seedlings grew faster and was able to form buds. Conclusion: Three types of bacteria have been isolated and identified from the tissue culture seedlings of 84K poplar infected with bacteria. The treatment of darkness at variable temperatures for 21 days, combined with the method of shoot tip culture has the best elimination effect. With the advantages of simplicity, rapidity, high stability, and no toxicity, this set of methods can be popularized and applied in the elimination of bacteria from the tissue culture seedlings of woody plants infected with bacteria.

Objective: A multi-scale fusion method based on a cycle generative adversarial network for soil CT/SEM images (multi-scale fusion based on CycleGAN, MSF-CycleGAN) is for the first time proposed in order to address the obligatory dependence on paired datasets in super-resolution reconstruction of soil CT images. By integrating micro-structural priors from SEM imagery, the approach substantially enhances soil CT image fidelity while circumventing the prohibitive expense of high-resolution CT scanning, thereby offering a novel technical pathway and broad application prospects for intelligent forestry and agricultural management. Method: Firstly, this study constructed a dataset of soil CT and SEM images, encompassing soil column samples across three moisture levels and multiple freeze-thaw cycles, providing a data foundation for subsequent image resolution enhancement. Secondly, a CycleGAN model suitable for cross-domain transformation was introduced for the multi-scale fusion task of soil CT/SEM images. This model leveraged the different imaging characteristics of CT and SEM images to supplement low-resolution soil CT images. To improve the resolution of the generated images, upsampling modules were added to generator A, and downsampling modules were added to generator B. To enhance the authenticity and consistency of the images, the bilinear interpolation method was introduced to upsample the original images and then incorporate them into the calculation of the identity loss function. Finally, an improved ConvNeXt model was employed to segment the pores in the fused high-resolution images, construct a three-dimensional pore model and extract parameters. Result: Under the same experimental conditions, MSF-CycleGAN was qualitatively and quantitatively compared and analyzed with the super-resolution reconstruction algorithms. It was proved that the multi-scale fusion of MSF-CycleGAN could improve the resolution of soil CT images and the effect is more remarkable than that of the super-resolution reconstruction. In addition, ablation experiments were conducted to analyze the contributions of the introduction of SEM images and the improvement of the identity loss function to the overall performance, and the effectiveness of both designs was verified. The multi-scale image fusion experiments on soil columns with moisture contents of 50%, 75%, and 100% indicated that the fused three-dimensional models exhibited more fine pores, with pore quantity increasing twofold. The pore volume fraction increased by 3.93%, and the roundness of pores increased by 3.64%, while the fractal dimension increased by 0.55%. Quantitative experiments on pore parameters based on the high-resolution fused image segmentation quantification under freeze-thaw cycles conformed more closely to existing research patterns, confirming that the proposed method accurately and effectively enhanced the resolution of soil CT images. Conclusion: This study demonstrates the feasibility of improving the resolution of CT images through multi-scale fusion of soil CT and SEM images, providing a new technical approach to reduce the cost of acquiring high-resolution images and promoting the refinement and intelligent development of soil structure research.

Objective: The aim of this study is to estimate aboveground biomass (AGB) at individual tree scale in northern forests by synergistically utilizing UAV-LiDAR and UAV-RGB data. Pinus sylvestris var. mongolica and Populus. in Zhangwu County were used as the research object to investigate the influence of using combined data versus single data on AGB estimation in coniferous and broadleaf forests. The findings are to provide technical references for precise prediction of AGB at individual tree scale in windbreak and sand fixation plantations in Zhangwu County. Method: Multiple features at individual tree scale, including height, intensity, density, crown structure, spectrum, texture and vegetation index, were extracted from LiDAR point clouds and digital orthophoto map (DOM) derived from RGB optical imagery. Permutation importance (PI) and Boruta methods were used to select feature subsets. Combining these features with the aboveground biomass (AGB) data of individual trees calculated from field-measured tree height and diameter at breast height, three typical machine learning methods, including random forest (RF), extreme gradient boosting (XGBoost), and categorical features gradient boosting (CatBoost), were adopted to construct biomass estimation models for the two tree species, P. sylvestris var. mongolica and Populus. The modeling results using only LiDAR data, only DOM data, and a combination of both methods were compared. Result: 1) Point cloud height and crown structure were identified as key features for AGB estimation at individual tree scale for both species, whereas texture features only positively influenced the estimation of AGB for P. sylvestris var. mongolica. 2) For P. sylvestris var. mongolica, the estimation accuracy of AGB at individual tree scale based on combined data was highest, outperforming models based on single LiDAR and RGB imagery. The optimal models for the three datasets were ALL-PI-XGBoost, LiDAR-PI-XGBoost, and DOM-PI-RF, with R² of 0.77, 0.69, and 0.67, and RMSE of 10.94, 12.75, and 13.16 kg·plant^?1, respectively. For Populus, the estimation accuracy of AGB at individual tree scale was comparable when using combined and single LiDAR data, and both outperformed the model based on single RGB imagery. The optimal models for the three datasets were ALL-PI-XGBoost, LiDAR-Boruta-XGBoost, and DOM-Boruta-CatBoost, with R² of 0.85, 0.85, and 0.59, and RMSE of 17.63, 17.11, and 28.99 kg·plant^?1, respectively. Conclusion: The high-density point clouds and high-resolution images obtained from two types of low-cost UAV remote sensing technology can achieve high-precision, fast, and non-destructive estimation of individual tree aboveground biomass in the windbreak and sand fixation plantations in Zhangwu County. The use of combined data versus single data has different impacts on AGB estimation at individual tree scale in coniferous and broadleaf forests, with combined data significantly improving the accuracy of AGB estimation for P. sylvestris var. mongolica.

Objective: By integrating unmanned aerial vehicle light detection and ranging (UAV-LiDAR) data and global ecosystem dynamics investigation (GEDI) data, a“plot-local-region”estimation framework was constructed to estimate the aboveground biomass (AGB) of Gaofeng Forest Farm, providing a new approach for forest carbon storage monitoring. Method: Based on plot-level field measured data within the forest farm, this study evaluated the performance of three models: multiple linear regression (MLR), random forest (RF), and support vector regression (SVR), in estimating UAV-LiDAR-derived regional aboveground biomass (AGB). To augment the sample size at the regional scale, UAV-LiDAR-derived AGB estimated at GEDI footprint locations was combined with selected key GEDI footprint metrics to develop a footprint-level AGB estimation model. This model was subsequently employed to predict footprint-level AGB across the entire forest farm. The spatial interpolation of forest AGB was achieved by integrating UAV-LiDAR-derived local AGB with footprint-level AGB using empirical Bayesian Kriging (EBK) method. The inversion of AGB spatial distribution was implemented through EBK interpolation of key footprint metrics combined with UAV-LiDAR estimated AGB for model construction. Result: RF model demonstrated superior performance in estimating UAV-LiDAR-derived regional AGB compared to both MLR and SVR, achieving an R² of 0.95 with RMSE = 9.96 Mg·hm^?2 and rRMSE = 9.79%. The footprint-level AGB estimated by RF showed strong agreement with UAV-LiDAR regional AGB (R2 = 0.93, RMSE = 5.93 Mg·hm^?2, rRMSE = 5.84%). The synergistic interpolation of UAV-LiDAR local AGB and GEDI footprint AGB achieved a prediction accuracy of R² = 0.78, RMSE = 22.30 Mg·hm^?2, and MAE = 16.99 Mg·hm^?2 Compared with the AGB inversion results based on interpolated key features (fhd, rh₉₆, cover, pt₄ and pai), the AGB ranges in the study area obtained were more reasonable (49.26–193.27 Mg·hm^?2). Conclusion: This study is based on the“plot-local-region”AGB estimation framework, employing random forest algorithms and spatial interpolation methods to effectively integrate UAV-LiDAR and GEDI data. It overcomes the limitations of scarce field plot measurements and the spatial discontinuity of remote sensing data, and verifies the feasibility of using footprint samples for forest AGB estimation. The research achieves accurate AGB estimation in Gaofeng Forest Farm, providing essential data support for forest carbon storage assessment and sustainable management.

Objective: A reconstruction method for the missing parts of tree trunks for stem shape control is proposed to address the issue that when conducting forestry investigations using terrestrial laser scanning (TLS) technology, the upper part point cloud scanning of trees is incomplete due to the occlusion of branches and adjacent trees, resulting in the reduction of the extraction accuracy of parameters such as tree height and diameter. Method: In this study, 138 Larix olgensis trees in different sites and age groups were selected from a L. olgensis plantation in Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province, and TLS was used to obtain point cloud data, and trunk analysis was performed after logging. After splicing, cropping, and denoising the point clouds, the iterative random sample consensus (RANSAC) circular fitting algorithm was used to extract the point clouds of individual tree stems. The diameters at different heights on the stems were fitted using the least squares method to generate the stem shape data. A mixed-effect taper equation model was constructed based on the measured stem analysis data. The estimated values of the fitted parameters were used as known variables, while tree height and random effect parameters were treated as the parameters to be estimated. The stem shape data extracted by TLS were fitted tree by tree, and the missing parts of the tree stems were reconstructed using the fitted model. Finally, the tree height, stem shape, and standing timber volume were extracted according to the fitting model and compared with the extraction results obtained without reconstruction. Result: The parameters obtained through tree trunk reconstruction were more accurate than those extracted directly from TLS data. Especially, the estimation error of tree height was significantly reduced, with average deviation and root mean square error percentage reduced by 8.09% and 7.48%, respectively. The proportion of diameter extraction was improved, but there was no significant difference in accuracy. In the estimation of tree volume, the relatively high accuracy of tree volume before and after reconstruction was able to maintained, and the difference was not significant before and after reconstruction with measuremental method by section, and the root-mean-square error percentage of tree volume estimation after reconstruction with binary volume model method was reduced by 4.5%. Conclusion: The method of stem reconstruction by taper equation can effectively restore the missing part of the stem scanned by TLS, which significantly improves the extraction accuracy of TLS individual tree height, and provides new ideas and theoretical support for improving the application accuracy of TLS in forest parameter estimation and forestry survey efficiency.

Objective: This study analyzed and screened the active substances in the volatiles of Sabina przewalskii that attract Megastigmus sabinae. By verifying their attractiveness through field experiments, this study aims to provide scientific basis for protecting S. przewalskii forest land, improving the quality of S. przewalskii seeds and regeneration. At the same time, it is also to provide a basis for exploring the communication mechanism between M. sabinae and its host plants. Method: A Y-tube olfactometer was used to determine the attractiveness and repellency of 7 volatiles to M. sabinae. Monomers and their concentrations with optimal attractiveness were selected and their combination was used for indoor attraction experiments. The compound formula with superior attractiveness was identified and then used in conjunction with traps to conduct field trapping technique research. Result: 1) In the monomer experiment, at a concentration of 10 μg?μL^?1, there were five compounds that exhibited significantly higher attraction rates than the repellent rates for female M. sabinae. These compounds were sabinene, 2,4-dimethy lacet ophenone, α-terpineol, alpha-pinene oxide, and myrcene. At a concentration of 1 μg?μL^?1, the attraction rates of alpha-pinene oxide and myrcene were significantly higher than the repellent rates. For male adults, at a concentration of 10 μg?μL^?1, the attraction rates of 3-carene and myrcene were significantly higher than the repellent rates. At a concentration of 1 μg?μL^?1, the attraction rate of 2,4-dimethylacetophenone was significantly higher than the repellent rate, while the attraction rates of α-terpineol and alpha-pinene oxide were significantly higher than the repellent rates. 2) In the compound experiment, formula G had the highest attraction rate for female M. sabinae（57%, P<0.05）, followed by formulas B and A. Formula I had the highest repellent rate for M. sabinae. 3) In the field trapping experiment, traps with compound formulas G, A and B as lure cores had significantly higher trapping volumes than the control group. Formula G had the highest trapping volume, accounting for 34.1% of the total number of trapped insects. Formulas A and B accounted for 27.3% and 25.7% of the total number of trapped insects, respectively. Among traps of three different colors, yellow traps had the best attraction effect, trapping a total of 234 adult insects, accounting for 56.5% of the total number of trapped insects. Blue and green traps trapped 82 and 98 insects, respectively. The boat-shaped trap trapped 209 insects while the triangular trap trapped 205 insects. There was no significant difference in trapping volume between these two types of traps (P>0.05). Conclusion: All three formulas demonstrates an attractive effect in the field, with formula G exhibiting the greatest attraction effect on M. sabinae and showing potential as a lure core for traps. The most effective results are achieved when used in conjunction with yellow traps. Thus, in practical applications, formula G can be used as a core paired with a yellow trap to monitor the population of M. sabinae in the forest.

Objective: This study selected oak wood with low, medium, and high moisture content levels, combined with laser machine technical parameters (lens height, feed speed, light intensity), to analyze the effects of moisture content and laser parameters on slot depth and slot width as cutting outcomes. Response surface methodology (RSM) was introduced to model and guide laser processing for marquetry flooring and wooden crafts. Method: Moisture content (factor A) was evaluated alongside laser parameters (lens height B, feed speed C, light intensity D). Variance analysis and other methods were used to determine the significance of individual factors and their interactions. Result: For slot depth: single-factor significance followed B≈C>A>D, with B and C being highly significant, and A being nearly significant. The interaction term BC was significant, while quadratic terms for A (nonlinear effect) were highly significant and for C notably significant. The simplified RSM regression equation for slot depth was: Y = 522.14A² + 288.32C² + 235.9BC ? 359.23B ? 662.96C + 652.69. For slot width: single-factor significance followed B>D>A>C, with B being highly significant. No significant interactions were observed, but quadratic terms for A and B showed highly significant nonlinear effects. The simplified regression equation for slot width was: Y= 202.22A² + 179.51B² + 187.62B + 237.22. Conclusion: 1) The quadratic effects of moisture content were highly significant, indicating nonlinear impacts on cutting outcomes, particularly pronounced within specific ranges due to minimal influence at low moisture levels. 2) Lens height (B) critically affected both slot depth and width, emphasizing its prioritization in production parameter optimization. For maximizing slot depth, feed speed (C) should be optimized before light intensity (D); for slot width, light intensity (D) takes precedence. 3) With a water content of approximately 27.63%, to achieve a seam depth of 2 500 to 2 700 μm, the optimal parameter range is as follows: the lens height is approximately 5.7 mm, the feed rate is approximately 42 mm·s^?1, and the light intensity is approximately 62%.

Objective: The new round of forest rights reform (referred to as the“new forest reform”) has not succeeded in activating the forestland transfer market. From the dual perspective of transaction costs and credit constraints, this paper systematically evaluates the impacts and mechanisms of forest rights reform on forestland transfer, identifies its unintended effects, and offers guidance for developing a sound forestland transfer market and achieving efficient resource allocation. Method: Using stratified random sampling, we gathered plot-level data on 1 795 forestland parcels in Guangxi, Zhejiang, and Fujian Provinces (autonomous region) in 2021. Probit, Tobit, and propensity score matching models are employed to estimate the effects of forest rights reform on forestland transfer. A dual mediating effects model, centred on transaction costs and credit constraints, further reveals the key factors that hinder forestland transfer. Result: The benchmark regression results show that the reform has no significant effect on forestland transfer, including both inflow and outflow. Further empirical analysis reveals that this insignificance stems from unintended effects of the reform, which hinder the realisation of“Pareto improvement”in forestland transfers. The fundamental reason for this dilemma lies in dual offsetting effects related to transaction costs and credit constraints. Regarding transaction costs, the reform significantly reduces forestland disputes at the 5% statistical level, thereby lowering transaction costs, but it also significantly exacerbates forestland fragmentation at the 1% level, leading to increased transaction costs. These two channels offset each other, making it difficult for the reform to promote forestland transfer through cost reduction. In terms of credit constraints, the reform significantly facilitates forestland mortgage lending at the 5% level, indicating that credit constraints have been alleviated. However, the alleviation exerts opposite effects on the inflow and outflow of forestland: it provides financial support for farmers to expand their holdings, encouraging inflow, while reducing the incentive to transfer forestland out for funds, discouraging outflow. As a result, although the reform mitigates credit constraints, it leads to differentiated impacts on inflow and outflow, ultimately weakening its ability to promote forestland transfer through this channel. Conclusion: The expected positive impact of forest rights reform on forestland transfer has not materialised because of the dual obstacles posed by transaction costs and credit constraints. While the reform provides an essential policy starting point, further efforts are needed to reduce transaction costs, ease credit constraints, and strengthen market institutions to foster a robust forestland transfer market.

Objective: Exploring the impact and mechanism of the“Shan-Shui Initiative”on the development of regional forestry to provide theoretical support for improving the sustainable development policy and planning of ecological protection and restoration projects based on the synergy of economic and ecological benefits. Method: Based on the panel data from 33 county-level units in Zhejiang Province from 2010 to 2021, this study empirically tested the impact mechanism of the implementation of the“Shan-Shui Initiative”on the change of forestry green total factor productivity level by using the super-efficient SBM model and difference-in-difference model method. Result: 1) The implementation of“Shan-Shui Initiative”has a significant positive impact on regional forestry green total factor productivity. 2) The“Shan-Shui Initiative”contributes to the improvement of forestry green total factor productivity through regulatory and public effects. 3) The impact of“Shan-Shui Initiative”on forestry green total factor productivity varies significantly across different regional topography. Conclusion: Effective implementation of“Shan-Shui Initiative”and enhancement of forestry green total factor productivity require strengthened ecological conservation policies, optimized resource management systems, establishment of ecological compensation and green finance mechanisms, and reinforced green regulations and public participation.

Objective: This study quantitatively analyzes the impacts and mechanisms of various aspects of property rights security on rural households’ motivations to manage non-timber forest. The findings aim to provide decision-making insights for advancing reform of the collective forest rights system. Method: This research conducted a sample survey of 582 households in the collective forest areas of Zhejiang and Jiangxi. By applying the entropy method and Tobit model, we empirically estimated the effect of property rights security on households' investments in non-timber forest management. Furthermore, a mediating effect model of perceived property rights security was constructed to examine its role in mediating the effects of legal and factual property rights security on these investments. Result: 1) Both legal and factual property rights security significantly promoted labor inputs and cash inputs by farmers. 2) Perceived property rights security partially mediated the impact of legal property rights security on the labor and cash inputs in non-timber forest management, with mediation effects of 36.5% and 49.1%, respectively. Similarly, perceived property rights security also had a partial mediating effect on the impact of factual property rights security on labor and cash inputs, with mediation strengths of 24.9% and 26.1%, respectively. 3) The impact of property rights security varies among farmers with different forest sizes and income levels; those with smaller forest areas and lower forestry income levels are more vulnerable to property rights insecurity. Conclusion: To deepen the reform of the collective forest rights system, it is necessary not only to strengthen policy implementation at both legal and factual levels, but also to correctly guide the perceptions of farmers, effectively transforming policy effects into the subjective cognition of farmers, thereby enhancing their enthusiasm for managing non-timber forest products.

Objective: In view of different broadleaved tree species in Northeast China, this study explored the correlation between plant resource acquisition traits and defense traits and their driving factors, to reveal the correlation between the resource acquisition ability and defense ability of woody plants, to analyze the dynamic adaptation mechanism of woody plants to the environment, and to provide a scientific basis for forest ecosystem management. Method: In this study, we measured 20 phytofunctional traits in leaves, new twigs, and old branchs of five broadleaf species with different shade tolerance in temperate forests, including Betula platyphylla, Fraxinus mandshurica, Ulmus laciniata, Tilia amurensis, and Acer pictum subsp. mono, at three different life-history stages (seedling, sapling, and mature tree), and these traits were divided into resource-acquisition traits and defense traits, to explore the interrelationships and influencing factors of the two types of traits in woody plants. Result: There was weak correlation between leaf resource acquisition capacity and aboveground defense capacity, and the correlation between resource acquisition capacity and defense capacity varied at different life stages. At the seedling stage, the two capacities had a collaborative relationship (angle<90°); at the sapling stage, the two capacities were decoupled (angle≈90°); and at the mature tree stage, the two capacities had a trade-off relationship (angle>90°). Combining the effects of environmental factors (soil nutrients, soil pH, soil water content) and plant characteristics (life history stages, shade tolerance) on plant resource acquisition traits and defense traits, it was found that environmental factors (PC1 56%, PC2 73%) had a stronger effect on the two types of traits than plant characteristics (PC1 44%, PC2 27%). Conclusion: The coordination strategies between resource acquisition and defense vary across different growth stages. While environmental factors serve as the primary driving forces, plant characteristics also play a crucial role.

Objective: Starch produced by photosynthesis is temporarily stored in leaves during the day, and then degraded into maltose and glucose at night to provide energy for plant growth. β-amylase (BAM) is one of key enzymes in starch degradation. In this study, the function and molecular regulation mechanism of PeBAM3 were studied to clarify the function of BAM gene in the degradation of starch in moso bamboo (Phyllostachys edulis) leaves, so as to provide reference for the role of BAM gene in rapid growth of moso bamboo. Method: The diurnal variation of starch content in moso bamboo leaves was determined by anthrone colorimetry. A homologous gene PeBAM3 in the genome of moso bamboo was identified by BLAST using rice (Oryza sativa) OsBAM5 as bait. The coding region and promoter sequences of PeBAM3 were cloned and systematically analyzed by bioinformatics software. Based on transcriptome data of moso bamboo, the expression patterns of PeBAM3 in different tissues, shoots at different heights and shoots at different times within a day were analyzed. The co-expression network of PeBAM3 was constructed using the BambooNET public database, to screen the target transcription factor (TF). The real-time fluorescence quantitative PCR (qPCR) was used to detect the daily variations in expression of the TF and PeBAM3. The dual luciferase reporter assay (DLR) was applied to verify the regulatory relationship between the TF and PeBAM3. The function of PeBAM3 was validated by heterologous expression in rice. Result: The starch content in moso bamboo leaves reached its maximum value at the end of the day, and gradually decreases at night. The bamboo BAM gene PeBAM3, identified through screening, has an open reading frame of 1 635 bp, encoding 544 amino acids with a complete β-amylase conserved domain. The molecular weight of PeBAM3 is 59.50 kDa, with an isoelectric point of 6.48, an average hydrophobicity of –0.270, a protein instability index of 44.85, and a lipid index of 74.19. The promoter region of PeBAM3 (1 771 bp) contains a variety of regulatory elements related to light, stress, and hormones. Phylogenetic analysis showed that PeBAM3 is closely related to OsBAM5, suggesting that it might play an important role in starch degradation. Transcriptomic data analysis showed that PeBAM3 was relatively highly expressed in bamboo leaves and shoot buds. As the shoot height increased, the expression levels of PeBAM3 continuously rose. The expression of PeBAM3 responded to the change of photoperiod, rising at night and decreasing during the day. Co-expression network analysis revealed that the AP2/ERF (APETALA2/ethylene-responsive factor) TF gene PeERF1 was co-expressed with PeBAM3. The qPCR results demonstrated that their expression levels rose at night and decreased during the day, which was opposite to the starch content changing trend in leaves. DLR results indicated that PeERF1 was able to enhance the expression of PeBAM3. Compared with wild type, overexpression of PeBAM3 in rice led to dwarfism, reduced growth vigor in the aerial parts of transgenic rice plants, significantly increased β-amylase activity, significantly reduced starch content, and significantly increased glucose, fructose, and sucrose levels in transgenic rice leaves. Conclusion: The starch content in moso bamboo leaves shows a diurnal variation, rising in the day and falling at night. The expression level of PeBAM3 is inversely correlated with the starch content in leaves. PeERF1 can enhance the expression of PeBAM3. Overexpression of PeBAM3 promotes the degradation of starch in transgenic rice leaves. The results not only provide an important reference for in-depth analysis of the role of BAM in starch metabolism of moso bamboo, but also provide potential genetic resources for bamboo molecular breeding.