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  • Construction and Protection of Forest Resources
    Lingping DONG, Xiaojing HU, Wenle YANG
    Forest Engineering. 2024, 40(4): 1-10. https://doi.org/10.7525/j.issn.1006-8023.2024.04.001
    Abstract (175) PDF (44) HTML (153)   Knowledge map   Save

    The canopy width is a necessary variable for the growth of desert vegetation. Predicting the crown width of desert plant in different habitats can provide reference for the scientific management of desert vegetation. Taking the species of Haloxylon ammodendron in the Gurbantunggut Desert as the research object, select 6 commonly (M1, M2, M3, M4, M5, M6) used regression models, using tree height and ground diameter as survey factors, establish a canopy model of H. ammodendron in different habitats of highlands, gentle slopes, and flat lands. Perform regression analysis on the model using Origin and Anaconda software, select the optimal model based on four fitting accuracy standards (R2, RMSE,MAE, and MAPE). The model fitting results indicate that: in the tree height -shrub crown width and shrub ground diameter models, the R2 values of the six regression models are all greater than 0.5, the model fitting effect is good. M5 (cubic polynomial model) is the optimal model for tree height crown width and ground diameter crown width in three different habitats. All six models have statistical significance (Sig.<0.001), which has important reference value for predicting the crown size of H. ammodendron in the Gurbantunggut Desert, and provides a certain scientific basis for maintaining the ecology and vegetation restoration of the region.

  • Construction and Protection of Forest Resources
    Xiaodong WANG, Caihong ZHAO, Ruirui WANG, Yue ZHANG, Ling YANG
    Forest Engineering. 2024, 40(4): 19-28. https://doi.org/10.7525/j.issn.1006-8023.2024.04.003
    Abstract (142) PDF (30) HTML (123)   Knowledge map   Save

    This experiment used an indoor culture dish germination method to study the effects of exogenous addition of polyethylene glycol, sodium carbonate, and sodium bicarbonate on the embryos germination and physiological indicators of S. pohuashanensis seedlings. The results showed that polyethylene glycol treatment increased the germination percentage of S. pohuashanensis embryos by 15% to 25%, while sodium carbonate and sodium bicarbonate treatment reduced the germination percentage of S. pohuashanensis embryos by 88% and 85%, respectively. Polyethylene glycol can alleviate the inhibition of saline alkali stress on the germination of S. pohuashanensis embryos, and increase the germination rate of embryos under stress by 1-2 times. Polyethylene glycol can increase the activity of antioxidant enzymes in the embryos of S. pohuashanensis under saline alkali stress, resulting in an increase of 16.45%, 75%, and 80% in enzyme activities such as SOD, POD, and CAT, respectively. Polyethylene glycol reduced MDA in embryos under stress by 41.44%. Research has shown that polyethylene glycol can effectively alleviate the inhibitory effect of salt alkali stress on the embryos of S. pohuashanensis, improve the activity of antioxidant enzymes in S. pohuashanensis embryos, enhance the stress resistance of S. pohuashanensis, and provide scientific basis for establishing PEG priming technology to promote the germination of S. pohuashanensis embryos.

  • Construction and Protection of Forest Resources
    Fanghu LIU, Hongsheng ZHANG, Linghong TIAN
    Forest Engineering. 2024, 40(4): 49-57. https://doi.org/10.7525/j.issn.1006-8023.2024.04.006
    Abstract (142) PDF (18) HTML (126)   Knowledge map   Save

    In order to optimize the technical problems of cutting rooting of rare and endangered tree species Euptelea pleiospermum, using 1-year-old semi lignified branches of E. pleiospermum wood as cutting materials, an orthogonal experimental design was adopted to explore the effects of different substrates, exogenous hormones, concentrations, and treatment times on the rooting of E. pleiospermum wood cutting through the calculation of rooting rate, root effect index, and other indicators (Matrix type、hormone type, mass concentration, hormone treatment time were four factors, and each factor had four gradients). The membership function numerical method was used to comprehensively evaluate the rooting effect of 16 treatment combinations, providing technical reference for the expansion of E. pleiospermum wood. Among the four cutting substrate ratios (100% peat;V (peat)∶V (perlite)=5∶2; V (peat)∶V (vermiculite)=5∶2; V (peat)∶V (perlite)∶V (vermiculite)=5∶2∶2, V represents the volume ratio), peat: perlite (5∶2) had the best rooting effect, with a rooting rate, average root length, longest root length, average root number, and average root diameter of 56.67%, 6.74 cm, 7.47 cm, 5.73 stripes/ears, and 0.31 cm, respectively. The root effect index reached 1.74, which was much higher than the other three substrate ratios (P<0.05). The results of the orthogonal experiment showed that the rooting effect of cuttings soaked with ABT-1 at a concentration of 1 g/L for 5 seconds was the best, with a rooting rate of 65.73%, an average root length of 7.38 cm, an average number of 7.59 stripes/ears, a maximum root length of 7.52 cm, an average root diameter of 0.35 cm, and a root effect index of 1.87. Comprehensive analysis showed that the optimal treatment combination for rooting effect was (peat to perlite volume ratio 5∶2 as substrate, with the highest average membership function value in ABT-1 at a medium speed of 1.0 g/L for 5 seconds), and the lowest treatment combination was (peat to vermiculite volume ratio 5:2 as substrate, soaked in 0.8 g /L indole butyric acid (IBA) for 12 hours.

  • Forest Industry Technology and Equipment
    Miaoqi SUN, Cairong YUE, Yunfang DUAN, Hongbing LUO, Qiongfen YU, Guangfei LUO, Tianshu XU
    Forest Engineering. 2024, 40(4): 115-126. https://doi.org/10.7525/j.issn.1006-8023.2024.04.013
    Abstract (140) PDF (12) HTML (115)   Knowledge map   Save

    In order to explore the advantages and complementarity of optical data and synthetic aperture radar (SAR) data in forest type classification, this study focused on the overlapping area of Landsat8 data and ALOS2 data from one scene SAR image in Simao District, Puer City, Yunnan Province, China, and used hierarchical classification technology for forest type classification research. Three feature sets were constructed: optical feature set (spectral + vegetation + texture + terrain features), SAR feature set (backscattering + polarization decomposition features), and optical-SAR fusion feature set (spectral + vegetation + texture + terrain + backscattering + polarization decomposition features). Recursive Feature Elimination (RFE) was employed to perform stratified feature selection on the three feature sets, and random forest (RF) and support vector machine (SVM) were used for forest type classification. The SVM classification with the fusion of optical images and SAR data achieved the best results. The results showed, 1) In the first layer (vegetation/non-vegetation) classification, the overall accuracy was 98.57%, the Kappa coefficient was 0.971. 2) In the second layer (forest/non-forest) classification, the overall accuracy was 92.14%, the Kappa coefficient was 0.826. 3) In the third layer (coniferous/broad-leaved/mixed forest) classification, the overall accuracy was 83.47%, and the Kappa coefficient was 0.743. The fusion data showed an improvement of 6.74% in accuracy compared to optical data feature set classification and 29.24% compared to SAR classification. 4) In the classification of the third layer using fusion data, the influence of different window sizes (3×3, 5×5, 7×7, 9×9) of texture features in optical images was compared, and the highest accuracy was achieved with a 7×7 texture window. Results shows that, the accuracy of forest type classification using multi-source data is higher than that using a single data source.

  • Road and Traffic
    Baochang WANG, Shufa SUN, Jiayi ZHANG, Jinhao LIU
    Forest Engineering. 2024, 40(4): 186-195. https://doi.org/10.7525/j.issn.1006-8023.2024.04.020
    Abstract (138) PDF (12) HTML (120)   Knowledge map   Save

    In order to improve vehicle′s trafficability in the desert, based on the analysis of the desert soil parameters and the theory of traficability of crawler vehicles on soft ground, a LY352J desert crawler transport vehicle equipped with triangular track shoes was developed. This vehicle can carry out personnel and material transportation, vehicle traction, and winch tration operations, mainly composed of key parts such as triangular track shoes, winch and cab. Through theoretical analysis and calculation, the parameters of each key component andh traction traficability of desert crawler transport vehicle on soft desert ground were determined. Creo software was used to build a virtual prototype, and RecurDyn (Recursive Dynamic) dynamic simulation software was used to simulate the optimal tension selection, straight driving, climbing, and turning of vehicle crawler. The results showed that, under the condition of 45% vehicle weight, the optimal tension of the track was 26.46 kN; under the condition of 26.46 kN track tension (45% vehicle weight), it could ensure the smooth operation and good performance of the vehicle; the maximum slope obtained by uphill simulation was 30°; in the steering dynamics simulation, the steering stability of the vehicle on the road was better, but it was easy to lose stability when turning, and it would appear lateral inclination. At last, the experiments of straight running, longitudinal climbing and turning of test vehicle were carried out in test site, and it was verified that the vehicle had good trafficability when actually walking in the desert terrain, and can overcome the drawbacks of wheeled transport vehicles sinking in sand, meeting the requirements of current desert terrain transportion operations.

  • Construction and Protection of Forest Resources
    Zicheng WANG, Yuanhang LYU, Wenbing WANG, Xinyue GUO, Lingbo DONG
    Forest Engineering. 2024, 40(4): 39-48. https://doi.org/10.7525/j.issn.1006-8023.2024.04.005
    Abstract (138) PDF (43) HTML (123)   Knowledge map   Save

    Quantifying the relationship between radial growth of Larix gmelinii (Rupr.) Kuzen of different ages and climatic factors, and provide decision making basis for adaptive management and management of natual Larix gmelinii (Rupr.) Kuzen forests. Therefore, based on the data of 159 Larix gmelinii (Rupr.) Kuzen.from Pangu Forest Farm of Tahe Forestry Bureau in Heilongjiang Province in 2022, this study adopted the method of systematic cluster method to divide the trees into young-age, middle-age and old-age group based on tree age. Then, using dendrochronology, standard chronology was established to analyze and compare the relationship between radial growth of trees of different age groups and climate factors, and multiple stepwise regression method was used to construct the prediction model of single tree radial growth sensitive to climate.The results showed that: 1) The total sample explanatory weight (EPS), mean sensitivity (MS) and signal-to-noise ratio (SNR) of the (total group, old-age group, middle-age group, and young-age groups) were higher, which indicated that the standard chronology of Larix gmelinii (Rupr.) Kuzen retained abundant climate information. 2) The main limiting factors for radial growth of Larix gmelinii (Rupr.) Kuzen were temperature in August of the current year, temperature from August to October of the previous year, and precipitation in February and July of the current year, and in July and December of the previous year. 3) There were significant differences in the response of Larix gmelinii (Rupr.) Kuzen to climate factors in different age groups. The radial growth of old-age Larix gmelinii (Rupr.) Kuzen was affected not only by the summer temperature of the current year but also by the summer temperature and precipitation of the previous year, showing a significant lag effect, while the young and middle age Larix gmelinii (Rupr.) Kuzen were less affected by environmental factors.

  • Construction and Protection of Forest Resources
    JING Jixin,CHEN Canyang,MAN Xiuling,HAN Zhaozhi
    Forest Engineering. 2024, 40(3): 1-10. https://doi.org/10.3969/j.issn.1006-8023.2024.03.001
    Abstract (138) PDF (22)   Knowledge map   Save

    In this study, the main trees of typical forest communities inpermafrost area of northern Greater Khingan Mountains were selected as the research objects, the contents of carbon(C) , nitrogen (N) and phosphorus (P) in leaves andsoil and their eco- logical stoichiometric characteristics were analyzed, and therelationship between leaves and soil C, N and P ecological stoichiometrywas discussed to provide theoretical basis for thestudy of nutrient cycling in forest ecosystem in this area. Results indicated that the C∶ N ratio of four tree leaves ranged from 25. 66 to 47. 92, the C ∶ P ratio ranged from 323. 83 to 603. 86, and the N:P ratio ranged from 10.21 to 20. 59. Larix gmelini exhibited the lowest C ∶ N and N ∶ P ratios, while Pinus sylvestris var mongolica had thehighest C ∶ N and C ∶ P ratios, Betula platyphylla had the lowest C ∶ N ratio and Populus davidiana had the highest N ∶ P ratio. The C ∶ N and C ∶ P ratios of all four tree species exceeded the global average, suggesting efficient utilization of N and P. Nevertheless, the leaf N ∶ P >20 of Populus davidiana was primarily limited by P in itsgrowth. The soil C ∶ N ratio of different communities ranged from 13. 89 to 18. 46, the C ∶ P ratio ranged from 35. 43 to 77. 19, and the N ∶ P ratio ranged from 1. 96 to 5. 26. Populus davidiana forests exhibited the highestC ∶ P and N ∶ P ratios, while having the lowest C ∶ N ratio. Betula platyphylla had the highest C ∶ N ratio and the lowest N ∶ P ratio. Pinus sylvestris var mongolica displayed the lowest C ∶ P ratio. The redundancy analysis results showed that there was a significant correlation between the ecological stoichiometry of C, N, and P in the leaves of four trees and the soil. The con-tent and stoichiometry of soil C, N, P had a significant impact on the carbon fixation and nitrogen and phosphorus absorption of trees.It can be seen that the four types of trees in the cold temperatezone of China have high N and Putilization efficiency, but the growthofPopulus davidiana is limited by P. The ecological stoichiometry of leaf C, N, and P is significantly correlated with soilecological stoichiometry.

  • Construction and Protection of Forest Resources
    Liying XU, Tongchao WEI, Jiayin WANG, Minghui HUANG, Wei PENG, Lanyi SHEN, Bingyang LIU, Dounan LIU
    Forest Engineering. 2024, 40(4): 29-38. https://doi.org/10.7525/j.issn.1006-8023.2024.04.004
    Abstract (136) PDF (49) HTML (117)   Knowledge map   Save

    In order to explore the adaptability of the roots and leaves of Amorpha fruticosa L. stoichiometric characteristics to nutrients, and to provide a basis for the study of fertilization and restrict modes of leguminous plants. We usedfertilization treatment with three factors (nitrogen (N), phosphorus (P), potassium(K)), and three fertilization levels (N1, N2, N3, P1, P2, P3, K1, K2, K3) to measure the carbon (C), N, P, K content of the roots and leaves of Amorpha fruticosa L. seedlings, and analyze the relationship between elements in the roots and leaves. Our results showed that the leaves had a stronger response than roots under P, K addition, and roots had a stronger response to N addition. Leaf and root N contents, root N/K and root N/P were increased significantly with increasing N addition level, root P/K, leaf P/K and root C/N decreased significantly. Leaf N, P and K content, root P content, root N/K and root P/K increased significantly, leaf N/K and leaf N/P decreased significantly with increasing P application; root and leaf K content increased significantly and root N/K, root P/K, leaf N/K and leaf P/K decreased significantly with the increasing of K application. Leaf C content, root P content, leaf K content and root K content were highly significantly positively correlated, while the relationship between leaf C, N contents and root C, N contents was not significant, while leaf and root N, P, and K contents were significantly negatively correlated with their corresponding C/N, N/P and N/K, respectively. The relationship between the ratio of carbon to nitrogen in leaf and root was insignificant, while the ratio of nitrogen to phosphorus, nitrogen to potassium and phosphorus to potassium in leaf were significantly correlated. The results of membership function analysis showed that in the accumulation of C, N, P and K contents of Amorpha fruticosa L., N2 was the best treatment. N addition resulted in P limitations to leaves and roots; P addition resulted N limitations to leaves and roots; K addition did not changed the limitation patterns. These results can provide a good basis for rational fertilization and scientific management of Amorpha fruticosa L..

  • Construction and Protection of Forest Resources
    Jintao LÜ, Yao GENG, Peng ZHANG
    Forest Engineering. 2024, 40(4): 71-78. https://doi.org/10.7525/j.issn.1006-8023.2024.04.008
    Abstract (133) PDF (7) HTML (110)   Knowledge map   Save

    In order to study the effects of top pruning time and retained stem height on the quality of Pinus koraiensis seedlings, a top pruning test was carried out with 4-year bare root seedlings of Pinus koraiensis as materials, and 3 retained stem heights (20, 25, 30 cm) and 5 top pruning times (April, May, June, July, August) were set. The root collar diameter, biomass, shoot to root ratio, root length, root surface area and root volume of seedlings under different top pruning treatments were measured. The results showed that top pruning treatment in the middle of the growing season (June) could significantly increase the root collar diameter growth of Pinus koraiensis seedlings by 23.68% compared with the control, but the effect of top pruning treatment at other times was not obvious. The top pruning treatment had no effect on the increase of biomass, the decrease of shoot to root ratio and the growth of thick roots, but had a significant effect on the growth of fine roots of Pinus koraiensis seedlings. The length of fine roots, surface area of fine roots and volume of fine roots were increased by 18.27%-84.95%, 9.38%-75.01% and 1.28%-64.68%, respectively, compared with the control. The top pruning in the middle of the growing season (June) increased the root collar diameter growth of Pinus koraiensis seedlings, promoted the growth of fine roots and promoted the quality of Pinus koraiensis seedlings to a certain extent.

  • Construction and Protection of Forest Resources
    Haiyang LI, Jun YE
    Forest Engineering. 2024, 40(4): 11-18. https://doi.org/10.7525/j.issn.1006-8023.2024.04.002
    Abstract (132) PDF (40) HTML (118)   Knowledge map   Save

    Climate change and forest vegetation affect the distribution of PM2.5 concentrations, and PM2.5 as an important air pollutant can also affect forest vegetation growth directly or indirectly. Currently, the technique of inverting daytime PM2.5 based on optical aerosol thickness (AOD) data is relatively mature, and as a complement to daytime PM2.5, nighttime PM2.5 is of great significance for the all-day PM2.5 monitoring. Based on the radiation transmission theory, the machine learning estimation model of nighttime PM2.5 concentration in the three northeastern provinces was established with nighttime light brightness, enhanced vegetation index and seven meteorological factors(2 m dewpoint temperature, 2 m temperature, u component of wind speed, v component of wind speed, atmospheric surface pressure, evaporation,precipitation) as input variables, and nighttime PM2.5 concentration as response variable, aiming to provide a reference for monitoring nighttime PM2.5 concentration in the three northeastern provinces. The results show that the model constructed based on the integration tree has high estimation accuracy, with a goodness of fit (R 2) of 0.68, a mean absolute error (MAE) of 7.05 µg/m3, and a root mean square error (RMSE) of 11.62 µg/m3. In addition, the model is found to have certain spatial and temporal sensitivity by analyzing the errors between the estimated and true PM2.5 values at each monitoring station in the three northeastern provinces. It can provide a reference for the forest vegetation conservation work by timely and accurately controlling the distribution of nighttime PM2.5 concentration.

  • Construction and Protection of Forest Resources
    Jian SHEN, Cairong YUE, Xilong GUO, Xin LI, Lanzhong ZHANG, Tianshu XU
    Forest Engineering. 2024, 40(4): 58-70. https://doi.org/10.7525/j.issn.1006-8023.2024.04.007
    Abstract (131) PDF (47) HTML (113)   Knowledge map   Save

    Quickly and accurately obtaining land use information can provide a reference for urban development and ecological environment protection. This study classifies land use types in Yunnan Province based on multi-temporal Landsat image dense time stacking and random forest algorithm on the Google Earth Engine (GEE) platform, analyzes the spatiotemporal change trends of LULC in Yunnan Province, and uses geodetectors to quantitatively evaluate key drivers factor. The results show that, 1) the average overall accuracy and Kappa coefficient of LULC classification in this study are 88.64% and 86.01%, respectively, which is highly accurate and meets the data usage requirements. 2) The land types in Yunnan Province are mainly forest land, cultivated land, grassland, and sparse shrub grass mixed land, accounting for 97.91%-98.38%. Land use transfer mainly involves the conversion of forest land and cultivated land, and the conversion of grassland and sparse shrub grass mixed land into cultivated land. 3) The land use intensity in central and eastern Yunnan in Yunnan Province is generally higher than that in other regions, while the land use intensity in northwest and southwestern Yunnan is lower. 4) There are significant differences in the influence of different driving factors on LULC. Vegetation type, average annual temperature and soil type have a relatively small impact on LULC changes. Elevation, slope, aspect, average annual precipitation, population density, GDP and population urbanization rate, etc., generally have a high impact on LULC changes, Among them, GDP, population density, and population urbanization rate have a higher impact on LULC changes. The research results can provide data basis and support for subsequent ecological and environmental protection policy formulation and regional sustainable development in Yunnan Province.

  • Forest Industry Technology and Equipment
    Kangkang LIU, Hao ZHONG, Wenshu LIN
    Forest Engineering. 2024, 40(4): 98-108. https://doi.org/10.7525/j.issn.1006-8023.2024.04.011
    Abstract (124) PDF (6) HTML (104)   Knowledge map   Save

    Airborne hyperspectral data can reflect the spectral characteristics of tree species, which can be used for precise classification of forest tree species. This study applies different machine-learning classification algorithms to classify tree species in hyperspectral images of unmanned aerial vehicles (UAV). Firstly, a UAV was used to collect hyperspectral data from the Maor Mountain Experimental Forest Farm in Heilongjiang Province, and a series of preprocessing was completed for the obtained data. Then, three different machine learning classification algorithms, namely, support vector machine (SVM) based on Gaussian kernel, random forest (RF), and K-nearest neighbor (KNN), were used to establish the tree species classification models, respectively, based on the full-band hyperspectral data. Meanwhile, tree species classification models were constructed based on the dimension-reduced full-band hyperspectral data using different band selection methods (successive projections algorithm, competitive adaptive reweighted sampling method and uninformative variable elimination method). Finally, the tree species classification model was constructed by combining different band selection methods and hyperspectral image texture features, and the results of different processing methods were compared. Research shows, the kernel SVM had the highest classification accuracy (87.55%) among the tree species classification models with full-band hyperspectral data. After selecting different bands, the stability of RF is the best among the three classification algorithms, and the accuracy rate was high, while the classification accuracy of the support vector machine based on the Gaussian kernel improved with the increase of feature dimension. The accuracy of the tree species classification model established by extracting texture features based on a grayscale co-occurrence matrix combined with band selection was higher than that of the model established by a single band selection. In particular, the K-nearest neighbor classification algorithm has the greatest improvement, which indicated that modeling with clearly partitioned features can achieve good classification results. This study used different feature selection methods combined with three different machine learning classification algorithms to achieve dominant tree species classification based on hyperspectral data, which provides technical reference for the combination of band selection methods and machine learning algorithms, and it is also of great significance for forest biomass retrieval and carbon storage estimation based on UAV hyperspectral data.

  • Construction and Protection of Forest Resources
    Ting LI, Dongxiang ZHANG, Desheng ZHANG, Qiang SUN, Yue ZHU
    Forest Engineering. 2024, 40(4): 79-87. https://doi.org/10.7525/j.issn.1006-8023.2024.04.009
    Abstract (121) PDF (35) HTML (106)   Knowledge map   Save

    Zhalong National Nature Reserve is the largest and world-renowned wetland in China, and its vegetation changes have a significant impact on the ecological environment of the wetland. This study focuses on the Zhalong Wetland in Qiqihar City. Based on MODIS data, the pixel binary model method and ArcGIS 10.2 software were used to analyze the spatiotemporal changes in vegetation cover of the wetland from 2001 to 2022. The aim is to reveal the trend of vegetation change in Zhalong Wetland, in order to provide reference and guidance for the ecological protection, restoration, and construction of the wetland. The results show that: 1) the vegetation coverage in the eastern region of Zhalong Wetland is better than that in the western region, and the overall spatial variation of vegetation coverage level shows a fluctuating increasing trend; The overall transformation is from low vegetation coverage to high vegetation coverage, with a significant increase in the area of high vegetation coverage, while the area of intermediate, medium, and low vegetation coverage gradually decreases. 2) There is a correlation between vegetation coverage and annual precipitation, average annual temperature, and annual water replenishment in the region. The high vegetation coverage area shows a significant positive correlation with annual precipitation and annual water replenishment (R=0.42; R=0.62), while the medium high vegetation coverage area shows a significant positive correlation with the annual average temperature of the previous year (R=0.46), and also has a certain correlation with the annual average temperature of the current year; The high vegetation coverage area also has a certain correlation with the annual precipitation of the previous year, showing a characteristic that the change in vegetation coverage lags behind the change in precipitation.

  • Forest Industry Technology and Equipment
    Jiuqing LIU, Fan LIU, Binhai ZHU
    Forest Engineering. 2024, 40(4): 150-159. https://doi.org/10.7525/j.issn.1006-8023.2024.04.016
    Abstract (117) PDF (9) HTML (101)   Knowledge map   Save

    To meet the requirements of fixed-point monitoring and reconnaissance tasks within forest areas by rotary-wing drones, a bionic perching robotic arm is designed through the study of birds' perching processes and the bionic research of legs and feet. The modular design and kinematics snalysis of the whole machine are carried out. The leg module employs Automatic Dynamic Analysis of Mechanical Systems (ADAMS) for kinematic trajectory simulation, while the claw module uses the D-H(Denavit-Hartenberg) parameter method to obtain the kinematic equation of the toetip. The workspace point cloud distribution of the claw module's toetip is derived through MATLAB simulation. A prototype is fabricated to establish an experimental system, which is then used to verify the activity range of the toe part and the overall perching capability of the machine. This design is simple and easy to control, capable of completing perching behavior in the laboratory stage.

  • Forest Industry Technology and Equipment
    Junfeng HU, Hao ZHU, Xiaowen HUANG, Baicong LI, Yafeng ZHAO
    Forest Engineering. 2024, 40(4): 109-114. https://doi.org/10.7525/j.issn.1006-8023.2024.04.012
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    Forest mobile robots based on visual navigation face the problem of limited computational power as edge devices and the navigation performance is greatly affected by illumination. To address this, a lightweight trunk detection method is proposed. This method uses visible and thermal image as inputs, minimizing the impact of illumination on navigation performance it also employs a feature extraction module based on Partial Convolution (PConv) and a Partial Efficient Layer Aggregation Network (P-ELAN) to achieve lightweight improvements to the baseline model. During training, the alpha-CioU loss function is used to replace the original CIoU loss function, increasing the accuracy of bounding box regression. The results show that the proposed tree trunk detection method for forest mobile robots reduces the parameter count of the original YOLOv7-tiny model by 31.7%, decreases computation by 33.3%, and improves inference speeds on Graphics Processing Units (GPU) and Central Processing Units (CPU) by 33.3% and 7.8%. The modified model maintains comparable accuracy while being more lightweight, making it an ideal choice for deployment on edge devices such as robots.

  • Road and Traffic
    Jun WANG, Shan WANG, Hao DONG
    Forest Engineering. 2024, 40(4): 175-185. https://doi.org/10.7525/j.issn.1006-8023.2024.04.019
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    In order to study the change rule of frost resistance of carbon nanofiber concrete under the action of salt-freeze-thaw cycle, the concrete specimens with four different carbon nanofibers (CNFs) mass admixture (0, 0.1%, 0.2%, 0.3%) were subjected to rapid freeze-thaw cycling test using 3.5% NaCl solution as the freezing and thawing cycling medium. The fiber modification mechanism was analyzed by scanning electron microscopy, X-ray diffraction, nitrogen adsorption and other microscopic technical means. Moreover, a freeze-thaw damage model was developed to evaluate the damage evolution of carbon nanofiber concrete under salt-freeze-thaw cycling conditions. The results indicated that CNFs could improve the salt-frost resistance of concrete, and the improvement effect was positively correlated with the dosage, and the freezing-resistance grade and durability index were increased by 100% compared with the baseline group at a mass dosage of 0.3 %. CNFs enhanced the compactness of concrete by bridging cracks, controlling nanoscale cracks, nucleation, and improving pore structure, which in turn improved the salt-frost resistance of concrete. The freeze-thaw damage models established based on different evaluation indexes conform to the Weibull distribution and had R 2 greater than 0.9, which can be used for evaluating and predicting the damage of carbon nanofiber concrete under salt-freeze-thaw cycle conditions.

  • Construction and Protection of Forest Resources
    Chunhui WANG, Xiuling MAN, Haixing LI
    Forest Engineering. 2024, 40(4): 88-97. https://doi.org/10.7525/j.issn.1006-8023.2024.04.010
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    Studying the variation patterns of soil microbial biomass and enzyme activity during the vegetation recovery processes of burned areas, providing a scientific basis for reforestation approaches and effectiveness assessment in burned forests. The three distinct types of Larix gmelinii seed tree-Betula platyphylla forests (MB), understory nursery-Betula platyphylla forests (FB), and Betula platyphylla forests (BB) in the severely burned areas in Daxing′an Mountains were selected as the research objects, with Larix gmelinii plantation(LL) served as a control. The soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and the activities of urease (URE), acid phosphatase (ACP), sucrase (SUC), and catalase (CAT) at depths of 0-5, 5-10, and 10-20 cm were measured. Results showed that: 1) The variations in soil MBC and MBN ranged from 239.16 to 852.09 mg/kg and 37.08 to 114.99 mg/kg, respectively. The order of MBC and MBN content was MB>FB>LL>BB, except for the 10-20 cm soil layer. 2) The activities of ACP, CAT, and URE were highest in MB. In FB, the average activities of ACP, SUC, and CAT were higher than those in LL, while the average activities of URE and ACP in BB were lower than those in LL. 3) Redundancy analysis showed that the interpretation rates of soil enzyme activities reached 46.8%, 24.9% and 4.5% for 0-5 cm SOC, SAP and MBN, and 61.8%, 11.4% and 4.0% for N O 3 --N, pH and MBC in 5-10 cm soil layer. The interpretation rates of N O 3 --N, pH and TN in 10-20 cm soil layer were 53.3%, 14.7% and 12.4%, respectively. Retaining trees with reproductive capacity as seed trees after a wildfire and implementing timely nurturing management have a positive promoting effect on soil microbial biomass and enzyme activity, contributing to the recovery of vegetation in burned areas.

  • Construction and Protection of Forest Resources
    ZHOU Donglan , WANG Xincheng , LU Jian , WU Xudong , ZHAO Wei , YU Fei
    Forest Engineering. 2024, 40(3): 11-19. https://doi.org/10.3969/j.issn.1006-8023.2024.03.002
    Abstract (114) PDF (19)   Knowledge map   Save
    To reveal the effects of high intensity thinning on leaf-soilnutrient relationships in Masson pine (Pinus massoniana) plantation, the physicaland chemical properties, nitrogen (N) and phosphorus(P) stoichiometric characteristics,as well as the cor- relationbetween leaves and soil nitrogen and phosphorus were analyzed inP. massoniana plantations 5 yearsafter thinning and non thinning(control). The results showed that high intensity thinningsignificantly increased soil pH, decreased soil water content, totalN,total P , available N, and available P contentin the soil at 0-20 cm, and had no significant effects on the N and Pcontent in the soilat 20-40 cm. High intensitythinning did not significantly affect leaf N content but significantly reduced leaf Pcontent, resultingin a 50% increase in leaf N:Pratio. In the control treatments, leaf N content was positively correlated with available N content in the soilat 10-40 cm, but this correlation was not significant after thinning. The correlation between leaf Pcontent and available P content in the soil was not significant both in the thinning and control treatments. Therefore, N is the limiting factorfor P. massoniana growth inthe study area, and high intensity thinning relieved the N limitation on P. massoniana growth.
  • Road and Traffic
    Hongjun LIU, Chengling HE, Feng CHEN, Zhijun ZHOU, Chao YANG
    Forest Engineering. 2024, 40(4): 218-224. https://doi.org/10.7525/j.issn.1006-8023.2024.04.023
    Abstract (112) PDF (5) HTML (96)   Knowledge map   Save

    Taking the marine-continental facies soft silty soil in the Pearl River Delta region as the research object, the changing rules of shear strength and shear strength indexes under different consolidation pressures and degrees of consolidation were investigated through indoor straight shear tests, and a three-dimensional logistic mathematical model of shear strength and corresponding indexes-degree of consolidation-consolidation pressure was proposed. The results showed that: when P≥200 kPa, U≥40%, the growth of soft soil cohesion (c) and internal friction angle (φ) was more obvious; when U=100%, campared to the initial state, the soft soil shear strength (τ) under the action of all levels of consolidation pressure increased by 7.89, 12.73, 13.50, 18.20, 22.38 kPa, respectively; the given three-dimensional mathematical model can directly calculate the shear strength index and shear strength under a certain consolidation pressure and consolidation degree; the research results can more accurately evaluate the overall stability of the soft soil foundation in this area during the step-by-step loading process.

  • Wood Science and Engineering
    Yang YANG
    Forest Engineering. 2024, 40(4): 160-167. https://doi.org/10.7525/j.issn.1006-8023.2024.04.017
    Abstract (109) PDF (3) HTML (91)   Knowledge map   Save

    Paulownia has usually been an important material for making resonant components of musical instruments, which has a significant influence on the sound quality of musical instruments. This study utilized a generalized regression neural network (GRNN) to develop the sound quality evaluation model of Yueqin based on the vibration performance of the soundboard. In this study, nine Yueqins were fabricated, and a prediction model for the sound quality of Yueqins was proposed based on their sound quality evaluation and the soundboard information of prepared Yueqins. Out of a total of 180 sets of data, 135 sets of data were randomly selected for training and the remaining 45 sets of data were used for validation. A model for evaluating the acoustic quality of Yueqin instruments was established using principal component analysis method and GRNN, and simulation prediction was performed. The results showed that based on the vibration characteristics of the soundboard, the prediction of the Yueqin sound quality can be achieved by using the Matlab simulation, and the accuracy of the prediction can reach 91.41%. In addition, this study demonstrated that the dynamic elastic modulus, acoustic radiation damping coefficient, elastic modulus, elastic and shear modulus ratio, acoustic impedance, loss tangent angle, and acoustic conversion efficiency of Paulownia wood resonator plates were all key factors influencing the acoustic quality of the finished Yueqin during its preparation.

  • Construction and Protection of Forest Resources
    WAN Shaohua, ZHANG Lei , LI Zhixin , ZHANG Hanguo, DAI Weizhao , SHI Baoying , YU Hongying
    Forest Engineering. 2024, 40(3): 33-46. https://doi.org/10.3969/j.issn.1006-8023.2024.03.004
    In order to understand the effects of different fertilizationtreatments on endogenous hormones andgrowth of Juglans mandshurica Maxim, a three-factor orthogonalfertilization test of N, P and K was conducted to determine the endogenous hormone contents and growth traitsof 6-year-old Juglans mandshuricaMaxim clones as test materials. The results showed that fertilization helped to increase the contents of fourendogenous hormones of Juglans mandshuricaMaxim, namely trans-zeatin (tZ) , gibberellin (GA3 ) , abscisicacid (ABA) and indole acetic acid (IAA), among which the content of trans-zeatin(tZ) changed the most; the three kinds of fertilizers, namely, nitrogen, phosphorus and potassium, had different influences on the endogenous hormones, and theinfluences on the contents of trans-zeatin(tZ) and gibberellin (GA3) were N>K>P , and the role ofaffecting abscisic acid (ABA) and indole acetic acid (IAA) content wasN>P>K; nitrogenfertilizer was theoptimal factorto enhance the content of the four endoge- noushormones, and the combination of fertilization treatments to enhance the content of the four endogenous hormones in the compre- hensiveanalysis was 0. 75 kg/plant of nitrogen fertilizer, 0. 3kg/plant of phosphorus fertilizer, 0. 15 kg/plant of potash fertilizer. Interms of growth, fertilization reducedthe variation in tree height within the asexual seed source, but the difference in net growth in treeheight between the different fertilizationtreatments wasnot significant, and the different fertilization treatments did not have asignifi- cant effect on the promotion of new shoot length and coarseness.
  • Construction and Protection of Forest Resources
    TANG Nana , TANG Xujun
    Forest Engineering. 2024, 40(3): 66-75. https://doi.org/10.3969/j.issn.1006-8023.2024.03.007
    Abstract (108) PDF (11)   Knowledge map   Save
    In order to improve the level of ecological environment protection of natural heritage and promote the sustainable devel- opment of Lijiang Scenic Spot in Guilin, taking the Lijiang Scenic Spot in Guilin as the research object, an ecological landscape quality evaluation indexsystem is constructed based on the analytichierarchy process, and the weights ofeach index factor are determined. The fuzzy comprehensive evaluation method is used to comprehensively evaluate the ecological landscapequality of the Lijiang Scenic Spot in Guilin. The results indicate that the comprehensive evaluation score of ecological landscape quality in Guilin Lijiang scenic areais3. 876 2, which is at a‘ good’level. Thescores of the four criterion layers (overall style B1 , cultural service value B2 ,aesthetic value B3 , ecologicaladjustment B4 )are all above the‘ general’level, and the score values are B1 = 3. 5871, B2 = 4. 2971, B3 = 3. 291 3, B4 = 3. 009 3, respectively.From large to small, it isrepresented by cultural service value, overall style, aesthetic value andecological adjustment. The ecological landscape quality of Lijiang Scenic Spot in Guilin is better in terms of culturalservice value,butweaker in terms of ecologicalregulation. The results of this study suggest that the Lijiang Scenic Spot in Guilin needs to continuous- lystrive to maintain the authenticity and integrity of its landscape form, achieve ecological protection and sustainable development,maintain the aesthetic value of its original ecology, and thereby enhance its socialeconomic value.
  • Construction and Protection of Forest Resources
    XU Jianjiao , ZHANG Hanwen, CHEN Huanwen, ZHOU Junhua , WANG Meihui, SHI Peng,YANG Qingshan, XIANGJiajian, YU Jia
    Forest Engineering. 2024, 40(3): 101-114,124. https://doi.org/10.3969/j.issn.1006-8023.2024.03.010
    To explore the selectivity of the H. ligniperda to volatiles from Pinus thunbergii in different physiological states, the dy- namic headspace adsorption was used to collect volatiles fromhealthy and harmed main trunks and roots of P. thunbergiiin different damage degrees. Thecollected volatile samples were identified and analyzed by gaschromatography-mass spectrometry (GC-MS) , and the electrophysiological and behavioral responses of H. ligniperdato the main volatiles identified in this paper (or published pa- per) fromP. thunbergii were analyzedby electroantennography (EAG)recording system and Y-type olfactory apparatus. The results showedthat there were significant differences(P<0. 05) inthe composition and content of volatiles in trunks and roots of P. thunbergii with different degrees of damage between healthyand different degree of damage. The relativecontent of the maincompound ( 1R) - ( +)-α -Pinene in the trunk decreased from healthy to wilted tree, and increasedslightly in the wilted to dead standing tree stage. Therelative content of (-)-β -Pinene increased significantly from the healthy stage to weakened tree, and gradually decreased in the weak- enedstage to dead standingtree. The relative content of (1R)-(+)-α -Pinene in the rootsgradually decreased during the transition from healthytree to dying tree stage, and its relative content increased in the dead standing tree. EAG test results showedthat among those 10 tested volatiles, there were 9 substances triggeredsignificant different EAG response values between female and male adults ofH.ligniperda. Femaleshad the highest response value to (1S)-(-)-α -Pineneat 0. 1 mg/mL, and males had the highest responsevalue to 0. 01 mg/mL Ocimene. The behavioral response results of Y-type olfactory apparatus showedthat different concentrations of volatiles had different effects on male and female H. ligniperda. 0. 01 - 100 mg/mL α -Pinene,100 mg/mL α -Terpinene, 10 mg/mL and100 mg/mL (1S)-(-)-α -Pinene, (1R)-(+)-α -Pinene had a strongattractive effect on both male and female adults H. lig- niperda, and 10 mg/mL(-)-β-Pinenehad a strong repellenteffect on both male and female adultsH. ligniperda. Thus, 0. 01-100 mg/mLα -Pinene, 100 mg/mLof α -Terpinene, 10 mg/mL and 100mg/mL of (1S)-(-)-α -Pinene, (1R)-(+)-α -Pinene could be usedas an attractant component for male and female adults H. ligniperda, and 10 mg/mL of (-)-β -Pinene could be used as an repellent component for adults H. ligniperda.
  • Forest Industry Technology and Equipment
    Lei LIU, Weiwei JIA, Xiaoyong ZHANG, Jinyou HE, Simin WU, Shixin LU, Yuepeng LIANG
    Forest Engineering. 2024, 40(4): 137-149. https://doi.org/10.7525/j.issn.1006-8023.2024.04.015
    Abstract (106) PDF (4) HTML (90)   Knowledge map   Save

    Using remote sensing methods to accurately estimate aboveground biomass carbon stock (ABGCS) in forest canopy layers and light saturation value of carbon storage, aiming to replace the cumbersome procedures of traditional large-area surveys, providing references and basis for carbon storage estimation, and improving the efficiency of sustainable forest management. In this study, the ABGCS in Jiayin County, Yichun City, Heilongjiang Province in 2017 was selected as the research object. Landsat 8 OLI remote sensing images and forest resource two-class survey data were used to construct parameter models of stepwise multiple regression model (SMR), non-parameter models of BP neural network model (BP-NN), random forest model (RF), support vector regression model (SVR) to estimate and reverse the spatial distribution of ABGCS in Jiayin County. The research results showed that the estimation accuracy of non-parameter models was significantly higher than that of parameter models. Among them, the fitting accuracy of the three non-parameter models (BP-NN, RF, SVR) was increased by 25.0%, 12.2%, and 7.3%, respectively, compared with the parameter model (SMR). By comprehensive comparison of the evaluation indexes of the four models in ten-fold cross-validation, the performance of the models was analyzed: BP-NN>RF>SVR>SMR, among which the BP-NN model fitted the largest R 2 (0.785) and the smallest RMSE (3.572 t/hm2), MSE (12.757 t/hm2), MAE (2.687 t/hm2). From the perspective of carbon storage residual segmentation test results, all four models exhibited varying degrees of overestimation and underestimation of carbon storage. The BP-NN model had the smallest ME and MRE values in each carbon storage segment, indicating strong generalization ability. The light saturation value of ABGCS was determined to be 63.056 t/hm2 using a cubic model, which was close to the predicted ABGCS light saturation value by BP-NN (64.232 t/hm2). Therefore, the BP-NN model has a relatively ideal effect in estimating ABGCS in Jiayin County, providing important basis for dynamic monitoring and research of forest carbon storage.

  • Road and Traffic
    Ankang LI, Mingbao LI, Junjie ZHENG
    Forest Engineering. 2024, 40(4): 204-217. https://doi.org/10.7525/j.issn.1006-8023.2024.04.022
    Abstract (106) PDF (4) HTML (89)   Knowledge map   Save

    In order to improve driving safety and comfort of drivers on curved roads in forest areas, a driving simulation test was adopted to evaluate the driving comfort on curved roads in forest areas from a dynamic perspective using eye movement and heart rate as evaluation indexes. Based on the theory of spatial sight distance, five different spatial visual distance scenarios of curved roads in forest areas were established, and the results showed that the rate of change of pupil diameter and the growth rate of heart rate of the driver decreased with the increase of spatial sight distance, and the driving comfort increased continuously. The minimum spatial sight distance values considering the pupil diameter change rate and heart rate growth rate were 101 m and 89 m, and the appropriate spatial sight distance values considering the pupil diameter change rate and heart rate growth rate were 128 m and 132 m.

  • Construction and Protection of Forest Resources
    LYU Yuanhang , WANG Zicheng , DONG Lingbo
    Forest Engineering. 2024, 40(3): 20-32. https://doi.org/10.3969/j.issn.1006-8023.2024.03.003
    To solve the problemof quantitatively evaluatingthe dynamic changes of soil erosion in different forest types in Maoer Mountain Experimental Forest Farm, based on thesecondary survey data of MaoerMountain in 1983, 1993, 2004, and 2016 and Landsat remote sensingimage data, this paper used the RUSLE model to dynamically evaluate the soil erosion modulus of Maoer Moun-tainExperimental Forest Farm, and quantified and analyzed therelationship between different foresttypes and soil erosion. Results showed that: the averageannual soil erosion of MaoerMountain Experimental Forest Farm infour periods was 0. 26, 0.24, 0. 10, 0. 17 t/(hm2 ·a) , respectively. The areas with soil erosion intensity between 0 - 1 t/( hm2 · a ) in each period accounted for98.79% , 98. 68% , 99. 88% , 98. 88%of the totalarea, respectively. In1983—2016, 70. 4% of the areas where soil erosionintensity did not change, 25. 1% of theareas where high-levelerosion intensity shifted to low-levelerosion intensity, whileonly 4. 5% of the areas where low-levelerosion intensity shifted to high-level erosion intensity, indicating that the overall soilerosion status of Maoer MountainExperimental Forest Farm was improving. In 1983,the average soil erosion modulus of six forest types, namely, soft broad-leaved natural forest, hard broadleaved natural forest, Larix olgensisartificial forest, Pinus sylvestris var. mongholica artificialforest, Quercus mongolica natural forest, and mixed needle broadnatural forest,was 0. 150, 0. 161, 0. 054 t/(hm2 ·a) , 0. 110, 0. 121,0. 083 t/(hm2 ·a) , respectively. By 2016, the average soil erosion modulus had decreased by 53. 7% , 61. 2% , 30. 3% , 83. 0% , 46. 8% , 23. 2% , respectively. Except for theslight increase in soil erosion insoft broadleaved natural forest, Larix olgensis artificial forest, and mixed needle broad natural forestduring 2004—2006 (0. 003-0. 016 t/(hm2 ·a) ) , the average soil erosion in other foresttypes showed a downward trend year by year.
  • Wood Science and Engineering
    Chuang SONG, Liping SUN, Pengkun WANG, Yang YANG
    Forest Engineering. 2024, 40(4): 168-174. https://doi.org/10.7525/j.issn.1006-8023.2024.04.018
    Abstract (105) PDF (6) HTML (85)   Knowledge map   Save

    In view of the uncertain mechanical properties of knot-bearing wood and the difficulty of judging whether it is usable, this article proposes a method to evaluate the usability of wood containing knots by detecting the bending properties of wood containing knots. The common tree Quercus mongolica, which accounts for 15%-20% of the total forest area in Northeast China, is selected as the experimental object. Firstly, the object detection algorithm is used to identify the areas containing knots on the suface of wood, followed by spectral extraction of the identified area and the construction of a quantitative prediction model. Finally, the mechanical properties of wood containing knots are analyzed through deep learning. The experimental results indicate that the SPA-SVM prediction model proposed in this article has excellent predictive ability for the bending properties of wood, with experimental results indicators of R 2=0.96, RMSE=0.58, and RPD=5.09. The prediction model proposed in this article can accurately predict the bending properties of wood containing knots. The predicted results have a small error with the actual values, which meets the experimental requirements and standards. The predicted results can provide a basis for whether the wood can be used.

  • Forest Industry Technology and Equipment
    Yafeng ZHAO, Xiaolu LIU, Dongdong WANG, Mengxue WANG, Wenhua SONG, Junfeng HU
    Forest Engineering. 2024, 40(4): 127-136. https://doi.org/10.7525/j.issn.1006-8023.2024.04.014
    Abstract (105) PDF (5) HTML (90)   Knowledge map   Save

    To address the challenge of accurately extracting phenotypic parameters from in situ root images collected from minirhizotrons amidst background noise interference, this paper proposes a minirhizotron root phenotypic parameter measurement system based on an improved U-Net model. In the U-Net network, optimized ASPP (Atrous Spatial Pyramid Pooling) and ECA (Efficient Channel Attention) modules are employed to increase the receptive field and enhance the ability to capture detailed features, thereby obtaining precise segmentation images. The experimental results show that the mean intersection over union and mean pixel accuracy of the improved U-Net model are 87.07% and 91.85%, which are 2.49% and 2.3% higher compared to the original U-Net, respectively. Comparing with measurements obtained using WinRHIZO root analysis software, the determination coefficients for the root length and area are 0.951 8 and 0.984 9. respectively. The Spearman correlation coefficients are 0.972 5 for the root length and 0.975 7 for root area. This indicates the system′s capability to accurately measure the root length and area.

  • Road and Traffic
    WANG Wenfeng , TAN Jianping , CAO Minghui
    Forest Engineering. 2024, 40(3): 197-203. https://doi.org/10.3969/j.issn.1006-8023.2024.03.020
    In order to study the effect of concrete shrinkage and creep on the interfacial shear and relativeslip of steel-concrete composite beams under long-term loading, a simple and practical finiteelement method is proposed. On the premise that the load-slipislinear and there is no lift between the steelbeam and the concrete layer, a finite element model for the long-term performance analy-sisof a partially shear coupled steel-concrete composite beam is established based on the initial strain method of concreteshrinkage andcreep analysis. The interface behavior is simulated by establishing the master-slave relationship and special elements of the correspond-ingjoints between the concrete slab and the steel beam. By comparing the calculation results of simply supportedbeams under concen-trated loads with the existing literatures, the effectiveness of the proposed method is verified. Based on this, the influence of shrinkageand creep on the interfacial shear and relative slip of steel-concrete composite beams is studied. The results show that the interaction of shrinkageand creep makes the interfaceslip of the simply supported steel-composite beam increase with time to a large extent, but thesingle shrinkage effect makes the interface slip decrease,although the change is negligible. At the same time, due to the positive corre-lation between interfacialshear and slip, the shrinkageand creep effect also makes the interfacial shear at the end increase with time,showing a rapid growth in the early stage and a slow growth in the late stage.
  • Road and Traffic
    JIN Xiuwei, LU Qingrui , LI Dongwei, CHEN Shijun, ZHANG Haijun, HONG Jinfeng
    Forest Engineering. 2024, 40(3): 184-196. https://doi.org/10.3969/j.issn.1006-8023.2024.03.019
    In order to study the influencing factors of the development of freeze-thaw temperature field in cement improved soil lay- er, this paper takes the freezing projectof a subway tunnel in Guangzhou Metro Line 3 as the background, simulates the freeze-thawtemperature field of the tunnel through the coupling of water and heat, studies the influence law of the whole process development of thefreeze-thaw temperature field,and proves the accuracy of the model by comparing with themeasured data. Theinfluence of thermal conductivity , volumeheat capacity, originalground temperature, cement content and other factors on the freeze-thaw temperature fieldisanalyzed. The results showthat during the whole process of freeze-thaw temperature field development, the soil is greatly cooled first , and afterforming a stable freezingcurtain, the coolingrate slows down, and the thickness of the effective freezing wall increases slowly. After entering the natural thawingstage, the temperature rises rapidlyuntil it reaches the phase transition stage. After along period of time in thisstage, the soil quicklyreturns to positive temperature. The influence of different factors on the freezing tempera-turefield is analyzed. The volume heat capacity of the soil and the original ground temperature are negatively correlated with the freez-ingeffect of the freezing temperature field, and have little effect on the naturalthawing temperature field. The decrease of thermal con-ductivity of soil will inhibit the development of freezing temperature field, but itcan shorten the period of natural thawing. When the cementcontent is 12 % , the soil freezingeffect is the best, and the development rate of the thaw settlement temperature field is the fas-test, and the natural thawing periodis the shortest.
  • Road and Traffic
    Yue JIA, Xingchen ZHAO, Yaofei LUO
    Forest Engineering. 2024, 40(4): 196-203. https://doi.org/10.7525/j.issn.1006-8023.2024.04.021
    Abstract (102) PDF (5) HTML (88)   Knowledge map   Save

    To explore the feasibility of coal gangue powder applied in micro-surfacing, the coal gangue powder and activated coal gangue powder were selected to replace the filler of micro-surfacing mixture, and the different combination specimen was formed. The Hamburg wheel tracking test, accelerated wear test and shear fatigue test were used to analyze the road performance and interlayer property of micro-surfacing mixture with different fillers, and the significant influence of different factors on long-term performance of micro-surfacing was analyzed. The results showed that the high temperature performance, moisture susceptibility, abrasion resistance, long-term skid resistance of micro-surfacing were improved when the coal gangue powder was selected to replace the mineral powder, and the improvement effect of high temperature activated coal gangue powder was better, and the substitution amount of coal gangau powder had a higher impact on the different properties of micro-surfacing than the coal gangue powder. But the road performance and interlayer property of micro-surfacing were damaged due to the cement was replaced by the coal gangue powder. The long-term performance of micro-surfacing was closely related to the dosage of coal gangue powder, the dosage of coal gangue powder was greater, the long-term performance of micro-surfacing was better. The mineral powder was replaced completely by the coal gangue powder, the high temperature performance, moisture susceptibility, abrasion resistance, long-term skid resistance and shear fatigue life of micro-surfacing were improved by about 26.8% and 36.4%, 33.5% and 40.0%, 33.4% and 45.1%, 4.7% and 6.8%, 9.5% and 10.4%, respectively. The research results will provide reference basis for coal gangue applied in asphalt pavement maintenance technology.

  • Forest Industry Technology and Equipment
    HAN Dongtao , MA Yuewei , LIU Jinhao , CUI Xiaoqing
    Forest Engineering. 2024, 40(3): 170-177. https://doi.org/10.3969/j.issn.1006-8023.2024.03.017
    Trailers need to operate under various conditions, including full load bending, full loadtwisting, emergency braking, andsharp turns. In order to solvethe problem of poor reliability and safety of the on-board systemof the trailer under full load condi- tion, a three-dimensional assembly model of a small logging trailer was established, and staticanalysis was performed. Through finite element analysis, we studied the structural deformations and stress distributions of the trailer under four typical working conditions. Un- der fullload bending conditions, the maximumdisplacement was 4. 517 7 mm, the maximumstress was 115.19 MPa, and thesafety factor was3. 08. Under full load twisting conditions,the maximum displacement was 0. 984 48 mm, the maximum stress was 71. 929MPa, and the safety factor was 4. 935. Under full load braking conditions, the maximum displacement was 4. 994 6 mm, themaximum stress was 120. 05MPa, and the safetyfactor was 2. 957. Under emergencyturning conditions, the maximum displacementwas4. 365 8 mm, the maximum stress was104. 64 MPa, and the safetyfactor was 3. 39. Resultsshowed that the smallskidding trailer designedin this study had strong stability under full load workingconditions in the forest, which ensured the reliable collection and transportationof wood. Future researchcan further optimize trailerdesign and performance to meet evolving needs and environmental requirements.
  • Construction and Protection of Forest Resources
    ZHU Shunwan , Liu Lixia , HU Xuefan , DAI Wei , WANG Yuerong , LI Fang
    Forest Engineering. 2024, 40(3): 47-55. https://doi.org/10.3969/j.issn.1006-8023.2024.03.005
    In order to explore the management measures to improve the biodiversity of mixed forest of Larix principis-rupprechtii, through investigations and monitoring of understoryplant communities in mixed forests ofLarix principis-rupprechtii subjected to four differentthinning intensities - control group( Ⅰ) , light ( Ⅱ), moderate ( Ⅲ)and heavy ( Ⅳ) - within the Beijing Forest Farm, thisstudy analyzed variations in understory vegetation. Results revealed thatunder the four thinning intensities, the number of understory shrub species were 5, 7, 7, 6 respectively, while herbaceousspecies were 11, 11, 10, 12, respectively. Sharedspecies encompass species included Rubus crataegifolius, Corylusheterophylla, Spiraea salicifolia, Deutzia scabra, Deyeuxia pyramidalis, Carex tristachyaThunb. , and Crepidiastrum lanceolatum. As theforest canopy closure decreased, the number ofshrubs and herbaceousplants in- creased. In the moderate thinning intensity plots ( Ⅲ) , thenumber of shrubs was the highest,while in the heavy thinning intensity plots( Ⅳ) , the number of herbaceous plants was the highest. Increased thinning intensity prompted a rise in light-loving shrubs suchasZabelia biflora, Sambucus williamsii,and Forsythia suspensa, underscoring the sunlight's impact on vegetation. Significant varia- tions were observedin the ranking of importance values of shrubs and herbs across differentthinning intensities. Notably, species like Spiraea salicifolia and Rubus crataegifolius consistently ranked among the top three in all intensities. However, Corylus heterophylla on- lyappeared in the top three at controlgroup ( Ⅰ) , while Forsythia suspensa was exclusive to heavy thinning( Ⅳ). In theherbaceous layer, Deyeuxiapyramidalis ranked among the top three in light and moderate intensities, with a particularly high value of 37. 16 in theheavy intensity ( Ⅳ). Analysisof species diversity, communitysimilarity, and understory diversity suggested that different thinning in-tensities influence species composition anddiversity, increased thinningintensity positively impacted diversity, especially in the herba- ceous layer. The resultsof this study provide an important reference for optimizing the management strategy of mixed larch forest of Larixprincipis-rupprechtii to improve the conservation effectof biodiversity.
  • Wood Science and Engineering
    LIANG Yuwei, HE Lan, ZHANG Liang , ZHANG Haiyang , JIANG Guizhang , LIU Ruizhe , LIU Zhenbo
    Forest Engineering. 2024, 40(3): 115-124. https://doi.org/10.3969/j.issn.1006-8023.2024.03.011
    In order to explore the impact of oil heat treatment on theacoustic vibration performance and dimensional stability of bamboomaterials, and to reduce the adverseeffects of cracking, deformation, and damageto sound quality of bamboo musical instru-mentsduring use, the experimentused soybean oil as the heatingmedium to heat treat bamboo, with heat treatment temperatures of140 ℃ , 170 ℃ ,and 200 ℃ and heating times of 2 and 4 hours. The vibrationspectrum of thespecimens before and after treatment was obtained using the dual channelFFT analyzer, and took the first to fifth bendingvibration frequencies. Its acousticvibration per- formance parameters were analyzed to study the effect of oil heat treatment on the acoustic vibration performance and dimensional stabil-ity of bamboo. After treatment, the specific dynamic modulus of elasticity (Esp )and sound radiationquality constant (R ) of bamboo hadsignificantly increased,and the density (ρ ) ,acoustic impedance ( ω ) , dynamic loss angle tangent (tanδ ) , E/G showed adownward trend, and the acoustic vibration efficiency had been improved. After being treated at 200 ℃ for 4 hours, the materials withbamboo nodes showed thegreatest improvement in acoustic vibration performance, with an increase in Esp of 29. 20% , a decreasein ρ of 15. 12% , anincrease in R of 33. 75% , a decreasein ω of 3. 41% , a decrease in tanδ of 40. 52% , and a decrease in E/G value of 2. 33%. Theminimum volume dry shrinkage and maximum anti hygroscopic expansion were 0. 33%and 56. 95% , respectively. The volume dry shrinkage and volume hygroscopic expansion decreased with increasing treatment time and temperature. Results showed thatwhen the oil heat treatment time was 200 ℃ and thetime was 4 hours, theacoustic vibrationperformance of the specimens was betterimproved. Oil heat treatment had positive effects on improving the acoustic vibrationperformance and dimensional stability of bamboo.
  • Wood Science and Engineering
    XIE Yuqiang, SHE Yanhua HUANG Junjie, LI Meng, HE Jiaming
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