Objective: Facing the requirements of implementing the major national strategy of Yellow River Basin ecological protection and high-quality development, and of promoting the integrated management of “mountains, rivers, forests, farmlands, lakes and grasslands” systems in China, the traditional approaches of forestry development and vegetation restoration in dryland regions, such as the Loess Plateau, must be changed by adding the considerations of water resources limitation and the impacts on water resources, and by paying attentions to the optimization of multiple forest functions/services. It is required to explore how to overcome the long-standing problems of neglecting water carrying capacity, low afforestation survival rate and poor tree growth, river runoff reduction and endangering to regional water supply safety, and the overall low functions of forests, so that to achieve the overall improvement of the multifunctionality of forests through their scientific management. Method: To meet the scientific and technical requirements of deep understanding of forest-water interrelations and of multifunctional forest management (MFFM), long-term studies since 2000 on the dryland forest ecohydrology and MFFM techniques were carried out in the Jinghe River basin and the regional important source-water area of the rocky Liupan Mountains on the Loess Plateau of northwest China. These studies were designed around the key issues of “structure”, “pattern”, “process”, “coupling”, and “scale”, using the multiple methods of observation comparison and statistical analysis as well as model simulation, at multiple scales from single tree to region. Result: The studies showed that: 1) The essence of high-quality forestry development is MFFM with quantitative and precise decision-making. Therefore, it is required to deeply understand and precisely quantify the impacts of site conditions and stand structure on the multiple functions of forests, to clarify the importance order of forest functions based on their complex interactions and supply-demand relations, and to optimize the competing functions to meet the societal demands of both dominant and other functions simultaneously under the precondition of ensured forest stability, by the rational designing and regulation of forest quantity, quality (structure) and spatial distribution pattern within basins. 2) The forest-water coordinated and multifunctional management approach was proposed, this means that besides considering the restrictions of available land area and seedlings and site quality for afforestation, new considerations should be added to the water resources management and MFFM through embedding them into the traditional single-function oriented decision processes of forest management. These decision processes involve four decision levels, they are the rational forest cover of basins (how much to afforest?), forest spatial distribution (where to afforest?), vegetation type and tree species composition (with which tree species?) and stand structure (how to manage forests?). 3) The related technical achievements were summarized according to the decision levels. For determining the reasonable forest cover of loess basins, the potential forest cover merely based on the annual precipitation limit can be updated to the reasonable forest cover by considering both the precipitation limit and water yield requirement through using the established empirical relations and the simulation results of watershed hydrological models. 4) For making the decisions of reasonable spatial distribution of forests within basins, the water yield differences among site types and their responses to afforestation should be utilized with the help of simulation results of distributed hydrological models or the regional vegetation carrying capacity calculation system developed in this study. For the MFFM decision at stand scale, a five-step decision-making procedure was suggested, namely, site quality classification, determining main functions and their priorities for each site type, investigating the structure characteristics of existing forest stands, diagnosing the structure and functions of existing forest stands, and compiling a structure/function-oriented management plan. For setting up the reference and goal of MFFM, ideal stand structures of multifunctional water-retention forests with different degrees of detail were proposed: the generalized ideal stand structure expressed as “3×0.7+X” (canopy density around 0.7, 0.6–0.8; ground coverage above 0.7; ratio of tree height to DBH below 0.7 m/cm, at least not higher than 0.9; X presents other requirements), the multifunctional density of middle-aged larch (Larix principis-rupprechtii) plantations determined by weighing the density needs of individual functions and stand stability, the varying multifunctional densities of larch plantations along elevations and ages determined based on the variation rules of main forest functions and their priorities. Conclusion: The theoretical advancement and technical feasibility of forest-water coordinated multifunctional management has been proved, as a viable way to realize the high-quality forestry development in dryland regions. Through a thorough understanding and quantitative analysis of the multiple functions with varying environment and forest structure, combined with the application of MFFM techniques proposed in this paper, the rational forest quantity (forest cover), quality (structure), and distribution pattern can be scientifically designed and adjusted, to realize the overall promotion of multiple functions to better meet the diverse societal demands. However, the achievements are still limited, thus more theoretical and technical research of forest-water coordinated and multifunctional management of forests should be carried out according to local situations to help the life community governance of “mountains, rivers, forests, farmlands, lakes and grasslands” systems and the ecological protection and high-quality development of the Yellow River Basin.

Objective: The response of average height of dominant trees and site index (the average height of dominant trees with a baseline forest age of 15 years) of black locust (Robinia pseudoacacia) plantations to climatic and site factors was studied on the Loess Plateau, for establishing a model to evaluate site quality. Method: Based on the survey of sample plots and collected literature data, the single factor response law and appropriate form of response function of the average height of dominant trees were determined using the envelope method, and then a model was established by coupling multiple factors and calibrated with the measured data to evaluate the spatial difference in site index. Result: The impact of topography positions on the average height of dominant trees varied greatly, with a relative score of: gully bottom 1.000 > tableland 0.906 > lower part of ridge slope 0.837 > middle part of ridge slope 0.438 > gully slope 0.210 > upper part of ridge slope 0.176 > hilly top 0.000. Within the variation range of mean annual precipitation (MAP) below 550 mm, the average height of dominant trees increased with rising MAP rapidly, and thereafter gradually tended to level-off; the average height of dominant trees increased first and then decreased with rising mean annual air temperature (MAT) , with an optimal range of 7.5–11.0 ℃. The model of average height of dominant trees was established by coupling the effects of climatic and site factors, with a satisfactory fitness ( R² = 0.72). According to the effects on the average height of dominant trees, both MAT and MAP on the Loess Plateau were divided into four levels (<6.0 ℃, too cold to grow; 6.0–7.5 ℃, cold and not suitable or relatively suitable for growth; 7.5–11.0 ℃, mild and the most suitable for growth; >11.0 ℃, warm and relatively suitable or not suitable for growth. <400 mm, too dry to grow; 400–450 mm, dry and not suitable for growth; 450–550 mm, moist and more suitable for growth; >550 mm, wet and the most suitable for growth). Then, the areas where black locust afforestation cannot be carried out on the Loess Plateau were determined, and the climate zoning of the rest areas where black locust afforestation can be carried out was proposed. The mild-wet, mild-moist, warm-wet and mild-dry subzones are suitable for black locust growth with an average site index of medium or higher classes (>7.5 m); while the cold-dry/moist and warm-moist subzones are not suitable for black locust growth as a whole. The site index of all site types in each subzone was calculated using fitted model for evaluating the site quality. Conclusion: The site index of black locust plantations on the Loess Plateau is affected by both climatic and site factors. The climatic zoning and site assessment with site index considering these effects can guide the refined site selection for afforestation and rational management of black locust plantations on the Loess Plateau.

Objective: In this study, the spatiotemporal variation of vegetation carbon densities (VCD) of the tree layer, understory shrub layer and herb layer of larch (Larix principis-rupprechtii) plantations in the Liupan Mountains area of southern Ningxia of northwest China were investigated and analyzed, and the VCD models considering the effects of multiple factors of site quality and stand structure were established, so as to provide theoretical basis and decision-making tools for estimating VCD and their sustainable management of the larch plantations under complex topographic conditions in the mountainous regions of northwest China. Method: The VCD of tree, shrub and herb layers of larch plantations in the study area was determined by the combined application of sample plot inventory and mathematical models. The upper boundary line method was used to determine the response pattern and corresponding function form of VCD to each main influencing factor (forest age, density, mean annual precipitation, mean annual air temperature, slope aspect). A VCD model that can reflect the comprehensive impact of multiple factors was constructed through multiplicative coupling, and then the measured data were used to calibrate and validate the model. Result: 1) The average VCD of the existing larch plantations in the Liupan Mountains area was 46.82 t C·hm^-2, of which the tree layer accounted for 94.92%, while the shrub layer and herb layer only accounted for 4.76% and 0.32%, respectively. 2) The VCD of tree layer firstly increased rapidly with the increase of forest age, stand density, and mean annual precipitation, and then increased slowly and gradually tended to its maximum value after exceeding the certain threshold values of those factors. The corresponding threshold values for those influencing factors were 30 years of forest age, 1500 tree·hm^-2 of tree density, and 525 mm of mean annual precipitation. The VCD of tree layer firstly increased and then decreased with rising mean annual temperature and reached its peak at 6°C. It decreased nearly linearly with rising slope aspect (0° to due north, increasing with the deviation angle from north direction to both sides). 3) The VCD of the understory shrub-herb layers decreased linearly with rising tree layer VCD, and varied with mean annual temperature and precipitation as well as slope aspect in the same patterns of tree layer VCD and the same threshold values of 6 °C and 525 mm. 4) The established multi-factor coupled model of VCD was able to better estimate the variation of VCD of tree layer and understory shrub-herb layer, with R² of 0.8** and 0.7**, respectively. (5) According to simulation results of the model, the VCD of larch plantations firstly increased and then decreased with rising elevation, showing a relatively bigger difference among elevation gradients, the elevation range with the highest VCD was 2200—2400 m. Due to the effects of topography and climatic factors, there existed a certain horizontal difference, namely decreasing from west to east and from south to north. The VCD on shady slopes was higher than that on sunny slopes, with a difference of about 20% for tree layer and up to 100% for shrub-herb layers. Conclusion: The average VCD of the larch plantations in Liupan Mountains area is 46.82 t C·hm^-2 and mainly composed of tree layer. The VCD is jointly affected by the multiple factors of site quality (precipitation, temperature, slope aspect) and stand structure (age, density). The VCD of understory shrub-herb layers is also influenced by the tree layer biomass. The spatiotemporal variation of VCD of larch plantations can be better explained and predicted by the multi-factor coupled model. The reasonable selection of site types for afforestation and tree density for forest management is beneficial to maintain a better VCD with expected vegetation layer composition for the larch plantations.

Objective: This study was aimed to deeply understand and quantitatively evaluate the hydrological effects of plantations ofPinus tabuliformis, an important afforestation tree species in Xining City, Qinghai Province of China, for providing scientific basis for the coordinated forest-water management. Method: Representative sample plots of middle-aged and closed stands of P. tabuliformis plantations were selected in the Huangshui Forest Farm, Xining City. During the growing season of 2021 (June-October), the variations of precipitation in open field, canopy intercession, stemflow, throughfall, tree transpiration, forest floor evapotranspiration, and soil moisture were monitored simultaneously, and the water yield from sample plots was calculated based on water balance. Result: The study showed: 1) The precipitation in the growing season amounted to 396.5 mm, while the canopy interception, tree transpiration, forest floor evapotranspiration amounted to 117.6, 109.4, 187.5 mm, respectively, accounting for 29.66%, 27.59%, 47.29% of precipitation during the same period, and showing an obvious monthly variation of firstly increase and then decrease. 2) The water storage of 0-100 cm soil layer was increased by 130.2 mm, showing an extra water input of 189.3 mm from outside (deep soil layers and upslope). The volumetric soil moisture of 0-100 cm soil layer varied as a consumption period from June to August, showing an overall decrease trend with values of volumetric soil moisture of always below 10%, indicating the existence of soil drought stress; while as a recovery period from September to October, showing a fluctuating upward trend with values of volumetric soil moisture of always above 9.3%. 3) The total evapotranspiration in the growing season amounted to 414.5 mm, which was 18.0 mm higher than the precipitation. After considering the influences of extra water input and soil water storage changes, the net water yield from the stand plot was calculated as ?18.0 mm, indicating that the plantation did not contribute to, but used/decreased the water yield from hillslope or watershed. Conclusion: In conclusion, even if the precipitation in the growing season of 2021 was higher than the mean annual precipitation of Xining City, the evapotranspiration of the closed stand of P. tabuliformis plantation cannot be satisfied by the natural precipitation under the semi-arid climate of Xining City. Therefore, it is necessary to maintain the stand stability against drought stress by lowering the tree density (canopy density) to reduce stand evapotranspiration or by appropriate irrigation to make up the water deficit, so as to ensure the desired dominant functions of urban landscape plantations.

Objective: In this study, the seasonal variation in particle morphology, membrane fatty acid composition and molecular weight of gutta-percha was investigated, and the correlation between particle morphology, and fatty acid composition and molecular weight of gutta-percha was also analyzed, which would lay a theoretical foundation for further elucidating the biological function of Eucommia ulmoides gum particles and revealing the mechanism of E. ulmoides gum synthesis. Method: The rubber particles from leaves growing on the new branches of 10-year-old E. ulmoides were collected from June to November, and the morphological differences of rubber particles at different growth stages were observed by using light microscope and electron microscope, and the composition and content of fatty acid in rubber particles were also analyzed by gas chromatography-mass spectrometry (GC-MS). Meanwhile, the characteristic parameters of rubber particles were determined by size-exclusive chromatography (SEC). The relationships between the morphology, fatty acid composition of rubber particles, as well as molecular weight and molecular weight distribution of rubber particles were investigated. Result: 1) The results showed that the rubber particles size in E. ulmoides leaves increased gradually with the passage of months (from June to November), and the average diameter was 3.99 μm in June and increased to 6.7 μm in November. The proportion of small rubber particles (d<5 μm) decreased from 65.91% in June to 19.09% in November, while the proportion of large rubber particles (d≥5 μm) increased from 34.09% in June to 80.91% in November. 2) Fatty acid determination showed that 26, 30 and 26 kinds of fatty acids were detected in rubber particles of E. ulmoides leaves in August, October and November, respectively, with 15 saturated fatty acids being the same. The palmitic acid (C16:0) had the highest content, followed by tetracyclonic acid (C24:0). Meanwhile, seven unsaturated fatty acids were found to be unique to the rubber particles of E. ulmoides leaves collected in October, and three unsaturated fatty acids including myristicoleic acid (C14:1), trans-linoleic acid (C18:2n6t) and α-linolenic acid (C18:3n3), were found to be unique to the rubber particles of E. ulmoides leaves collected in August and October. 3) Determination of characteristic parameters of gutta-percha indicated that the molecular weight distribution peaks of gutta-percha in leaves collected in June, July, August, September, October and November were 3, 6, 6, 3, 5 and 3, respectively. Additionally, the molecular weight distribution value (D) of E. ulmoides rubber from June to November varied from 2.18 to 6.00, indicating that the molecular weight difference of E. ulmoides rubber in leaves in June was small and concentrated, while the molecular weight difference of E. ulmoides rubber in leaves in November was large and scattered. Conclusion: With the passage of months, the size of E. ulmoides rubber particles gradually increases, and rubber particles in different months contain a few of special fatty acids which are dependent on the growth period. The molecular weight of gutta-percha increases with the passage of months and tends to be stable. In the early stage (from June to August), most of the molecules with little molecular weight difference have been found, while in the late stage (from September to November), most of the molecules with large molecular weight difference have been found.

Objective: Leaves are rich in sources, easy to sample, and have little impact on the plant after collection, such they are ideal materials for plant asexual reproduction. However, the regeneration efficiency ofRobinia pseudoacacia leaves is not high enough to meet the requirements of genetic transformation. In this study, an efficient regeneration system of R. pseudoacacia leaves in vitro was established by optimizing the important factors in the regeneration process, which would lay a good foundation for R. pseudoacacia seedling reproduction, mutagenesis breeding, genetic transformation and further development of molecular breeding of R. pseudoacacia. Method: The isolated leaves of R. pseudoacacia tissue culture seedlings were used as explants, the whole process of regeneration of adventitious buds from the isolated leaves was observed to investigate the effects of genotype, sampling period, dark treatment duration as well as plant growth regulators on the regeneration of adventitious buds fromR. pseudoacacia leaves. Meanwhile, the IBA concentration suitable for rooting of adventitious buds was screened. Result: 1) Diploid genotype Pu-18-22 had the best regeneration ability; 2) Subculture of tissue culture seedlings for 45 days was the best time for selecting explants; 3) Darkness treatment for 14 days was the best darkness treatment time; 4) The optimal medium for adventitious bud regeneration was MS (culture medium) + N-(Phenylmethyl)-9H-purin-6-amine 3.0 mg·L^?1 + Kinetin 1.0 mg·L^?1 + 2,4-Dichlorophenoxyacetic acid 0.1 mg·L^?1 + Sucrose 30 g·L^?1 + Agar 6.5 g·L^?1; The adventitious bud induction rate of Pu-18-22 was 96.67%, and 7.4 adventitious buds were regenerated per leaf on average; 5) The best rooting medium for adventitious buds was 1/2MS + Sucrose 30 g·L^?1 + Agar 6.5 g·L^?1 ＋ 3-Indolebutyric acid 0.3 mg·L^?1, and the rooting rate was 100%. Conclusion: The leaves of diploid R. pseudoacacia Pu-18-22 tissue culture plantlets are used as explants that are inoculated into MS culture medium + N-(Phenylmethyl)-9H-purin-6-amine 3.0 mg·L^?1 + Kinetin 1.0 mg·L^?1 + 2,4-Dichlorophenoxyacetic acid 0.1 mg·L^?1 + Sucrose 30 g·L^?1 + Agar 6.5 g·L^?1. After 14 days of dark treatment, the leaves are transferred to normal light culture. After 45 days of the light culture, the regenerated adventitious buds are then transferred to the rooting medium of 1/2MS culture medium + Sucrose 30 g·L^?1 + Agar 6.5 g·L^?1 + 3-Indolebutyric acid 0.3 mg·L^?1, After the adventitious shoots take root, the seedlings are hardened and transplanted to obtain the complete regenerated plants.

Objective: In this study, the effect of strip cutting with different widths on the structural characteristics of underground rhizomes of Phyllostachys edulis was investigated, in order to explore the adaptation mechanism of underground rhizome system of P. edulis to strip cutting with different widths, and provide a theoretical basis for the scientific management of P. edulis forests. Method: A pure bamboo forest with the same site conditions, bamboo age structure, and slope aspect was targeted, and strip cuttings were conducted with three different strip widths, 6 m, 8 m, and 10 m, and a strip length of 30 m. The same standard reserved bands between the cutting strips were set. In October 2019, the bamboo rhizome characteristics in the different width cutting bands and reserved bands were investigated. The total rhizome length, rhizome node number, average rhizome diameter, average internode length, rhizome dry weight and other indicators in different soil layers and different rhizome age were measured, and the indicators were used for analysis of their response differences to different logging bandwidths. Result: 1 ) The total length and dry weight of bamboo rhizome in 8 m cutting band were significantly greater than those in 6 m cutting band ( P < 0.05 ), but had no significant difference with those in 10 m cutting band. The average rhizome diameter of 8 m cutting band was significantly smaller than that of 10 m cutting band ( P < 0.05), but not significantly different from that of 6 m cutting band. The number of rhizome nodes in 8 m cutting band was significantly greater than that in 6 m and 10 m cutting bands ( P < 0.05). There was no significant difference in the average internode length of bamboo rhizome among the three width cutting bands, but the length showed a decreasing trend with the increase of bandwidth. Compared with the reserved strip, the total rhizome length, rhizome node number and rhizome dry weight of three kinds of cutting strips showed an increasing trend. 2) Compared with the retention zone, the structural characteristics of the each rhizome age stage showed different amplitudes of variation among different width cutting zones. In the young rhizome section, the total rhizome length, average internode length and rhizome dry weight in the 8 m bandwidth harvesting band increased by 49.20%, 45.48% and 58.38%, respectively. In the middle-aged rhizome section, the total rhizome length, rhizome number and rhizome dry weight in 6 m and 8 m cutting bands increased significantly ( P < 0.05). In the old rhizome section, the total rhizome length, rhizome node number and rhizome dry weight of bamboo rhizomes in the 6 m and 8 m cutting bands decreased, while those in the 10 m cutting band was the opposite. 3) In 0–20 and 20–40 cm soil layers, the number and dry weight of rhizomes in 8 m and 10 m cutting bands were significantly greater than those in reserved bands ( P < 0.05). In 0–20 cm soil layer, the total rhizome length, number and dry weight of rhizomes in 8 m cutting band were 80.83%, 87.50% and 45.27% greater than those in reserved band, and the average rhizome diameter and average internode length in 10 m cutting band were 7.25% and 5.34% smaller than those in reserved band. In 20–40 cm soil layer, the five indexes of bamboo rhizome in 8 m cutting band were greater than those in retaining band, especially the increments of total rhizome length, rhizome node number and rhizome dry weight were significant. 4) The total number of rhizome buds in the cutting zone was generally more than that in the retention zone. The total number of rhizome buds in the 8 m cutting zone was significantly greater than that in the 6 m and 10 m cutting zones ( P < 0.05). There was no significant difference in the total number of rhizome buds in the retention zones between the three different bandwidths. The proportion of weak buds of bamboo rhizomes harvested in different widths was higher than that of strong buds. The proportion of strong buds in 8 m cutting band was the highest (33.75%), and the proportion of empty buds in 6 m cutting band was the highest (18.26%). Conclusion: Reasonable cutting bandwidth can promote the extension and expansion of underground bamboo rhizome, further affect the yield and quality of bamboo shoots and timber, improve the economic benefits of bamboo forest management, and also provide effective solutions for the future mechanized management of bamboo forests. In this study, the indexes of bamboo rhizome with 8 m band width are better than those with 6 m and 10 m band width. Therefore, 8 m band width can be used as a reference for future mechanized management of bamboo forest.

Objective: The XGBoost algorithm was applied to establish a remote sensing factor-stock volume model containing forest age, to evaluate the effectiveness of combining the remote sensing estimated forest age factor with the remote sensing factor to improve the accuracy of forest volume estimation, and to provide a new idea and method to achieve efficient, fast and accurate forest volume estimation on a large scale. Method: Taking Jiangle County, Fujian Province as a case, firstly, based on the time-series Landsat images from 1987—2016, combined with the measured stock volume data of subcompartment of forest resource inventory and planning, the LandTrendr forest disturbance and restoration monitoring algorithm was used to monitor the annual stand turnover disturbance and estimate the forest age in the disturbance area; Second, based on the GF-1 image spectral, texture, and topography features, the recursive feature elimination random forest algorithm (RFE-RF) to estimate the forest age in the non-disturbed area; Finally, the GF-1 image spectral and texture factors were combined with the forest age factor by the extreme gradient boosting algorithm (XGBoost) to estimate the forest stock of the study area. The accuracy of forest stock estimation with and without the forest age factor was compared to further verify the importance of remote sensing forest age factor to improve the accuracy of forest stock estimation. Result: The error of forest age obtained by using LandTrendr algorithm in the forest disturbance area was only 1-2 years, and the accuracy of forest age estimation was significantly better than that of the traditional estimation of forest age using remote sensing factors (error of 4-12 years). When only conventional remote sensing factors were used to estimate the volume, the model R² of XGBoost was 0.59 and the average RMSE was 30.72 m³·hm^?2,the rRMSE was 16.46%; after adding the forest age factor, the model R² increased to 0.73, the average RMSE decreased to 23.73 m³·hm^?2, the rRMSE was 13.26%, and the average overall accuracy of the stock volume estimation improved by about 10.4% to 84.4%. Conclusion: The accuracy of the XGBoost algorithm combined with the forest age parameter for estimating the stock volume is close to the requirements of the relevant regulations of forest resources survey, which can provide important technical support for the rapid survey and assessment of forest resources on a large scale.

Objective: This paper aims to explore the effects of garden plant smellscape which is odor and the multi-dimensional interactive perception of garden environment caused by smell on human health, by deeply analyzing the difference of effects of olfactory, visual and olfactory-visual interactive stimulation related to garden plants on human physiological and psychological responses, so as to provide theoretical basis and new ideas for garden plant smellscape design. Method: In a randomized controlled study, the odor of four common garden plants in northwest China and the panoramic images of their corresponding landscape were used as stimulus materials, and 312 college students were selected to be subjected the stimuli. NeuroSky brainwave tester, OMRON upper arm electronic sphygmomanometer and VISHEEW multiparameter biofeedback instrument were used to measure physiological indicators of the students in the virtual simulation laboratory. The emotions induced by smellscape and the perception of the overall environment were evaluated by state anxiety scale (S-AI) and smellscape emotion scale (SD). For physiological index data, One-way ANOVA was used to screen out indicators with significant differences. Spearman correlation analysis was used to test the correlation between each experimental stimulus factor and these indicators, and then multiple linear regression method was used to analyze the relationship between each indicator and different stimulus factors. Finally, one-way ANOVA and LSD postmortem test were conducted for the screened index data. For psychological indicators, ANOVA and LSD postmortem test were performed on the S-AI scale data, and Wilcoxon rank sum test was performed on the mean score data of each adjective option in SD. Result: The results of physiological measurement showed that: 1) In the olfactory stimulation group, before and after stimulation, the amplitude of α, β brainwave and skin electroencephalogram (SC) decreased significantly in the grass, Pinus tabuliformis and Rosa chinensis groups, and the amplitude of α and β brainwave decreased the most in the pine scent group (Δα=?24%, Δβ=?19.8%). The SC value decreased the most after smellingR. chinensis (ΔSC=?13.3%). 2) The amplitude of α, β brainwave and SC were significantly increased by visual stimulation in most experimental groups. The amplitude of α brainwave was increased the most by viewingR. chinensis (Δα=76.3%), and the amplitude of β brainwave and SC were increased the most by viewing Osmanthus fragrans (Δβ=92.7%, ΔSC=90.8%). 3) The amplitude of α and β brainwave induced by olfactory and visual interaction increased significantly in R. chinensis and O. fragrans, and SC induced by olfactory and visual interaction increased significantly in the 4 plant smellscape. The amplitude of α and β brainwave increased the most in R. chinensis olfactory and visual interaction group (Δα=29.7%, Δβ=39.6%). O. fragrans olfactory and visual interaction group (ΔSC=22.6%) had the highest increase in SC. The results of psychological measurement showed that olfactory-visual interaction was more likely to enhance participants' positive psychological perception of the environment, such as ‘attraction’, ‘uniqueness’ and ‘coordination’, than olfactory stimuli alone. Conclusion: The olfactory and visual interaction associated with garden plant smellscape can make people relax physically and psychologically to a certain extent. Olfactory and visual interaction shows a compromise effect in central nervous system and an accumulative effect in autonomic nervous system, and can generally enhance people's positive psychological perception of the environment. In the future, garden plant smellscape design should start from the perspective of multi-dimensional perception interaction and give full play to its health effect.

Objective: This study aims to explore the adaptive reasons of Anoplophora glabripennis larvae to Fraxinus pennsylvanica, a traditional resistant species, in terms of intestinal bacteria diversity. Method: The A. glabripennis larvae were fed withF. pennsylvanica and Salix matsudana, respectively , and the high-throughput sequencing technology was used to sequence 16S rDNA of the larvae intestinal bacteria, with which the molecular identification and diversity analysis of intestinal bacteria were conducted. Subsequently, through accumulation culture, 31 strains of cellulose-degrading bacteria were screened out from unfed larvae. The cellulose-degrading ability of each strain was determined by the transparent circle diameter (D)/colony diameter (D) as the standard, and the filter paper re-screening test was conducted on the four strains with the strongest cellulose-degrading ability. Result: The results showed that Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae and the genus Lactococcus were predominant in the larvae intestinal tract after being fed with F. pennsylvanica. Whereas Phylum Firmicutes, Class Bacillus, Order Lactobacillales, Family Enterococcaceae and the genus Enterococcuswere predominant in the larvae intestinal tract after being fed with S. matsudana. Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacteriales, Family Enterobacteriaceae and the genus Raoultella were predominant in the both feedings. The most significant difference between the two groups was that the relative abundance of Family Streptococcaceae and genus Lactococcusin the larvae feeding on F. pennsylvanica was significantly higher than that in the larvae feeding on S. matsudana , while the relative abundance of Family Enterococcaceae and genus Enterococcus was significantly lower than that in the larvae feeding onS. matsudana. In the intestinal bacterial community of larvae feeding directly on the branch of F. pennsylvanica, there were abundant species of cellulose-degrading bacteria, belonging to 4 phyla, 5 classes, 5 orders, 7 families, 7 genera and 15 species. At the genus level,Microbacterium, Cellulomonas and Pseudomonas were predominant. Among them, two strains ofPseudomonassp. and two strains of C. flavigena had the strongest cellulose-degrading ability. The filter paper was decomposed significantly in the re-screening test, which further verified that the strains had strong cellulose-degrading ability. Conclusion: Family Streptococcaceae and genus Lactococcus are the predominant bacteria in the intestinal tract of A. glabripennis larvae feeding onF. pennsylvanica, which may play an important role but do not degrade cellulose directly. Genera Microbacterium and Cellulomonas in Phylum Actinobacteria and genus Pseudomonas in Phylum Proteobacteria are not the predominant group of bacteria, but they have strong cellulose degradation ability and may play a role in cellulose degradation. These bacteria co-exist in the intestinal tract of A. glabripennis and are involved in its adaptation process to the F. pennsylvanica.

Objective: In this study, we analyzed the differences in the release of monoterpenes from the trunk of healthy and weak Picea koraiensis, evaluated their fumigation toxicity to adult of Ips typographus, and tested their synergistic and antogonistic effects on aggregation pheromones of the bark beetle. Based on these investigation, we aims to produce efficient semiochemicals for population regulation of I. typographus in the forest. Method: Dynamic headspace sampling was used to collect the volatiles released from the stem of healthy and weak P. koraiensis. Gas chromatography was used to qualitatively and quantitatively analyze the monoterpenes. The toxicity of the monoterpenes against adult I. typographus was determined by using the headspace fumigation method, and the behavioral effects of the monoterpenes on I. typographus and its natural enemy, Thanasimus substriatus(Coleoptera: Cleridae) were analyzed in the forest. Result: The major monoterpenes from the trunk ofP. koraiensis were identified, including S-(–)-α-pinene, R-(+)-α-pinene, S-(–)-β-pinene, myrcene, 3-carene, (–)-limonene, and (+)-limonene. The total amount of monoterpenes in healthy stems was significantly higher than that in weakened stems, while the release amount of R-(+)-α-pinene and (+)-limonene showed no significant difference between healthy and weakened stems. The LC₅₀ values of seven monoterpenes against I. typographus ranged from 3.10–4.50 μL?mL^?1, with (+)-limonene showing the strongest toxicity. There were significant differences in LC₅₀ values among the seven monoterpenes, but not between male and female adult beetles. The field behavioral test showed that 3-carene, (–)-limonene, and (+)-limonene significantly reduced the trap catches of I. typographus by aggregation pheromones, but S-(–)-β-pinene showed no effect on the trap catches. Compared to (–)-limonene and (+)-limonene, 3-carene was able to significantly improve the trap catches of the predator T. substriatusby aggregation pheromones. Conclusion: The trunk of P. koraiensis can release seven major monoterpenes. The weakened spruce, suitable for colonization byI. typographus, releases less monoterpenes than the healthy spruce. These monoterpenes have fumigation toxicity against I. typographus and may be involved in regulating tritrophic relationships between spruce, I. typographus, and T. substriatus. Limonene can be used as a repellent for ecological prevention and control of I. typographus.

Objective: This study aims to explore the impact of the expiration of the first round subsidies for the sloping land conversion program (SLCP) on the income inequality among farmer households, which would provide decision-making reference for improving the follow-up SLCP policy and promoting common prosperity. Method: Based on the field survey data of 1 733 farmer households in five Provinces (autonomous region) of Hebei, Sichuan, Gansu, Ningxia and Hunan in 2019 and 2021, with the re-centralization impact function (RIF) regression model, this paper empirically tested the impact of the expiration of the subsidies for the SLCP on the inequality of internal income and income structure of farmer households, and further investigated the heterogeneous impact of the expiration of the subsidies for the SLCP on the internal income inequality of farmer households at different levels of education and the conversion scale. Result: 1) The estimated result of the expiration of the subsidies for the SLCP on the income inequality among farmer households was significantly positive at the level of 5%. 2) Different metrics were selected to replace Gini coefficient, and the RIF model constructed by the different metrics passed the robustness test, indicating that the research results were reliable. 3) From the perspective of income structure, the estimated results of the expiration of the subsidies for the SLCP on the inequality from farmer households’ internal wage income and production income were significantly positive respectively at the level of 10%, the estimated results of farmer households’ internal transfer income was significantly negative at the level of 10%, and that of farmer households’ internal property income was not significant. 4) For farmer households at different levels of education, after the expiration of the subsidies for the SLCP, the estimated results of internal income inequality of farmer households at and below primary school and below junior high school were significantly positive at the level of 5% and 10%, respectively, while the estimated results of internal income inequality of farmer households at and above high school were significantly negative at the level of 10%. For farmer households with different scale of the SLCP, the estimated result of the internal income inequality from farmer households with medium scale and above of the SLCP was significantly positive at the level of 10%, but the estimated result of the internal income inequality from farmer households with small-scale of the SLCP was not significant. Conclusion: The expiration of the first round of subsidies for the SLCP widens the income inequality among farmer households to a certain extent. The expiration of subsidies for the SLCP expands the inequality of farmer households’ internal wage income and production income respectively, but reduces the inequality of farmer households’ internal transfer income. There exist great different impacts of the expiration of subsidies for the SLCP on income inequality among the types of farmer households. The expiration of subsidies for the SLCP aggravates the income inequality among the farmer households with middle and low education background and with medium and above scale of the SLCP, but alleviates the income inequality among farmer households with high education background, and has no significant impact on income inequality of farmer households with small scale of the SLCP. Based on the above, this paper puts forward corresponding suggestions from the aspects of broadening farmers’ employment channels, promoting the development of subsequent related industries and carrying out targeted policy assistance.

Objective: To reveal the distribution law of tree height-to-diameter ratio in each stratum of typical natural broad-leaved forest in mid-subtropical zone, to provide a typical reference in the aspect of height-to-diameter ratio of broad-leaved trees for the sustainable management of artificial broad-leaved forest, semi-natural broad-leaved forest and natural broad-leaved forest in mid-subtropical zone. Method: In Jian’ou Wanmulin provincial nature reserve, 50 m×50 m plots were set up in 5 typical natural broad-leaved forest in mid-subtropical zonerespectively. Themean tree height-to-diameter ratio and standard deviation of each stratum in the typical stand was calculated to analyze its changes with the stratum, and the Mann-Whitney U test was used to analyze the significance test of the difference between the average height-to-diameter ratio in each stratum. Skewness and kurtosis are used to describe the degree of deviation and dispersion of the height-to-diameter ratio distribution. The normal distribution and Weibull distribution function were selected to fit the distribution of the height-to-diameter ratio of each stratum in each plots, and the fitting effect was tested by χ² test. Result: The mean tree height-to-diameter ratio in 5 sample plots was integrated, the mean tree height-to-diameter ratio of the whole stand was 103.1, and the mean tree height-to-diameter ratio of each stratum decreased with the increase of the stratum height. The order and value were as follows: the stratum Ⅲ (112.7) > the stratum Ⅱ (89.0) > stratum Ⅰ (66.9)and NLRS(112.7) > LRS(78.3).The mean tree height-to-diameter ratio between the stratum Ⅱ and stratum Ⅲ in plot 4 was significantly different, and the average height to diameter ratio of trees between stratum in other plots was extremely significant.The results of skewness showed that the tree height-to-diameter ratio of each stratum was skewed to the right. The variation of skewness of the tree height-to-diameter ratio in each stratum was irregular.The normal distribution function was used to fit the distribution of tree height-to-diameter ratio of each stratum, and all the results passed the Chi-square test. However, most of the results of Weibull distribution function did not pass the Chi-square test. Conclusion: In the typical natural broad-leaved forest of the mid-subtropical zone,the tree mean height-to-diameter ratio of each stratum has an extremely significant difference, and the tree mean height-to-diameter ratio decreases with the increase of the stratum height.The distribution of tree height-to-diameter ratio in each stratum was right skewed. The tree height-to-diameter ratio of the whole stand and the stratum Ⅰ was relatively dispersed, while the stratum Ⅱ and stratum Ⅲ were relatively concentrated. The fitting effect of normal distribution function on tree height-to-diameter ratio of each stratum was good, but the fitting effect of Weibull distribution function was not ideal.In the typical natural broad-leaved forest of the mid-subtropical zone, the height-to-diameter ratio distribution was significantly different from that of diameter distribution. The height-to-diameter ratio distribution of the whole forest and the stratum Ⅲ was normal, but the diameter distribution of the whole forest and the stratum Ⅲ was inverted J. The average height/diameter ratio in each stratum and the distribution of height/diameter ratio in each stratum reflected in this study belong to the height/diameter ratio characteristics under ideal circumstances.