Taking Larix principis-rupprechtii plantation as the research object based on the cutting space unit composed of cutting tree and its surrounding adjacent tree the effects of cutting space unit size and spatial parameters on the radial growth of adjacent tree before and after cutting were explored It is of great significance for the rational management and protection of Larix principis-rupprechtii and provides reference for further scientific research The sample plot survey was carried out before harvesting After harvesting 105 adjacent trees around the harvested tree were sampled by micro-core method to measure their radial growth The results show that The average spatial structure parameters of adjacent trees in each cutting space unit changed after cutting and the angle scale increased to 0 5 while the size ratio and competition index decreased The radial growth therefore changes From 2018 to 2022 the average annual radial growth of adjacent trees was 476 92 m 472 57 m 427 34 m 605 12 m and 782 90 m respectively The average annual radial growth in the two years before tending felling 2018—2019 was 474 74 m and the average annual radial growth in the two years after tending felling 2021—2022 was 694 01 m The radial growth before tending felling showed a downward trend and the radial growth after tending felling was significantly higher than that before tending felling There was a significant difference in the radial growth rate of adjacent trees in different logging space units P<0 05 and the average growth rate of adjacent trees was 54 66% The average growth rate of adjacent trees in the smallest logging space unit 0 55 m2 was 75 93% and the average growth rate of adjacent trees in the largest logging space unit 12 00 m2 was 26 03% The average radial growth rate of adjacent trees with logging space unit area< 10 m2 was significantly higher than that of adjacent trees with area>10 m2 There were significant differences in the radial growth rate of adjacent trees before logging P<0 05 After cutting the competition intensity of the adjacent tree itself is divided into three levels Low CI<2 21 Medium 2 21≤CI≤3 35 and High CI>3 35 The corresponding average radial growth increments were 235 58 m 223 26 m and 106 19 m respectively The average growth change rates of adjacent trees were 51 5% 75 9% and 98 25% respectively All adjacent trees had different degrees of growth release mild release moderate release and severe release accounting for 16% 20% and 21% respectively It can be seen that thinning reduces the intensity of competition increases the radial growth rate and results in growth release

The oak tree species group holds the top position in both distribution area and standing volume in China Studying its growth process provides a basis for the utilization and management of oak forests In the present study we focused on eight common oak species Q aliena Q aliena var acutiserrata Q variabilis Q acutissima Q wutaishanica Q mongolica Q myrsinifolia and C fargesii We combined the analytic timber data from eight main distribution provinces and analyzed the average growth and annual in crement of tree height DBH and volume for each species We also conducted model fitting and accuracy assessment on the overall growth of these three indicators The growth status and fitting results varied among oak species across different distribution areas The annual increment of tree height and DBH showed a downward trend after twenty years for deciduous oak species while that of evergreen oak species began to decline after ten years Significant differences were observed in the mean annual increment of Q aliena between different distribution areas P<0 05 while no significant differences were observed between different distribution areas for Q mongolica and Q variabilis P>0 05 The optimal model equation of each growth indicator were best described by quadratic curve models for deciduous oaks while it was predominantly Richard models for evergreen oaks In short there are differences in the growth of oak species in different distribution areas and the competition of evergreen oak stands will appear earlier than deciduous oak The findings from this study can provide a valuable scientific reference to estimation of carbon sink in oak forests

The study aimed to investigate the effect of canopy and lateral branches on photosynthesis and leaf area of poplar trees of different ages In this paper poplar trees were taken as experimental objects and different canopy layers were divided according to three kinds of poplar trees of different ages 6 12 and 18 years old The primary lateral branches of the canopy were stratified from the outside to the inside to analyze photosynthetic characteristics leaf area and water use efficiency WUE and the differences in photosynthetic characteristics of leaves of different canopy layers and lateral branches of poplar trees of different ages were systematically studied The results showed as follows 1 The photosynthetic characteristics of the same age increased significantly with the increase of canopy and the lateral branches increased gradually from inside to outside P<0 01 2 In canopy 4 and 5 except for WUE value photosynthetic parame ters of 18-year-old were higher than those of 12-year-old Pn value was higher by 16 96% Gs value was higher by 54 50% and Tr value was higher by 32 52% In the canopy 3 the highest water utilization rate of 12-year-old was 4 678% and 25 447% respectively higher than that of 18-year-old and 6-year-old 3 There were significant differences in the photosynthetic parameters of leaves at different branches of the crown in the three kinds of age showing that the upper branch>the middle branch>the lower branch 4 Net photosynthetic rate was significantly positively correlated with Gs Tr and WUE P<0 01 and was significantly positively correlated with specific leaf area P<0 05

In order to solve the problems of high empty bud rate and poor fruit set in the cultivation of chestnut pollination varieties can be rationally allocated In Chencang district of Baoji city for the main varieties ‘Taishan No 1’ and ‘Qinli No 2’ ‘Hongli’ ‘Xinzao li’ ‘Shifeng’ ‘Sheli’ and two main varieties were selected as pollination varieties and their fruit characteristics fruit traits and quality were measured and analyzed The results show that 1 In addition to ‘Taishan No 1’ and ‘Qinli No 2’ as pollinating species outcrossing significantly improved the seed setting rate and achievement rate of chestnut and reduced the empty bud rate 2 ‘New chestnut’ as the parent significantly reduced the empty bud rate of chestnut and ‘She chestnut’ as the parent significantly increased the fruit yield seed kernel protein and starch content of chestnut and ‘Shifeng’ as the parent significantly increased the soluble sugar content of chestnut kernel and reduced the fat content 3 Based on the analysis of yield fruit traits and principal components three pollination combinations ♀×♂ with high yield and high fruit quality were selected as ‘Qinli No 2’בShili’ ‘Qinli No 2’בShifeng’ and ‘Taishan No 1’בSheli’ Reasonable variety pollination configuration can effectively reduce the empty bud rate of chestnut fruit in Chencang district Baoji city improve the fruit quality and yield and achieve high yield and high-quality cultivation

This study investigated the effects of canopy microenvironment on chestnut fruit ripening and explored the use of ethephon to promote uniform maturity in delayed canopy regions thereby facilitating mechanized harvesting The main planted chestnut ‘Yanshanzaofeng’ in Qiangxi County Hebei Province was used as the research object and the canopy was divided into upper middle and lower layers and four directions east west south and north with a total of 12 areas Microenvironmental factors were measured in different regions of the canopy from chestnut expansion to ripening Bulb dehiscence was recorded daily in different regions of the canopy and fruit ripening differences between dehiscence and ripening were analysed Bulb dehiscence was correlated with microenvironmental factors and areas with late fruit ripening were sprayed with ethylene glycol to promote consistent fruit ripening There were highly significant differences in light intensity in different areas of the canopy and no significant differences in temperature or humidity The general trend of light intensity and temperature was from bottom to top gradually increasing from north to south with the maximum difference in light intensity between the upper south-facing layer and the lower north-facing layer amounting to 56 40 klx The humidity was lower>middle>upper with a trend of increasing humidity from south to north The onset of bulb dehiscence varied from 1 to 4 d between canopies and was generally 2-6 d later in north-facing canopies than in other directions The onset of maturity varied from 1 to 6 d between canopies and from 2 to 6 d between orientations Fruit ripened later in the lower canopy and in the north-facing centre than in the other canopies light intensity was highly significantly negatively correlated with bulb dehiscence and ripening while it was highly significantly positively correlated with bulb dehiscence rate Spraying 200 mg L ethylene glycol can advance the ripening period of chestnut crowns by 1-4 d and shorten the ripening period by 5-6 d There are differences in fruit ripening in different regions of the chestnut canopy and it is recommended that 200 mg L ethylene glycol be sprayed on the lower canopy and northward central canopy fruits to promote ripening when the upper bulb appears to be slightly yellow 22 August and that tree machinery be used for harvesting the fruits when they are slightly dehiscent

This study explores the correlation between biodiversity abiotic factors and productivity at different spatial scales Using the natural secondary forest in the Changbai Mountain as the study area quadrats with different spatial scales 50 m×50 m 20 m×20 m 10 m×10 m were established The optimal indicators representing species diversity and structural diversity were determined by constructing a multiple regression model and then the relative effects of biodiversity and abiotic factors on productivity were analyzed and compared through structural equation model The results show that the effects of biodiversity and abiotic factors on community productivity were significantly spatial scale dependent At each spatial scale there was a positive correlation between species diversity and productivity and with the increase of spatial scale the positive correlation between species diversity and productivity gradually became smaller from significant positive correlation to insignificant positive correlation At each spatial scale there was a negative correlation between structural diversity and productivity and with the increase of spatial scale the intensity of negative effect between them gradually increased from insignificant negative correlation to significant negative correlation Abiotic factors had certain effects on aboveground biomass at different spatial scales thus further affecting changes in productivity Stand productivity was related to the joint action of biological diversity and abiotic factors and was restricted by spatial scale This conclusion could provide scientific theoretical support for biodiversity conservation ecosystem function improvement and forest forward succession management in Changbai Mountain area

Analysis of diversity of fruit and seed traits FSTs of 32 P dactylifera plants introduced in Yuanjiang Yunnan Province was carried out and the excellent single plant in the population was preliminarily identified which provided the basis for further research and breeding of improved varieties 11 parameters of 32 P dactylifera plants were measured The methods of Shannon-Wiener index and principal component analysis etc were employed to interpret the diversity of FSTs and primarily to determine the excellent individual plants in the population The mean transverse and longitudinal diameters TD and LD of fruits single fruit dry weight SFDM and fruit edible rates FER of the 32 P dactylifera plants were 1 9-2 7 cm 2 9-4 2 cm 1 9-5 6 g and 77 8%-94 9% respectively the coefficient of variation CV for fresh seed weight FSW was the highest 29 9% followed by SFDM 29 7% with CV of FER the lowest 5 3% SFDM was significantly positively correlated with the other parameters P< 0 05 or P<0 01 The FER was significantly negatively correlated with fruit moisture content TD and LD of seed seed fresh weight and seed moisture content P<0 01 A comprehensive score of ≥1 000 was identified as the breeding standard for improved varieties with 5 plants selected from 32 individual plants which accounting for 15 6% of the total plants The fruit and seed variety of the single plant of P dactylifera is rich and the proportion of excellent single plant in the population is low so the breeding of good varieties is important to increase its yield and value

The study aims to investigate the physiological mechanism of biochar with nitrogen application on mitigating the germination of ‘Paulownia 1201’ seeds under Cd stress and to provide a reference for the application of biochar and nitrogen for remediation of the Cd-contaminated soil Taking the seeds of ‘Paulownia 1201’ as the test material we investigated the effects of different concentrations of the Paulownia biochar treatment solution with nitrogen on the germination characteristics antioxidant levels osmotic substances and nutrient levels of seeds under Cd stress 1 Biochar nitrogen and their combinations significantly enhanced the germination potential germination rate germination index and vigor index of the seeds As the concentration of the treatment solution increased the length of young shoots root length fresh weight and free amino acid content were increased reaching their maximum values at 5 g L biochar while the starch content showed a decreasing trend 2 When biochar or nitrogen was applied alone the contents of GR activity Pro and MDA were decreased while H2O2 did not change significantly The lowest contents of Pro and H2O2 were observed at 5 g L SS and SP were increased with the increase in treatment concentrations Additionally the activity of APX was initially increased and then decreased with the germination time 3 When biochar and nitrogen were applied together the activities of APX and GR enzymes reached their maximum values MDA and H2O2 were decreased while Pro was increased slightly The overall improvement effect was Biochar with nitrogen>biochar>nitrogen The application of biochar and nitrogen can enhance the antioxidant and osmoregulation ability of Paulownia seeds promote the accumulation of nutrients and significantly promote seed germination In particular biochar combined with nitrogen is the best treatment

To solve the problems of single fertilization only chemical fertilizer application and soil compaction in walnut orchards in southern Shaanxi five treatments were set up including no fertilization CK single chemical fertilizer application T1 chemical fertilizer combined with organic fertilizer T2 chemical fertilizer combined with bio-organic fertilizer T3 chemical fertilizer combined with organic fertilizer and bio-organic fertilizer T4 Long term targeted fertilization experiments were conducted to study the effects of different fertilization modes on soil mechanical composition bulk density aggregates saturated hydraulic conductivity organic matter yield and economic benefits The results showed that 1 In the 0-80 cm soil layer the silt content range of T4 treatment was 81 42%-85 83% with an average value of 82 95% which was significantly improved compared to other fertilization treatments The T4 treatment showed the smallest bulk density in the 0-80 cm soil layer range which was an average decrease of 5 37% compared to the CK treatment The soil organic matter content of T4 treatment was the highest with an increase of 26 32% 43 28% 57 00% and 104 95% compared to CK treatment in the 0-20 cm 20-40 cm 40-60 cm and 60-80 cm soil layers respectively T4 treatment transformed soil aggregates from 0 053-0 25 mm to larger aggregates>0 25 mm The saturated hydraulic conductivity of T4 treatment was the highest in the 0-20 cm and 40-60 cm soil layers second only to T3 treatment in the 20-40 cm and 60-80 cm soil layers and there was no significant difference compared to T3 treatment 2 The walnut yield of T4 treatment was the highest among all treatments with 2 11 times 2 14 times 2 01 times and 7 45 times higher than that of CK in 2015 2017 2019 and 2021 respectively The fertilizer input and total input of T3 treatment were the highest but the yield income and net income of T4 treatment were the highest The net income under T4 treatment was 17 98 times higher than that of CK treatment The overall score of soil quality and economic benefits of T4 treatment was higher than that of other treatments Therefore under the conditions of this experiment the combination of chemical fertilizers with organic fertilizers and bio-organic fertilizers has significant effects on improving walnut yield and soil physicochemical properties

Aiming at the defects of under-enhancement over-enhancement and detail loss of traditional image enhancement methods in processing non-uniform forest canopy images a forest canopy image enhancement method based on improved black-winged kite optimization algorithm IBKA is proposed Local contrast increases the difference between light and dark in the image global adaptive Gamma correction equalizes the brightness between light and dark the Gaussian blurring process enriches the details in the image inverted exploration optimization strategy and avoidance behaviors in migration improve the exploration ability of the black-winged kite algorithm and the ability to jump out of the local optimal solution The enhancement method uses IBKA to find the optimal parameter for adaptive image enhancement The proposed method outperforms the comparison algorithms in entropy value and FSIM in forest canopy image enhancement while obtaining a moderate average gradient and pixel mean It is shown that the proposed method comprehensively improves the quality of non-uniform forest canopy images

Biomass is a key indicator for evaluating the growth status of rubber forest Accurate estimation of biomass is not only crucial for maintaining the ecological balance and environmental protection of rubber forest but also directly affects the estimation of carbon storage and health status of rubber forest The rubber forest in Danzhou City Hainan Province was taken as the research object three phases of Sentinel-2 images were selected by using the Google Earth Engine GEE cloud platform the band reflectivity was extracted and the vegetation index and texture features were calculated as the basic data for the inversion Pearson correlation coefficient method random forest-based recursive feature elimination RF-RFE and Boruta feature selection methods were used to screen out the optimal feature subset Four machine learning models support vector machine random forest back propagation neural network and Bayesian neural network were used to estimate the rubber forest biomass The results showed that 1 The Boruta-BNN meth od showed the highest prediction accuracy of R2=0 73 RMSE=17 42 t hm2 2 Multi-temporal imagery as a data source can obtain better estimation results compared to single moment imagery In general the Boruta-BNN method can well reveal the relationship between remote sensing features and biomass and multi-temporal image information can help improve the estimation accuracy of rubber forest biomass These research results provide scientific basis and technical support for the protection and field management of rubber forest in Hainan Province

The classification of tree species and their spatial location display are difficulties in forest ecological investigation and are of great significance for forest management and biodiversity conservation This study explores the application value of the combination of GF-2 multispectral image data and LiDAR point cloud data from unmanned aerial vehicles in the classification of tree species in mountainous bamboo forests Taking the mountainous areas in central Fujian as an example we extracted spectral and texture features of GF-2 imagery as well as height features intensity features terrain factors and canopy height model CHM features from LiDAR data Random forest RF was used to select feature variables and the application potential of single GF-2 image single LiDAR data and the combination of GF-2 image and LiDAR data in tree species classification was compared Three distinct feature combination schemes were designed and two machine learning classifiers-Random Forest RF and Support Vector Machine SVM -were employed for the classification and recognition of tree species within the distribution area of bamboo forests The research results indicate that the 25% importance of all echo intensities in the LiDAR feature set is the highest and the mean blue light band 11~~B1~~Mean and green normalized vegetation index GNDVI of window 11×11 in GF-2 texture features perform well Compared with different data sources GF-2 combined with LiDAR data has better classification accuracy than single source data Scheme F3 combines terrain factors and canopy height features to improve the accuracy of tree species classification was improved from 78 47% to 92 55% with an overall accuracy of 92 55% and a kappa coefficient of 0 91 With the addition of auxiliary features the classification accuracy is significantly improved and the recognition accuracy of bamboo forest tree species is improved

Aux IAA gene family plays an essential regulatory role in the auxin signal transduction pathway and plant development In this study 51 Aux IAA genes were identified from the genome of Zanthoxylum bungeanum Zb Phylogenetic tree analysis conserved motif composition and gene structure analyses revealed that the ZbIAA genes were classified into seven subfamilies Members within the same subfamily shared a similar gene structure Furthermore 34 genes 67% exhibiting tandem repeats and segmental duplications The promoter sequences of ZbIAA genes contained numerous cis-acting elements related to plant hormones and growth development Expression profiles of ZbIAA genes during different developmental stages of Sichuan pepper thorns revealed that ZbIAA1 ZbIAA5 ZbIAA25 ZbIAA30 and ZbIAA44 had significantly higher expression levels than other members They may play an important role in the development of Sichuan pepper thorns Codon usage bias analysis showed a preference for A T-ending codons within the ZbIAA gene family with 25 preferred codons and two unbiased ones This research lays a theoretical foundation for further functional analysis of the ZbIAA gene family

In order to establish a suitable ISSR-PCR reaction system for Parashorea chinensis this study used young leaves of Parashorea chinensis as the test material and used the L16 45 orthogonal experimental design to optimise the five factors of ISSR-PCR reaction i e template DNA Mg2+ dNTPs Taq DNA polymerase and primer concentrations and to establish an optimal ISSR-PCR reaction system suitable for Parashorea chinensis On the basis of the optimisation the primers and the optimal annealing temperature were selected and the stability of the reaction system was verified by using five Parashorea chinensis family lines as materials The results showed that the optimal ISSR-PCR reaction system 20 L for Parashorea chinensis was composed of 90 ng of template DNA 0 3 mol L of primers 0 2 mmol L of dNTPs 2 5 mmol L of Mg2+ and 1 0 U of Taq DNA polymerase and that the three ISSR-PCR reaction systems with good reproducibility and high polymorphism were screened Three ISSR primers with good repeatability clear bands and high polymorphism were selected and the optimal annealing temperature of the best primer UBC864 was 56 9 ℃ The optimised reaction system and primers were used to detect the ISSR-PCR bands of five Parashorea chinensis samples and the results showed that the above reaction system was stable and reliable The optimized ISSR-PCR system and primer candidates are suitable for the genetic diversity analysis of Parashorea chinensis which can lay a foundation for the conservation and utilisation of Parashorea chinensis germplasm resources

Investigating and analyzing the structure and dynamics of Fagaceae community in the subtropical evergreen broad-leaved forest of Malipo is important for exploring the coexistence mechanism and dominance of Quercus Lithocarpus and Castanopsis This study provided an empirical study for understanding Fagaceae coexistence We set four 600 m2 plots in the Malipo natural reserve in May 2021 Excel 2019 and SPSS 25 0 software were used to analyze the dominant group by both individual number and basal area and make static life table and survival curve to understand the differentiation among different genera and their coexistence mechanisms 1 The average basal area of Fagaceae and Lithocarpus were 57 04% and 32 82% which made them the dominant family and genera respectively 2 The diameter class distribution of the three genera was all barrel-shaped with small proportion of seedlings and large trees 17 43% and large proportion of small- and middle-sized trees 82 57% 3 The survival curves of the three genera all fitted the Deevey-Ⅱ type The mortality of Quercus and Castanopsis species was increased with increasing in diameter class whereas after becoming saplings Lithocarpus species become stablized Fagaceae especially Lithocarpus is the dominant group in the evergreen broad-leaved forests of Malipo The differentiation in community dynamics species distribution and diversity among these three genera are important reasons for their coexistence and dominance

Based on the measured biomass data of 40 Robinia pseudoacacia in the coastal forest areas of Qinhuangdao City, a single-tree biomass model was established, and the nonlinear measurement error model was used to establish the univariate and bivariate compatible biomass model of Robinia pseudoacacia. To eliminate heteroscedasticity, logarithmic transformation and weighted regression methods were applied. The accuracy of the model was tested by the determination coefficient (R2), standard deviation of the estimated value (SEE), total relative error (TRE), mean systematic error (MSE), mean prediction error (MPE) and mean percentage standard error (MPSE). The results showed that the parameters of the univariate model and bivariate model independent biomass models were stable and had good applicability, the determination coefficient (R2) was above 0.8, the total relative error (TRE), mean systematic error (MSE) and MSE were stable in a certain range, and the average predicted accuracy of the model was above 90%. The accuracy of the two models was the highest in the overall part and the lowest in the crown part. The test results of the univariate and bivariate compatible models were similar to the test results of the independent model, and the fitting effect, predicted accuracy and accuracy of the model were improved compared with the independent model. After comparing the independent model and the compatible model, the bivariate compatible model was selected as the optimal model, and considering the difficulty of variable measurement in field survey, the univariate compatible biomass model should be established with DBH as the variable in the future research of Robinia pseudoacacia biomass data. The results can provide reference for the accounting of Robinia pseudoacacia biomass and carbon storage in the coastal area of Hebei Province.

In order to investigate the effect of rejuvenation on the cuttings of hard-to-root trees the experiment measured the growth and physiological indices of 1-year-old Acer mono seedlings under different rejuvenation pruning treatment and observed and analyzed the anatomical structure of cuttings The results showed that the stem length stem diameter petiole length water content leaf area net photosynthetic rate transpiration rate and stomatal conductance of new branches of Acer mono seedlings were significantly increased by the treatment while the intercellular CO2 concentration was significantly decreased The contents of soluble protein soluble sugar chlorophyll and activities of POD SOD and CAT of Acer mono seedlings were significantly increased by the treatment while the contents of MDA flavonoid and total phenol were significantly decreased The bast fibers between the cortex and the phloem were not obvious the cortical cells were larger and the xylem was thinner The results showed that pruning a year>pruning for two years>no pruning The seedlings of Acer mono were restored to rejuvenation after the pruning treatment the seedlings of Acer mono showed a better growth state thus reducing the difficulty of asexual reproduction providing technical support for the seedlings of Acer mono and laying a foundation for further research on the physiological mechanism of anti-aging of Acer mono

This study aims to investigate the relationship between forest fire occurrences and their driving factors in the Qinling Mountains from 2003 to 2018 and to predict the probability of forest fires Based on MODIS satellite fire point data from 2003 to 2018 logistic regression random forest and support vector machine models were developed to predict forest fire occurrences in the Qinling Mountains and their accuracy was evaluated The random forest model which provided better fitting results was chosen to create the forest fire risk level map The results showed that 1 The random forest model had better fitting results for predicting forest fire occurrences with an accuracy of 87 04% and an AUC value of 0 949 2 The importance of the driving factors for forest fire occurrences in the Qinling Mountains in descending order were NDVI average monthly wind speed elevation average monthly atmospheric pressure wind speed atmospheric pressure average monthly precipitation slope average monthly air humidity air humidity con secutive days without precipitation and precipitation amount 3 The eastern and southern parts of the Qinling Mountains were identified as areas prone to forest fires It is recommended to increase forest fire prevention publicity in these counties to reduce human-caused fires and to enhance infrastructure such as lookout towers to ensure early detection and early suppression of forest fires

Lhasa as the core area of the national ecological security barrier construction faces the risk of bio-ecological security caused by the invasion of Datura stramonium In order to explore the impact of the invasion of Datura stramonium on soil seed bank characteristics in Lhasa this study took the soil seed bank of Datura stramonium with different invasion levels within the urban area of Lhasa central Tibet Plateau as the research object and revealed the differences in the soil seed bank of soil with different invasion pressures by means of field surveys and seed germination experiments aiming at providing a basis for the scientific prevention and control of the invasive plants in Tibet The results show that 1 The total number of plants in the soil seed bank was 46 belonging to 18 families and 43 genera mainly annual herbs Among them there were 10 invasive alien species which w distributed in each sample site 2 Mild invasion of Datura stramonium significantly increased the species diversity of plant communities in the invaded site P<0 05 but the community diversity tended to decrease with deeper invasion 3 Pearson correlation analyses showed that both light and heavy invasive pressure from Datura stramonium had negative effects on the native species Digitaria cruciata Lepidium apetalum Artemisia wellbyi Plantago depressa and Pseudognaphalium affine This study clarifies the effect of Datura stramonium invasion on the community structure of soil seed bank in Lhasa area and provides some scientific basis for the Datura stramonium of local biological invasions

In order to reveal the characteristics of ectomycorrhizal fungi EMF diversity of Pinus armandii in subtropical karst mountain typical P armandii plantations in Central Guizhou were selected as the investigation sites and the EMF associated with P armandii was analyzed by combining morphological and molecular biology techniques The results showed that a total of 21 EMF OTUs were identified belonging to 12 families and 12 genera EMF OTUs richness of Basidiomycetes and Ascomycetes were 80 95% and 19 05% respectively indicating that Basidiomycetes were significantly more abundant than Ascomycetes The dominant groups of EMF community in P armandii were Thelephoraceae and Sebacinaceae Soil pH and total phosphorus were important factors affecting EMF community of P armandii

Long term development of mineral resources will have a huge impact on the quality of regional ecological environment Comprehensive and accurate monitoring and evaluation of the ecological environment quality in mining areas is of great significance for ensuring regional sustainable development Based on Landsat images from 2001 to 2020 this study constructed an improved remote sensing ecological index ND-RSEI to analyze the spatiotemporal variation pattern of ecological environment quality in Fengfeng mining area and explored the factors affecting the spatiotemporal variation of ND-RSEI The results indicate that 1 ND-RSEI has a strong ability to distinguish urban areas gangue hills and industrial squares and is suitable for evaluating the ecological environment quality of mining cities 2 From 2001 to 2020 the overall ecological environment quality in the research area was at a good level with poor areas mainly dis tributed in urban areas and factory clusters The excellent areas were mainly high vegetation covered areas with flat terrain The proportion of areas with improved ecological environment quality was 32 1% and the proportion of areas with deteriorated ecological environment quality was 25 2% The overall ecological environment quality has improved to some extent The exploitation of resources has led to the deterioration of the ecological environment with 8 out of 11 mining areas showing a degradation trend and 3 mining areas showing an improvement trend being discontinued mining areas 3 The combination of land use type and other factors with land use type is the main factor explaining the spatial heterogeneity of ND-RSEI among which the influence of human factors on ecological environment quality is gradually increasing

Monitor and analyze the spatial and temporal changes in ecological environment quality and its influencing factors to provide theoretical support for the rational formulation of restoration decisions in this region and orderly carry out restoration work This paper takes Xilingol League Inner Mongolia as the research area and uses the Google Earth Engine GEE platform to build improved remote sensing ecological index IRSEI model to monitor and evaluate the changes in the ecological environment quality in the Xilingol League from 2001 to 2021 The results show that 1 From 2001 to 2021 the mean values of the improved remote sensing ecological index IRSEI and the remote sensing ecological index RSEI in Xilingol League first increased then decreased and then increased again Areas with poor and more poorer ecological quality were mainly concentrated in the southwest of the study area accounting for 29%-37% Areas with good and excellent ecological quality were mainly distributed in the northeast accounting for 18%-27% The area proportion of regions with poorer ecological quality or worse was still larger than that of regions with goodecological quality and excellent 2 From 2001 to 2021 the proportion of the area where the overall ecological environment quality has improved reached 8 96% and the overall improvement ratio is slightly greater than the deterioration ratio 3 NDVI is the main ecological response factor and the average Q value of the 7 influencing factors is NDVI>NDBSI>WET>SI~~T>LST Research shows that IRSEI can monitor regional ecological quality at low cost quickly and accurately and can better monitor long-term changes in ecological quality in mining cities providing theoretical support for the region to reasonably formulate restoration decisions and carry out restoration work in an orderly manner

Climate and forest cover exert a profound influence on the generation of baseflow in watersheds The protection and restoration of forest cover are important for maintaining the stability of baseflow in watersheds and improving the efficiency of water use The mechanisms of groundwater recharge and baseflow generation are complex and the response mechanisms of basin baseflow to climate change and forests are not yet fully understood In this paper the Mississippi River Basin is taken as the research object the baseflow is calculated based on a long series of daily runoff data the spatial and temporal distribution pattern of baseflow is analyzed and the main driving factors of baseflow are explored The results demonstrated that the area-normalized baseflow values of the 94 sub-basins exhibited considerable spatial variability ranging from 0 007 2 to 4 386 5 m3 s·km2 The distribution of these values exhibited an uneven pattern with an overall increasing trend from the northwest to the southeast The baseflow index exhibited a similar pattern of variability ranging from 0 22 to 0 79 with a considerable discrepancy between sub-basins Climate and vegetation were the primary factors affecting baseflow but their effects on baseflow were somewhat disparate Precipitation and the proportion of forested land have a significant positive effect on baseflow while potential evapotranspiration has a significant negative effect Climate factors have a stronger effect than vegetation factors with precipitation being the main driver of baseflow and the proportion of forested land being a secondary driver This study elucidates the mechanisms of climate and forest effects on baseflow and has implications for the sustainable use of forests and water resources

The study of spatiotemporal changes in net primary productivity NPP of vegetation and its driving factors is of great significance in gaining a deeper understanding of vegetation growth status and guiding regional ecological construction and sustainable development planning Based on the MODIS NPP topography vegetation type climate and land use data of the Upper Minjiang River Basin the spatiotemporal characteristics of vegetation NPP and its driving factors in the Upper Minjiang River Basin from 2000 to 2020 were analyzed by trend analysis coefficient of variation partial correlation analysis and geographical detector The results showed that 1 From 2000 to 2020 the vegetation NPP in the Upper Minjiang River Basin generally showed a fluctuating trend of alternating upward and downward movements and the average annual vegetation NPP in the 21-year was 498 76 g m2·a The spatial distribution was high in the southeast and low in the northwest with an average coefficient of variation of 11 70% for the 21-year vegetation NPP with only 1 85% of the area showing degradation 2 The vegetation NPP in the Upper Minjiang River Basin was affected by climate factors and human activities and mean annual temperature and elevation were the dominant factors affecting changes in vegetation NPP and the two-factor interaction 52 38% was greater than the nonlinear 47 62% and the interaction of mean annual temperature and land use had the highest influence The average annual temperature suitable for the increase of vegetation NPP in the watershed is 10 04-16 01 ℃ and the average annual precipitation is 910 63-1 063 95 mm The study revealed the effects of natural factors and human activities on vegetation NPP which can provide a basis for the development of high-quality ecological protection and restoration strategies in the Upper Minjiang River Basin according to local conditions

Based on land use change in-depth study of the driving factors affecting regional Ecosystem Service Value ESV has important practical value for regional ecological environment optimisation and human-land relationship coordination Based on the land use data of Yanqi Basin from 1980 to 2020 the land use transfer matrix ecosystem service value assessment hotspot analysis trade-offs and synergies and geodetector were used to comprehensively analyse the land use change spatial and temporal evolution of ESV and ecosystem service trade-offs and synergies in the Yanqi Basin as well as to explore the mechanism of spatial variation of ESV spatial differentiation mechanism The results show that 1 Land use changes in Yanqi Basin were remarkable with a significant decrease in the area of unused land and grassland and the largest increase in the area of arable land 2 The ESV increased significantly mainly manifested in the rise of ESV in arable land waters and wetlands and the rise of water containment and waste treatment serv ices 3 The areas of both high-value and low-value ESV zones increased significantly and the area of the ESV high-value zone in Yanqi Basin increased significantly The area of high and low ESV areas increased significantly and the synergistic relationship among ecosystem services in Yanqi Basin was dominated by an increasing trend 4 The main factors influencing the spatial differentiation of ESV in Yanqi Basin were NDVI and annual average temperature the interaction among factors showed an enhanced relationship and the natural factors had a stronger explanatory power than the socio-economic factors The findings of this paper can provide theoretical references for the development of ecological protection and restoration programmes in the Yanqi Basin oasis

Due to specific geographical and climatic factors Xi'an faces relative scarcity of water resources with a considerable amount of precipitation resources being inefficiently conserved and consequently lost each year Understanding the trends in the functionality of water conservation and its influencing factor is crucial for Xi'an to overcome water resource challenges and enhance ecological security To address this the present study utilized the InVEST model to assess the spatial characteristics of water conservation in the urban area for the years 2010 and 2020 analyzing the trends in variation Additionally the FLUS model was employed to predict land water conservation for the year 2030 under both natural development and ecological conservation scenarios with subsequent analysis The results indicate the following Firstly the FLUS model demonstrated high accuracy with an OA value of 0 91 and a Kappa coefficient of 0 87 showcasing its applicability to Xi'an Secondly from 2010 to 2020 urban and rural ecological green spaces constituting 48 97% to 49 03% of the total area contributed to 71 93% to 73 68% of the city's water conservation exerting the most significant impact among all land-use types The disparity in urban and rural ecological green space orea proportions with 2 99% to 3 13% in the northern plains and 83 18% to 83 46% in the southern mountainous region resulted in a spatial pattern of water conservation characterized by “lower in the north higher in the south” Thirdly during the period from 2010 to 2020 Xi'an experienced a decrease of 4 24 billion cubic meters in land water conservation with a 67 15% contribution from the reduction in forest area by 38 94 km2 and an increase in grassland area by 20 19 km2 Lastly under the natural development scenario the total water conservation in 2030 increased by 5 25 billion cubic meters for the entire city while under the ecological conservation scenario an additional 7 million cubic meters were conserved Simultaneously the proportions of forest grassland and water bodies increased restraining the expansion of impermeable surfaces This research holds significance in providing valuable insights for Xi'an to formulate rational urban and rural ecological green space planning strategies to address water-related ecological issues

The establishment of plantation forests typically results in a gradual depletion of soil fertility a phenomenon that may further impair the soil's water conservation function This study conducts a system atic analysis of the differences in soil water retention and hydraulic conductivity between Larix kaempferi plantation forests and adjacent natural secondary forests in the Xiaolongshan region of Gansu Province to assess the specific impacts of plantation forest establishment on soil water conservation capabilities Although the two forest types differ in soil particle composition both are characterized by silty clay loam soils with robust water retention properties However the soil of the Larix kaempferi plantation forests exhibits significantly lower organic matter content P<0 001 and a higher bulk density P<0 01 compared to that of the natural secondary forests These disparities in soil texture particularly in structural differences result in the plantation forests having considerably lower saturated water content P<0 001 non-capillary water holding capacity P<0 001 and saturated hydraulic conductivity than the natural secondary forests Considering the relative degradation of the water conservation function in the soil of Larix kaempferi plantation forests it is recommended that plantation forests no longer serving production functions should gradually undergo naturalization transformations through enhancing the accumulation of soil organic matter to progressively restore and enhance the soil's water conservation capabilities

In order to investigate the effect of moisture on the energy-absorbing properties of wood the compressive mechanical response and energy-absorbing properties of balsa wood with different moisture contents under different compression directions were investigated by quasi-static compression tests and the corresponding energy absorption diagrams were established The results were as follows 1 The compression stress-strain curves and transverse compressive failure morphology were unaffected by moisture content while the longitudinal compressive failure morphology shifted from brittle fracture damage to shear and delamination splitting damage with increasing moisture content Water molecules played a role in plasticizing and stress dispersion 2 The compression properties of balsa wood along the grain were more sensitive to moisture change than those perpendicular to the grain As moisture content increased the crushing strength and plateau stress decreased nonlinearly under axial compression R2>0 90 and they decreased linearly under transverse compression R2>0 93 Compared with the specimen with 1 92% moisture content both the crushing strength and plateau stress of the specimen with 26 89% moisture content decreased by more than 44% the max min ratio of longitudinal compression plateau decreased from 3 78 to 1 58 while the transverse ratio remained basically unchanged Too high or too low moisture content is not conducive to the steady-state damage of wood 3 The lower the moisture content the higher the energy-absorbing capacity of balsa wood As the moisture content decreased the shoulder point shifted to the direction of high stress and high energy absorption value and the cushioning performance increased significantly The moisture content of 14 09% is the turning point of the longitudinal energy absorption properties 4 The mathematical models between the compression energy absorption properties and the moisture content of balsa wood with different grains combined with the energy absorption diagram can guide the moisture content control and grain configuration of shock-absorbing wood so as to ensure its application safety

It is of great ecological and economic significance to use ornamental plant materials to repair heavy-metal-contaminated soil In order to explore the differences of tolerance among Hydrangea cultivars under high lead stress 41 Hydrangea cultivars were used as experimental materials in this study Through soil pot experiments 6 indexes were comprehensively analyzed by membership function and the comprehensive evaluation value D value of lead tolerance was obtained Cluster analysis was carried out to identify high lead-tolerant Hydrangea cultivars The results showed that high concentration of lead stress inhibited the plant height and biomass of most Hydrangea cultivars Different cultivars have different enrichment and transport of lead 41 Hydrangea cultivars were divided into 3 types by cluster analysis including 2 high lead tolerance cultivars 27 medium lead tolerance cultivars and 12 low lead tolerance cultivars The high lead-tolerant cultivars ‘Xue Jingling’ and ‘Jia cheng’ of Hydrangea performed well in both growth morphology and heavy metal enrichment They had strong remediation potential for Pb-contaminated soil and could be used as alternative options for ornamental plant remediation materials

The study aims to examine the flowering and breeding characteristics of the native plant Deutzia parviflora promote the resistance breeding and resource utilization of Deutzia as well as enrich the species of flowering shrubs in the northern region The morphological characteristics of flower organs flowering phenology pollen viability stigma acceptability and breeding system of D parviflora were observed and analyzed 1 D parviflora began to bloom in late April and ended in mid-May in Beijing Its flowering type is concentrated flowering with a group flowering period of 22-23 d and a single flowering period of 8 d which can be divided into 8 stages 2 The stigma acceptability at the petal flattening stage was the strongest and the pollen viability at the stamen expansion stage was the highest 3 The optimal medium for pollen viability determination was 100 0 g L sucrose+0 3 g L H3BO3+0 2 g L CaCl2 4 Pollen can be dried and stored in the short term within 10 d at -20 ℃ and -80 ℃ in the medium term 10-30 d and at -80 ℃ for a long time more than 30 d 5 The pollen-ovule ratio of D parviflora was 23 695 93 the out-crossing index was 3 the fruit setting rate of xenogamy was the highest There is no apomixis in D parviflora and the breeding system is a mixed mating system dominanted by outcrossing mechanism requiring pollinators and it is more fertile and can be used as a parent for hybrid breeding in the genus Deutzia Its low self-incompatibility is not due to dichogamy and herkogamy