[Objective]By analyzing the quantitative changes in land use types,identifying driving mechanisms,and examining land cover transition patterns along with spatial proximity relationships in Changsha from 2000 to 2020,this study aims to reveal the underlying trends of land-use transformation in the city.[Method]Using a PLUS model-based mask extraction approach on raster datasets,this study examined the correlations and underlying mechanisms of various driving factors influencing land use change patterns in Changsha from 2000 to 2020.The land-use expansion module employs adaptive relationships to simulate spatial evolution,enabling analysis of dynamic processes within the study area.Based on the land-use spatiotemporal change data of Changsha from 2000 to 2020,a linear regression model was fitted to investigate the temporal and quantitative relationships among different land use types.The optimal fitting line was obtained by minimizing the sum of squared residuals between observed values and model predictions.The 12 selected driving factors were normalized to generate raster spatial distribution maps,contribution rates,and root mean square errors.Using the random forest algorithm,development probabilities for various land types were calculated.Based on three research objectives-natural development,ecological benefit maximization,and urban economic growth-three future scenarios(natural development,ecological conservation,and urban expansion)were established to simulate future land changes.[Result]Changes in land use categories showed a high correlation with time sequences,with linear regression coefficients averaging over 0.85.The main driving factors and their contributions vary among different land categories.The expansion area of urban land was mainly affected by elevation.The contribution rate of elevation reached 0.16 during the period from 2000 to 2010,and the RMSE value was 0.23.During the period from 2010 to 2020,the contribution rate of elevation decreased to 0.15,and the RMSE value was 0.24.Future land use simulations under the ND(Natural development),EP(Ecological protection),and US(Urban spread)scenarios predict urban expansion areas of 145.22 km2,46.93 km2,and 317.64 km2,respectively,highlighting the significant role of government policies and measures in influencing the spatiotemporal evolution of urban land use.[Conclusion]From 2000 to 2010,urban expansion demonstrated a steady growth trend in both scale and duration,while the decline rates of arable land and forest land accelerated during the same period.From 2010 to 2020,the expansion rate of construction land slowed down and stabilized,effectively mitigating the reduction trends of ecological lands such as arable land and forest land.In the influence mechanism,elevation is the primary factor;during this period,number of soil types exhibited the lowest impact intensity.The temporal variation patterns of these driving factors align closely with Changsha's actual development trajectory:extensive and rapid urban expansion from 2000 to 2010,followed by controlled expansion scale and slower growth rates from 2010 to 2020.
[Objective]Market demand in the wood furniture supply chain is strongly affected by seasonal fluctuations,unexpected disturbances,and multi-factor coupling,which often limits the accuracy and stability of traditional single forecasting models.To address this issue,an AMBOP-SRC model is proposed for market demand forecasting in the wood furniture supply chain,with the aim of improving forecasting accuracy,robustness,and generalization capability.[Method]First,the wood furniture sales data were cleaned,normalized,and aggregated at the weekly level to construct a demand time series.Then,a SARIMA model was employed to capture the linear trend and seasonal patterns of the demand series,and the initial residuals were extracted.Next,an SVR model optimized by particle swarm optimization(PSO-SVR)was used to fit the nonlinear fluctuations contained in the residual series.On this basis,an adaptive movement block optimization procedure(AMBOP)algorithm was introduced to dynamically optimize the parameters and collaborative forecasting process of the hybrid model,thereby improving search efficiency and prediction stability in a high-dimensional parameter space.Finally,ablation experiments,comparative experiments,and generalization experiments were conducted,and model performance was evaluated using indicators such as RMSE and MAE.[Result]Ablation experiments demonstrate that the absence of any component in the AMBOP-SRC forecasting model leads to a significant decline in predictive performance.The AMBOP method not only optimizes model parameters but also effectively balances the relationship between seasonal fluctuation modeling and emergency response,achieving deep adaptation to the characteristics of the furniture industry.Performance comparison experiments show that the AMBOP-SRC forecasting model significantly outperforms classical forecasting methods in the corresponding field,effectively improving the accuracy and interpretability of wooden furniture supply chain demand forecasting.Generalization experiments indicate that the AMBOP-SRC forecasting model exhibits strong adaptability across different datasets,making it applicable to demand forecasting in key stages of the wooden furniture supply chain.[Conclusion]The AMBOP-SRC forecasting model is highly suitable for wooden furniture supply chain demand forecasting,featuring high prediction accuracy and excellent generalization performance.Its results provide crucial decision-making references for furniture enterprises in optimizing inventory turnover rates and dynamically adjusting production plans,thereby enhancing supply chain resilience.
Polyploid breeding is one of the important ways to create new varieties of forest trees and cultivate excellent germplasm.This article systematically reviewed recent advances in the induction of polyploidy in forest trees using physical,chemical,and biological methods both domestically and internationally.The physical method is represented by temperature change and mechanical damage,which is easy to operate,but has the problems of low induction rate and poor controllability.Colchicine treatment,as the representative of chemical methods,is the most mature and widely used method.It is the mainstream method for polyploid creation of forest trees.However,high chimerism incidence and prolonged recovery time post-treatment remain major drawbacks.Biological methods such as protoplast fusion and endosperm culture have developed rapidly in recent years,showing unique advantages in overcoming distant incompatibility and reproductive isolation and shortening the breeding cycle.At present,the research on polyploid breeding of forest trees mainly focuses on representative tree species such as poplar and eucalyptus,and homologous tetraploid and triploid plants have been successfully obtained through various methods.Polyploid plants exhibit giant organs,significantly improved fiber length and wood properties,as well as enhanced stress resistance.In the future,the collaborative application mode of the three methods should be further optimized,and the application potential of emerging technologies such as gene editing in polyploid creation should be actively explored to promote the development of forest polyploid breeding in the direction of high efficiency and precision.
[Objective]This study explored the soil arbuscular mycorrhizal(AM)fungal communities in park green spaces under the context of urbanization,aimed to provide foundational data support for the soil microbial diversity and ecological conservation of parks in Nanchang City.[Method]In this study,three urbanization gradient levels(high,medium,and low)were divided according to the proportion of impervious surface area in the built-up area of Nanchang City,and 63 sample plots of park green space soil were sampled and investigated.High-throughput sequencing technology was used to detect the community characteristics of arbuscular mycorrhizal(AM)fungi in the soil,analyze the differences in the structural composition,Alpha diversity and Beta diversity of AM fungal communities,and reveal the correlation between AM fungal communities and soil physicochemical properties through RDA analysis.[Result]The AM fungal communities in the park green spaces of Nanchang City were predominantly composed of dominant genera such as Glomus and Paraglomus.The Shannon and Simpson indices exhibited a significant logarithmic increase with rising urbanization intensity by 3.89％and 1.90％,whereas the Dominance index showed a significant logarithmic decrease by 44.36％.Soil pH value,electrical conductivity,soil organic carbon content and total nitrogen content were positively correlated with the abundance of genera such as Glomus,Claroideoglomus,Scutellospora and Gigaspora;total potassium content,moisture content and soil bulk density were positively correlated with the abundance of genera such as Archaeospora and Diversispora,and soil total phosphorus content was positively correlated with the abundance of genera such as Paraglomus.[Conclusion]With the increase in urbanization intensity,species diversity and community evenness of AM fungi communities increased,while the dominance of the dominant genera weakened.Soil physicochemical factors such as soil organic carbon,pH value,total phosphorus content,and total potassium content play a key role in influencing the composition of AM fungal communities.
[Objective]To investigate the key growth and physiological mechanisms underlying the adaptation of different families of Choerospondias axillaris to low phosphorus stress,so as to provide theoretical basis for the subsequent cultivation of high phosphorus efficiency and excellent varieties.[Method]High-phosphorus-efficient families(L56,LF001)and low-phosphorus-sensitive families(L44,R27)were selected as experimental materials.A pot experiment was conducted under two phosphorus levels:normal phosphorus(16.0 mg/g,NP)and low phosphorus(0.2 mg/g,LP).Growth and physiological indices,including ground diameter,plant height,biomass,tissue phosphorus content,root activity,the activities of acid phosphatase(ACP),superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and nitrate reductase(NR)in rootswere measured to analyze the responses of morphological and physiological traits of different families to low phosphorus stress at the seedling stage.[Result]1)Under LP stress,the growth of four families was significantly inhibited,while the root-to-shoot ratio,root activity,POD activities and phosphorus use efficiency(PUE)increased significantly.ACP and NR activities showed a decreasing trend,whereas SOD and CAT activities tended to increase.The responses of these indicators to LP stress exhibited significant variation among families;2)Under low phosphorus stress,except for seedling height,the growth indexes such as ground diameter,root dry matter mass,total dry matter mass accumulation,root activity,ACP,SOD,NR activity and PUE of family L56 and LF001 were significantly higher than those of family L44 and R27;3)There were obvious family differences in the response of antioxidant enzyme system(SOD,POD,CAT)to low phosphorus stress:L56 showed extremely high SOD activity and high POD and CAT activity;lF001 showed extremely high POD activity and high SOD and CAT activity.R27 showed higher POD activity,but lower SOD and CAT activity.L44 showed higher CAT activity,but lower POD and SOD activity;4)Correlation analysis showed that there was a significant positive correlation between root-shoot ratio,root activity and antioxidant enzyme activity(SOD,POD,CAT)of Choerospondias axillaris at seedling stage.There was a significant positive correlation between NR and ACP,ground diameter,root dry weight,aboveground part dry weight and other growth indexes.The aboveground P accumulation was significantly positively correlated with aboveground part dry matter,but significantly negatively correlated with PUE.[Conclusion]L56 and LF001 belong to the synergistic and efficient type of high accumulation and high efficiency.
[Objective]To understand how radial growth of Abies fargesii var.faxoniana on different slopes in the mid-Min mountains responds to major climatic factors,how stable these responses are under climate change,and to provide a scientific foundation for elucidating the adaptive mechanisms of subalpine coniferous forests in response to climate change,thereby informing their conservation and management strategies.[Method]Using 48 tree-ring cores collected from the east and west slopes of the mid-Min mountains and using the dplR package in R,tree-ring chronologies were developed and growth trends were removed.Spearman correlation analysis and 21-year moving correlation analysis were applied to examine the responsiveness and stability of A.fargesii to monthly precipitation,mean temperature,mean maximum temperature,and mean minimum temperature from 1951 to 2022.[Result]Significant differences in the statistical characteristics of the standard chronologies between the eastern and western slopes were present.A.fargesii on the east slope exhibited higher sensitivity to the key climatic factors,with divergent response relationships,response stability and temporal patterns compared to that on the west slope.The negative correlation between the eastern-slope A.fargesii chronology and previous May precipitation became significant after the beginning of the 21st century,whereas the significantly negative correlation with current September precipitation gradually weakened after 1975.Meanwhile,trees on the west slope displayed unstable correlations with current June and September precipitation,but maintained a significant and stable positive association with previous August precipitation.Radial growth on both slopes was limited by July-August air temperatures of the previous year but promoted by air temperatures during the dormant period and growing season of the current year,with trees on the western slope more sensitive to air temperature.Trees on the west slope exhibited a gradual weakening of the previously significant negative response to the previous July mean temperature,while those on the east slope showed temporal instability in the same correlation.[Conclusion]The response patterns of A.fargesii on the eastern and western slopes of the central Minshan mountains to precipitation and air temperature were inconsistent,and the response relationships exhibited marked non-stationarity and dynamic variability across different time scales,indicating that slope aspect is an important factor influencing the climatic response of radial growth in A.fargesii.
[Objective]Taking Wuyishan national park as a case,this study developed a community participation in social-ecological systems(CP-SES)framework to identify the key factors and mechanisms influencing community participation.The aim is to promote effective community engagement and achieve harmony between humans and nature.[Method]Based on Ostrom's social-ecological system(SES)framework,this study constructed a tailored CP-SES analytical framework.A questionnaire survey and semi-structured interviews were conducted in the townships within and surrounding Wuyishan national park to collect data.An ordered multinomial logistic regression model was employed to identify significant influencing factors.[Result]Four key factors were identified as significantly impacting community participation in Wuyishan national park:1)"Community empowerment"within the governance system(OR is 2.325,P<0.05);2)"Willingness to insure"(OR is 1.430,P<0.05)and"skills training"(OR is 1.850,P<0.05)within the actor system;3)"Human-wildlife conflict"under interactions and outcomes(OR is 0.641,P<0.01).Community empowerment,willingness to insure,and skills training were found to be primary drivers promoting participation,whereas human-wildlife conflict was a significant impeding factor.The analysis of mechanisms revealed that community empowerment enhances residents'motivation by granting decision-making power and broadening participation channels.Residents'willingness to insure,driven by the benefits of commercial insurance,positively alters their attitudes and strategies towards the national park.Skills training overcomes the limitations of low educational attainment,thereby enhancing livelihood security and participatory impetus.Conversely,human-wildlife conflict undermines livelihoods,leading to negative attitudes towards the park and hindering community participation.[Conclusion]Based on the CP-SES framework adapted from Ostrom's social-ecological systems(SES)framework—comprising subsystems of resource systems,resource units,governance systems,and actors—this study provides a panoramic characterization of the logical interplays among various elements within the action situation of community participation in national parks.Addressing the critical issues diagnosed and the influencing factors identified through this framework,it is imperative to secure community empowerment,strengthen skills training,and refine human-wildlife conflict compensation mechanisms.Such measures are essential to facilitate robust community participation and achieve the sustainable development of both national parks and local communities.
[Objective]To precisely obtain the dynamic responses of fruits and flower buds under vibratory excitation and determine their detachment states through coupled modeling of wood viscoelasticity and tree dynamics,so as to provide reference for the design of vibratory harvesting parameters for Camellia oleifera fruits.[Method]Creep data of C.oleifera wood samples were first obtained via compression creep tests,and the generalized Kelvin-Voigt model was employed to fit the creep data to determine the viscoelastic parameters of the wood.Subsequently,finite element simulations of compression creep tests were conducted to verify the predictive accuracy of the identified viscoelastic parameters.On this basis,a finite element model of the C.oleifera tree was further established based on the viscoelastic constitutive model,and both modal analysis and transient dynamic analysis were performed to obtain the modal shapes and natural frequencies of the tree.The inertial force responses of C.oleifera fruits and flower buds under vibratory excitation were then calculated,and finally the detachment rates of the fruits and buds were predicted based on the peak inertial forces.[Result]1)Compared with conventional binary and ternary models,the generalized viscoelastic models can significantly enhance the goodness-of-fit for creep data within the testing duration,which enables accurate characterization of the short-term creep mechanical behavior of C.oleifera wood(achieving 99.92％predictive accuracy);2)At specific excitation frequencies,branch amplitudes far exceed that of the trunk;this"branch-dominated resonance"pattern can serve as a basis for excitation frequency selection;3)Under trunk excitation at the selected frequency of 9.428 Hz(with a 10 mm amplitude and a 400 mm excitation height),the fruit detachment rate reaches 93.94％and the bud detachment rate remains only 6.06％,meeting the requirements for high-efficiency and low-damage harvesting.[Conclusion]This study reveals the"branch-dominant resonance"phenomenon in the C.oleifera tree at specific frequencies,delineates the distinct inertial force responses between fruits and flower buds under vibratory excitation,and establishes detachment criteria based on peak inertial forces.These findings provide a quantifiable parametric design guideline for the efficient and low-damage vibratory harvesting of C.oleifera fruits.
[Objective]The fine root biomass and morphological characteristics of Pinus tabulaeformis plantation with different forest age and density in Daqing mountain of Hohhot City,Inner Mongolia were studied,and the relationship between forest age and density and fine roots and soil nutrients was clarified,so as to provide a theoretical basis for the scientific management of Pinus tabulaeformis plantation in Daqing mountain area.[Method]Twenty-four plots of Pinus tabuliformis plantations were established,comprising eight treatment types with different stand age classes and densities:young stands with medium density,young stands with high density,middle-aged stands with low density,middle-aged stands with medium density,middle-aged stands with high density,mature stands with low density,mature stands with medium density,and mature stands with high density.The root coring method was employed to collect fine root and soil samples from two depth layers(0-20 cm and 20-30 cm),investigating fine root biomass,morphological characteristics,and their relationships with soil nutrients under different stand ages and densities.[Result]The fine root biomass,root length density and root surface area density were concentrated in the 0-20 cm layer.In young forests,with the increase of density,fine roots showed an increasing trend.From middle-aged forest to mature forest,the fine roots showed a trend of increasing first and then decreasing with the increase of density.The total biomass,root length density and root surface area density of fine roots reached the maximum of 411.60 g/m2,830.87 m/m2 and 224.05 m2/m3 at medium density in middle-aged forest.Soil organic matter,total nitrogen,total carbon,available nitrogen and available phosphorus content were positively correlated with fine root biomass,root length density and root surface area density,but negatively correlated with fine root specific root length and specific surface area.[Conclusion]In the scientific management of Pinus tabulaeformis plantation in Daqing mountain,combined with the synergistic effect of forest age and density,high-density planting mode should be adopted in the young forest stage,and medium-density planting mode should be adopted in the middle-aged forest and mature forest stage,which is more conducive to promoting the growth and development of trees.
[Objective]To provide theoretical and technical support for the sustainable management and soil fertility maintenance of larch plantations.[Method]Larix olgensis plantations with basically the same site conditions were selected.In 2018,selective cutting operations with different intensities(25％,35％and 45％)were carried out according to the stock volume,and non-selective cutting was set as the control.Subsequently,three fixed sample plots were set up in the stands with different selective cutting intensities.In August 2023,after five years of selective cutting operation,the coverage thickness,standing stock,soil physical and chemical properties of litters were measured in each plot.Through single factor analysis of variance,Mantel analysis and structural equation modeling,the changes of litter cover thickness,standing stock and soil physical and chemical properties under different selective cutting intensities and their relationships were studied.[Result]After 5 years of selective cutting,the litter cover thickness decreased by 17.4％,30.3％,and 31.0％at 25％,35％and 45％selective cutting intensities,respectively,compared to the control stand.The undecomposed litter layer thickness decreased by 32.7％and 36.1％at 35％and 45％selective cutting intensities,respectively,compared to the control stand.The semi-decomposed litter layer thickness decreased by 25.7％,44.2％,and 43.4％at 25％,35％,and 45％selective cutting intensities,respectively,compared to the control stand.High-intensity selective cutting(45％)significantly reduced soil bulk density in the 0-10 cm layer by 17.7％compared to the control.Moderate-intensity selective cutting(35％and 25％)also reduced soil bulk density in the 20-40 cm layer,with reductions of 15.0％and 11.0％respectively.Soil moisture content increased by 40.8％(0-10 cm),21.8％(10-20 cm),and 18.7％(20-40 cm)after high-intensity selective cutting compared to the control.The maximum soil compaction degree in 0-40 cm soil layer was 785.0 kPa in control forest,724.4 kPa in 25％selective cutting forest,525.6 kPa in 45％selective cutting forest and 503.9 kPa in 35％selective cutting forest.Under the moderate selective cutting(35％),the soil pH,total nitrogen,total phosphorus,organic carbon and hydrolyzable nitrogen in the 0-10 cm soil layer increased by 5.5％,21.7％,39.8％,45.4％and 51.3％respectively compared with the control.Under the high intensity(45％)selective cutting,the contents of available potassium and available phosphorus in the 0-10 cm soil layer increased by 30.0％and 60.4％respectively compared with the control.The results of structural equation modeling showed that selective cutting had a significant positive effect on soil moisture content and soil chemical properties,and a significant negative effect on soil bulk density,litter cover and litter stock,and also had a significant negative effect on soil chemical properties through changing litter cover and litter stock.[Conclusion]Selective cutting management can significantly reduce the accumulation of litter on the surface of forest land,improve the microenvironment in the stand,and be beneficial to the decomposition of litter such as larch needles on the surface.After selective cutting with medium and high intensity(35％,45％),it can accelerate the decomposition of litter,effectively promote the circulation of soil nutrients,and play an important role in maintaining soil fertility and preventing soil acidification.
[Objective]To clarify the radial growth dynamics of Abies nephrolepis across different diameter classes in the Changbai mountains,reveal the response patterns and differences in growth to climatic factors among trees of various diameter classes,and to provide a scientific basis for forest management under climate change.[Method]Three different diameter classes of[15,25),[25,35)and[35,45)cm were continuously monitored by radial growth measuring instruments.The growth season was determined by the zero growth method,and the radial growth sequence was extracted.The dynamic relationship between the radial increment of different diameter classes and climate factors was explored by sliding correlation analysis.[Result]1)There was a significant difference in the daily radial increment sequence among[25,35)cm,[15,25)cm and[35,45)cm in the growing season of 2022(P<0.001).The total radial growth and average growth rate increased with the increase of diameter class,and the maximum growth rate of the[25,35)cm diameter class was the fastest.The maximum growth rates of[25,35)cm and[35,45)cm were at the beginning of the growing season,while the maximum growth rate of[15,25)cm was at the middle of the growing season.2)In the growing season of the year,there was a strong dynamic consistency between the radial growth of different diameter classes of A.nephrolepis and the response of climatic factors,but there were differences in the strength of the relationship with climatic factors at different stages,and the climatic factors with significant positive and negative correlations were different.As the growing season progresses,the daily radial increment of each diameter class of A.nephrolepis is similar to the dynamic response trend of average temperature and soil temperature.The radial growth of A.nephrolepis[15,25)cm was promoted by mean air temperature and 10 cm soil temperature,and was more inhibited by soil water content and air relative humidity.The negative correlation between radial growth and photosynthetically active radiation at[25,35)cm was stronger.The radial growth of A.nephrolepis[35,45)cm was more strongly inhibited by average temperature and 10 cm soil temperature,and also showed a stronger negative correlation with saturated water vapor pressure deficit,indicating that this diameter class tree was more vulnerable to temperature and drought stress,but it showed stronger adaptability and regulation ability to photosynthetically active radiation.[Conclusion]The radial growth of A.nephrolepis is affected by a variety of climatic factors.The physiological processes and competition of different diameter A.nephrolepis are different,which makes their radial growth dynamics and the response relationship with climatic factors different.Through the study,the response dynamics of various climatic factors and the radial growth of different diameter classes of A.nephrolepis were obtained.Differentiated conservation measures such as monitoring temperature and humidity dynamics,paying attention to the health status of diseased and weak plants,and preventing and controlling high temperature and drought stress should be taken for[15,25),[25,35),and[35,45)cm Abies nephrolepis to maintain growth stability and carbon sequestration.
[Objective]To explore the regulatory effect of novel miRNA phe-novel-miR276 on lignin synthesis in moso bamboo,so as to provide theoretical reference for material quality improvement and molecular breeding of moso bamboo.[Method]Using bioinformatics methods,we analyzed the novel differentially expressed miRNA(phe-novel-miR276)screened in the preliminary study of moso bamboo.qRT-PCR was applied to detect its expression patterns in different moso bamboo tissues,followed by calculation of relative expression levels and differential analysis.The phe-novel-miR276 was cloned to construct an overexpression plant vector,which was transformed into rice via Agrobacterium mediation for screening positive transgenic lines.Lignin content as well as POD and SOD activities of transgenic and wild-type rice were determined,and intergroup differences of each index were compared and analyzed.[Result]1)Sequence analysis revealed that phe-novel-miR276 shares high homology with the miR398 family,suggesting it is a new member of the miR398 family;2)phe-novel-miR276 is expressed in the roots,stems,and leaves of P.edulis,with the highest relative expression level in the roots;3)Phloroglucinol staining showed that the lignin staining depth in the stems and leaves of transgenic lines was lighter;meanwhile,the results of the microdetermination method indicated that the total lignin content in the stems and leaves of transgenic lines was significantly reduced;4)qRT-PCR detection demonstrated that,compared with wild-type rice,the expression level of Os10g36848-the rice homologous target gene of phe-novel-miR276(encoding ferulate 5-hydroxylase,F5H)-was significantly downregulated in transgenic lines.Additionally,the POD and SOD activities in transgenic lines were significantly higher than those in wild-type rice,respectively.[Conclusion]In P.edulis,phe-novel-miR276 exerts its regulatory role by downregulating the expression of lignin biosynthesis-related target genes,and indirectly affects the activity of the antioxidant enzyme system in plants.
[Objective]This study aims to systematically elucidate the distribution patterns and main influencing factors of fuel loads in three fuel types(herb layer,litter layer,and humus layer),construct high-precision prediction models for fuel load,and to accurately identify high-fire-risk areas in Chinese fir forest regions and develop differentiated forest fire management strategies.[Method]Based on 702 standard sample plots of Chinese fir forests in Hunan Province,surveyed from 2020 to 2022.Fifteen factors,including aspect,slope position,slope gradient,and canopy closure were selected.One-way analysis of variance was used to examine the distribution characteristics of fuel loads among the three fuel types,and Pearson correlation analysis was applied to investigate the correlations between 15 factors and 3 types of fuel loading.Prediction models for fuel load,including linear regression,random forest,gradient boosting,and XGBoost,were developed using Python 3.8.[Result]1)The fuel loads in the litter layer(0.615-21.110 t/hm²)and humus layer(0-44.210 t/hm²)of Cunninghamia lanceolata forests in Hunan Province exhibited extremely wide ranges.The mean fuel loads,in descending order,were:humus layer(11.647 t/hm²),litter layer(6.407 t/hm²),and herb layer(0.638 t/hm²),with significant differences among the three(P<0.01);2)The fuel load of the herb layer was primarily driven positively by herb cover(r=0.673)and significantly suppressed by canopy closure(r=-0.290)and stand density(r=-0.240).For the litter layer,litter thickness was the core influencing factor(r=0.657),while elevation(r=0.098)and slope position(r=-0.119)indirectly regulated its accumulation by affecting decomposition rates.The fuel load of the humus layer was significantly positively correlated with humus thickness(r=0.780),elevation(r=0.167),and total growing stock(r=0.180);3)The gradient boosting model performed best for the herb layer(R2=0.682 6)and litter layer(R2=0.751 8),while the XGBoost model achieved the best performance for predicting the humus layer fuel load(R2=0.665 5).The machine learning models(random forest,gradient boosting,and XGBoost)significantly outperformed the traditional linear regression model and demonstrated good generalization capability.[Conclusion]1)The extremely high fuel loads in the litter and humus layers of some C.lanceolata forest stands in Hunan Province pose a significant risk for forest fire occurrence and rapid spread;2)Canopy closure has opposite effects on the herb layer(highly significant negative correlation)and the litter layer(highly significant positive correlation);therefore,when implementing thinning operations,managers should balance the fire risks of both layers,and promptly remove logging residues after thinning to avoid a sharp increase in litter input.In addition,litter decomposition is slower and accumulation is greater at high-elevation upper slope positions;thus,prescribed burning or mechanical removal of thick litter layers should be carried out before the dry winter-spring season.Moreover,some stands have developed deep humus layers,and areas with thick humus accumulation should be prioritized for ground-fire prevention and regularly inspected;3)The gradient boosting and XGBoost prediction models exhibit high accuracy and strong stability,providing technical support for dynamic fuel monitoring,precise fire-risk zoning,and scientific fire prevention decision-making in C.lanceolata forest regions.
[Objective]To explore the changes of growth,photosynthesis,and other physiological indices of Carya illinoinensis under drought stress and rewatering,and to provide a reference for the study of drought resistance mechanisms and breeding of drought-tolerant cultivars in C.illinoinensis.[Method]Two-year-old grafted seedlings of 10 C.illinoinensis cultivars from southern provinces were used as test materials,with rootstocks being'Shaoxing'seedlings.Drought stress and rewatering treatments were conducted through potted water control.Growth status of each cultivar was investigated on day 0(D0),day 5(D5),day 10(D10)of drought stress,and day 10 after rewatering(R10).Leaf photosynthetic parameters,leaf anatomical structures,and related physiological indicators were measured.Principal component analysis and membership function analysis were used to comprehensively evaluate the drought resistance of the 10 cultivars.[Result]1)Under drought stress,all cultivars showed wilting symptoms such as leaf curling and branch drooping.Leaf thickness(LT),lower epidermal thickness(LET),palisade tissue(PT),and spongy tissue thickness(ST)decreased to varying degrees.Among them,'TJS'showed the largest decline,with LT,LET,PT,and ST significantly decreasing by 27.42%,29.96%,32.67%,and 40.19%,respectively,compared with D0.'C28'had the smallest decline,with decreases ranging from 4.73%to 13.22%for the four indicators compared with D0;2).Compared with D0,'KD'exhibited the highest net photosynthetic rate(Pn)and transpiration rate(Tr)at D10[4.53 μmol/(m²·s)and 1.2 mmol/(m²·s),respectively],with the smallest decreases(68.01%and 83.72%,respectively).'MD'showed the smallest decrease in stomatal conductance(Gs)(75.86%)'WQT'exhibited relatively low Pn,Gs,and Tr values with the largest decreases,reaching 91.30%,94.44%,and 95.35%,respectively;3)Root activity of different pecan varieties initially increased and then decreased.At D10,although root activity decreased for all varieties,it remained significantly higher than that at D0 for all except'XN'and'FKT'.Among these,'NKL'exhibited the greatest difference,with root activity increasing by 1-fold compared with D0.Leaf relative electrical conductivity(REC)gradually increased over time,with significant differences between D10 and D0;4)At R10,the leaf anatomical structures and photosynthetic characteristics of the 10 seedlings basically recovered to normal levels,while root activity remained at a high level.However,the recovery degrees of various indices also differed among cultivars;5)The comprehensive evaluation scores of the cultivars were ranked as:'KD','C28','NKL','MD','XN','FKT','WQT','TJS','BN',and'GX 5'.[Conclusion]Timely rewatering can alleviate the drought damage of C.illinoinensis and make the root vitality overcompensate.Therefore,when the drought time in summer and autumn is longer than 10 days,the plants should be watered in time;In addition,when planting C.illinoinensis in southern provinces with seasonal drought,it is advisable to consider drought-resistant varieties such as'KD','C28'and'NKL'.
[Objective]To explore the suitable planting density of the main varieties of Populus sect.Aigeiros in the Jianghan plain,establish a more scientific and suitable technical system for poplar afforestation in the Jianghan plain,and to provide technical support and theoretical support for efficient stand cultivation.[Method]4 main Section Aigeiros were selected in the Jianghan plain and planted in spring in 2017.Three replicates were set up in the experiment.In each replicate,five initial planting density zones(6 m×2 m,6 m×3 m,6 m×4 m,6 m×5 m,and 6 m×6 m)were designed.Different varieties were randomly arranged in the same density zone using a random block design.There were 12 plants per density,per variety,and per plot.From 2017 to 2024,the tree height and DBH were investigated after each leaf fall for eight consecutive years.Then,the changes in growth of different varieties at different densities over the years were analyzed,and multiple comparisons and analysis of variance were conducted.[Result]Under the same density,the DBH,tree height,volume per plant,and volume per unit area of P.deltoides'Huashi 2'were all optimal,while P.deltoides'2025'was the worst.Compared with other species,P.deltoides'Danhong'was suitable for cultivation of large-diameter wood at small density,while P.deltoides'Huashi 2'was more suitable for maximizing the benefits of the accumulated volume at medium density.There were extremely significant differences in DBH,tree height,volume per plant,and volume per unit area among different densities and varieties in the 8th year after planting.[Conclusion]With the growth of tree age,the DBH and volume per plant of the four black poplar cultivars decreased with the increase of density,and the growth rate slowed down after 6 years.The differences in tree height growth under different initial planting densities were small,but the growth also slowed down after 6 years.At the density of 6 m×2 m,P.deltoides'Huashi 2',P.deltoides'Danhong'and Populus×euramericana'Chulin 2'could obtain the maximum volume per unit area,while P.deltoides'2025'could obtain the maximum volume per unit area at the density of 6 m×6 m.P.deltoides'Huashi 2'and P.deltoides'Danhong'are more suitable for cultivation in the Jianghan Plain.They feature rapid growth,and can be cultivated as short-rotation stands for medium-and small-diameter timber,while also possessing great potential for targeted cultivation of large-diameter timber.The interaction effect between varieties and density began to emerge after 3 years.The interaction effect between cultivars and density began to emerge after 3 years,with growth indicators differing among the 4 poplar stands,but these differences weakened or disappeared as stand age increased.
[Objective]To investigate the applicability of unmanned aerial vehicle(UAV)LiDAR,handheld LiDAR,and their fused point cloud data for individual tree parameter extraction and aboveground biomass estimation,and to improve the accuracy of single-tree scale modeling in complex forest stands.[Method]The study was conducted in five plots of Pinus kesiya at the Puwen experimental forest of the Yunnan Academy of Forestry and Grassland.UAV LiDAR point cloud data and handheld LiDAR point cloud data were collected separately as two independent data sources,followed by data fusion of the two datasets.The watershed algorithm was applied to segment individual trees from the UAV LiDAR point cloud,whereas a distance-based clustering algorithm was used for the handheld and fused point clouds.Then,a total of 71 variables were extracted from individual tree point clouds,including 4 structural features,40 height-related variables,10 density variables,and 17 voxel-based features.The Boruta algorithm and random forest feature importance ranking were used for variable selection,and key variables were then used to build random forest models for AGB estimation.The modeling accuracy of different data sources was compared.[Result]1)The overall segmentation F-scores for UAV,handheld,and fused point cloud data were 0.90,0.95 and 0.97,respectively;2)The R2 values of tree height estimation from UAV,handheld,and fused data were 0.93,0.94 and 0.94,respectively,with RMSEs of 1.43 m,1.74 m,and 1.68 m.The fused data achieved a DBH estimation accuracy of R2=0.95 and RMSE is 2.13 cm;3)For the three types of point cloud data,71 variables were extracted and independently selected using the Boruta algorithm and Random forest.For each dataset,eight key variables were identified separately and used for single-tree aboveground biomass modeling;4)The estimation accuracy of individual tree above-ground biomass based on UAV point cloud data was R2=0.83,RMSE is 85.69 kg/plant and rRMSE is 44.53％;based on handheld point cloud data,R2=0.87,RMSE is 72.02 kg/plant and rRMSE is 36.34％;and based on fused point cloud data,R2=0.86,RMSE is 70.65 kg/plant and rRMSE is 36.72％.[Conclusion]The individual tree biomass model constructed based on the random forest method demonstrated good predictive performance across different data sources,with the fused point cloud data from UAV and handheld LiDAR showing superior accuracy and stability.
[Objective]To reveal the genetic basis of important economic traits in Dendrocalamus latiflorus,elucidate the patterns of genetic variation,and to accelerate the process of genetic improvement and precision breeding.[Method]Eight geographically diverse D.latiflorus provenances were evaluated,with provenance codes LZ-1,LZ-2,LZ-3,LZ-4,BS,YD,JY,and FJ.Seedling stage phenotypic variation was analyzed by assessing above-and below-ground morphological traits and biomass.Genetic parameters were estimated.Superior provenances were identified using membership function for comprehensive evaluation.[Result]11 phenotypic traits showed significant(P＜0.05)or extremely significant(P＜0.01)differences among different provenances of Ma bamboo(Dendrocalamus latiflorus).Among them,provenance YD had the highest number of shoots(8.83);provenance LZ-4 had the highest values for leaf expansion number,average root length,leaf area,ground diameter,and plant height(25.63,9.76 cm,9 566.77 mm²,19.70 mm,2.96 cm,respectively);provenance LZ-3 had the highest number of roots,average root diameter,root biomass,and culm number(23.19,1.22 mm,1.20 g,1.64,respectively);provenance FJ had the largest culm biomass(82.93±24.46 g).The genetic coefficient of variation for each trait ranged from 0.34%to 36.92%,and heritability(H2)exceeded 0.50 for all traits;heritability was extremely high for plant height(0.96),culm number(0.95),leaf area(0.94),ground diameter(0.92),and number of shoots(0.89).Correlation analysis showed that the number of bud emergence was significantly(P＜0.05)or extremely significantly(P＜0.01)positively correlated with leaf expansion number,mean root length,mean root diameter,bud biomass,and leaf biomass.Leaf area was extremely significantly(P＜0.01)positively correlated with bud biomass,leaf biomass,root biomass,total biomass,and culm number.Regarding phenotypic genetic gain for each trait,provenance LZ-4 was the most prominent,with positive genetic gains for multiple traits,including number of shoots(2.53%),leaf expansion number(7.03%),average root length(1.84%),bud biomass(2.56%),leaf biomass(1.24%),and ground diameter(2.23%).Based on principal component analysis,four principal components were extracted,with a cumulative contribution rate of 79.034%,covering key phenotypic characteristics such as growth activity,root development,and biomass accumulation of Ma bamboo.The comprehensive evaluation results showed that provenance LZ-4 had the highest comprehensive score(1.179).[Conclusion]The eight provenances of Ma bamboo showed differences in seedling traits,among which provenance LZ-4 performed best,followed by JY,BS and LZ-2.
[Objective]To reveal the differences in growth rhythms and ecological strategies among three dominant Castanopsis species in the subtropical broadleaved secondary forests of Chongyi County,Jiangxi Province,and to provide a theoretical basis for classified management,structural regulation,and sustainable management of this region and similar subtropical secondary forests,as well as methodological references for multidimensional tree growth simulation under small-sample conditions.[Method]Three dominant Castanopsis species-C.fargesii,C.faberi,and C.carlesii-in the subtropical secondary forests of Chongyi County were selected for analysis.Sample trees were subjected to stem analysis to obtain precise time-series data of annual radial growth.Five classic growth functions(Logistic,Gompertz,Hossfeld IV,Korf,and Richards)were applied to fit and compare the growth processes of DBH,height,and volume for each species.The Richards model,identified as the best-fitting function in most cases,was used to construct a system of nonlinear compatible growth equations.These equations were then estimated using the seemingly unrelated regression(SUR)method.Additionally,logarithmic transformation was introduced to correct heteroscedasticity in allometric growth models,thereby improving model stability.Based on the modeling results,growth rate and maturation patterns of the three species were further compared and analyzed.[Result]Among the five tested models,the Richards function provided the best fit across multiple growth dimensions.The SUR-based compatible model revealed significant residual correlations between DBH and volume(r=0.875 1),and between DBH and height(r=0.682 0),validating the necessity of joint modeling.After logarithmic transformation,the allometric models exhibited a substantial reduction in mean systematic error(18.7％to 56.7％),while maintaining high R2 values and stable fitting performance.Growth pattern analysis showed that C.faberi and C.carlesii had stronger early growth potential and faster maturation,making them suitable for timber-oriented management.In contrast,C.fargesii exhibited a slower growth rate but demonstrated strong ecological adaptability,making it ideal for deployment in ecological conservation forests.[Conclusion]Under limited sample conditions,this study successfully developed nonlinear compatible models for DBH,height,and volume of three dominant Castanopsis species,and effectively identified interrelationships among growth dimensions using the SUR method.The introduction of logarithmic transformation significantly improved the performance of the allometric models by reducing heteroscedasticity.Furthermore,through a comprehensive analysis of current annual increment and mean annual increment,the study further reveals significant differences among the three Castanopsis species in growth rates of diameter at breast height,tree height,and stem volume,as well as in maturation patterns.C.faberi and C.carlesii exhibit a fast-growing strategy,whereas C.fargesii shows a stable and conservative strategy,reflecting interspecific differences in resource utilization and environmental adaptation.
[Objective]This study proposed a high-precision,high-efficiency method for surface defect detection of particleboard that is suitable for practical industrial scenarios to address the problems of high missed detection rate,slow detection speed,and insufficient ability to identify complex defects associated with traditional detection methods in current particleboard production,thereby achieving a dual optimization of detection accuracy and real-time performance.[Method]Based on RT-DETR-r18,ablation experiments were conducted using the control variable method to verify the effectiveness of the three key modules:ECG-CFNet,FSA,and MPCA.Several mainstream lightweight backbone networks,including Swin Transformer and VanillaNet,were substituted for comparison of their training performance.The improved model was further compared with SSD,Faster-RCNN,YOLO series,and the original RT-DETR to validate its superiority.Key indicators such as mAP@50 and GFLOPs were adopted,combined with performance curves,PR curves,and visualization results,to comprehensively evaluate the detection accuracy,efficiency,and industrial applicability of the model.[Result]Comparison experimental results on standard defect image datasets show that the proposed improved algorithm achieves 91.9%in terms of mean detection accuracy(mAP@50),which is 2.9%higher than the original RT-DETR-r18 model.At the same time,the number of parameters of the model and the computational complexity are both decreased,which suggests that while guaranteeing the improvement of the detection accuracy,the detection efficiency is optimized as well.Specifically,in the detection of typical defect types such as cracks,shavings and black spots,both show higher recognition rates and lower false alarm rates.[Conclusion]The improved RT-DETR algorithm significantly improves the accuracy and real-time performance of particleboard surface defect detection while maintaining low computational resource consumption,and has strong industrial deployability and application prospects.
[Objective]To screen out Camellia oleifera cultivars with strong heat tolerance and provide a theoretical basis for breeding new heat-tolerant varieties.[Method]A pot experiment was conducted using the method of high-temperature stress in an intelligent greenhouse on seedlings of two C.oleifera cultivars,'Dabieshan 1'and'Changlin 53'.Nine time gradients were set:0(CK),4,7,14,21,28,35,42 and 49 d.Ten physiological and biochemical indicators were measured,including relative water content,relative electrical conductivity,malondialdehyde content,hydrogen peroxide content,superoxide dismutase activity,peroxidase activity,catalase activity,soluble sugar content,soluble protein content,and free proline content.The heat tolerance of the two C.oleifera cultivars was comprehensively evaluated using the average membership function value of each physiological indicator.[Result]1)The leaf relative water content of both cultivars decreased continuously with the extension of high-temperature treatment,and the decline accelerated after 7 days of stress.After 49 days of high-temperature treatment,the leaf relative water content of both cultivars reached its minimum,with'Dabieshan 1'at 71.40%and'Changlin 53'at 63.32%.The relative electrical conductivity,malondialdehyde content,and hydrogen peroxide content increased continuously with the extension of high-temperature treatment and reached their maximum at the 49th day;2)The activities of superoxide dismutase and peroxidase in the leaves of both cultivars first increased and then decreased.The catalase activity in'Dabieshan 1'leaves showed a continuous upward trend,while that in'Changlin 53'increased in the early stage of stress and began to decrease after 42 d of stress;3)The proline,soluble sugar,and soluble protein contents in'Dabieshan 1'leaves continued to increase.In'Changlin 53'leaves,proline and soluble protein contents continued to increase in the early stage of stress,reached their maximum at the 42th day,and then decreased;soluble sugar content continued to increase in the early stage of stress,reached its maximum at the 35th day,and then began to decrease;4)The average membership function value of'Dabieshan 1'was 0.559,and that of'Changlin 53'was 0.449,indicating that the heat tolerance of'Dabieshan 1'was superior to that of'Changlin 53'.[Conclusion]Under high-temperature stress,the physiological response patterns of the two C.oleifera cultivars seedlings were different.The comprehensive membership function evaluation showed that the average membership function value of'Dabieshan 1'(0.559)was higher than that of'Changlin 53'(0.449).The heat tolerance of'Dabieshan 1'was superior to that of'Changlin 53'.
