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- 1Genetic transformation and functional characterization of Chimonanthus praecox SAMT gene in tobacco
- 2Forest canopy height estimation using LiDAR and optical multi-angler data
- 3Quantitative analysis of stand spatial structure of Cunninghamia lanceolata non-commercial forest based on Voronoi diagram.
- 4Forest carbon sequestration potential in China under the background of carbon emission peak and carbon neutralization
- 5ENVI-met model; sensitivity analysis; three-dimensional temperature field of vegetated scenes
- 6Responses of leaf morphological traits for broadleaved woody plants along the altitudinal gradient of Changbai Mountain,northeastern China. Journal of Beijing Forestry University
- 7Changes in forest resource carbon storage in China between 1949 and 2018
- 8Bioinformatics analysis of expansin gene family in poplar genome.
- 9Pathway and method of forest health assessment using remote sensing technology
- 10Transcriptome analysis of gene expression profiling in the suspension cells of Populus tomentosa treated by histone deacetylase inhibitor TSA
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- 1Effects of soilforming rocks and sprout ages on the bark quality of Pteroceltis tatarinowii
- 2Changes of configuration and major chemical components for eucalyptus wood pretreated by steam cracking
- 3Biomass and net primary productivity of three plantation communities in hilly land of lower subtropical China.
- 4Overexpression of Populus euphratica peuMIR156j gene enhancing salt tolerance in Arabidopsis thaliana
- 5Quantifying the soil carbon changes following the afforestation of former arableland
- 6Rapid light-response curves of PSⅡ chlorophyll fluorescence parameters in the leaves of Salix babylonica, Salix ‘J172’ and Salix leucopithecia to Cd2+ stress
- 7Effects of stand density on community structure and species diversity of Cupressus funebris plantation in Yunding Mountain, southwestern China
- 8Spatial continuity of fuels in major coniferous forests in Beijing mountainous area: fuel vertical continuity and crown fire occurrence.
- 9Life table and survival analysis of Osmanthus fragrans wild population
- 10Studies on the wood fiber-rock wool-composites
- More+
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, Available online ,
doi: 10.12171/j.1000-1522.20230098
Abstract:
Objective This project investigates the extraction process of Morus alba leaves flavonoids and their free radical scavenging ability, inhibition of α-glucosidase and α-amylase activity, aiming at obtaining a novel preparation method that fully maintains the activity of Morus alba leaves flavonoids, and providing a theoretical basis for the development and utilization of Morus alba leaves resources. Method The ultrasonic-semi-bionic method was used to extract the flavonoids from the Morus alba leaves. We investigated the effects of four factors (liquid-to-material ratio, ultrasonic time, ultrasonic temperature, and ultrasonic power) on the yield of Morus alba leaves flavonoids and the average scavenging of DPPH· and OH· radicals. The extracting process was optimized using the response surface test to evaluate the inhibitory effects of Morus alba leaves flavonoids on α-glucosidase and α-amylase. Result The results showed that optimal extraction conditions of Morus alba leaves flavonoids were as follows: ratio of liquid to solid 30 mL/g, ultrasonic time 97 min (the time ratio of the three stages 1∶2∶2), ultrasonic temperature was 49 ℃, ultrasonic power was 400 W. Under conditions, the flavonoid yield up to (38.23 ± 0.42) mg/g was obtained with an average clearance rate of (57.04 ± 0.97) %. Under optimal conditions, the IC50 value for α-glucosidase inhibition by Morus alba leaves flavonoids was (1.081 ± 0.130) g/L, and that for α-amylase inhibition was (1.204 ± 0.190) g/L. The free radical scavenging ability of Morus alba leaves flavonoids extracted by ultrasonic-semi-bionic method was stronger than that of the ultrasonic method, and the yield of Morus alba leaves flavonoids extracted by ultrasonic-semi-bionic method was higher than that of the semi-bionic method. Conclusion Morus alba leaves flavonoids extracted by ultrasonic-semi-bionic method have good free radical scavenging ability and inhibitory effect on α-glucosidase and α-amylase. Compared with the single extraction method, the Morus alba leaves flavonoids extracted by ultrasonic-semi-bionic method have higher bioactivity and yield. Morus alba leaves flavonoids can be developed as blood glucose regulating products for people with high glucose levels, and the ultrasonic-semi-bionic method can provide a better technical reserve for the industrial preparation of Morus alba leaves flavonoids.
, Available online ,
doi: 10.12171/j.1000-1522.20230156
Abstract:
Objective In order to further analyze the interaction between wood cell wall and water, the changes of physical environment (pores) and the binding state of water of wood cell wall before and after furfuryl alcohol modification were investigated. Methods The fast-growing poplar (Populus cathayana) was taken as the research object, and the physical environment of water in the wood cell wall was modified by furfuryl alcohol. The microscopic morphology, modifier distribution, functional groups and pore structure of the modified wood were characterized by scanning electron microscopy, confocal laser scanning microscope, Fourier transform infrared spectrometer and nitrogen adsorption under oven-dry state. Besides, differential scanning calorimetry thermoporosimetry and two dimensional low field nuclear magnetic resonance were used to analyze the changes of physical environment and the binding of water in the cell wall before and after modification under low humidity, air-dry, high humidity and fiber saturation state. Results The mass percent gain and bulk percent gain of wood modified by furfuryl alcohol were 35.1% and 12.6%, respectively, accompanied by cell wall thickening. After modification, the specific surface area and pore volume of wood cell wall were reduced by 29.9% and 35.3%, and furfuryl alcohol resin blocked part of the pores in wood cell wall. From the low humidity state to the fiber saturation state, the pore volume of both untreated and furfuryl alcohol modified wood showed an increasing trend, and the maximum distribution of cell wall pore size of untreated wood ranged from 3.41 to 5.65 mm3/g, at an increase of 65.7%. The maximum cell wall pore size distribution of furfuryl alcohol modified wood rose from 2.99 to 4.63 mm3/g, increased by 54.9%. Under different water conditions, the pore volume of furfuryl alcohol modified wood was all lower than that of untreated wood. Moreover, at high relative humidity, the effect of water on the pore volume of wood cell walls was more pronounced. With the increase of relative humidity, the moisture content of both untreated wood and furfuryl alcohol modified wood became greater, while the moisture content of furfuryl alcohol modified wood was lower compared with that of untreated wood under the same conditions, suggesting a reduction in hygroscopicity. As the moisture content increased, the T1/T2 value of cell wall water in untreated and furfuryl alcohol modified wood decreased, and the water mobility enhanced. The T1/T2 values of two types of cell wall water in furfuryl alcohol modified wood were much higher than those in untreated wood, which further indicated that furfuryl alcohol modification changed the physical environment of cell wall, and the mobility of water molecules weakened with the increasing bound of confining space. Conclusion After modification by furfuryl alcohol, furfuryl alcohol resin entered the cell wall of wood and polymerized in situ, resulting in lower cell wall pore volume of modified wood than that of untreated wood under oven dry, low humidity, air-dry, high humidity and fiber saturation state. Besides, in the high humidity state, the pore volume showed a greater growth rate. The variations in the physical environment gave rise to a decrease in the space of wood cell walls to hold water, and at the same time, the physical binding of water molecules by the cell wall increased, leading to a decrease in mobility.
Abstract:
Objective Ecological spatial networks play an important role in safeguarding ecological processes, maintaining ecological security, and enhancing ecosystem services. Currently, most of the research on ecological spatial networks focuses on potential networks, with relatively little attention paid to the study of existing ecological spatial networks. Based on long-term land use data, the extraction of existing ecological spatial networks and analysis of their structural evolution characteristics provides an important basis for optimizing network structure, constructing regional ecological security patterns, and enhancing regional ecosystem service functions. Method Taking the Inner Mongolia sand-prevention belt as the research area, this study first used spatial morphological analysis method to analyze the spatial distribution characteristics of multiple landscape components in 1990, 1995, 2000, 2005, 2010, 2015, and 2020. Then, using the core area as the node and bridges as edges, the existing ecological spatial network of the research area was constructed. The structural evolution characteristics of the existing ecological spatial network were studied using various topological structure indicators, such as degree, degree distribution, diameter, average path length, and clustering coefficient in complex network analysis. Result The landscape components in the research area were mainly core areas and connecting bridges, which accounted for 32.13% and 28.72% of the research area, respectively, followed by edges, islands and rings. The core area had been decreasing continuously, while the number of islands had been gradually increasing. The average degree of the ecological spatial network in the research area fluctuated between 20.01 and 39.98 over the past 30 years, and the power-law characteristics of degree distribution were obvious, with the power-law index showing an upward trend. The network diameter decreased from 24 in 1990 to 17 in 2020, and the average path length increased from 4.2 in 1990 to 5.14 in 2020. The average number of connected subgraphs was 61 over the past 30 years, showing an increasing trend, while the average size of connected subgraphs was 33.35, showing a decreasing trend. The network had a strong degree-degree correlation, and there was no obvious quantitative relationship between degree and clustering coefficient. Conclusion The trend of various indicators over the past 30 years indicates that the ecological spatial network in the research area is a scale-free, non-hierarchical, assortative small-world network. The network has strong heterogeneity but shows a decreasing trend, with local connections being dense and community structure being obvious. However, long-distance connections across communities are decreasing, and the network is gradually splitting into multiple isolated subgraphs, resulting in a decrease in overall connectivity. Optimization of the landscape pattern in the research area can be achieved through measures such as building cross-regional ecological corridors and increasing connections between different communities.
Abstract:
Objective In order to improve the gap-filling accuracy of net ecosystem productivity(NEE) under long-term missing, this study used the Artificial Neural Network(ANN) and Bi-directional Long Short-Term Memory(Bi-LSTM) to combine the environmental factors and temporal characteristics of NEE, proposing the ANN-BiLSTM model. Method This study took the NEE data and micro-meteorological data of Yanchi Observatory in Ningxia of northwestern China as the research object, and evaluated the gap-filling results of the ANN-BiLSTM model, Random Forest(RF), ANN, K-Nearest Neighbor(KNN), Support Vector Regression(SVR) and Marginal Distribution Sampling(MDS) under long-term absence of NEE by randomly eliminating five kinds of missing scenarios for 7, 15, 30, 45 and 90 d. Result When the number of missing days was ≤ 30 d, the gap-filling accuracy of each model was relatively reliable. The ANBiLSTM model had the highest gap-filling accuracy. The mean coefficient of determination (R2) was 0.48−0.56. The root mean squares of errors (RMSE) and mean absolute error(MAE) were 0.68−1.92 μmol/(m2·s) and 0.45−1.3 μmol/(m2·s). When the missing data days were ≥ 45 d, MDS cannot process missing values. The gap-filling accuracy of ANN-BiLSTM model was significantly higher than machine learning. The mean value of R2 > 0.45, RMSE and MAE were 0.79−1.95 μmol/(m2·s) and 0.50−1.31 μmol/(m2·s). Conclusion When the length of missing NEE data in temperate desert shrub ecosystems is > 30 d, we suggest to use ANN-BiLSTM to interpolate the missing data, which can improve the accuracy of long-term NEE gap-filling results to a certain extent.
, Available online ,
doi: 10.12171/j.1000-1522.20230052
Abstract:
Objective The nonlinear mixed-effects tree height-DBH model of Cunninghamia lanceolata based on stand dominant height and climate factors is established, which provides theoretical basis for the research on growth and forest management. Method Based on the annual monitoring and evaluation of national forest resources of Guangxi Zhuang Autonomous Region, southern China in 2020, this study used the data of DBH and height of each tree, climate data of 25 Cunninghamia lanceolata sample plots, chose the basic model with the highest simulation accuracy among seven common height-DBH models. On this basis, stand competition, site condition and climatic factors were used to build generalized nonlinear model, then used the sample plot effect to build nonlinear mixed-effects model. The 10-fold cross-validation method was applied to the test of three models. Result Chapman-Richards model was the basic height-DBH model with the highest accuracy. The stand dominant height, basal area of forest stands and the mean annual precipitation was significantly related to the tree height growth, which were used to build generalized nonlinear model. Through comparative analysis, the study selected three random parameters to build nonlinear mixed-effects model. The adjustment determination coefficient of basic model, generalized nonlinear model and nonlinear mixed-effects model were 0.674 2, 0.797 3 and 0.857 3, respectively, the mean absolute errors were 1.607 5, 1.270 1 and 1.010 6 m, the root-mean-square errors were 2.032 1, 1.632 1 and 1.338 4 m, and the relative root mean square errors were 20.796 4%, 16.703 3% and 13.697 3%, respectively. The nonlinear mixed-effects model showed the best fitting effect. Conclusion Using nonlinear mixed-effects tree height-DBH model based on stand dominant height and climatic factors can better describe the height-DBH curve of Cunninghamia lanceolata, which is suitable for the prediction of tree height on a large scale.
, Available online ,
doi: 10.12171/j.1000-1522.20230011
Abstract:
Objective The rapid development of unmanned aerial vehicle remote sensing has provided a new direction for diameter at breast height (DBH) prediction. This study was suitable for extracting individual tree crown factors from sample plots through unmanned aerial vehicle remote sensing technology, estimating indicators such as DBH and stand basal area per hectare, and achieving accurate and efficient forest resource monitoring and management. Method Based on the ground survey data of 33 Cunninghamia lanceolata plantations in Jiangle National Forest Farm, Fujian Province of eastern China, ten traditional models and two machine learning methods were used to estimate the individual DBH. Based on different combinations of independent variables, the impact of different factors on the estimation of DBH was analyzed. Result According to the fitting results of traditional model parameters, it can be seen that the crown radius was significantly positively correlated with DBH, while the stand density, crown deviation factor, and competition index were all significantly negatively correlated with DBH. The optimal competition index introduced in the traditional model modeling process was CI2, which was related to the overlapping internal angles of tree crowns, and the fitting result of model power logistic model was the best, followed by the power function model (with intercept). The power function model (with intercept) had the best estimation effect when using test data for estimation. RF models all had high fitting effect. Using test data to estimate, different competition indices had varying degrees of improvement in model fitting, and the competition index CI3, which was related to the overlapping area of tree crowns, achieving the best effect. The goodness of fit of SVR model was less than that of random forest and slightly greater than traditional model. When estimating the DBH, the model containing competition index CI4 related to the size of competing trees was the optimal model. Conclusion Both traditional models and machine learning models have achieved certain results in fitting and estimating the DBH of individual trees, and the use of RF models is more effective. Adding competition indices related to tree crowns to different combinations of independent variables in the model can improve the prediction accuracy, increase the R2 and reduce EMA, ERMS, and AIC. The optimal competition index introduced for different models is the competition index CI2 related to overlapping internal angles, and in the machine learning methods, the competition indexes CI3 and CI4 related to the size of target trees and competing trees also achieve good results. The improvement effect of CAI on DBH estimation still needs further verification.
, Available online ,
doi: 10.12171/j.1000-1522.20220182
Abstract:
Objective The ovule abortion of Camellia oleifera is serious. Only a few ovules could develop into mature seeds, but its abortion mechanism is not clear. The research investigated abortion period, microstructure changes and abortion reasons of ovules to clarify the abortion process and to provide certain theoretical basis and practical significance for increasing the yield of Camellia oleifera. Method The fruits of C. oleifera cv. ‘Huashuo’ were chosen as the experimental material. The ovule morphology in Camellia oleifera fruit was observed under stereomicroscope. We counted the proportion of abortive ovules. The stage of losing activity of abortive ovules was observed by FDA staining technique and stereomicroscope. The histological changes of fertile and abortive ovules were clarified by paraffin technique and microscopic observation, and the starch grain distribution in fertile and abortive ovules was marked by K-KI2 staining and PAS reaction. The CFDA fluorescence tracing experiment and laser confocal microscopy were used to reveal assimilate transport pathways in fertile and abortive ovules. The qRT-PCR was used to analyze the expression of genes related to sugar and energy metabolism, reactive oxygen species metabolism, and apoptosis processes in fertile and abortive ovules. Result (1) The microscopic observation showed that the size of fertile and abortive ovules differed after 26 WAA (weeks after anthesis). The results of FDA staining indicated that the abortive ovules gradually lost their activity during fruit development. (2) At 37 WAA, the proportion of abortive ovules reached 64.08%. (3) Microscopic observation showed that the embryo and endosperm of fertile ovules developed normally, and the inner and outer integuments were tightly united; the abortive ovules had no endosperm cells, and the space between the inner and outer integument was wild. Starch grains were observed in both the suspensor and endosperm of fertile ovules, and only a few starch grains were observed on the shrunken inner integuments of abortive ovules. (4) CFDA fluorescence tracing results revealed differences in assimilate transport modes between fertile and abortive ovules. There was no callose deposition on the inner integument of fertile ovules, while callose deposition can be seen on the inner integument of abortive ovules. (5) Genes related to sugar and energy metabolism, reactive oxygen species metabolism, and apoptosis processes were differentially expressed in fertile and abortive ovules. Conclusion The abortive ovules have abnormal structure and lack starch accumulation. There are some callose depositions on inner integument. There are differences in the transport modes of assimilates between abortive ovules and fertile ovules. Different expressions of genes about material and energy metabolism, antioxidant action and apoptosis processed in the ovules might be related to the abortion of Camellia oleifera ovules.
, Available online ,
doi: 10.12171/j.1000-1522.20230190
Abstract:
Objective Puffed wood-based metal composite (PWMC) is decorative metallic wood material with a high thermal conductivity and moderate density. To provide technical reference for its future high value-added applications in the fields of interior decoration and household wooden products, the research on painting properties and lightfastness of PWMC has been carried out in this paper. Method Waterborne polyurethane paints were coated on PWMC surface. We studied the effect of the painting number on the colorimetric parameters and gloss. The relationship between sandpaper grit and film adhesion was investigated by comprehensively analyzing the surface roughness parameters. Meanwhile, the surface color changes and gloss loss rate were characterized after 720 h artificially accelerated UV ageing treatment. The photodegradation mechanism was also analyzed by comparing the surface chemical structures. Result Clear varnish finishes play a dual role of protection and decoration for PWMC. After the three-primers and two-topcoats painting treatment, the total color difference values of PWMC, wood area, and metal area were 10.26, 9.07 and 3.22, respectively. It indicated that the color variation of the wood area was larger than that of the metal area. The gloss value difference between wood and metal areas decreased from 17.7 to 2.3 after painting, representing that the painting treatment resulted in a more uniform surface gloss. The roughness parameters of PWMC wood and metal areas were similar when sandpaper grit was 240. It maintained a flat and homogeneous surface, thus PWMC had a best paint film adhesion (level 0). Under artificially accelerated UV ageing of 720 h, PWMC wood area changed to greenish-yellow, and the lightness of wood and metal areas increased. The colorimetric parameter changes and light loss rate of wood and metal areas were reduced after painting. It confirmed that the enhancement of waterborne polyurethane paints on the lightfastness of PWMC. Infrared spectroscopy and X-ray photoelectron spectroscopy showed an increase in the oxidation state of carbon atoms, indicating oxidative degradation happened in PWMC wood area and coating paints under light irradiation. Conclusion The painting properties and lightfastness were investigated, providing a theoretical and technical basis for the value-added utilization of PWMC.
Abstract:
Objective This study clarified the relationship between stand spatial structure characteristics and soil nutrient content in Fraxinus mandshurica plantation, revealed the factors of stand spatial structure affecting soil nutrient, and obtained the optimal measures of stand spatial structure based on improving soil nutrients, providing scientific basis for precise management and effective soil management of Fraxinus mandshurica plantation. Method Fraxinus mandshurica plantation with 4 kinds of stand density and 2 kinds of mixed proportion was taken as the object in Maoershan region of Heilongjiang Province of northeastern China. Correlation analysis and path analysis were used to find out the relationship between soil nutrient content and stand structure factors, such as mix ratio, stand density, angular scale, size ratio, opening degree and competition index. Result The surface soil nutrient content of mixed forest was significantly higher than that of the four density pure forests, and the contents of organic carbon, total nitrogen, total phosphorus, total potassium, available phosphorus and available potassium were increased by 27.3%, 31.8%, 18.2%, 7.3%, 15.2% and 6.4%, respectively. There were significant differences in soil nutrient contents among different densities of pure plantations (P < 0.05), and soil nutrient contents decreased with stand density increasing. The contents of surface soil organic carbon, total nitrogen, total phosphorus, total potassium, available phosphorus and available potassium of the minimum density pure plantation were increased by 42.7%, 35.4%, 19.8%, 8.9%, 41.3% and 28.4% compared with those of the maximum density pure plantationt, respectively. The soil nutrient content increased with the increasing of angle scale, size ratio and openness, but decreased with the increasing of competition index. Stand density and competition index had direct negative effects on most soil nutrient contents, and angular scale, size ratio and openness were positively correlated with most soil nutrient contents. The interaction of structural characteristic factors directly or indirectly affected soil nutrient content. Conclusion The soil nutrient content of mixed Fraxinus mandshurica plantations is higher than that of pure Fraxinus mandshurica plantations. The soil nutrient contents of low density of pure plantations are higher than that of high density of pure Fraxinus mandshurica plantations. In the process of management of Fraxinus mandshurica plantation, more mixed forests should be built to keep reasonable stand density as the general keynote and reduce the competition index among trees. On the basis of adjusting the angle scale to make the trees tend to random distribution, the inferior trees should be cut down according to the size ratio to increase the opening degree, gradually change the state of unreasonable growth space of forest trees and then improve the nutrient condition of forest land.
Abstract:
Objective Ecological security pattern can provide important basis for optimizing various elements of ecological system and improving regional ecological security. Method In this paper, four important ecosystem service functions, i.e., carbon sequestration, habitat quality, soil conservation, and water conservation, were calculated using the InVEST model in the Xiaoluanhe River Basin of Weichang County. And a comprehensive evaluation of ecosystem service functions in the region was carried out. The minimum cumulative resistance (MCR) model was used to construct ecological corridors in this area. Result Within the region, 14 ecological sources were identified, and 34 ecological corridors were constructed with 19 of them were of high importance. Comprehensive ecological service function and the spatial distribution pattern of ecological source in the south, middle and north parts of the Xiaoluanhe River Basin in Weichang County were significantly different. The forest area in the southern mountainous area was large, the comprehensive ecosystem service function was high, and the ecological corridor network was dense. The human disturbance in the central agricultural and pastoral areas was serious, which had hindered the ecological processes between the south and north. In the northern area near the Saihanba Forest Farm, four important ecosystem service functions were relatively high, and there were some large ecological sources, and the importance of ecological corridors was high. The overall ecological connectivity of the Xiaoluanhe River Basin was low, except the river itself, there is only one ecological corridor connecting the north and south was locating at the eastern edge of the basin, which had played an important role in the regional security pattern. Conclusion The ecosystem service function and ecological security pattern of the southern, central and northern areas of the Xiaoluanhe River Basin in Weichang County differed greatly, and the security pattern constructed can provide theoretical reference for formulating appropriate ecological conservation and restoration strategies in each part of the region.
Abstract:
Objective This study aimed to compare the storage of total organic carbon and the distribution of active organic carbon in ant nests and reference soils and to provide the key data support for expounding the impact of ant colonization on processes and mechanisms of carbon sequestration in forests of neighbouring mountains in the Napahai wetlands. Method We compared total organic carbon storage, active organic carbon components (i.e., total, microbial, easily oxidized, particulate, and dissolved organic carbon (total organic carbon, microbial biomass carbon, easily oxidized carbon, particulate organic carbon, and dissolved organic carbon), and their distributions (MBC/TOC, EOC/TOC, POC/TOC, DOC/TOC) in ant nests and the reference soils in the Spruce-Fir community of neighbouring mountains in the Napahai wetlands. We also explored the ant-induced changes in soil physicochemical properties on organic carbon storage and active organic component distribution. Result Ant colonization significantly affected SOC accumulation and carbon distribution (P < 0.05). Soil organic carbon storage was 5.7 times higher in ant nests than in reference soils; the concentrations of TOC, MBC, EOC, and POC in ant nests increased by 3.8, 2.7, 4.0, and 3.5 times, respectively. The average ratios of MBC/TOC, POC/TOC, and DOC/TOC in reference soils were 0.43%, 3.3% and 3.21% higher than that in the reference soils. In contrast, the ratio of EOC/TOC in ant nests was 0.15% higher than that in reference soils. The soil layer and treatment had interactive effects on concentrations of TOC, MBC, POC, and DOC (P < 0.05), while there was no significant interaction on EOC. The regression analysis showed that MBC, POC, DOC and EOC can explain 96.45%, 96.35%, 95.13% and 94.27%, respectively, of the changes in total organic carbon. Principal component analysis showed that soil density, total nitrogen and available phosphorus were the main controlling factors of SOC storage, while available nitrogen and phosphorus, soil density were the main driving factors of active carbon accumulation, and total kalium are the main influencing factor for the distribution of particulate organic carbon and dissolved organic carbon. Conclusion Ant colonization mainly induced the changes soil density, total and available nitrogen, and available phosphorus, which in turn regulated total organic carbon storage and active organic carbon distribution. These results would contribute to the understanding of fauna regulatory mechanisms for soil carbon sequestration in the forests of neighbouring mountains in the Napahai wetlands.
Abstract:
Objective In China, the Pine wood nematode (Bursaphelenchus xylophilus) takes Monochamus alternatus and M. saltuarius as propagative materials, leading to catastrophic damage to forests since they infect the forest trees. Predicting the invasion risk of pine wilt disease has critical referred values for forest protection and quality improvement, and as a result, is related to national ecological security and carbon neutralization. Method Based on the data of 24 distribution points for M. saltuarius and another 55 points for dead pine trees (hosts of M. saltuarius before eclosion) as well as 20 abiotic and biotic variables in Lixian County, we predicted the potentially suitable distribution areas for M. saltuarius and dead pine trees using GIS analytical tool and the MaxEnt model. Furthermore, the MaxEnt jack-knife of variable importance was applied to analyze the influence of main factors on the areas of M. saltuarius and dead pine trees, respectively. Considering that the occurrence of pine wilt disease at least requires both elements (i.e., M. saltuarius and pine trees), we evaluated the invasion risk of pine wilt disease by predicting the potential occurred regions of B. xylophilus based on weighting and integrating data of the occurrence of the M. saltuarius and dead pine trees generated by MaxEnt models. Result The results showed that mean area values under curves of the suitable distribution areas of M. saltuarius and dead pines were 0.993 and 0.969 from the MaxEnt models respectively, which indicated that the model predictions were ideal and can be used to forecast the potential invasion risk of pine wilt disease. Assessing the invasion risk of pine wilt disease demonstrated that the risk was highest when mean annual temperature ranged from 7.8 ℃ to 10.1 ℃ and the precipitation in the wettest season was 348 mm to 358 mm as well as within 1.5 km from the nearest residential point. The model estimated that the high-risk area of pine wilt disease was 10 616 hm2, accounting for 7.1% of the total area of coniferous forests in the County, which was distributed zonally along the roads across villages and towns. Conclusion Using GIS spatial technology and MaxEnt modelling can benefit the prediction of the invasion risk of pine wilt disease for the forest zones in western Sichuan. However, there still exists great uncertainty in the transmission and occurrence of pine wilt disease due to economic construction and climate change. Therefore, it is necessary to strengthen the monitoring of pine wood nematodes (B. xylophilus) and their propagative materials along the residential areas and roads, promoting the preventive and controlled emergency response to ensure the ecological security of forest zones in western Sichuan.
Abstract:
Objective The research on the regulation of NF-Y nuclear factor on cone development in conifers has not been reported yet. Through the cloning, expression characteristics and functional analysis of PtNF-YC1 gene of P. tabuliformis, it provides a basis for the functional study of conifer NF-Y gene family in the reproductive development of conifers. Method (1) The relationship between PtNF-YC1 and Arabidopsis thaliana NF-YC subfamily proteins was analyzed by phylogenetic tree. (2) Tobacco was transiently transformed to detect the subcellular localization of PtNF-YC1. (3) The expression characteristics of PtNF-YC1 in different tissues of P. tabuliformis were analyzed based on transcriptome data. (4) PtNF-YC1 was heterologously transformed into Arabidopsis, and the flowering time of different transgenic Arabidopsis lines under long-day and short-day was compared. The transcriptome sequencing of each transgenic line under long-day was performed to screen the genes related to PtNF-YC1 regulating flowering. (5) The protein interaction between PtNF-YC1 and candidate proteins was verified by Y2H and BiFC. Result The open reading frame of PtNF-YC1 was 897 bp, which encoded 299 amino acids, had a typical NF-YC conserved domain, and a close relationship with the homologous genes of AtNF-YC3/4/9. The subcellular localization showed that PtNF-YC1 was localized in the nucleus and cytoplasm. The analysis of expression patterns in different tissues showed that PtNF-YC1 could be expressed in needles, vegetative buds, male and female cones and roots, but the expression abundance was the highest in male cones and stems. PtNF-YC1 heterologous transformation of Arabidopsis delayed flowering under short day. It is proved that PtNF-YC1 interacts with PtCOL5 through Y2H and BiFC. Conclusion PtNF-YC1 has the function of regulating flowering time and is a candidate gene for inducing cone development through photoperiodic pathway of P. tabuliformis.
, Available online ,
doi: 10.12171/j.1000-1522.20230044
Abstract:
Objective In order to solve the problems of poor recognition effect and low accuracy of forest fire smoke detection model caused by small sample size, scattered sample features and small proportion of smoke images in forest fire smoke data set, rapid and accurate recognition and detection of forest fire smoke were realized. Method Aiming at the sample characteristics of the forest fire smoke image dataset with few samples, this study proposed a forest fire smoke image detection method based on multi-head attention mechanism. Firstly, data enhancement method was used in the training stage to expand the number of training data and reduce the risk of overfitting. Then the feature extraction module and the feature aggregation module were designed. The multi-head attention mechanism was introduced into the feature extraction module and the appropriate location was discussed to make the model pay more attention to the local features of the fire and solve the problem of information loss caused by fewer smoke images. In the feature aggregation module, FPN-PAN module was used for feature fusion of deep and shallow semantic information of images. Finally, the detection head module was set to output the experimental results. Test precision rate, recall rate, false alarm rate, detection rate and F1 value were used to test the effectiveness of this method on the small sample public data set and the self-built fire smoke small sample data set. Result The experimental results show that adding mosaic data enhancement and multi-scale transformation at the same time in the data enhancement stage can get better detection results. Models that add a multi-head attention mechanism after the fourth convolutional module of the feature extraction module performed best. Compared with the existing methods such as meta-learning short-duration memory network, matching network and lightweight target detection network, the proposed method had better detection effect. The accuracy rate reached 98.79%, the recall rate was 98.28%, the detection rate was 97.33% and the false positive rate was only 6.36%. Conclusion The experimental results show that the proposed method has better discriminative ability and generalization ability than the existing fire smoke detection models.
, Available online ,
doi: 10.12171/j.1000-1522.20220373
Abstract:
Objective Cunninghamia lanceolata is a unique timber species in southern China, which has good greening effect and also high economic value. In this article, the relationship between radial growth dynamics of Cunninghamia lanceolata and climatic factors was investigated at different time scales to provide a basis for scientific management of Cunninghamia lanceolata in the study area. Method In this study, the radial growth of Cunninghamia lanceolata trees was continuously monitored for 4 years (July 2017−June 2021) using a radial growth meter to analyze their radial growth and determine the growing seasons, while partial and sliding correlation analyses were conducted to investigate the effects of climate factors such as temperature, humidity, and precipitation on Cunninghamia lanceolata radial extension. Result (1) Cunninghamia lanceolata has periodic daily radial changes, which are mainly reflected in three stages, the first stage is contraction, the second stage is recovery, and the third stage is growth; the seasonal dynamics of radial changes in Cunninghamia lanceolata undergoes a trough period, a rise period and a stable period; there are interannual differences in radial changes in Cunninghamia lanceolata, but the time series of diameter growth and cumulative change trends are basically the same. (2) The cumulative radial growth curves of Cunninghamia lanceolata were combined to determine the growing season of Cunninghamia lanceolata in Changle, Fujian, from February to September each year. (3) The average relative humidity, rainfall, minimum temperature and average temperature were the main influencing factors, and the net increase of Cunninghamia lanceolata had a significant positive correlation with rainfall. The sliding correlation analysis showed that the correlation coefficient increased and then decreased with the change of growing season time. Conclusion The radial growth of Cunninghamia lanceolata is closely related to climate factors such as relative humidity, precipitation and temperature, therefore, studying the radial variation characteristics of Cunninghamia lanceolata and its response to climatic factors provides an important technical pathway and reference model for better planning of survival strategies for the target tree species.
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Objective The purpose of this study is to clarify the material quality of forest ecological multi-functions in Xianrendong National Nature Reserve in Liaoning Province, which can effectively improve the regional environmental quality and enhance the regional ecological service function. Method Taking the forest ecosystem in the nature reserve as the research object. According to the 2018 observation data of the Liaodong Peninsula Forest Ecosystem National Observation and Research Station in Liaoning and survey data of the forests. Using the methods of model quantification, distributed calculation and correlation analysis, three major service categories and six functional categories of support, regulation and supply were selected to study the material quality of forest ecological services in nature reserves and their trade-offs and synergies. Result (1) The material quantity of forest ecological service function is as follows: Support service 644.42 × 103 t/year, including conservation soil volume 644.10 × 103 t/year, tree nutrient accumulation 323.85 t/year. Regulation service 40.88 × 103 t/year, including solid The carbon release amount is 40.16 × 103 t/a, and the air purification amount is 719.12 t/year. Among the material amount of the Supply service, the amount of water supply is 148.27 × 107 m3/year, and the amount of negative ions supplied is 274.97 × 1020 pcs/year. Soil conservation > carbon fixation and oxygen release > air purification > forests nutrient fixation. (2) Substances of each evaluation index: the amount of forest conservation soil is 555.15 × 103 t/year for soil consolidation and 88.95 × 103 t/year for fertilizer retention; the accumulation of nutrients in forests is in the order of nitrogen retention (291.02 t/year) > potassium retention (25.33 t/year) > Phosphorus retention (7.50 t/year); forests absorb carbon 28.56 × 103 t/year and release oxygen 11.60 × 103 t/year; forests absorb gas pollutants from large to small, sulfur dioxide (817.50 t/year) > nitrogen oxidation Compound (255.80 t/year) > fluoride (242.00 t/year), blocking TSP, PM10 and PM2.5 were 82.3 t/year, 46.7 t/year and 10.6 t/year, respectively. (3) The dominant tree species (groups) with larger amounts of ecological service function substances include natural secondary oak forests, red pine forests and larch forests. The material quality of service function was significantly positively correlated with stand area and stock volume 9 (P < 0.01), and positively correlated with DBH, tree height and canopy density (P < 0.05). (4) The quality of ecological service functions in the administrative division of the protected area is the highest in the administrative department, while the lowest in Sanjiashan Village; there is a trade-off between support and adjustment services, synergy between support and supply services, and synergy and trade-off between adjustment and supply services. Conclusion The forest ecosystem has outstanding quality of Soil conservation, Carbon sequestration and nutrient release, Water supply and Negative oxygen ion supply. Forest area and stock volume play an important role in the quality of ecological service. Synergies and trade-offs are common among ecological services. In terms of space, the mountains are closed to support forests and prevent the loss of forestry land. In terms of forest stands, protect rare tree species, gradually increase the tree species group type, promote forest stand renewal and succession, and combine in situ protection with afforestation. Taking multiple measures simultaneously and following the laws of nature are effective measures to improve ecological services.
Abstract:
Objective To clarify the differences in the anatomical characteristics of the xylem of trees in different habitats and the growth changes of the xylem of trees under warm and dry climate conditions. Method The relatively dry and relatively wet habitat sampling sites were set up in mixed coniferous forests in Muling City, Heilongjiang Province, and Pinus koraiensis, Quercus mongolica, and Tilia amurensis were sampled. Micro-sections were cut with a rotary microtome to obtain the anatomical parameters of the xylem. Result The mean vessel area (MVA) and vulnerability index (Vx) of Quercus mongolica in the relatively dry habitat increased significantly, but the theoretical xylem-specific hydraulic conductivity (Ks) of Quercus mongolica did not differ significantly between the two habitats. From relatively wet habitat to relatively dry habitat, MVA, Vx, and Ks of Tilia amurensis were significantly reduced. Among the three tree species, only the mean tracheid area (MTA) and Vx of Pinus koraiensis did not differ significantly in the two habitats, and at the same time, the Ks was significantly increased in the relatively dry habitat. The tree-ring widths (RW) of Pinus koraiensis, Quercus mongolica, and Tilia amurensis in relatively dry habitat were all significantly positively correlated with the Palmer drought severity index (PDSI) of the growing season, and the sensitivity decreased when the water content of soil rose. The Ks of Quercus mongolica in the relatively dry habitat was significantly negatively correlated with the PDSI from November of the previous year to October of the current year. The RW and MVA of Tilia amurensis in the relatively dry habitat was significantly positively correlated with the lowest temperature in the previous non-growing season (PNG). Conclusion At the beginning of the growing season, drought was an important factor that restricted the tracheid area and hydraulic efficiency of Pinus koraiensis in the Muling area. In the future, Pinus koraiensis may feel the change of climatic conditions in northeast China more strongly. Tilia amurensis reduces hydraulic efficiency in relatively dry habitats to improve hydraulic safety. The growth and MVA of Quercus mongolica in the relatively dry habitat were greater than that in the relatively wet habitat, so future warm and dry climate conditions may be more beneficial to the growth of Quercus mongolica but there was also a risk of cavitation to it. Clarifying whether drought stress due to global warming will alter tree growth is critical to adjusting current silvicultural practices, which is better for mixed coniferous forests to cope with future warming and drying climatic conditions.
, Available online ,
doi: 10.12171/j.1000-1522.20220146
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Objective Based on the study of Arabidopsis thaliana plant height traits and the epistatic network models, this research aimed to explore and reveal the processes or patterns of multiple genes interacting with each other in a complex network during plant growth by constructing interactive regulatory networks at different levels. Method 84 recombinant inbred lines (RILs) of Arabidopsis thaliana were selected for the subsequent experiment, from which a total of 417 495 single nucleotide polymorphisms (SNPs) and plant height growth data across 8 time points were acquired. Through the functional mapping method, correlation analyses were performed on different genotypes and plant height traits previously obtained through sequencing. Afterwards, taking into account the concept of modularization from systems biology and ideas on dimensionality reduction from statistics, a system of ordinary differential equations was further adopted to construct not only a sparse, directed and quantifiable module, but also an epistatic interaction network among the genes. Eventually, database from the Arabidopsis Information Resource (TAIR) was utilized to perform enrichment analyses and functional annotations on candidate genes in various functional modules. Result The findings obtained herein showed that most functional modules seen from the macroscopic scale in the gene regulatory network not only played a positive regulatory role throughout the growth of Arabidopsis thaliana but also changed corresponding interaction strategy with time. On the other hand, from the microscopic view of the gene regulatory network, AT4G29140, the gene closely associated with structural development of Arabidopsis thalian, was found to only play an up-regulating role onto other loci and be subjected to only down-regulating effects from ageing-related genes. Moreover, AT4G36910, the gene responsible for maintaining cellular homeostasis, was found to display passive regulatory attitudes and have functional expressions that greatly depend on the regulation from other genes. Last but not least, AT4G22680 is speculated to execute its regulatory functions by regulating RP1 expressions. Conclusion This study has taken the context of complex network, conducted correlation analysis, and successfully probed into the epistatic mechanism affecting the growth of Arabidopsis thaliana, thereby providing a novel set of method and thought process for analyzing the genetic structures of plants.
, Available online ,
doi: 10.12171/j.1000-1522.20220053
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Objective The swift moth, Endoclita excrescens (Lepidoptera: Hepialidae), is a polyphagous forest insect causing great damages to Manchurian ash (Fraxinus mandshurica) in Northeast China. The spatial patterns of the moth at fine-scale were investigated in this study, which will provide basic information for precision-targeted management. Method Spatial analysis by distance indices (SADIE) was employed to measure spatial aggregation and spatial association of the count of bored holes and the DBH (diameter at breast height) of the host-tree, which were marks of a marked spatial point pattern. The spatial randomness of the distribution of ash tree was tested by the L function. The independence between mark and point was tested by the conditional mean function. Mark variogram and Stoyan mark correlation function were used to measure spatial autocorrelation. Each plot was divided into quadrats to calculated SADIE aggregation indices and clustering indices. Two density plans were used to devide the plot. Result Results from SADIE indicated that bored holes significantly aggregated in the two plots (G1 and G2). In plot G1, patches and gaps were separated and located at the two ends of the plot, respectively; while in plot G2, patches and gaps were mixed. In plot G1, trees with small number of bored holes were significantly close to other trees with small number of bored holes at distances of 4.0−4.8 m or 14.5−16.0 m; while in plot G2, same spatial patterns were identified at distances of 8.5−9.0 m. The results from mark variogram functions showed that there were no significant spatial autocorrelations at small distances in both plots. The spatial patterns of the ash tree and its DBH were strongly associated with the patterns of bored holes, respectively, indicating both of them play roles in the spatial pattern formation of bored holes. Results from either SADIE spatial aggregation index or L function suggested that the host trees were spatially aggregated. And the results from conditional mean of the mark function showed that the mark (count of bored holes) was independent on the point (tree location). Conclusion The spatial pattern of the bored hole of the swift moth is aggregation in the stand of ash. Both the location and size of the host tree shape the spatial patterns of bored holes.
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Objective The research on the negative air ion concentration(NAIC) of urban forest in different geographical spaces, so as to provide scientific support for the theoretical study of negative air ions and the site selection basis of forest therapy base. Method From September 2019 to January 2020, and from May to August 2020, three forest environments with different geographical locations, forest area and surrounding environment gradients in Guangzhou, Guangdong Province: exurban forest, suburban forest, and downtown forest were selected, and an urban control group was set up to compare NAIC differences. Pearson correlation analysis and multiple stepwise regression analysis were used to explore the correlation between NAIC and air oxygen content, temperature, relative humidity and wind speed. Result (1) NAIC of natural forests is distinctly higher than that of planted forests; In planted forests, NAIC of high canopy density forests is significantly higher than that of middle canopy density forests. (2) The NAIC of urban forest in different geographical spaces is prominently different, including exurban forest > suburban forest > downtown forest > urban control group. (3) The ability of NAIC generation in forest environment is evidently better than that in urban environment. (4) The seasonal variation of NAIC in exurban forest and suburban forest is summer > spring > autumn > winter, while that in downtown forest and urban control group is autumn > winter > spring > summer. (5) NAIC of exurban forest and suburban forest is remarkably positively correlated with air oxygen content, temperature and relative humidity, while the NAIC of downtown forest and urban control group is noticeably negatively correlated with air oxygen content and temperature; NAIC of suburban forest is significantly negatively correlated with wind speed, while that of exurban forest is notably positively correlated. (6) The NAIC of exurban forest is closely related to relative humidity and temperature; The NAIC of suburban forest is mainly affected by air oxygen content, wind speed and temperature; The NAIC of downtown forest and urban control group is most affected by temperature. Conclusion The geographical space has a significant impact on NAIC. Distance from the city center and the forest area reaching a certain scale and concentrated contiguous has a positive impact on NAIC. The relevant results provide a theoretical basis for the location of forest therapy bases. The environmental impact factors of NAIC of urban forest in different geographical spaces are different. It is suggested that future research should comprehensively consider the synergistic effects of different factors in many aspects, such as meteorology, stand, terrain, and surrounding environment, and further explore the impact mechanism of NAIC and various environmental factors.
, Available online ,
doi: 10.12171/j.1000-1522.20220411
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Objectives : Control of Verticillium wilt of the smoke tree in the forestry farm of Badaling by studying the effect of different combination of chemicals and application techniques, we are exploring effective methods for the prevention and control of Verticillium wilt to ensure the health of smoke tree and the safety of the red leaf landscape in Beijing. Methods : We selected five fungicides including Bacillus subtilis, 50% Azoxystrobin, 156 g/L Propiconazole, 50% carbendazim and 45% Prochloraz and set up 12 treatments to control Verticillium wilt in Badaling Forest farm by using injecting root and trunk or a combination of both. Result : Analysis of the 2021 control data showed that the combination treatment 12 (root injection of propiconazole combined with trunk injection of carbendazim and azoxystrobin) was the most effective, with a corrective disease index of only 5, significantly different from the control (p < 0.05) and a corrective control effect of 88%. By comparing the disease indices of each treatment for the period 2021-2022, it was found that the most efficacy control combination for that year was root injection of propiconazole combined with trunk injection of carbendazim and azoxystrobin, with a corrected disease index of 5 and control effectiveness was 88%. Moreover, 26.67% of trees in this combination treatment remained healthy and had the highest number of healthy trees. The combination with the lowest disease index in May of the following year was a combination of Bacillus subtilis with root irrigation combined with trunk injections of carbendazim and azoxystrobin, which showed a good treatment efficacy with the highest number of healthy trees, and the severely diseased sample trees from previous years all turned to be healthy or lightly diseased. And, the combination has a disease index of only 3.33. Conclusions : This study suggested that the combination of propiconazole in root irrigation and trunk injections of carbendazim and azoxystrobin was most efficacy, and that the combination of Bacillus subtilis in root irrigation and trunk injection of carbendazim and azoxystrobin performed well in terms of disease treatment and control, both of which can be used as control options for Verticillium wilt.
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Objective Camellia oleifera is a woody oleiferous plant with high economic and ecological value. Euproctis pseudoconspersa is one of the main pests of C. oleifera, which seriously restricts the yield and quality of C. oleifera. In order to provide scientific basis for early warning and specific prevention and control of the E. pseudoconspersa, the potential distribution of E. pseudoconspersa was simulated and predicted in this study. Method Based on the distribution data and biological climate data of E. pseudoconspersa in China, MaxEnt model and ArcGIS software were used to predict the suitable areas for E. pseudoconspersa in China under the current climate, and the distribution range and potential suitable areas of E. pseudoconspersa in China in the 2050 and 2070 under SSP1-2.6, SSP2-4.5 and SSP5-8.5 climate change scenarios, and then the dominant environmental variables affecting the distribution of its potential suitable areas were analyzed. Result (1) The dominant environmental variables affecting the distribution of the suitable habitat of E. pseudoconspersa were the precipitation of driest month, the annual precipitation, the min temperature of coldest month, the mean diurnal range (mean of monthly (max temp - min temp)) The optimum conditions were 28-148 mm the precipitation of driest month, 1 290−2 080 mm the annual precipitation, 1.0−10.1 ℃ the min temperature of coldest month and 7.2−8.5 ℃ the mean diurnal range (mean of monthly (max temp - min temp)). (2) Under the current climate conditions, the total suitable area of E. pseudoconspersa accounts for 20.0% of China’s land area, mainly distributed in the middle and lower reaches of the Yangtze River and South China, with a high suitable area of 642 000 km2, a medium suitable area of 618 000 km2, and a low suitable area of 660 000 km2. (3) In the next two periods and three climate scenarios, the suitable area of Camellia oleifera moth will be enlarged to different degrees, with the newly increased area of 94 000-331 000 km2 and the migration distance of the geographical distribution center between 24.4-125.1 km. The more obvious the climate warming is, the more the potential distribution area increases, and the farther the geographical distribution center moves. Conclusion E. pseudoconspersa has a wide range of habitats in China, including almost all the provinces in southern China. In the future climate change scenario, the suitable habitat of E. pseudoconspersa will expand northward, westward and other high latitude inland areas. Therefore, it is suggested that relevant departments should make plans and policies in advance to strengthen the observation and control of E. pseudoconspersa, so as to reduce its losses to camellia oleifera industry.
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Objective Leaf nutrient resorption is the ability of plants to recycle nutrients from senescent leaves and transport them to other tissues and organs, which is one of the main strategies for plant nutrient utilization. Previous studies show that nitrogen (N) or phosphorus (P) addition generally reduces or does not affect leaf nutrient resorption efficiency. However, there are still few studies on the effects of N and P addition and their interaction on leaf nutrient resorption efficiency and the underlying mechanisms. Method To answer this question, we performed an experiment of N and P addition in an alpine meadow, measuring leaf nutrient resorption efficiency in four dominant species (Elymus nutans, Deschampsia cespitosa, Artemisia roxburghiana, Potentilla anserina). Result We found that (i) N addition had positive effects or no impact on leaf N resorption efficiency (NRE) in graminoids and forbs, while it did not affect P resorption efficiency (PRE) among four plant species. (ii) P addition had no effect on leaf NRE among four species or PRE in forbs, but it significantly increased leaf PRE in graminoids. (iii) N + P addition together reduced leaf NRE in E. nutans, A. roxburghiana and P. anserina, but increased NRE in D. cespitosa. Moreover, the combination of N + P addition did not affect leaf PRE among four species. Conclusion Overall, our study indicates that alpine plants adopt three nutrient resorption strategies for more nutrient supply: full resorption (increased green leaf nutrient but no change in senescent leaf), partial resorption (more increase in green leaf nutrient than senescent leaf) and no resorption (similar increase in green and senescent leaf nutrient). These findings reveal the diversity and complementarity of plant strategies of nutrient internal cycle in alpine grasslands.
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Objective In order to determine the physiological adaptation mechanism of the 4-age wintering larva of M. alternatus to low temperature stress. Method The 4-age wintering larva of M. alternatus were collected from Dexing, Jiangxi province, in mid-March of the 2021, seven temperature gradients of 25 ℃ (control), 4, 0, −5, −10, −15 and −20 ℃ and three time gradients of 30 min, 1 h and 3 h were set, the cold tolerance, the content of cold-resistant substances, the activity of antioxidant enzymes and the damage of midgut under low temperature stress were determined. Result (1) Near the supercooling point (−9.27 ± 0.90) ℃, the 50% lethal time was about 1.9 hours, and the 99% lethal time was about 2.8 days, Under low temperature stress below the supercooling point (−15 ℃), the lethal time of 50% and 99% is about 1/3 of that under low temperature treatment of −10 ℃. (2) After low temperature stress treatment, the water content of the 4-age wintering larvae did not change significantly, the fat content and glycogen content were significantly decreased after 3 h at 0 ℃ (P < 0.05), and the sorbitol content was significantly increased after 1 h at −5 ℃ (P < 0.05), and significantly decreased after 1 h at −20 ℃ (P < 0.05). (3) After low temperature stress treatment, the activities of antioxidant enzymes (SOD, POD, CAT) were significantly increased (P < 0.05). (4) The midgut of the 4-age wintering larvae of M. alternatus was decomposed after −15 ℃ treatment for 3 h, and vacuoles appeared between cells. After −20 ℃ treatment for 3 h, the midgut cells were ruptured, and the cell vacuoles escaped and filled the whole intestinal cavity, and the vacuoles disappeared. Conclusion This study clarified the physiological response of oxidative stress of the fourth instar overwintering larvae to low temperature stress, which could enrich and improve the study on cold tolerance mechanism of M. alternatus.
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Objective China’s urbanization development has entered a stage where the central cities lead the development of metropolitan areas and city agglomerations. How to promote the harmonious development of urbanization and the ecological environment in urban areas has become an important issue for high-quality urban development. Research about the spatio-temporal response of ecosystem services to urban expansion helps to characterize the spatial and temporal evolution of urban development and ecosystem services, promote the synergistic development of cities and ecosystems, and help formulate and implement sustainable planning strategies. Method Taking Jinan metropolitan area as the target area, we studied the spatial and temporal characteristics of each city’s expansion based on the Urban Expansion Index calculation, evaluated the Ecosystem Service Value based on per unit area, and analyzed the temporal and spatial differentiation characteristics of ecosystem services. Furthermore, we studied the spatio-temporal response of ecosystem services to urban expansion of the Jinan metropolitan based on GTWR. Result The results showed that: (1) From 1980 to 2020, urban expansion of the Jinan Metropolitan Area was characterized by time series and regional differentiation. The urban spatial expansion rate and intensity are sorted from high to low, small cities, large cities, megacities, and medium-sized cities. (2) The ecosystem services of the metropolitan area are decreasing year by year. The mainstream of the Yellow River and floodplain, Dongping Lake and its surrounding areas, and mountainous areas in central Shandong are important areas with high value of ecosystem services. The proportion of synergistic relationships in metropolitan areas is slightly lower than that of trade-off relationships, with megacities accounting for the highest proportion. (3) Urban expansion in the Jinan metropolitan area has a negative impact on ecosystem services, while the intensity of negative effects decreased year by year. The impact of urban expansion on the functions of ecosystem services of different subcategories was significantly different. Conclusion We clarified the distribution pattern of spatio-temporal variation of urban expansion of different cities in the Jinan metropolitan area, and further analyzed the development state of gradual deterioration of ecosystem services during the study period. Based on the GTWR model, we quantified the different driving characteristics of urban expansion on ecosystem services at the spatial level. The results can provide a decision-making basis for the high-quality sustainable development of metropolitan areas.
, Available online ,
doi: 10.12171/j.1000-1522.20220367
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Objective In recent years, the rapid development of urbanization has made the contradiction between economic development needs and ecological protection increasingly prominent, and the construction of an ecological security pattern is of great significance for realizing the harmonious coexistence between man and nature and the optimization of the spatial structure of the national territory. Method Taking Guangzhou As an example, the ecological source sites were selected using the Remote Sensing Ecological Index (RSEI), and ecological corridors, ecological pinch points and barrier points were extracted by the Minimum Cumulative Resistance (MCR) model and circuit theory, so as to construct the ecological safety pattern of Guangzhou City. Result The results show that: (1) the ecological and environmental quality of Guangzhou from 1990 to 2020 is relatively good, with the average value of RSEI decreasing from 0.60 to 0.58 and then increasing to 0.60, showing a trend of “first decreasing and then increasing”, but the difference between the habitat quality in the south and the north is large. (2) A total of 25 ecological source sites were identified, with a total area of 1 511.26 km2, accounting for 20.33% of the total area of Guangzhou, mainly concentrated in the northeast of the study area, with only 3 ecological source sites in the south; a total of 50 ecological corridors were extracted, including 20 primary corridors with a total length of 114.06 km, 22 secondary corridors, and 8 potential corridors. (3) A total of 48 ecological pinch points were identified, with the current land use types mainly being forest land, farmland and construction land, of which the largest area is 19.09 km2, located in the area of Lianhua Mountain in Panyu District, and the smallest pinch point is only 0.11 km2 in area; a total of 12 ecological barriers were identified, mainly in Huangpu District and Conghua District, where the current land use is mainly arable land and construction land, with the largest area of 0.42 km2 located in the north of Dongpu Farm in Conghua District, and the smallest area of 900 m2; 63 fracture points were identified, mainly in Baiyun District and Huangpu District in central Guangzhou. Conclusion The research results can provide data support for the optimization of the future urban spatial pattern and ecosystem restoration in Guangzhou City, and at the same time provide a reference for the construction of the ecological security pattern of other super-large cities.
, Available online ,
doi: 10.12171/j.1000-1522.20220266
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Objective In this study, 10 Sect. Aigeiros clones of Populus are used as experimental materials to study the changes of growth, physiological and biochemical characteristics under drought stress, analyze the drought resistance ability of different clones, and screen out excellent clones with strong drought resistance, with the aim of providing basis for the selection of poplar varieties on dry sites. Method The drought stress was simulated by pot experiment, and four water gradients were set up to measure the changes of nine indexes of the ten clones under different degrees of water deficiency, to investigate the effects of different degrees of drought stress on the growth and physiological indexes of eachclone. Result Under continuous drought stress, the differences in seedling height increment, ground diameter increment and biomass increment among the 10 clones were significant, among which the clones 1733 and 1627 were significantly different from the control 2025. The chlorophyll content of clones, except for clone 1716, showed a trend of increasing and then decreasing, with a small increase in mild drought and a decrease in moderate and severe drought. The cell membrane permeability of of the leaves each clone showed an increasing trend with the continuation of drought time, and under severe drought stress, the cell membrane permeability increased to the maximum, with the largest increase in clones 1716 and 1722, and the smallest increase in clones 1733 and 1641;. The malondialdehyde (MDA) content showed a pattern of change in which it first increased and then decreased, and was the highest content in moderate drought; the superoxide dismutase (SOD) and peroxidase (POD) activities first increased and then decreased, and the activitiesy was were the highest under moderate drought, and compared with normal water supply, clones 1627 and 1733 showed the greatest elevation of SOD activity, and clones 1733 and 1641 showed the greatest elevation of POD activity. The accumulation of osmoregulatory substances gradually increased with increasing drought severity, and under severe drought, the clones1627 and 1733 had the highest proline (Pro) content and the highest increase, which were significantly different from the control 2025. Principal component analysis showed that under severe drought stress conditions, the 10 clones were 1733, 1627, I-107, 1641, 1640, 1725, 1723, 2025, 1716 and 1722 in order of their drought resistance. Conclusion The variation of each index of the 10 clones under drought stress was significantly different. Considering the integrated principal component analysis model, it was tentatively concluded that the clones 1733 and 1627 have strong drought tolerance and can be used as test materials for further studies in dry stands.
, Available online ,
doi: 10.12171/j.1000-1522.20220391
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Objective To explore the influence of the spatial structure of Picea asperata secondary forest on the lighting in the forest, and to provide data support and theoretical reference for understanding the characteristics and influencing factors of the light environment in the forest. Method Taking the 4 hm2 fixed sample plot in Pangquangou National Nature Reserve as the research object, the sample plot is divided into 100 blocks of 20 m × 20 m small quadrat. Between July and August 2021, the relative coordinates and DBH of the living trees (DBH ≥ 1 cm) in the small plot were measured, and the hemispherical canopy images were obtained by hemispherical photography. The light environment parameters in the forest were analyzed and obtained, the spatial structure characteristics and light distribution characteristics of the plot were studied, and the correlation between the spatial structure of the forest and the light environment in the forest was verified. Result (1) The canopy opening (CO) and the light under the forest mainly showed that the edge was smaller than the interior, and the leaf area index (LAI) showed that the edge was larger than the interior. The total light (Atot) value on the forest is large as a whole, and there is a large difference among regions. Only 13.7% of the light can enter from the upper part of the forest to the lower part of the forest. (2) The distribution pattern of forest trees is mainly characterized by cluster distribution. The degree of size differentiation is sub superiority-moderate, moderate and moderate-inferior. The mixed degree of tree species is zero-weak,medium-weak and medium-intensity. (3) The horizontal distribution pattern of tree species was significantly positively correlated with CO (P < 0.05), the spatial isolation degree was significantly positively correlated with Lai (P < 0.05), and was significantly negatively correlated with direct sunlight (Tdir) and total sunlight (Ttot) under the forest (P < 0.05). Conclusion There is a certain correlation between the light in the forest and the spatial structure of the forest. The horizontal distribution pattern of trees mainly affects CO, and the mixing degree among tree species mainly affects LAI, Tdir and Ttot.
Abstract:
Objective This study aimed to reveal the influence laws and mechanisms of forest types and forest age on the carbon storage of sand fixation plantation ecosystems in the Nenjiang River Basin in temperate semi-arid regions, and to provide a scientific basis for the practice of carbon sink management in sandy plantations. Method Relative growth equations and carbon/nitrogen analyzer were used to simultaneously estimate the ecosystem carbon stocks (vegetation and soil), annual net carbon sequestration of vegetation and related environmental factors (soil moisture content, organic matter, total nitrogen, and so on) in two kinds of plantations with a chronosequences of young forests, middle-aged forests, and mature forests of 11, 30 and 45 years old Mongolian Pine(Pinus sylvestris var. mongolica) plantation (Ps); 6, 15 and 26 years old Populus × xiaohei plantation (Px) and 28 years old natural Siberian Elm (Ulmus pumila) forest (Up) at sand dune sites, and to determine the influence law and mechanism of forest types and ages on the ecosystem carbon storage. Result (1) The vegetation carbon storage of Ps and Px increased significantly than Up, which of Ps was the highest among three forest types. Moreover, the vegetation carbon storage of Ps and Px increased with the forest age, but the change trends of annual net carbon sequestration (ANCS) of vegetation with forest age were different between Ps and Px, the former is young forests > Mid-aged forests= mature forests; The latter increases with forest age. (2) In terms of soil carbon sequestration, Px was better than Up, while Ps was less than Up ; Moreover, the change law of soil carbon storage with forest age in Ps and Px was also different, increasing first and then stabilizing and increasing, respectively. And both forest types all changed the spatial distribution pattern of soil carbon storage. In the horizontal space, Ps reduced the carbon storage in the upper and lower soil layers, and its soil carbon storage increased with the forest age in the upper soil layer; while Px increased the soil carbon storage in the middle and upper soil layer, and its carbon storage increased with the forest age in the bottom soil layer; In the vertical space, the vertical stratification of soil carbon storage in young forests was evident and tended to weaken in mature forest stage. (3) In terms of ecosystem carbon sequestration, Ps and Px were similar and higher than Up. The ecosystem carbon storage of both Ps and Px increased with stand age. However, the distribution patterns of ecosystem carbon stocks for Ps and Px were mostly dominated by vegetation, which was clearly different from that of Up dominated by soil. (4) The ecosystem carbon storage and ANCS of Ps were mainly controlled by soil total nitrogen. The ecosystem carbon storage and ANCS of Px were mainly controlled by soil organic matter. Conclusion Therefore, the establishment of Ps and Px could not only fix sand, but also significantly increase forest carbon sink (about 4/5) in the temperate Nenjiang Sandy Land, which was dominated by vegetation carbon sequestration. Therefore, in the management of carbon sinks in sandy plantations, it is necessary to strengthen the maintenance of the vegetation carbon pool as well as to focus on the long-term carbon sequestration potential of the soil.
, Available online ,
doi: 10.12171/j.1000-1522.20220436
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Objective Based on the existing survey data from the 8th Landscape Plant Census of Forest Resources Type II survey data , the forest carbon sink capacity of Beijing was assessed to provide a theoretical basis for the scientific management of forest resources in the city. Method In this study, we adopt the forest stock expansion method to calculate the overall carbon stock, carbon density and changes in Beijing’s forests, and use the afforestation cost method and carbon tax method to assess the economic value of their carbon stocks. Result (1) The total carbon stock of the total forest in Beijing is 19 345 900 t, and the carbon density is 32.35 t/ha, among the regions, Miyun District, Yanqing District and Shunyi District have larger carbon stocks, accounting for 13.79%, 12.73% and 11.40% respectively, while those with higher carbon density are Shunyi District, Daxing District and Tongzhou District; the carbon density of both plains and mountains showed broadleaf forests > mixed forests > coniferous forests, and the carbon density of forests in plains was about 3.3 times higher than that in mountains; the carbon stocks in both mountains and plains were dominated by broadleaf trees; protection forests are the main contributors to the forest carbon stock. The carbon stock of protection forest is the main contributor to forest stock, among which soil and water conservation forest has the largest carbon stock of 4 141 500 t, while the carbon density of farmland protection forest is the largest at 175.23 t/ha; the carbon stock of dominant species is ranked as follows: other Populus spp. > Quercus spp. > Pinus tabuliformis > broadleaf tree > Platycladus orientalis > Robinia pseudoacacia > Betula spp. > Larix principis-rupprechtii > Populus davidiana, the carbon density was ranked as follows: other Populus spp. > Betula spp. > Larix principis-rupprechtii > Populus davidiana > Pinus tabuliformis > Robinia pseudoacacia > Quercus spp. > broadleaf tree > Platycladus orientalis; the carbon stock and carbon density in different origins were: planted forests > flycasting forests > natural forests; the carbon stock size in age group: middle-aged forest > young forest > mature forest > near-mature forest > over-mature forest, and the overall pattern of carbon density increased with the increase of age class. (2) From the first to the eighth forest resources survey, forest carbon stock and carbon density continued to increase; among the forest species, special-purpose forest had the highest growth rate and the highest carbon density; carbon stock of larch and aspen increased and then decreased, while acacia and birch showed a trend of decreasing and then increasing, and all other tree species showed an increasing trend, while carbon density of oleander, larch and aspen increased and then decreased, side cypress, Quercus and birch decreased and then increased, acacia and broadleaf tree continued to decrease, and poplar continued to increase; both natural and planted forests showed an increasing trend. (3) Based on the different carbon prices estimated by the afforestation cost method and the carbon tax method, the economic value of forest carbon stocks in Beijing ranged from 5.414 to 23.215 billion RMB, and the economic value of forest carbon stocks under the carbon tax method was higher. The economic value of carbon stock in each region of Beijing under the two calculation methods varied greatly, with Miyun, Yanqing, and Shunyi districts having the largest economic value of carbon stock; among all dominant tree species, poplar had the highest economic value of carbon stock; and among age groups, middle-aged forests had the largest contribution to Beijing. Conclusion Beijing’s forests have obvious carbon sequestration potential, but the overall carbon sink is relatively low. In the future, we should pay attention to the matching of forest structure, strengthen the management of forest land cultivation, enhance the function of Beijing’s forest carbon sink, improve the value of carbon sink, and stimulate the vitality of forestry management.
, Available online ,
doi: 10.12171/j.1000-1522.20220336
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Objective Branch CO2 efflux is one of the important components of stand carbon release. Studying the change of branch CO2 efflux of Larix principis-rupprechtii under simulated nitrogen deposition could provide a theoretical basis for the management of carbon sequestration and sink increase of L.principis-rupprechtii forest under the background of nitrogen deposition. Method 25-year-old and 32-year-old plantations of L. principis-rupprechtii were selected. Four nitrogen addition treatments: control (CK, 0 kg/(ha·year)), low nitrogen (N1, 75 kg/(ha·year)), medium nitrogen (N2, 150 kg/(ha·year)) and high nitrogen (N3, 225 kg/(ha·year)) were set. From June to October in 2021, the branch CO2 efflux was monitored in situ using LI-8100A, and the branch samples were collected to determine the nitrogen content. Result (1) The CO2 efflux and air temperature of L. principis-rupprechtii branches basically showed a “single-peak” monthly change, and the peak appeared from June to August. The air temperature could explain the changes of branch CO2 efflux of two stands by 37% ~ 82% and 40% ~ 70%, respectively. (2) The average branch CO2 efflux of L. principis-rupprechtii at 25-year-old and 32-year-old from June to October showed an increasing trend with the increase of N addition intensity, but only differed significantly under N3 treatment (P < 0.05). The CO2 efflux of CK, N1 and N2 treatments at 25-year-old was significantly higher than that at 32-year-old (P < 0.05). The temperature sensitivity (Q10) of branch CO2 efflux was decreased by N addition except for 32-year-old plantations under N1 treatment. (3) Nitrogen addition significantly increased the 25-year old branch nitrogen content ; there was no significant change in shoot nitrogen content in 32-year-old (P > 0.05). There was a significantly negative linear relationship between the branch CO2 efflux of L. principis-rupprechtii and the branch nitrogen content at both ages (P < 0.01). The nitrogen content can explain 16% (25-year-old) and 32% (32-year-old) variation of branch CO2 efflux. Conclusion The branch CO2 efflux was affected by air temperature, nitrogen addition and forest age. All three factors should be considered when constructing a tree carbon release model of L. principis-rupprechtii.
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Objective Based on the Hegyi intraspecific and interspecific competition indexes related to distance, the prediction model of DBH increment of spruce fir natural forest was constructed based on initial DBH and Hegyi competition index. Method In order to explore the effects of competition and growth on DBH growth of individual trees, the measured data of three 1 ha permanent sample plots of spruce fir in Jingouling Forest Farm in 2013 were utilized. Based on the nonlinear Logistics model, individual tree initial DBH and intraspecific and interspecific competition indexes were gradually added. The nonlinear mixed-effects model was utilized to improve the model accuracy. Result The results of model fitting showed that the model had the best fitting effect when initial DBH, intraspecific and interspecific Hegyi competition indexes were used as predictive variables, the best fitting efficiency occurred based on the species-level of random effect, and a0 + a2 + a3 were set to be random parameters, and without heteroscedasticity. The adjusted R2, RMSE and TRE of modeling data were 0.512 6, 0.607 1, 3.651 9%, respectively. The adjusted R2, RMSE and TRE of validation data were 0.509 8, 0.624 2, 3.883 1%, respectively. The residual distribution of validation data did not show obvious heteroscedasticity. Conclusion The factors affect the diameter growth of target trees in spruce fir natural forest, including self-growth factors and external factors. Among the self-growth factors, initial DBH is the main factor and plays a positive role to promote DBH increment. Among the competition factors, interspecific competition and intraspecific competition have obvious inhibition effects on the growth of individual tree DBH increment. The nonlinear mixed effect model based on species-level can provide a theoretical basis and technical reference for the DBH growth of target trees in natural spruce fir forests in the study area.
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Objective To explore a management regime that takes into account the cultivation of large-diameter tree and ecological benefits base on the mature Pinus tabuliformis plantation, as well as to provide a reference for mature plantation management in China. Method Taking 47- and 56-year-old Pinus tabuliformis plantations in Wangyedian Experimental Forest Farm in Chifeng City as the research object, the data of sample plots under close-to-nature management (CTNM), conventional management (CM) and no human intervention (NHI) were collected in 2013 and 2019. Two-factor variance analysis was used to compare the effects of three management regimes on mean DBH growth rate, mortality, seedling regeneration and diversity of trees, shrubs and herbs. Result There were significant differences in mean DBH growth rate and 6-year mortality of mature Pinus tabuliformis plantations under three management regimes (P < 0.05), CTNM was 0.40 cm/year and 3.55% respectively, CM was 0.36 cm/year and 1.44%, and NHI was 0.31 cm/year and 0.51%. The understory plants under CTNM increased 3 species in 6 years, while that decreased 5 species under CM and 9 species under NHI. The increase of Shannon-Wiener index and Simpson index of trees in 47- and 56-year-old stands in 6 years was CTNM > CM > NHI, while the decrease of tree seedling mortality and the Shannon-Wiener index and Simpson index of herbs in 47-year-old stands was CM < CTNM < NHI. The effects on tree growth, mortality and plant diversity under three management regimes disappeared over time. The mean DBH growth rate, Shannon-Wiener index and Simpson index of trees and herbs in 56-year-old stands were higher than that in 47-year-old stands under three management regimes. Conclusion Forest management can increase the mean DBH growth rate, reduce the tree mortality and delay the decline of plant diversity of mature Pinus tabuliformis plantation, suggesting that mature plantation should be managed regularly to improve the economic and ecological benefits. Compared with CM and NHI, CTNM is the best to maintain the plant diversity of mature Pinus tabuliformis plantation as well as to cultivate large-diameter tree.
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Objective Plants can use resources more efficiently by adjusting their own traits. Exploring the variation and correlation between twig and leaf traits of plants with different diameter classes is of great significance for understanding the intraspecific variation of plant functional traits and the resource acquisition strategies of plants. Method In Liangshui National Nature Reserve of Heilongjiang Province of northeastern China, three diameter classes of Betula platyphylla were selected (including small tree, middle tree and large tree). The twig cross-sectional area, individual leaf area, total leaf area, total leaf dry mass, twig dry mass and volume-based leafing intensity were measured in different diameter classes. One-way analysis of variance (ANOVA) was used to test whether there were significant differences in twig-leaf traits among varied diameter classes. The method of standardized main axis estimation was used to test whether the diameter class had an effect on the correlation between the twig and leaf traits. Result With the increase of diameter class, twig cross-sectional area showed an upward trend, individual leaf area and total leaf area showed a downward trend, but there was no significant difference in total leaf dry mass, twig dry mass, volume-based leafing intensity. The twig cross-sectional area was significantly positively correlated with individual leaf area, total leaf area and total leaf dry mass, but was significantly negatively correlated with volume-based leafing intensity, among them, the cross-sectional area of small trees and large trees had an isokinetic growth relationship of close to 1 with the total leaf area and total leaf dry mass, while the medium tree had an allometric growth relationship close to 1.5; individual leaf area exhibited significantly negative correlations with volume-based leafing intensity, showing an allometric relationship; the diameter class had a significant effect on the slope or intercept of the correlations between twig-leaf traits. Conclusion Within the same community, the difference in branch and leaf traits among different diameter classes of Betula platyphylla is its own resource acquisition strategy, and the branch and leaf traits undergo collaborative changes in order to obtain effective resources.
, Available online ,
doi: 10.12171/j.1000-1522.20220024
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Objective To study the phenotypic characteristics, growth and physiological characteristics of walnut seedlings under different nutrient deficiency conditions, so as to provide a theoretical basis for scientific and efficient management of walnut seedlings. Method Pot experiment was conducted to study the phenotypic characteristics and growth physiological changes of walnut seedlings deficient in N, P, K, Ca and Mg. Result (1) The leaf symptoms and occurrence time of walnut seedlings with different element deficiency treatments were different. Among them, the symptom of N deficiency appeared the earliest, Mg deficiency followed, and K deficiency appeared the latest. The aboveground biomass of seedlings lacking N and Mg decreased by 66.5% and 48.6% respectively compared with CK, and root biomass decreased by 48.0% and 55.0% respectively compared with CK; (2) The photosynthetic pigment content, net photosynthetic rate and stomatal conductance of walnut seedlings treated with element deficiency were significantly lower than those of CK. Among them, the photosynthetic pigment content of seedlings lacking N and Mg decreased the most, and the net photosynthetic rate and stomatal conductance of walnut seedlings lacking Ca and Mg decreased the most; (3) The chlorophyll fluorescence parameters of walnut seedlings treated with element deficiency showed significant differences, but in general, the chlorophyll fluorescence parameters of each element deficiency treatment were different. The values of ΦPSII, ETR, Fv/Fmand qP were significantly lower than those of CK, and the value of NPQ was significantly higher than that of CK, among which the change of P-deficient treatment was the most obvious; (4) The contents of IAA and ABA in walnut seedlings treated with element deficiency were significantly higher than those of CK, while the contents of Spm and Spd were significantly lower than those of CK, especially in N deficiency treatment. Conclusion Element deficiency had certain effects on photosynthetic efficiency and endogenous hormones of seedlings, and the effects of N deficiency, Mg deficiency and Ca deficiency were the most obvious. Therefore, in the management of walnut seedlings, we should pay attention to the observation of seedling growth, diagnose and identify the deficiency of elements as soon as possible, especially N, Ca and Mg elements that are easy to appear and have obvious symptoms, and supplement them in time, so as to improve the seedling quality of walnut.
, Available online ,
doi: 10.12171/j.1000-1522.20220219
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Objective Study on the difference in ecological stoichiometric characteristics and their changes with increasing age of conifers of deciduous and evergreen species in the cold temperate zone to reveal the relationship between ecological stoichiometric characteristics and growth stage of two different life forms of conifers, and to provide help for the study of plant growth and nutrient supply in cold-temperate of China. Method The contents and stoichiometric characteristics of C, N, P in Larix gmelinii and Pinus sylvestris var. mongolica from May to September were studied. The correlation between C, N, P and environmental factors was analyzed by homeostasis index and Pearson correlation coefficient. Result (1) During the different growth stage, monthly average N, P content of Larix gmelinii and Pinus sylvestris var. mongolica needles were both decreased with the increase of age class, while the C content increased with the increase of age class. The N and P contents of needles of Larix gmelinii from May to August were higher than those of Pinus sylvestris var. mongolica, while the C content was lower than those of Pinus sylvestris var. mongolica. (2) The monthly mean values of C∶N, C∶P and N∶P of needles of Larix gmelinii were higher than those of Pinus sylvestris var. mongolica. The N∶P of needles of Larix gmelinii of four age classs were all less than 14, while the N∶P of needles of Pinus sylvestris of four age classes from May to July was less than 14, and the N∶P of needles of Pinus sylvestris var. mongolica of four age classes was more than 16. The homeostasis of N, P and N∶P of Larix gmelinii needles was greater than that of Pinus sylvestris var. mongolica. (3) Soil moisture content was significantly correlated with the ecological stoichiometric characteristics of the needles of the two species. The N content of needles of Pinus sylvestris var. mongolica was significantly correlated with the stoichiometric ratio of C, N and P, and the C content of needles of Larix gmelinii was significantly correlated with N∶P and soil ammonium and nitrate nitrogen. Conclusion The two conifer species with different life forms in the northern Daxing’an Mountains have different adaptation strategies to cold climate and frozen soil.The Larix gmelinii is the dominant species in the top community, but its different growth stages were both limited by N. However, Pinus sylvestris var. mongolica the growth limiting factors of Pinus sylvestris var. mongolica are different due to seasonal changes.
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2023, 45(8): 1-15.
doi: 10.12171/j.1000-1522.20220422
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Objective In view of fine monitoring and evaluation needs of forest resources, the application potential of multi-temporal and multi-feature Sentinel-2 images in the identification of deciduous coniferous forests was exploratively studied, and a classification model was built according to the phenological characteristics of deciduous coniferous forests to provide method reference for identifying deciduous coniferous forests on a large scale. Method Based on the GEE platform, the difference between deciduous coniferous forests and other forests in different seasons was analyzed by taking Mengjiagang Forest Farm in Heilongjiang Province of northeastern China as the research area. In this study, four seasonal Sentinel-2 images of spring (May 7 and May 27), summer (August 9), and autumn (October 19) in 2020 were used to construct a multi-feature dataset by extracting spectral features, texture features, and topographic features. Feature optimization was carried out according to feature importance scores. Finally, the optimal model for identifying deciduous coniferous forests was established by a random forest classifier to achieve rapid extraction of deciduous coniferous forest in Mengjiagang Forest Farm. Result The experimental results showed that deciduous coniferous forests displayed obvious vegetation spectral features and seasonal characteristics. The multi-temporal image data contained more phenological period information on deciduous coniferous forests, and the images in spring and autumn can enable better differentiation between deciduous coniferous forests and other forests. In addition, near-infrared and short-wave infrared spectral information can greatly help identify deciduous coniferous forests. By the GEE platform and multi-temporal Sentinel-2 images, it is possible to extract vegetation information efficiently and quickly. The overall extraction accuracy and Kappa coefficient of deciduous coniferous forest reached 91.20% and 0.82, respectively. Conclusion The classification model constructed based on the GEE platform and Sentinel-2 image has certain feasibility and applicability for the rapid extraction of deciduous coniferous forest information, and the research results provide a certain reference value for the large-scale extraction of spatial location distribution information of deciduous coniferous forest.
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Objective This paper aims to reveal the spatial distribution pattern and the cause of formation of the natural plant ecosystem carbon storage in the semi-arid area of temperate Nenjiang River of Taihu National Wetland Park of Northeastern China along the lakeshore to the highland environmental gradient, and to provide a scientific basis for the long term carbon sink management of natural vegetation in the temperate semi-arid area of China. Method The ecosystem carbon storage (vegetation carbon storage and soil carbon storage), net primary productivity (NPP), annual net carbon sequestration (ANCS) and related environmental factors (water level, total nitrogen and total phosphorus, etc.) of eight plant communities, i.e. Typha angustifolia wetland (XYP), Typha minima wetland (XP), Phragmites australis wetland (L), tussock wetland (C), Calamagrostis epigeios meadow (F), wet Leymus chinensis grassland (S), dry Leymus chinensis grassland (H), sand dune Ulmus pumila sparse forest (Y) distributed along the lakeshore to the highland environmental gradient were simultaneously determined by relative growth equation and carbon/nitrogen analyzer method, so as to reveal its spatial differentiation law and its formation mechanism. Result (1) The vegetation carbon storage (0.98−27.86 t/ha) showed a downward and then ascending tendency along the lakeshore to the highland environmental gradient (Y > L, XYP, XP > C, F, S, H), and herbaceous carbon storage (0.30−8.11 t/ha) showed a stepwise decreasing trend (L, XYP, XP > C, F, S > H, Y). (2) The soil carbon storage (38.49−321.72 t/ha) showed a stepwise decreasing trend along the lakeshore to the highland environmental gradient, and there were obvious horizontal spaces (XYP, XP were the highest at all soil layers; L, C were higher at most soil layers; F, S, H only was higher at the surface layer; Y was the lowest at all soil layers) and vertical space (XYP, XP, L decreased with soil depth; F, S, H at middle and upper soil layers decreased; C and Y were similar at all layers) differentiation regularity. (3) Ecosystem carbon storage (66.35−329.94 t/ha) also showed a stepwise decreasing trend along the lakeshore to the highland environmental gradient, and its distribution pattern was mostly dominated by soil carbon storage (95.43%−99.04%), only Y soil carbon storage accounted for low proportion (58.2%); (4) The NPP (2.11−16.28 t/(ha·year)) and ANCS (0.68−7.00 t/(ha·year)) of vegetation showed a decreasing trend along the lakeshore to the highland environmental gradient (XYP, XP and L were significantly higher than the other five communities by 0.3−9.3 times), and the ANCS of L and XYP was higher than the average carbon sequestration of vegetation in China and the world by 10.6%−70.7%; (5) Ecosystem carbon stocks and annual net carbon sequestration of vegetation of plant communities in permanently flooded habitat in the lower part of the environmental gradient were controlled by water level; plant communities in seasonally flooded habitat in the middle environment gradient were controlled by SOM, TN, TP and AK; plant communities in arid habitats in the upper environmental gradient were controlled by SOM and AP. Conclusion Therefore, the spatial heterogeneity of water and nutrient redistribution caused by the micro-topography controls the distribution of plant communities and their carbon sinks along the lakeshore to the highland environmental gradient in the Nenjiang River of Taihu National Wetland Park of China, so the integrity of such environmental gradients should be protected.
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Objective This paper aims to explore the spatial and temporal evolution of net primary productivity (NPP) of vegetation in the Loess Plateau over many years and the combined impact of human activities and natural factors in the same period on it, so as to provide reference for the local ecological restoration planning and implementation. Method CASA model was used to calculate and analyze the NPP and its spatial and temporal distribution pattern of vegetation in the Loess Plateau from 2001 to 2019, and the driving factors and mechanisms of vegetation NPP were analyzed based on Geodetector. Result (1) The vegetation NPP in the Loess Plateau showed an overall significant increasing trend from 2001 to 2019, with an average annual increase rate of 5.59 g/(m2·year). The areas with significant increase in NPP were mainly distributed in the central gully and hilly gully areas of the Loess Plateau. The analysis of the spatial center of gravity of NPP based on the center of gravity model showed that the migration of NPP center of gravity in the Loess Plateau exhibited a periodic change feature, with the average NPP increment and growth rate in the southern part of the center of gravity being higher than in the northern part for most years. The significant NPP increased was detected mainly in the central gully area and hilly gully area of the Loess Plateau. Among different land use types, forest land had the highest mean NPP. Land use transfer was mainly transformed between cultivated land and grassland, accounting for 75% of the total change area, leading to the highest rate of linear changes in NPP. (2) The results of geographic detectors showed that annual precipitation and dryness index were the dominant natural factors affecting vegetation NPP in the Loess Plateau, followed by land use type, annual average temperature and slope. The results of the interaction detector showed that the interaction of factors was mainly bi-factor enhancement or nonlinear enhancement, and the factors that had no significant impact on vegetation NPP had a significant impact on NPP when interacting with other factors. The optimal range of vegetation NPP identified by the risk detector varied among different land use types. The optimum annual precipitation range for NPP of most land use types was 500−1000 mm. Except for unused land, the suitable temperature range for NPP of other land use types was between 10 and 14 ℃. The suitable altitude ranged for NPP of cultivated land and other land use types were 19.62−548.43 m and 1000−2500 m, respectively. The suitable slope range for NPP of the woodland was relatively spanned, and the suitable slope aspects varied among different land types. Conclusion The results of this study show that vegetation restoration on the Loess Plateau from 2001 to 2019 contributes significantly to ecosystem NPP. The interactions between environmental factors enhance the influence of single factors on vegetation NPP. Moreover, the optimal accumulation ranges of NPP of different environmental factors are different for varied land use types. Our study provides a theoretical basis for the vegetation restoration and management practices in this area.
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Objective The main purpose of this study was to explore how Robinia pseudoacacia coped with drought and rehydration caused by climate change, and to understand the changes of water physiology, non-structural carbon balanced allocation strategy and physiological and biochemical response mechanism during drought and rehydration. It helps to reveal the physiological mechanism of Robinia pseudoacacia forest decline and death under the background of overall climate change. Theoretical reference for cultivation irrigation of Robinia pseudoacacia forest was provided. Method In this study, the experimental method of natural drought was used, and the normal water supply was set and the water supply was stopped. Then, the physiological indexes of two years old Robinia pseudoacacia seedlings were measured, such as water status, pressure-volume curve parameters, non-structural carbon and antioxidant enzyme activities, and the effects of different treatments and period of drought on physiological parameters of Robinia pseudoacacia seedlings were compared. Result In the light drought period, the accumulation of starch and the ability of maintaining turgor pressure in cells of Robinia pseudoacacia leaves increased, and the osmotic regulation and antioxidant defense mechanism of roots and leaves were also started. During moderate drought period, the process of starch conversion to soluble sugar and Pro content increased significantly to improve osmotic regulation to cope with drought stress. At the same time, the activities of APX, SOD and POD reached peak values, and the osmotic regulation and antioxidant defense mechanism of root were fully activated. When Robinia pseudoacacia was in a severe drought, the content of starch and NSC in roots increased, the function of NSC gradually changed from the osmotic regulation of soluble sugar to the accumulation of starch. After rehydration, root and stem storage NSC decreased significantly. Conclusion The growth of Robinia pseudoacacia seedlings is significantly inhibited by drought stress, and its water transport, carbon metabolism and other physiological and biochemical reactions are significantly affected. When drought stress exceeds moderate drought, the physiological adaptability of Robinia pseudoacacia seedlings decreases. As drought stress intensifies, a net loss of carbohydrates may occur. During severe drought, more NSC seedlings will be distributed from leaves to roots, and NSC will gradually be used for osmotic regulation to storage, and may be used for restoration and reconstruction of hydraulic conduction after rehydration.
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Objective The species composition of forest community in Changbai Mountain Nature Reserve of northeastern China and its relationship with environmental factors were analyzed by the method of quantitative ecology, providing scientific basis for protection and sustainable management of forest ecosystems in the region, and providing references for similar researches. Method With the help of remote sensing data, a total of 40 sample points were selected from 750 m to 1 850 m above sea level in the Changbai Mountain Nature Reserve in different slope aspects along roads, and community surveys were carried out from August to September 2021. Based on the survey data, the importance values of different species in the sample plots were calculated. Then the two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) were used to divide the sample plots into different community types. Finally, combining with environmental data, the canonical correspondence analysis (CCA) and variation partitioning were used to explore relationships between the distribution of communities and environmental factors. Result (1) According to the results of TWINSPAN and DCA, the 40 sample plots were classified into 9 community types. (2) The CCA ranking results well reflected the relationship between community distribution and environmental factors. Among the 10 selected environmental factors, altitude, slope, annual mean temperature, isothermality, temperature seasonality, mean diurnal range, annual precipitation, precipitation seasonality, temperature annual range had greater impacts on species distribution. (3) The results of variational partitioning showed that these 10 tested factors could explain 46.8% variation of species distribution. Among these factors, topography, climate and their interaction respectively accounted for 8.0%, 29.1% and 9.7% of the variation, while 53.2% of the variation was unexplained. Conclusion The investigated area in Changbai Mountain mainly includes 9 types of forest communities, and the alteration of hydrothermal conditions caused by altitude is the main environmental factor affecting community distribution. The unexplained part is concerned to be associated with the complexity of community composition as well as the lack of environmental information such as soil properties etc.
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Objective The growth differences of Fraxinus mandshurica, Juglans mandshurica and Tilia amurensis artificially planted seedlings under different canopy densities of Pinus sylvestris var. mongolica forest were investigated in this study to provide theoretical basis and technical support for the selection of broadleaved trees suitable for regeneration under different canopy densities of P. sylvestris var. mongolica forest. Method A artificial regeneration experiment was conducted with two-year-old bare root seedlings of F. mandshurica, J. mandshurica, T. amurensis under the P. sylvestris var. mongolica forest. Furthermore, four light environments of P. sylvestris var. mongolica forest were applied, i.e. full light, canopy density of 0.4, 0.6 and 0.8. At the end of the growing season, the changes of seedling height, base diameter, photosynthetic parameters, photosynthetic pigment content and leaf nutrient content of the three seedlings were measured. Result By the end of the growing season, the height growth and ground diameter growth of J. mandshurica seedlings under canopy density of 0.6−0.8 were significantly higher than those under full light and canopy density of 0.4, and those were the largest under canopy density of 0.8. The height growth and ground diameter growth of F. mandshurica and T. amurensis seedlings under canopy density of 0.4−0.6 were significantly higher than those under full light and canopy density of 0.8. The height growth and ground diameter growth of J. mandshurica seedlings were better than F. mandshurica and T. amurensis seedlings under the four treatments. With the increase of canopy density, chlorophyll content of the three tree species showed a significant upward trend, and the trend of photosynthetic rate (Pn) was consistent with the trend of total chlorophyll content (Ct). The stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of J. mandshurica increased with the increase of canopy density; the Gs of F. mandshurica and T. amurensis showed an upward trend, and the Ci showed an overall trend of first increasing and then decreasing; transpiration rate (Tr) showed a downward trend with the increase of canopy density. The leaf N content of the three tree species increased with the increase of canopy density; there was no significant difference in the total C content of J. mandshurica leaves among the treatments. The total C content of F. mandshurica and T. amurensis leaves showed a downward trend with the increase of canopy density, among which, the total C content of F. mandshurica seedling leaves under full light, canopy density of 0.4 and 0.6 treatments had no significant difference, but they were all higher than that under canopy density of 0.8 treatment; total P content in the leaves of T. amurensis increased first and then decreased, J. mandshurica decreased gradually, while total P content in the leaves of F. mandshurica was not significantly different among the treatments, and total K content decreased first and then increased as a whole. The growth of J. mandshurica was better than F. mandshurica and T. amurensis under different canopy densities of P. sylvestris; the growth of J. mandshurica was better than F. mandshurica and T. amurensis under different canopy densities of P. sylvestris; among them, the photosynthetic rate of T. amurensis under each canopy density did not change significantly, the change of light intensity had little effect on it. Conclusion This study conducted a comparative analysis of the growth of three broadleaved tree species under different canopy densities of P. sylvestris var. mongolica forest in one year of pianting. It was found that F. mandshurica, T. amurensis and J. mandshurica can grow in the soil environment of P. sylvestris var. mongolica forest in the year of planting, and all of them have certain negative tolerance. F. mandshurica and T. amurensis grow better in canopy density of 0.4−0.6 than in full light and canopy density of 0.8, J. mandshurica grows best in canopy density of 0.8, and the growth status of J. mandshurica under different canopy densities is better than F. mandshurica and T. amurensis. With the growth of seedlings, the relationship between J. mandshurica and its surrounding vegetation and its demand for light resources may change. Thus, to provide a solid theoretical basis for the regeneration of P. sylvestris var. mongolica plantation, followed investigations are still needed.
Abstract:
Objective Rational cutting can promote the growth of trees and increase the productivity of stands. It is of no important practical significance to determine cutting with the aim of optimizing the spatial structure of stands. In this study, the natural forest composed of different tree species in Changbai Mountain of northeastern China was taken as the object, and the combination weight method of AHP-CRITIC was adopted to construct single tree cutting index, in order to provide a new guiding tool for the selection of natural forest cutting wood in this area. Method In this paper, the monitoring data of 4 natural forest fixed samples with different dominant tree species were adopted, four spatial structure indexes, including mingling degrees (M), uniform angle index (W), dominance degrees (U) and Hegyi competition index (CI) were used, and the individual tree felling index (Fi) was constructed according to AHP-CRITIC combination weight method. The spatial structure changes of stand before and after cutting simulation with different intensities were analyzed. Result After cutting, the spatial structure of the four sample plots was optimized to a certain extent: the mingling degrees increased, the degree of tree size differentiation decreased, the horizontal distribution pattern of stand tended to random distribution, and the pressure of stand competition was greatly relieved. The competition index showed a trend of continuous decline with the increase of cutting intensity. Under 30% cutting intensity, the competition index decreased by 24.80%−34.88% at most, the size ratio decreased by 24.97% at most, and the mixing degree increased by 12.76% at the highest. The felled trees were mainly concentrated in the area with high density, and most of the felled trees were small and medium-sized in DBH. Conclusion Through comparative analysis of data before and after simulated cutting, it is proved that for natural pure forest, moderately increasing cutting intensity can better regulate the spatial structure of the stand, while for natural mixed forest, relatively low intensity cutting can optimize its overall structure and maintain a higher degree of tree species mixing. At the same time, the research proves that it is reasonable for AHP-CRITIC combination weight method to construct cutting index, which basically realizes the optimization and adjustment of natural forest stand structure in Changbai Mountain, and can provide technical support for reasonable selection of cutting wood and reasonable management of forest.
Abstract:
Objective It is an important premise to clarify the timber assortment structure of Cunninghamia lanceolata plantations and build a reasonable outturn model, aiming to increase the wood yield, improve the forest management techniques and optimize the management plan for Cunninghamia lanceolata plantations. Method Based on the 492 felling areas of Cunninghamia lanceolata plantations from 6 state-owned forest farms in Fujian Province of eastern China in the past 15 years, the response of 6 timber assortment outturn (i.e., dimension timber, non-dimension timber, commercial timber, fuel wood, merchantable timber, refuse wood) to each factor, including average DBH, average height, stand age, stand volume, stand density and site quality, was investigated. On this basis, the main stand factors affecting the yield of timber species were screened, the timber outturn model for final felling stands of Cunninghamia lanceolata was constructed and the applicability of the model was evaluated. Result Among the stand factors of Cunninghamia lanceolata final felling stands, average DBH and average height showed much larger influence than other stand factors on the outturn of each timber assortment, followed by stand volume, age and density, and the influence of site quality was relatively small. The dimension timber, commercial timber and fuel wood timber assortment outturn model system using average DBH and average height as predictive variables showed good fitting and validating results. Based on this, the timber assortment outturn model of non-dimension timber, merchantable timber and refuse wood timber assortment outturn model was constructed. The prediction errors of the timber assortment outturn for different diameter classes were small and stable. Conclusion This study reveals the timber assortment structure rule, as well as its influencing factors for Cunninghamia lanceolata final felling stands. The model system can be used to calculate the timber assortment yield of Cunninghamia lanceolata final felling stands, and provide support for the formulation of rational production plan of Cunninghamia lanceolata plantations.
2023, 45(8): 94-108.
doi: 10.12171/j.1000-1522.20230027
Abstract:
Objective Accurate acquisition of tree growth parameters is a necessary prerequisite for obtaining forest information and phenotypic characteristics and is of great significance in forest character assessment, forest carbon sink measurement, and optimization of forest management strategies. Nowadays, accurate extraction of tree growth parameters from light detection and ranging data and prediction of tree growth parameters in the future will provide technical support for the digital development of forestry. Method In this study, an artificial intelligence based approach to tree growth parameter extraction and prediction was proposed. Four tree species in Nanjing Forestry University, i.e., sakura, ginkgo, liriodendron, and Chinese fir, were selected as experimental objects. First, airborne laser scanning was used to obtain the point cloud data of four tree species sample plots, and the individual tree segmentation algorithm was used to obtain a single tree point cloud. Second, growth parameters such as DBH height, tree height, and crown width were automatically extracted from the single tree point cloud using the circle fitting and Gaussian filter algorithms, and supplemented with artificial in-situ measurement data (measured in 2015, 2017, 2019, 2021, and 2022). The time series of single tree growth parameters of different tree species were constructed as the training sample set for the deep learning network. Finally, a deep learning network for predicting tree growth parameters was constructed with a two-layer Gated Recurrent Unit (GRU) network, and an attention module was introduced to compensate for the shortcomings of traditional recurrent neural networks in capturing long-term dependencies. The network took the time series of individual tree growth parameters from 2015 to 2021 as the input, relied on training data and stochastic gradient descent algorithm to approximate the network parameters to the real tree growth situation, and was used to predict the growth parameters of individual trees in 2022. Result The network performed best in the prediction of tree height, with the R2 not less than 0.83 and root mean square error (ERMS) less than 0.50 m. The prediction results of the ginkgo tree were the best among the four species (R2 = 0.95, ERMS = 0.31 m). The depth prediction network still had an acceptable performance in the prediction of parameters such as DBH height and crown width, R2 was not less than 0.81, DBH height ERMS was less than 2.50 cm, crown width ERMS was less than 0.32 m. The model in this paper predicted well (R2 ≥ 0.86) with less error compared with other tree parameter prediction methods such as linear regression and LSTM networks. Conclusion The cascaded recurrent neural network can effectively predict the future tree growth and improve the prediction accuracy of tree growth parameters, while the introduction of GRU and attention model has certain robustness in the time-series prediction of growth parameters, which provides a new idea for the intelligent management and visualization analysis of forests.
2023, 45(8): 109-122.
doi: 10.12171/j.1000-1522.20210386
Abstract:
Objective With the vigorous development of big data, artificial intelligence and other information technologies, information services in various fields have been transformed from data services to knowledge services. This paper captures the problems of complicated, multi-source heterogeneous and difficult access to forestry knowledge, and through the research on construction method and application scenario of knowledge graph of afforestation tree species based on ontology, in order to provide a more effective way to organize and express knowledge in the field of afforestation. Method This article takes the knowledge related to afforestation tree species as the research object, takes the actual needs of afforestation work as the research hotspot, and constructs an afforestation tree species ontology covering seven types of concepts such as afforestation tree species, diseases and pests, experts, organizations, provinces, application products and afforestation technology, 12 attributes such as tree species alias, Latin name and forest species type, and seven relationships such as distribution, application and research by discussing and exchanging with experts in afforestation field using the seven-step method. A knowledge graph of afforestation tree species was constructed based on the entities, attributes, and relationships defined in the ontology model of afforestation tree species. Relevant knowledge applications based on the knowledge graph of afforestation tree species were designed and implemented. Result The research applied the knowledge graph technology to the actual scenario of afforestation tree species and completed the construction of knowledge graph, realized the knowledge Q&A and knowledge visualization based on afforestation tree species knowledge graph, and provided knowledge services for researchers and workers in afforestation field. In addition, the study proposed a map service model combining knowledge Q&A of afforestation tree species, GIS map and tree species pictures, and built a GIS map service platform of afforestation tree species to realize the problem of suitability of afforestation tree species in spatial location by “GIS map + tree species pictures + text description”. Conclusion The ontology model of afforestation tree species constructed in this thesis provides the possibility of subsequent knowledge reuse and sharing. The realized knowledge graph of afforestation tree species, knowledge Q&A of afforestation tree species and GIS map service platform effectively solve the problems of multi-source, heterogeneity, low data value and difficult access of forestry knowledge, and realize the transformation of domain information resources from data service to knowledge services. The knowledge scale of the knowledge graph of afforestation tree species needs to be further expanded and more application scenarios based on the knowledge graph need to be explored in subsequent studies, with the view to providing high-quality knowledge services for forestry development and research.
Abstract:
Objective Normal ovule (kernel) filling is the basis of hazel kernel formation. Insufficient ovule filling can frequently lead to the shriveled kernels or empty nuts in hazel. SEP belonging to the E class MADS-box gene plays an important role in ovule development of plants. To investigate the important role of ChSEP in hazelnut ovule development, the key ChSEP genes involved in the development of hazelnut ovules were identified. Then, polyclonal antibody against ChSEP was prepared, followed by immunohistochemical analysis of ChSEP using developing and aborted ovules as study materials. The present study is beneficial for better understanding of ovule development mechanism regulated by SEP in hazelnut. Method All SEP gene family members in hazelnut genome were identified using genome and transcriptome data, and prokaryotic expression vector construction containing important SEP gene, gene expression, and polyclonal antibody preparation were carried out. Finally, important SEP involved in ovule development regulation was detected by immunohistochemistry. Result (1) Three ChSEP sequences were identified in the genome of hazelnut, including Cor0054610.1, Cor0008190.1 and Cor0119400.1. All SEP proteins contained SRF-TF and K-box motifs. Polyclonal antisera of Cor0054610.1 was prepared, and the molecular mass of polyclonal antibody E18305 and E18306 was about 45 kDa, and 1−2 ng antigen could be detected after 1∶1000 dilution. (2) Immunohistochemical analysis showed that ChSEP was expressed in the integument of both developing and abortive ovules. The expression of ChSEP in integuments was higher than that in cotyledons. There was no significant difference in the distribution of ChSEP between developing and abortive ovules. Conclusion This study provides evidence that ChSEP (Cor0054610.1) is involved in the regulation of hazelnut ovule development at both transcriptional and protein levels, and provides a scientific basis for better understanding of the ovule development mechanism in hazelnut.
Abstract:
Objective Genetic diversity and genetic relationship of the leaves from 15 commercially available common types and 7 new ornamental peach germplasms were studied and identified by simple sequence repeat (SSR). The purpose of this study was to explore the genetic distance between the new germplasm and commercially available common varieties, and to provide reference for the origin, evolution, development and utilization of ornamental peach and parental selection. Method TP-M13-SSR PCR amplification and fluorescent capillary electrophoresis detection were carried out using 36 pairs of primers, and the amplification efficiency and polymorphism were analyzed. Genetic relationship of new ornamental peach germplasm ‘T13’, ‘T9-1’, ‘T10’, ‘T20’, ‘T22’ and ‘Zaohua’ was identified, and fingerprints of 22 ornamental peach germplasm resources were constructed using 6 SSR loci, and Neighbor-Joining clustering and comprehensive analysis combined with phenotypic traits was performed. Result 36 pairs of highly polymorphic primers were screened from 29 pairs of primers. A total of 183 polymorphic alleles and 98.396 effective alleles were detected. Average of observed heterozygosity was 0.341, and average of expected heterozygosity was 0.739. Average of Shannon’s information index was 1.546, and average of polymorphism information content of primer was 0.683, ranging from 0.510 to 0.841. The new germplasm ‘T20’ and ‘T10’ had the largest similarity coefficients with the existing variety ‘Taijie’, which were 0.95 and 0.92, respectively. ‘T20’ and ‘Taijie’ had the same phenotypic traits, including branch shape, petal color and petal type. The new germplasm ‘T13’ and the existing variety ‘Wubao tao’ had the highest similarity coefficient, which was 0.86. Similarity coefficient between the new germplasm ‘T22’ and other existing varieties was very small, and its phenotypic characters were quite different from the other 21 germplasms. Similarity coefficient of the new germplasm ‘T9-1’ and ‘Zaohua’ with the existing variety ‘Zhufen chuizhi’ was the largest, which was 0.94. Conclusion In this study, through the construction of SSR fingerprint map, the ornamental peach germplasm resources can be identified more intuitively and quickly, providing technical and theoretical support for the later innovation of ornamental peach germplasm resources, the establishment of germplasm resource banks, and the protection and utilization of germplasm resources.
2023, 45(8): 142-147.
doi: 10.12171/j.1000-1522.20220262
Abstract:
Objective The amount of Bursaphelenchus xylophilus carried by vector insects has an important impact on the transmission and damage of pine wilt disease, so it is necessary to clarify the carrying amount of Monochamus saltuarius vectoring B. xylophilus in China. Method The number of B. xylophilus carried by M. saltuarius was investigated in Dahuofang Experimental Forest Farm in Fushun City, Liaoning Province of northeastern China in 2018 to 2020. Pinus koraiensis trees infected by M. saltuarius were sawn into one meter long logs, sealed with wax at both ends to retain moisture, and placed in cages. The newly emerged M. saltuarius was collected every day. Meanwhile, the M. saltuarius was collected from infected P. koraiensis by hanging sentinel traps and shock-dropping methods, and brought to the laboratory. All the collected live M. saltuarius trees were dissected into three parts: head, thorax and abdomen to separate nematodes by the Bayman funnel method, then the number of B. xylophilus was counted. Result 58 vectors were tested carrying B. xylophilus among 160 newly emerged adults of M. saltuarius, accounting for 36.25% of the total. The average number of B. xylophilus carried by each M. saltuarius was 336.74, and the maximum number was 5 560. The average number of B. xylophilus carried by each female adult and male adult was 458.52 and 191.54, respectively, with no significant difference between male and female. 38 vectors were tested carrying B. xylophilus among 274 M. saltuarius adults collected in forest, accounting for 13.87% of the total. The average number of B. xylophilus carried by each M. saltuarius was 214.92, and the maximum number was 2 486. The average number of B. xylophilus carried by each female adult and male adult was 161.81 and 280.53, respectively, with no significant difference between male and female. The average number of B. xylophilus in thorax, head, and abdomen of M. saltuarius was 35.88, 0.88, and 0.34, respectively. The number of B. xylophilus in vector’s thorax was much higher than that in the other two parts. Conclusion It is found that the number of B. xylophilus carried by M. saltuarius in China was much lower than M. saltuarius in Japan and M. alternatus in this study. There was no significant difference in the carrying amount between male and female adults of M. saltuariu, and B. xylophilus was mainly distributed in the thorax of the vector.
Abstract:
Objective Slope length is an important factor affecting the formation of slope runoff and soil erosion processes. This study focused on the sediment concentration at different slope lengths in the loess area of western Shanxi Province of northern China, aiming to explore the variation of sediment concentration in slope runoff with slope length and elucidate the influence of slope length factors on slope erosion process. Method In order to reveal the variation law of runoff sediment concentration with slope length and to clarify the slope erosion process, the runoff sediment concentration and soil detachment rate at different locations within 0−5 m slope length were measured using 7.5 and 10.0 L/(min·m) unit width discharge on the 5° and 20° slopes, respectively. Result (1) The runoff sediment concentration increased gradually with the increase of slope length, and increased faster under the larger slope gradient and flow discharge. In addition, the increase of slope gradient and flow discharge will increase the runoff sediment concentration. (2) The soil detachment rate first increased and then decreased with the increase of slope length, and the peak position moved toward the slope top with the increase of flow discharge and slope gradient. The soil detachment rate increased with the increase of slope gradient and flow discharge. (3) The S-shaped curve can well fit the variation of runoff sediment concentration with slope length under various conditions, and the coefficient of determination R2 ≥ 0.97. The three parameters in the curve model can well reflect the characteristics of slope erosion, namely, the maximum sediment carrying force (a) increased with the increase of slope gradient and flow discharge, the position with the fastest erosion rate (xc) decreased with the increase of slope gradient and flow discharge, and the changing rate of sediment concentration (k) increased with the increase of slope gradient and flow discharge. (4) Based on the S-curve process theory and experimental calculation value, if the rainfall intensity of 60 mm/h was taken as the prevention object, it was recommended that the distance between vegetation engineering slope protection measures and slope top under 5° conditions should not exceed 426 cm, and the distance between vegetation engineering slope protection measures and slope top under 20° conditions should not exceed 313 cm. If the rainfall intensity of 90 mm/h was taken as the object of prevention, it was recommended that the distance between the vegetation engineering slope protection measures and the slope top under 5° conditions should not exceed 366 cm, and the distance between the vegetation engineering slope protection measures and the slope top under 20° conditions should not exceed 283 cm. Conclusion Based on the theoretical process of slope erosion and the results of erosion tests, this study proposes and simulates an S-shaped curve growth process of slow increase, rapid increase, and slow increase to saturation of sediment content with slope length. Based on the characteristics of the curve, the layout method of slope protection measures in the loess area of western Shanxi Province is proposed. This helps to deeply understand the mechanism of slope erosion and provide a basis for estimating the parameters of slope erosion models and laying out soil and water conservation measures in the loess area of western Shanxi Province.
2023, 45(8): 156-162.
doi: 10.12171/j.1000-1522.20230104
Abstract:
Objective The macrostructure and physiological functions between the internode and node of Phyllostachys edulis are quite different. Fibers and parenchyma cells are the two main components in either Phyllostachys edulis internodes or nodes, full comparison and understanding of the differences between fibers and parenchyma cells in terms of structures and properties can provide a theoretical basis for their directional separation and efficient utilization. Method The fibers and parenchyma cells in both bamboo internodes and internodes were isolated by physical and chemical separation methods. Subsequently, the chemical composition, thermal stability, and microstructure of bamboo fibers and parenchyma cells were studied by Fourier infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and field emission scanning electron microscopy. Result The morphology of the ends of fibers extracted from the internodes and the bamboo nodes both exhibited sharp and slender shapes. As for parenchyma cells, the long cells and short cells could be clearly distinguished in the internode, while the parenchyma cells in the node showed round, oval, or square cell shapes. The content of cellulose in the internode was higher than that in the node, and the content of lignin in the internode was lower than that in the node, but the hemicellulose content was not significantly different between the internode and the node. The cellulose content in fibers was higher than that in parenchyma cells, the lignin content in fiber was lower than that in parenchyma cells, and the hemicellulose content in fiber was not different from that in parenchyma cells. With respect to thermal stability, the maximum decomposition temperature in internode parenchyma cells was lowest at 390.32 ℃, and the maximum decomposition temperature in node fiber was highest at 393.54 ℃. Conclusion The fiber morphological difference between the internode and the node of bamboo is not very significant. The parenchyma cells in the internode can be divided into long cells and short cells, but distinguishing between long cells and short cells in the node is not obvious. The cellulose and lignin contents are different in fiber and parenchyma cells at different locations, but the hemicellulose contents are not different. The thermal stability of fiber and parenchyma cells in the bamboo node is slightly higher than that in the internode, suggesting that the thermal stability of the bamboo node is slightly higher than that in the internode.
Establishment Time:1979
CN 11-1932/S
ISSN 1000-1522
Supervisor:Sinopec Research Institute of Petroleum Engineering
Sponsors by:
