Objective: To calculate and simulate the compensation standards and targets for forest carbon compensation in the Qiantang River Basin from 2000 to 2020, so as to provide a scientific basis and policy support for the establishment of a sound forest carbon compensation mechanism that can reflect the value of carbon sinks in the basin and key ecological function areas. Method: The IPCC inventory method is used as the basis for constructing a carbon emission accounting system to calculate the carbon emissions of county units in the Qiantang River basin. The CASA model is used to calculate the carbon absorption of each county unit in the Qiantang River basin, and Arcgis software was used to absorption forest carbon absorption by zones and analyse the contribution of forest carbon absorption to total carbon absorption. The carbon compensation model is used to calculate the amount of forest carbon compensation in the Qiantang River basin, and the target and spatial selection of carbon compensation are simulated. Result: Between 2000 and 2020, the carbon emission intensity of the Qiantang River basin is clearly polarized, with the higher carbon emission intensity concentrated in the northeastern part of the basin, namely Yuhang District, Hangzhou City and Xiaoshan District. The important ecological function areas in the basin have a lower carbon emission intensity. In contrast to carbon emissions, the economically developed areas in the basin absorb less carbon, with the urban area of Hangzhou absorbing the least amount of carbon. Forest carbon absorption contributes most to the total carbon sequestration in the basin, and the absorption shows an overall increasing trend. The better the economic development of the county units and the more rapid urbanization, the lower their forest carbon compensation rate, and vice versa the higher the forest carbon compensation rate. Changshan County, Kaihua County, Tonglu County, Jiande City and Chun'an County are able to obtain higher standards for carbon compensation due to their large forest carbon surplus, while Lin'an District and Yuhang District obtain lower compensation standards. Hangzhou City and Xiaoshan District pay a larger amount of compensation due to their large deficits in forest carbon revenues and expenditures. Chun'an County, Jiande City, Kaihua County, Changshan County, Yuhang District, Lin'an District, Fuyang District and Tonglu County are the receiving areas and recipients of forest carbon compensation. Conclusion: The economic development of each county unit in the Qiantang River Basin is extremely unbalanced, with a mismatch between ecological carrying capacity and economic development capacity, and a serious mismatch between carbon supply and demand. It is necessary to take the lead in establishing a sound compensation mechanism for forest ecological protection in the basin that reflects the value of carbon sinks, and provide a model for the establishment of an ecosystem carbon compensation mechanism for the whole country by adopting diversified forest carbon compensation method, clarifying the targets of forest carbon compensation, improving the coordination mechanism between government compensation and market compensation, and establishing a forest protection and construction system for national important functional areas based on carbon revenue and expenditure accounting.

Objective: From two levels of species group and species to research the spatial distribution pattern of different characteristics of dominant species group, also to research the spatial associations between groups and within groups and their laws of change with scales. To explore spatial distribution pattern of dominant species and the causes of intercorrelation of subtropical evergreen broad-leaved forest community in Dinghushan Mountain, further to reveal the coexistence and distribution of dominant species in communities, and to provide a theoretical basis for biodiversity conservation in this region. Method: Based on the survey data of the top 10 dominant species in the 20 hm² subtropical evergreen broad-leaved forest community in Dinghushan Mountain, the spatial distribution point patterns of species groups and within groups were analyzed using the relative neighborhood density index Ω_r, and the spatial correlation between species groups and within groups was analyzed using the multivariate point pattern g₁₂ equation. Result: 1) Aggregation distribution was not only dominant at the species level, but also the main type of spatial distribution pattern at the species group level. The degree of significant aggregation detected in each dominant species group showed a downward trend with the increase of detection scale. 2) The strategies of maintaining dominance of each characteristic dominant species group in the community were different, which reflected the difference of association among species groups. Diameter class dominant species group and quantitative dominant species group competed for survival resources with two different survival strategies respectively from large diameter class and high quantity. In the end, the two species had different spatial distribution and maintained their advantages together with their own characteristics, showing a significant negative correlation at all detection scales. The diameter class dominant species group and the diameter class and quantitative dominant species group were almost independent and unrelated at all detection scales. The quantitative dominant species group and the diameter class and quantitative dominant species group were in a complementary state in the vertical spatial distribution of the community, and in the same or similar spatial distribution in the horizontal space, there was a significant positive correlation at all scales. 3) There were differences in the spatial associations among the groups of characteristic dominant species: the spatial correlation among the dominant species in the diameter class group was mainly positive, and the spatial associations among species within the quantitative dominant species group were different, and the spatial associations of the two species (Castanopsis chinensis and Acmena acuminatissima) within the diameter class and quantitative dominant species group were significantly negative correlated. Conclusion: The spatial distribution pattern at the species group level were consistent with those at the species level. Aggregated distribution was still the main type of spatial distribution pattern of the community. The strategies of maintaining dominance in the community were different for each characteristic dominant species group, which reflected the differences in spatial association among the species groups. The diameter-class dominant species group and the quantitative dominant species group were complementary in horizontal space, and the two groups showed significant negative correlation at all detection scales. The quantitative dominant species group and the diameter class and quantitative dominant species group were complementary in vertical space and overlapping in horizontal space, and had significant positive correlation at all detection scales.

Objective: The soil physicochemical properties, dynamic characteristics and changing trends of soil labile organic carbon (LOC) before and after forest fires in the secondary forests of Pinus massoniana were analyzed, and the impact of moderate forest fire intensity on the stability of the soil carbon pools was quantitatively evaluated, which can provide a reference for quantitative research on the effects of moderate forest fire intensity on soil carbon balance and carbon cycle. Method: The secondary forests of P. massoniana in mature forests, middle-aged forests and young forests were selected, and the soil samples from 0-60 cm layers in the burned area and adjacent unburned forests were collected. The soil physicochemical properties, fine root biomass and the soil LOC component content were measured and analyzed, and the soil carbon pool management index (CPMI) was calculated to explore the soil carbon pool change characteristics. The path analysis was used to explore the direct and indirect effects of soil CPMI. Result: Compared with the control plots, the soil bulk density increased by 3.80%-4.85%, soil pH increased by 4.21%-5.78%, and total soil phosphorus increased by 7.97%-12.44% in the 0-60 cm soil layers of each forest age after the forest fire. The soil moisture content decreased by 3.41%-3.97%, soil total nitrogen decreased by 15.09%-17.45%, and soil organic carbon decreased by 10.07%-14.31%. The soil labile organic carbon (LOC) in the young-aged, middle-aged and mature forests decreased by 22.70%, 19.48% and 17.48%, respectively. The soil CPMI of the secondary forest of P. massoniana with different forest ages was different in response to forest fire. The soil CPMI of young forest, middle-aged forest and mature forest was 26.15, 30.57 and 32.09, respectively, showing a increasing trend with the increase of forest age. Soil CPMI of P. massoniana secondary forest had a very significant correlation with each component of soil LOC (P < 0.01), and also had a very significant correlation with soil physicochemical properties and soil fine root biomass (P < 0.01). Path analysis showed that soil TN had the greatest direct effect on soil CPMI, with a path coefficient of 1.786, followed by soil TP and soil fine root biomass, with the path coefficients of -1.021 and 0.981, respectively. Conclusion: Moderate forest fire intensity has an important impact on the stability of soil organic carbon pool in the secondary forest of P. massoniana. The difference in soil nutrients released by mineralization of soil active organic matter among the three forest ages after forest fire is the key to the stability of soil carbon pool in the secondary forest of P. massoniana. The stability of soil organic carbon pool increases with the increase of stand age and soil depth. Therefore, when formulating the ecological restoration strategy in the burned area, the protection of mature forest land should be strengthened, and the artificial tending of young and middle-aged forest land should be strengthened to promote the natural regeneration and restoration of the secondary forest of P. massoniana after the fire.

Objective: This study applied computer vision technology to process the multispectral images of young Aquilaria sinensis canopy, and build a total nitrogen estimation model, to realize the nondestructive estimation of the nitrogen nutrition status of Aquilaria sinensis and explore the new image processing methods and new estimation model for Aquilaria sinensis nutritional monitoring. Method: Based on the canopy images of Aquilaria sinensis seedlings obtained by the multispectral camera, the improved exponential semi-soft threshold function was used to wavelet denoise the multispectral image, and the Fourier-Merlin transform (FMT) registration and genetic algorithm-back propagation neural network (GA-BPNN) algorithm were combined to achieve accurate segmentation of the multispectral image. Then, the spectral texture features of the segmented images were extracted as independent variables to establish the Elastic Net (EN) total nitrogen estimation models improved by artificial bee colony algorithm (ABC), beetle antennae search algorithm (BAS), and hybrid gray wolf optimization algorithm (HGWO). Finally, the model accuracy was verified and evaluated by using the leave-one-out cross-validation method to determine the optimal model, which was compared with the traditional partial least squares regression (PLSR), ridge regression (RR) and multiple stepwise regression (SR) models. Result: 1) The improved wavelet exponential semi-soft thresholding method could effectively remove strong noise in near-infrared images, and was superior to wavelet soft thresholding, hard thresholding and traditional semi-soft thresholding methods. 2) The segmentation effect of GA-BPNN was better than that of Otsu threshold, maximum entropy and minimum cross entropy segmentation, and the segmentation effect combined with FMT registration was significantly better than that of direct segmentation of images in various bands. 3) As for the EN models, based on the verification result of the single spectral feature, single texture feature and comprehensive feature models, the optimization effect of the three optimization algorithms was ranked as ABC>HGWO>BAS, and the estimation accuracy of the three feature models was ranked as comprehensive feature > single spectral feature > single texture feature. For the ABC-optimized EN models (ABC-EN), the determination coefficient (R²) of the comprehensive feature model was 0.829 4, which was 10% and 54% higher than that of the single spectrum and texture feature models respectively, and the mean square error (MSE) was 0.169 5, which was 30% and 63% lower than that of the single spectrum and texture feature models respectively. 4) The comparison result of estimation accuracy between ABC-EN and other traditional models were: ABC-EN > RR > PLSR > SR, and the R² of RR, PLSR and SR model were 0.748 3, 0.651 2, and 0.577 9, which were lower than the ABC-EN model we proposed. Conclusion: The wavelet exponential semi soft threshold denoising method can effectively remove the strong noise in the multispectral image of young Aquilaria sinensis, and the segmentation algorithm combined with FMT and GA-BPNN has achieved good segmentation result. The ABC-EN model built by fusion features of spectrum and texture is the best estimation model of total nitrogen in the canopy of aloe vera seedlings. Therefore, the method proposed in this paper has certain practical significance for monitoring the nitrogen nutrition status of Aquilaria sinensis, and is beneficial to the realization of precise operation in the process of Aquilaria sinensis cultivation and management.

Objective: UAV LiDAR technology has become an important technical means to obtain refined forest parameters. Individual tree segmentation using LiDAR point cloud data is the basis for extracting refined forest parameters, and the accuracy of forest parameters acquisition depends on whether the individual tree segmentation is accurate or not. To address the problems that existing individual tree segmentation algorithms is difficult to extract trees under high canopy cover stand conditions with low overall accuracy, this study proposes a layered segmentation method based on CRR (canopy relief ratio), combined with watershed algorithm and the local maximum clustering algorithm based on point cloud to provide a new strategy to improve the accuracy of individual tree segmentation. Method: The ULS(unmanned aerial vehicle laser scanning) data were used to segment the individual tree of high canopy cover Pinus kesiya var. langbianensis plantation using the watershed algorithm, the local maximum clustering algorithm and the stratified segmentation method based on CRR proposed in this paper, and the effects of the watershed algorithm on the individual tree segmentation result under 4 CHM spatial resolutions and 3 DSM interpolation method were analyzed separately for the watershed algorithm, and the result of the visual interpretation of individual tree crown from UAV high-resolution images were used as validation, with detection rate r, accuracy p and F-score as evaluation indexes. Result: In young forest, the CCR is higher, and the segmentation accuracy of the watershed algorithm is better than that of the local maximum clustering algorithm for single-layer forest. In middle-aged and near-mature forest, the CCR is lower, and the watershed algorithm can easily identify Simao Pine branches as canopy, and the segmentation effect of the local maximum clustering algorithm is better than that of the watershed algorithm. The segmentation method based on CCR combined with the watershed algorithm and the local maximum clustering algorithm has the highest accuracy (F=0.75). The layered-segmentation method based on CCR fully considers the differences in stand structure among different age groups, and the layered-segmentation method had the highest accuracy (F=0.75), which is better than watershed algorithm (F=0.71) and local maximum clustering algorithm based on point cloud (F=0.68). Secondly, in the watershed algorithm, when the resolution is 0.5 m × 0.5 m, the CHM individual tree segmentation accuracy obtained by interpolation using the inverse distance weighting (IDW) is the highest (r = 0.70, p = 0.94 and F = 0.81). Conclusion: The accuracy of using only one individual tree segmentation algorithm is often unsatisfactory due to the differences in stand structure. The combination of the watershed algorithm and the local maximum clustering algorithm can expand the applicability of a single segmentation method under different stand and thus improve the accuracy of individual tree segmentation by determining the respective applicability range through CCR.

Objective: The spatial distribution of different tree species is the basis of forest inventory and forest dynamic monitoring, and is of great significance to the protection of forest ecosystems and the sustainable management of forest farms. Method: In this paper, Wangyedian forest farm in Inner Mongolia is selected as the research area. Multi-temporal Sentinel-2 multi-spectral data is used on the Google Earth Engine(GEE)cloud computing platform to extract band reflectance characteristics and spectral index characteristics. The simple non-iterative clustering(SNIC)superpixel segmentation algorithm and the support vector machine(SVM)machine learning classification method are used to identify object-oriented dominant tree species, and the impact of different multi-temporal data combinations on the classification result is analyzed. Result: Experimental result show that the classification accuracy of multi-temporal data combination is significantly higher than that of single-temporal data in each season. Comparing the multi-temporal data combination, The classification accuracy of the combined data of spring and autumn time series is similar to that of multi-season data combination, and their overall accuracy is 94.5%, 95.0%, 95.8%, respectively. Conclusion: The object-oriented classification method proposed in this paper based on multi-temporal data and SNIC algorithm can identify dominant tree species quickly and accurately. Among them, the classification result using multi-season data combination is the best, and the time series data of the spring and autumn seasons can also obtain good classification result, and the overall accuracy is a little lower than the optimal result.

Objective: This study aims to reveal the characteristics of germination and growth of lateral buds on rhizome, explore the effect of rhizome carbon on the growth of lateral buds, and provide a reference for promoting germination of lateral buds and increasing the yield of bamboo forests. Method: One-year-old rhizomes of Indocalamus decorus with basically same rhizome diameter were used as the material. The rhizome segments with a mother culm (M) or without mother culm (N) were selected, and three different lengths of rhizome segments (L1, 3 cm; L2, 6 cm; L3, 9 cm) were retained by cuting off the rest part. The position of lateral bud germination and the growth of each treatment were investigated, the number, ground diameter and height of the young culms were measured, and the photosynthetic pigments and non-structural carbohydrate content were measured and analyzed. Result: 1) there was no significant difference in the germination ratio and growth of lateral buds over different parts of the rhizome in ML1 treatment, while lateral buds were sprouted out much more at both segment ends than those in its middle part in other treatments. It was showed that more lateral buds sprouted apically or basally, and the bias characteristics became more dramatic with the increase of the rhizome segment length. 2) Compared with the treatment without a mother culm, the ground diameter and height of young culms with a mother culm treatment were significantly increased with the same rhizome segment length, but there was no obvious difference in the number of young culms in general between the two treatments. As the increase of the rhizome segment length, the number of young culms increased in the treatment without mother culms, while the number of young culms in the treatment with a mother culm showed little difference. There was no significant difference in the ground diameter and height of young culms whether the rhizome segment had a mother culm or not. 3) The content of photosynthetic pigments and NSC in the leaves of young culm in the treatment with a mother culm were significantly higher than those in the treatment without mother culm. However, the content and proportion of NSC components in different rhizome lengths were different. At the same time, the soluble sugar content in young bamboo leaves with ML1 treatments showed no significant change compared with that in young bamboo leaves with ML2 and ML3 treatments, but the content of starch and NSC was significantly higher. The change of photosynthetic pigment content was opposite. The results indicated that the shorter rhizome segment with a mother culm had excessive carbohydrate accumulation and photosynthesis was inhibited by feedback. Effects of rhizome with mother culm or not on the diameter, height, photosynthetic pigment and NSC of young bamboo were significantly higher than those of the length of the rhizome segment. Conclusion: Carbon has an obvious restrictive effect on the germination of lateral buds on rhizome, which is an important factor causing the positional bias of the lateral bud germination. The continuous increase of carbon supply could gradually eliminate this biased germination characteristics, and the rhizome segment carbon gives priority to ensuring the quantity of young bamboo, and then the quality. Increasing the carbon storage capacity of rhizome segment is an important way to improve the lateral bud germination rate.

Objective: Itoh peony 'Bartzella' is a popular type of cut flowers among consumers. In this study, fresh cut flowers of Itoh peony were used to study the physiological effect of ethylene induced senescence in order to provide a theoretical basis for the regulating technology of fresh-keeping. Method: The 'Bartzella' cut flowers were exogenously pretreated with 20 μg·L^-1 nano silver (NS), 5 and 20 μL·L^-1 2-chloro-2-ethyl phosphoric acid (CEPA, ethephon) for one hour, respectively. The flowering and senescence characteristics of 'Bartzella' cut flowers were observed by inserting the flowers in vase. The dynamic changes of ethylene release from petals were measured by gas chromatography. The water status of flower branches was measured by weighing method. The membrane lipid peroxidation level was determined by spectrophotometry and the energy state was determined by HPLC. With principal component analysis, the relationship between ethylene metabolism, lipid peroxidation and energy state was analyzed. Result: 1) The results showed that cut flowers of 'Bartzella' absorbed water rapidly, reached full bloom in 24 h after vase inserting, and the vase life was only 3~4 days. The vase life was able to be significantly prolonged in the presence of NS, and the vase quality was improved. However, CEPA accelerated the senescence process of cut flowers, and had a significant dose effect. 2) The cut flowers in vase for 6 h had the characteristics of ethylene climacteric peak. Compared with the control, the ethylene release peak of NS pretreatment decreased by 26.95%, while CEPA significantly promoted the ethylene release, and 5 and 20 μL·L^-1 CEPA increased by 11.52% and 125.50%, respectively. 3) From opening to senescence, 'Bartzella' cut flowers experienced a process of water imbalance and membrane lipid peroxidation intensification of flower branches. NS was able to improve the water status of flower branches, inhibit the increase of MDA content and the decrease of soluble protein content. CEPA had the opposite effect with nano silver. 4) NS promoted the transformation and accumulation of active substrates and improved the activity and energy charge level of key enzymes in respiratory metabolism of petals. However, the effect of CEPA was opposite to that of NS for cut flowers. CEPA decreased the content of respiratory substrates, the activity of key enzymes in respiratory metabolism and the level of energy charge. Conclusion: The cut flower of Itoh peony 'Bartzella' belongs to an ethylene hypersensitive type. From opening to senescence process, 'Bartzella' cut flower is jointly regulated by ethylene, water and energy metabolisms. This study suggests that controlling ethylene and energy metabolisms should be a basis strategy to improve the quality of cut flowers of Itoh peony 'Bartzella'.

Objective: This study aims to provide a theoretical basis for the construction of chestnut canopy productivity and proper bud retention, by investigating the effects of fruit loading in different canopy layers on photosynthetic characteristics, growth and development and fruit quality. Method: Three main branches with the opening angle greater than 60° of Chinese chestnut variety 'Yanshan Zaofeng' were targeted, and the branches with one (F1), two (F2) and 3 (F3) fruit loads were selected from different directions in the upper, middle and lower canopy layers, respectively. The leaf area, specific leaf area and photosynthetic indexes were measured in July. The fruits were collected at the fruit ripening stage in September, and the single fruit weight, transverse and vertical diameters and related contents were determined. The differences of leaf and fruit indexes under different bulb loadings were analyzed, and the optimal fruit loading suitable for each canopy layer was explored based on both economic benefits and fruit quality. Result: 1) There were differences in leaf photosynthesis and growth and development indexes under different fruit loads (P < 0.05). With the increase of bulb load, the net photosynthetic rate, instantaneous water use efficiency, leaf area and relative chlorophyll content all decreased significantly, while the transpiration rate and intercellular CO₂ concentration increased significantly. The starch content of leaves decreased in all canopy layers, and the soluble sugar content of leaves decreased in the middle and lower parts of the canopy, but increased in the upper part of the canopy. 2) There were to some degrees differences in fruit indexes under different fruit loads (P < 0.05). With the increase of fruit load, the single-fruit weight, total nitrogen content, starch content and soluble sugar content of fruits decreased in all canopy layers, but the empty bud rate increased. The single fruit weight, fruiting percentage, and starch and soluble sugar contents of fruits were the lowest in the F3 treatment; Due to weak light in the lower part of the canopy, the F3 treatment had higher empty bud rate, and the horizontal and vertical diameters of the fruit were smaller, and the ripening stage was delayed. Conclusion: The fruit loading has a significant effect on the leaf photosynthesis and fruit quality of chestnut. It is suggested that in the actual production of chestnut, the fruit loading of each fruiting branch in the upper, middle and lower canopy layers should be controlled at 3, 2~3, and 1~2, respectively.

Objective: The germination rate of Myrica rubra (bayberry) seeds is low and the germination time is long, which causes breeding difficulties. This study aims to resolve the physiological and biochemical rules of bayberry seed germination, and provide a theoretical basis for the development of efficient germination technology. Method: The newly sown bayberry seeds, which root lengths were 0~1, 1~2, 2~3 and more than 3 cm at four germination stages respectively, were collected from the sand storage nursery. The dynamic changes of enzyme activity, hormones, total phenolic substances and the expression of related genes regulating seed germination were measured. Result: It was found that during seed germination, the dynamic changes of peroxidase (POD), superoxide dismutase (SOD), ascorbic acid peroxidase (APX) and α-amylase were basically the same, the activities of these enzymes increased from just sown to the state with young root of 0~1 cm, and then decreased when the young root was more than 1 cm. The activity of catalase (CAT) increased steadily, and β-amylase activity fluctuated all time, increase-decrease, and increase-decrease again. The dynamic change pattern of indoleacetic acid (IAA) and Zeatin (ZR) content was basically the same, which had a trend of increasing first and then decreasing. The content of abscisic acid (ABA) generally showed a decreasing trend, and the content of gibberellin (GA₃) basically remained unchanged. The total phenol content first increased and then decreased. Compared with the control without germination, the expression of MAPKKK 15 and TUA2 genes increased during germination, while the expression of YMCIBHLH1, PHYA, MAPKKK18, MAPKKK14, YMSQS1, FOA1 and WRKY6 genes decreased, and the expression of HD2B, RVE1 and YMBZIP genes increased or decreased. Conclusion: In conclusion, antioxidant enzymes, amylase, IAA, ZR and ABA are mainly involved in the regulation of seed germination process of Myrica rubra, and the expression of some key genes in ABA signaling pathway and GA signaling pathway has changed. The results of this study would provide theoretical support for the development of techniques to promote seed germination of bayberry.

Objective: This study aims to clarify the effect of the different kinds of resin-stimulant pastes on resin production and growth of Pinus elliottii, and to screen out the resin-stimulant paste suitable for P. elliottii in Guangdong, so as to guide actual production and reduce the cost of resin tapping. Method: This study was conducted in the half-sib progeny test forest of P. elliottii in Hongling Seed Orchard, Taishan, Guangdong. Six treatments were set, and they were non-tapping (T0, for growth control), conventional tapping without any resin-stimulant paste treatment (T1, for experimental control), and tapping treated with different components of resin-stimulant pastes (T2-T5). The main components of the pastes were K₂SO₄, naphthalene acetic acid (NAA), benzoic acid (BA) and 2-chloroethylphosphonic acid (CEPA), respectively. In 2018, the trees were treated and harvested seven times, and in 2019, they were treated and harvested six times. Before the treatment, the basic value of resin yield was harvested without resin-stimulant pastes. The resin yield and growth trait were all measured per tree. Result: The result in 2018 showed that the effects of both family and resin-stimulant paste treatment were extremely significant (P < 0.01), however their interaction effects were not significant (P > 0.05). The first two collections showed that the resin stimulating effect was extremely significant, with the resin increase rate over 135%. However, resin stimulating effect decreased in the third collection. By the fourth time, only T5 treatment group had a stimulating effect, but it did not reach a significant level. From the fifth to seventh times, T2-T4 treatment group did not have a significant stimulating effect, but T5 treatment still maintained the resin increase rate of more than 19%. The total yield of resin for seven collections showed that T5 treatment group had the best resin stimulating effect, with a resin increase rate of 51.73%. The result in 2019 showed that the family effect was not significant in the first collection (P > 0.05), while the family effect in the other collections was extremely significant (P < 0.01). The background value of the resin yield in each treatment group showed no significant difference, and then the following six collections showed significant resin stimulating effect, with the resin increase rate ranging from 29% to 269%. The total of the resin yield for six collections showed that T5 treatment had the best resin stimulating effect, with a resin increase rate of 160.61%. The ranking of resin production of each family varied greatly in different years and different treatments, and among them family I2 and I7 were relatively stable. The result of the two-year growth showed that the family effect was significant, however there was no significant difference in the growth among the different treatment groups, and there was no significant difference in the one-year increment of tree height and diameter at 0.9 m height among different treatment groups. The resin production of different collections in the same year had an extremely significant correlation. The correlation coefficient ranged from 0.245 5 to 0.854 4. In the two years, the first harvest of resin production had the lowest correlation coefficient with the total production. The correlation analysis between the resin production and growth showed that there was a stable extremely significant and positive correlation between resin production and diameter at 0.9 m height, however the correlations between resin production and height growth showed no significant, significant, or extremely significant levels in different periods of time and with different treatments. A significant negative correlation was even detected between resin production and height in 2018. Conclusion: The resin-stimulants with different components have significantly different effects on the resin increasing of P. elliottii. The same resin-stimulant pastes have different resin increasing effects under different climatic conditions. This study shows that T5, with 20% sulfuric acid and 3% CEPA as the main components, has the best and most stable resin stimulating effect, and has no significant interaction with the family. Thus, T5 is suitable for popularization in P. elliottii forests. The resin yield of the same tree varies greatly at different harvests. When measuring resin yield traits, it should be avoided to only use the data of the first resin tapping. The resin production of different families also changes greatly in different harvests, different years, and different treatments. Among the 11 families tested, the resin productions of families I2 and I7 are relatively high and stable. The use of resin-stimulant pastes has no significant effect on the growth of tree height and diameter at 0.9 m height in a short period of time. There is a strong correlation between resin production and tree diameter. To a certain extent, tree diameter could be used as an indirect selective indicator of resin production. Although the correlation between resin production and tree height is weak, the resin-stimulant effect of P. elliottii with higher tree height is more significant when the T2, T3 and T4 resin-stimulant pastes are applied.

Objective: The MYB-related transcription factor family plays an important role in plant growth and development and stress response, but functional studies on members of this family in poplar have rarely been reported. In this study, a MYB-related gene PagMYBR96 that responds to salt stress was identified in Populus alba × P. glandulosa '84K' based on transcriptome sequencing data. Further, the gene was cloned and its characteristics and the involved biological processes were analyzed in order to provide a reference for subsequent gene function and regulatory mechanism studies and forest genetic engineering breeding. Method: The PagMYBR96 gene was amplified from 84K poplar cDNA using PCR, and the physicochemical properties of the encoded protein sequence were analyzed. The conservative domain, evolutionary relationship, hydrophilicity, hydrophobicity, transmembrane region, signal peptide, phosphorylation site, and secondary structure of the protein were analyzed using bioinformatics analysis. Agrobacterium-mediated transient transformation of tobacco leaves was used to analyze the subcellular localization of the protein. The activity of transcriptional activation of the protein was analyzed by yeast transformation screening assay. The temporal and spatial expression patterns of the gene were analyzed by RT-qPCR. The biological processes and metabolic pathways involved in the gene were analyzed using gene co-expression and functional annotation and enrichment analysis. Result: The 882 bp PagMYBR96 gene was cloned from 84K poplar, and could encode protein with 293 amino acids, with a molecular weight of 33 306.33 Da, and a theoretical isoelectric point of 6.32. The protein contains a conservative MYB domain and its characteristic amino acids. The protein is closely related to the homologous protein of Salix dunnii, and has no transmembrane region and signal peptide. It may be a hydrophilic protein. PagMYBR96 is a nuclear localization protein and has no activity for transcriptional activation in yeast. The gene spatio-temporal expression pattern showed that PagMYBR 96 was able to respond to salt stress in both roots and leaves of 84K poplar, and its expression was up-regulated at the early stage of stress, and then gradually returned to normal after reaching the peak. PagMYBR96 and 518 co-expressed genes were related to cellular processes, metabolic processes, biological regulation, response to stimulation, developmental processes, and were significantly enriched in GO terms such as ubiquitin-like protein conjugating enzyme activity, ubiquitin-like protein transferase activity, ubiquitin-protein transferase activity, ubiquitin conjugating enzyme activity. In addition, these genes were also significantly enriched in the pathways of aminoacyl-tRNA biosynthesis, ubiquitin mediated proteolysis, and pyruvate metabolism. Conclusion: The PagMYBR96 gene of 84K poplar can respond to salt stress in different tissues, and participate in plant growth and development and stress response through different biological processes. It is worth noting that the functions of PagMYBR96 and its co-expressed genes are related to processes such as protein degradation mediated by the ubiquitin proteasome system and pyruvate metabolism, which is also the direction that needs to be explored in future research.

Objective: Paracarophenax alternatus is a newly found miniature phoretic mite that has parasitic and lethal effects on the eggs of Monochamus alternatus, a main vector of pine wood nematode in China. This study aims to further understand the mite's habitat adaptability by investigating its phoretic characteristics by M. alternatus adults, and to evaluate its application potential in order to provide an important basis for establishing scientific filed application technique. Method: The indoor breeding, behavior observation, simulation experiment and field trapping investigation were conducted to study the distribution of the mites on the body surface of M. alternatus adults, the transmitting law during M. alternatus adults feeding, oviposition and co-breeding, and the amount of the mites carried by the M. alternatus adults trapped in the field. Result: The female adult mites were taken as phoretic state, P. alternatus actively transferred and aggregated in the ventral grooves of M. alternatus adults, and the number of mites carried by both male and female M. alternatus adults on the metathorax was the most. During the feeding process, each female and male M. alternatus adult transmitted an average of 3.0 and 2.9 P. alternatus to the pine branches in 1 hour, respectively. During the process of ovipositon, an average of 6.5 P. alternatus were able to be transmitted to the egg-laying site per egg laid. The mites were able to be transmitted from one to another of M. alternatus adult. An average 39.3 P. alternatus individuals were transmitted from mites-carrying M. alternatus to non mites-carrying M. alternatus, and after 2 days of co-breeding, the transmitted percentage was 8.1%. After 10 days of co-breeding, the transmitted number and percentage increased to 192.2 and 38.5%, respectively. In different feeding combinations, the transmitted number and percentage were the highest in the M. alternatus gender combination from mites-carrying M. alternatus males to non mites-carrying M. alternatus females. In the inhabited forest of P. alternatus, the mites-carrying percentage of M. alternatus adults is 55.0%, of which 39.2% were male and 61.6% were female, and the latter was significantly higher than the former. A single M. alternatus male adult carried an average of 247.3 mites, and a single female adult carried an average of 291.4 mites. There was no significant difference between these two. Conclusion: P. alternatus can actively aggregate on the M. alternatus adults, be transferred among different individuals, and then accelerate diffusion and expansion of populations through feeding, oviposition and other living activities of M. alternatus adults. The phoresy characteristics of the mite do not only reflect P. alternatus' population habitat adaptability, but also show its strong a bio-control potential. In the future field practices, it is recommended to release high-density P. alternatus population in the activity area of M. alternatus adults or eggs, using its phoresy characteristics to exert its biological control effect.

Objective: At present, scholars mainly use linear model to study the relationship between drill resistance and wood density. There are great differences among the models, and the generality of the models is poor. This paper discusses the model form between drill resistance and wood density, and whether different tree species or similar tree species can share a mathematical model, in order to provide a basis for indirect measurement of wood density by micro drill resistance method. Method: 1) The resistance of 8 tree species including softwood and hardwood was measured by Resistograph 650-S. Two thirds of the measured data of each tree species was used as the modeling data set, and the remaining one third of the measured data was used as the test data set. 2)Using the total modeling data set, the linear model, logarithmic model and the mixed model of linear model and logarithmic model between the average drill resistance and wood absolute dry density were established respectively. The model with the highest determination coefficient was selected as the total model between the average drill resistance and wood absolute dry density, and the model form was selected to represent the relationship between drill needle resistance and wood absolute dry density. 3)The 2 class models of softwood and hardwood between drill resistance and absolute dry density were established by using the selected model form. 4)The sub models of each tree species between the average resistance of drill needles and absolute dry density were established respectively using the selected model form. 5)The test data set was used to test the estimation standard error and average estimation accuracy of the total model, class model and sub model. Result: 1) The determination coefficients of linear model, logarithmic model and mixed model of linear model and logarithmic model established using the total modeling data set are 0.942, 0.952 and 0.961 respectively. 2)The determination coefficients of softwood class model and hardwood class model are 0.780 and 0.864 respectively, and the determination coefficients of the sub model of each tree species are 0.397-0.943. 3)The total estimation standard errors of total model, class model and sub model are 32.222, 31.635 and 27.121 kg ·m^-3 respectively, and the average estimation accuracy is 95.554%, 95.636% and 96.292% respectively. 4)There was no significant difference in the estimation standard error and average estimation accuracy among the total model, the class models and the sub models at the significance level of 0.1. Conclusion: 1) The mixed model of linear model and logarithmic model has the highest determination coefficient. Therefore, it is more appropriate to use the mixed model of linear model and logarithmic model to study the relationship between drill resistance and wood absolute dry density. 2)The estimation standard error of sub model is the smallest and the average estimation accuracy is the highest. Therefore, it is appropriate to use the sub model to predict the absolute dry density of wood. 3)When the measurement accuracy is not high, the total model can be used to estimate the absolute dry density of wood to reduce the modeling workload.

Objective: The wood from which lignin and hemicellulose were removed was used as the sensor skeleton, and the effect of the solid content weight ratio of the wood and conductive polymer on the performance of the pressure sensor was studied in order to develop low-cost and high-performance sensor devices based on green natural materials. Method: Using balsa wood as raw material, lignin and hemicellulose components were selectively removed from cell wall by two-step method, and wood-based aerogel was prepared by freeze-drying as sensor skeleton. The aerogel skeleton was dipped into the mixed solution of conductive polymer poly (3, 4-ethylenedioxythiophene) -poly (styrene sulfonate) (PEDOT∶PSS) and couling agent 3-glycidoxypropyltrimethoxysilane solution (GOPS) by dipping method, and the low temperature heating after freeze drying made the three crosslink, so that the 3D layered wood-based micro-pressure sensor was prepared. The structure and morphology of the sensor were characterized, and the electrical and sensing properties were tested. The influence of the solid content weight ratio of wood-based aerogel skeleton to PEDOT∶PSS on the sensing performance of the pressure sensor was discussed. Result: The wood-based aerogel has good mechanical compressibility, high porosity and special layered structure, which is beneficial to the adsorption of mixed solution of PEDOT∶PSS and GOPS. The conductivity of CPG-0.25, CPG-0.5 and CPG-0.75 are 0.02, 0.15 and 3.04 mS ·cm^-1, respectively. The maximum compressive strain is 72%, 62% and 51% respectively. The micro-pressure sensitivity is 95.93 (R²=99.6%), 96.88 (R²=99.8%) and 108.34 kPa^-1 (R²=99.1%), respectively. The results show that with the increase of the solid content ratio of PEDOT∶PSS, the conductivity of the composite conductive aerogel increases continuously, the maximum compressive strain of the sensor decreases, and the sensitivity of the sensor under micro-pressure (1.5 kPa) increases gradually. The micro-pressure sensitivity of the pressure sensor CPG-0.75 is the highest, and it shows good linearity and excellent stability (the relative resistance of 5 000 loading-unloading cycles under 2 kPa changes stably, with no obvious fluctuation). Conclusion: The solid ratio of wood-based aerogel to PEDOT∶PSS has great influence on the micro-pressure sensitivity of the pressure sensor. With the increase of the solid content weight ratio of PEDOT∶PSS, the conductivity of the composite conductive aerogel is enhanced, and the micro-pressure sensitivity of the sensor is improved. On the one hand, the 3D arched layered porous wood-based aerogel skeleton enables the sensor to generate more contact under the action of slight pressure, thus resulting in a larger resistance change rate, which makes the sensor have excellent micro-pressure sensitivity. On the other hand, this skeleton structure has good mechanical compressibility, which makes the sensor have good stability.

Objectives: The objectives are to select appropriate methods to measure stem fluid flow to reveal its dynamic changes and influencing factors according to the unique biological characteristics and anatomical structure of bamboo plants. It is conducive to in-depth elucidating their physiological and ecological processes and mechanisms, and providing scientific basis for accurate management, efficient utilization and ecological management of water and nutrients in bamboo forests. Method: The methods for measuring stem sap flow in bamboo plants was originated from woody plants, including heat pulse method, heat dissipation probe method and stem heat balance method.Among them, the heat pulse method is not limited by environmental conditions such as terrain, but the measurement results are uncertain under the condition of low transpiration; the cost of the heat dissipation probe method is relatively low, but the sensor is prone to measurement errors caused by the radial gradient formed by the flow density, which needs to be verified and calibrated; the stem heat balance method does not require probe drilling, andthe instrument wraps the bamboo stem to obtain real-time data, but the basic assumptions of stable flow conditions and constant temperature need to be met. Usually, the three assay methods are combined and mutually validated to obtain more reliable flow measurement results. Result: The stem flow of bamboo plants has a relatively common patterns in daily variation, night dynamics and seasonal scales, showing a similar "peak" curve. The daytime flow of bamboo plants starts in the early morning, then increases continuously, reaches a peak in the afternoon, and then continues to decrease, reaching the lowest value after nightfall; the flow changes in sunny weather generally show a "single-peak" curve, and the rainy weather shows a "multi-peak" curve. The nocturnal flow generally maintains a low flow, significantly lower than the daytime flow under different seasons and environmental conditions, and the variation is small. On the seasonal scale, the liquid flow is the lowest in spring, the highest in late summer and early autumn, from winter to summer, the time when the flow begins to rise and the peak is gradually advanced, and the reverse is reversed from summer to winter. There are also differences in the flow pattern of bamboo plants at different growth stages.Factors influencing changes in the flow of bamboo plants include physiological anatomy different from those of woody plants and environmental factors. Among them, the hollow stem and underground whiplash root system of bamboo plants are the biological basis for influencing fluid flow. Environmental factors have a strong correlation between air temperature, saturated water vapor pressure difference and solar radiation and changes in stem flow by influencing transpiration and plant root pressure. Different measurement methods, such as the length of probe and the specific location of measurement, will also affect the measurement results. Conclusion: To put forward prospects for measuring the stem flow of bamboo plants in the future, it is theoretically necessary to explore the influencing mechanisms, and develop statistical and verification models; technically, the existing measuring methods should be integrated and improved, and suitable methods and technologies should be developed to improve the measurement accuracy; in the application of results, it is appropriate to set parameters based on differences in region, climate, terrain conditions and bamboo species to obtain a widely applicable model of measurements.