Hemicellulose is ubiquitous in plant cell walls, comprising one of the three major components. Currently, the industrial utilization of hemicellulose primarily focuses on its degradation to produce low-molecular-weight xylo-oligosaccharides, xylose, and furfural. Recent studies have shown that crystalline xylan exhibit unique physicochemical properties and can be converted into high-value-added xylan nanocrystals, which has become a research hotspot in the utilization of plant polysaccharides in recent years. Xylan nanocrystals are primarily composed of the five-carbon sugar xylose as the repeating structural unit, and the relatively weak interchain interactions usually require external stabilizers such as water molecules to stabilize the crystalline structure. Xylan nanocrystals exhibit spherical, lamellar, and rod-like morphologies, with sizes typically ranging from tens to hundreds of nanometers, which are determined by the different preparation methods. The unique chemical structure of xylans also leads to their preparation methods being different from those of traditional lignocellulosic-based nanocrystals. Additionally, xylan nanocrystals possess excellent biocompatibility and nanoscale effects, making them have great application potential in various fields. This review summarizes the typical structures of hydrate xylan nanocrystals, acetylated xylan nanocrystals, and xylan co-nanocrystals, and introduces the influence of water molecules and the chemical structure of xylan on their unit cell parameters. The review systematically discusses the top-down and bottom-up approaches for the preparation of xylan nanocrystals, with a focus on analyzing the effects of different preparation methods on the morphology, size, degree of polymerization, yield, and physicochemical properties of the xylan nanocrystals. It also provides an overview of their applications in emulsification, consumer chemicals, and anti-counterfeiting materials, and discusses the current challenges and future development and application prospects of xylan nanocrystals based on the related research achievements.

Since the inception of the Three-North Shelter Forest Project (also known as the Great Green Wall Project, GGWP) in 1978, extensive tracts of artificial shelter forests and public welfare forests have been established. This initiative has been instrumental in fortifying the ecological security barrier in northern China. In the early phases of the GGWP, certain shelterbelts constructed therein have undergone degradation. In response, the Chinese government has commenced the allocation of tasks related to the restoration of these degraded plantations within the project framework. The overarching objective is to ensure the continued efficacy of the ecological protection functions of the ecosystem in the GGWP area. In light of the scientific issues emerging from the research on the degradation of shelterbelts during the sixth phase of the GGWP, this paper undertakes a comprehensive and meticulous analysis of the definition, scope, causative factors, and restoration strategies pertaining to the problem of degraded plantations. It further presents an overarching systematic approach and corresponding countermeasures. The degraded plantations within the GGWP area, as defined in this study, are artificial plantations (including shrubs) that exhibit pronounced growth decline and a substantial reduction in ecological functions, such as windbreak and aeolian sand fixation. The restoration of degraded plantations not only needs to address the overt degradation of plantations but also needs to address the underlying systematic land degradation. The fundamental cause of this systematic degradation is attributed to inadequate post-construction management. This deficiency, in turn, leads to the deterioration of both soil and water conditions. In this region, water emerges as the most limiting factor for post-construction management. This study conducts an in-depth and exhaustive analysis of the natural, disaster-related, physiological, design-related, and anthropogenic factors that instigate the degradation of plantations in the GGWP area. Given the vast expanse of the GGWP area, the restoration of degraded plantations should commence with a classification, grading, and zoning process based on the characteristics of natural endowments, followed by the implementation of targeted and precise measures. Regarding the restoration of degraded plantations in the GGWP, the traditional degradation assessment index system, which predominantly relies on the visual appearance of vegetation, should be gradually transitioned into a system that integrates the functional attributes of vegetation with appearance-related indicators. The article also suggests to categorize the degradation degree into mild, moderate, and severe levels, and to implement distinct levels of enclosure protection, replanting, or resowing restoration strategies accordingly. Finally, this paper aims to enhance the management and protection of plantations throughout full-cycle. Additionally, it advocates for the establishment and refinement of a comprehensive full-cycle management and protection system for plantations. This study is expected to offer valuable insights and reference points for China’s endeavors in the restoration of degraded plantations within the GGWP and the formulation of relevant technical measures and regulations.

Objective: In this study, morphological description and phylogenetic analysis were conducted on a twig beetle species that damages Pinus sylvestris var. mongolica. The fungi in the galleries produced by the insect were isolated, purified and identified to clarify the taxonomic status of this twig beetle and its interaction with pine dieback pathogen. The study would provide a basis for controlling diseases and pests in the Three-North protection forest of P. sylvestris var. mongolica. Method: The phylogenetic analysis method based on morphological characteristics and the mitochondrial cytochrome oxidase subunit I (COI) gene fragment was used to identify the species of the twig beetle. Additionally, traditional approaches and phylogenetic tree based on ITS sequences were used to obtain the fungal recognition from the galleries of the twig beetle. Result: It was confirmed that the twig beetle belonged to Pityophthorus morosovi using combination of morphological observation, DNA sequences alignment and phylogenetic analysis. This twig beetle was cylindrical and the body length was approximately 1.46–2.00 mm. The basal part of the pronotum contained scale-like tubercles densely covered with hairs, the rear half and the elytra contained distinct punctures and blunt ends on the elytra. Meanwhile, 42 fungal strains were isolated from the galleries, belonging to 4 genera 4 species. Diplodia sapinea was the dominant fungus of P. morosovi, accounting for more than 60%. Conclusion: It is the first time to determine P. sylvestris var. mongolica as a new host tree species for the twig beetle. Phylogenetic analysis has revealed the genetic relationship of this twig beetle with other species. This study supplies genetic data for biodiversity of bark beetles. Meanwhile, it is found that D. sapinea was the dominant symbiotic fungus of twig beetle, speculating that P. morosovi may be a vector of the pine dieback pathogen.

Objective: This study aims to explore the the differences in the response of dominant tree radial growth of Larix principis-rupprechtii growing on different slope aspects in the semi-arid area of Liupan Mountine to meteorological and soil factors, so as to provide a scientific foundation for predicting forest growth and adaptation forestry management strategies under future climate change. Method: The research focused on L. principis-rupprechtii plantations growing in Diediegou small watershed of Liupan Mountain. Eleven sample plots were established along the different slope orientations (northwest slope-north slope-northeast slope-southeast slope). The annual average basal area increment (BAI) of individual dominant trees was determined. Pearson correlation analysis and structural equation model were used to analyze the impact of slope aspect difference on dominant tree’s BAI during 3 distinct periods: a climate-stable period (1995—2004), a rapid warming period (2005—2015) and a rapid precipitation increase period (2016—2020). Result: 1) In the period of rapid warming, drought stress resulted in a rapid decrease in BAI of older dominant trees (23–26 a) on the northwest semi shady slope and north shady slope (average rate was –57.2 mm²·a^?1, P<0.01). However, the younger dominant trees (9–14 a) were hardly influenced by rapid warming, the BAI on the northeast semi shady slope and the southeast semi sunny slope showed an obvious increase (the average rate was 125.43 mm²·a^?1, P<0.01). 2) During the climate-stable period, the temperature difference of slope aspects had a greater impact, showing a negative correlation with the northwest shady slope and a positive correlation with other slopes, but the correlation degree was different. During the rapid warming period, BAI showed a positive correlation with precipitation on the northeast semi shady slope and southeast semi sunny slope, a negative correlation with temperature on the northwest semi shady slope and north slope, and the soil thickness had a greater correlation with BAI on all slopes. During the rapid precipitation increase period, BAI in major slope aspects showed a significant positive correlation with standardized precipitation evapotranspiration index (SPEI), and the BAI on the semi shady slopes also showed a significant positive correlation with precipitation, while the BAI on the shady and southeast semi sunny slopes showed a significant negative correlation with temperature (P<0.05). 3) During the climate-stable period, temperature was the main influencing factor, with direct and indirect influence coefficients of 0.55 and –0.221, respectively. During the rapid warming period, soil factors had a greater impact on BAI growth, and there was a significant positive correlation between soil thickness and BAI, with a total influence coefficient of 0.533. During the rapid precipitation increase period, BAI was only significantly positively influenced by SPEI, with a total influence coefficient of 0.29. Conclusion: In the climate-stable period, the difference in radial growth of L. principis-rupprechtii between slope aspects is relatively small, and the different slope aspects are more affected by temperature. In the rapid warming period, there is significant difference in radial growth between slope aspects, and at this time, different slope aspects are more affected by soil thickness. After the rapid precipitation increase period, the radial growth difference between slope aspects begin to decrease, and SPEI is the main factor affecting the radial growth difference between slope aspects. These findings suggest that adjusting the stand structure can improve the power of L. principis-rupprechtii plantations in Liupan Mountain’s semi-arid region to withstand disaster stress and achieve long-term sustainable forest management.

Objective: Understory plants play a key role in maintaining the structure and function of plantation communities. Studying the changes in the anatomical structure of understory plants with nitrogen addition would help to understand the response and adaptation mechanism of understory plants to environmental changes. Method: In the present study, plant microtome technology was used to compare the leaf anatomical characteristics of dominant understory species and their plasticity in a chronosequence of Larix principis-rupprechtii plantation (juvenile forest, immature forest and near-mature forest) in Saihanba and their responses to nitrogen addition (0, 20, and 50 kg·hm^?2a^?1). The changes in the correlation between the anatomical characteristics of understory plants under different nitrogen treatments were examined. Result: 1) There was a certain regularity in the plasticity index of different leaf anatomical characteristics. The thickness of palisade tissue and lower epidermis was relatively stable, while the thickness of spongy tissue was more sensitive. 2) Nitrogen addition had no significant effect on 9 anatomical characteristics of understory plants (P>0.05), but significantly affected the correlations between the anatomical characteristics. Compared with low nitrogen addition, high nitrogen addition enhanced the relationship between leaf thickness related indexes, but weakened the relationship between vascular tissue related indexes. 3) The basic values of leaf anatomical characteristics of understory plants in the juvenile forest were significantly higher than those in the middle-aged forests and the near-mature forests, while there was no significant difference in the basic values between the middle-aged and near-mature forests. The leaf thickness related indexes of understory plants in young stands were promoted by nitrogen addition, while vascular tissue related indexes were inhibited. In contrast to the juvenile forest, leaf thickness related indexes in the near-mature forests were inhibited by nitrogen addition, while the vascular tissue related indexes were promoted. Leaf anatomical characteristics of understory plants in middle-aged stands had the highest response to nitrogen addition and most of them responded positively. Conclusion: This study suggests that the leaf thickness and vascular tissue of understory plants at different age plots may adopt different strategies to adapt to nitrogen fertilizer, which should be considered according to different situations when interpreting the response and adaptation mechanisms of plants.

Objective: In this study, the structure and diversity of rhizosphere bacterial communities in both wild and artificially cultivated Monochasma savatieri Franch ex Maxim. in Jiangxi Province were investigated to explore their relationship with soil physical and chemical properties. The aim of this study is to offer a theoretical basis for further studies on wild-simulated cultivation modes for constructing a healthy rhizosphere microenvironment for M. savatieri. Method: Rhizosphere soil bacteria originating two distinct habitats, the first being natural forests such as Camellia oleifera, Gardenia jasminoides and Pinus massoniana, and the second being artificially cultivated, were selected as research objects. The community structure characteristics of soil bacteria from different habitats were compared and analyzed by using field investigation, Illumina Miseq sequencing, and RDA analysis. Result: The results indicated that there were significant differences in the physico-chemical properties of the rhizosphere soil of M. savatieri between two distinct habitats. The Alpha diversity of artificial bionic cultivation was highest, but there was no significant difference in the alpha diversity among different forest types. In two habitats, Proteobacteria, Acidobacteriota, Chloroflexi and Actinobacteriota were the dominant bacteria phyla. At the genus level, the common dominant genera included Burkholderia-Caballeronia-Paraburkholderia, Bradyrhizobium, Candidatus_Solibacter, Occallatibacter, Bryobacter and uncultured bacterium. There were significant differences in the structure of the bacterial communities between wild and artificial bionic cultivation, with the highest abundance of Proteobacteria in artificial bionic cultivated habitats. The dominant genera unique to wild habitats, including Acidothermus, FCPS473, Conexibacter, Acidibacter, uncultured Acidobacteria_bacterium, uncultured_forest_soil bacterium, all significantly decreased in abundance in the artificial bionic cultivation habitats, while the abundance of dominant bacterial genera unique to artificially cultivated habitats (such as Sphingomonas, Granulicella, Haliangium and Mucilaginibacter), showed a significantly increased abundance in the artificial bionic cultivated habitat. Redundancy analysis (RDA) showed that total nitrogen, available potassium, alkali-hydrolyzable nitrogen, and organic matter were closely related to the composition of soil dominant bacterial communities. Conclusion: There are significant differences in the physico-chemical properties of the rhizosphere soil of M. savatieri between wild and cultivated habitats, as well as significant differences in the structure of bacterial communities. The similarity of the rhizosphere bacterial communities of M. savatieri from different wild habitat conditions is relatively high. The main environmental factors affecting bacterial community structure are soil total nitrogen, available potassium, alkaline nitrogen, and organic matter. This study provides a reference basis for the resource utilization of rhizosphere micoorganisms of M. savatieri.

Objective: A simple and convenient method for estimating forest carbon storage was proposed, and a scale-compatible and tree species-classified forest carbon storage model of volume-derived was constructed, which provided a method and technology support for estimating forest carbon storage of multi-scale and multi-tree species. Method: Based on the data of the 6th?9th national forest resource inventory and allometric growth equation, the scale-compatible and tree species-classified stand carbon storage model considering stand origin and age group was constructed by using the independent model of non-linear least square method and the simultaneous equations model of non-linear seemingly unrelated regressions with dummy variables. Heteroscedasticity was eliminated by weighted regression, and the model was evaluated by determination coefficient (R²), standard error of estimate (SEE), mean prediction error (MPE), total relative error (TRE) and variance percentage (VP). Meanwhile, using the data of the National forest and grass ecological comprehensive monitoring in 2021, the differences of forest carbon storage estimation by different scale models were compared. Result: 1) A total of 2 974 scale-compatible forest carbon storage models were constructed. Compared with the independent model, there was no significant difference in R² of the simultaneous equations model. The independent model and the simultaneous equations model were 1 383 and 1 591 categories, respectively. The average values of the model R² were 0.966 1 and 0.965 2, MPE were 0.75% and 0.78%, respectively, the R² of the simultaneous equations model only decreased by 0.000 9, and the MPE only increased by 0.03%. 2) A total of 2 520 tree species-classified forest carbon storage models were constructed. As with the results of the scale-compatible model, there was no significant difference in R² between the independent model and the simultaneous equations model. The independent model and the simultaneous equations model were both 1 260 categories. The average values of the model R² were 0.944 3 and 0.942 4, MPE were 0.48% and 0.49%, respectively, the R² of the simultaneous equations model only decreased by 0.001 9, and the MPE only increased by 0.01%. 3) Four forest carbon storage models with different modeling methods (independent-scale model, independent-tree species model, simultaneous-scale model, simultaneous-tree species model) were established. Compared with the independent model, the parameters variation of the simultaneous equations model was smaller. Four forest carbon storage models with different modeling methods contained 46 157 and 23 935 parameters a and b respectively. The average values of parameter a in the independent model and the simultaneous equations model were 0.596 5 and 0.620 0, respectively, and the ranges were 2.318 6 and 2.192 2, respectively. The range of parameters in the independent model was 0.126 4 higher. The average values of parameter b were 0.933 2 and 0.931 8, respectively, and the ranges were 0.672 3 and 0.505 6, respectively. The range of the independent model was 0.166 7 higher. 4) When estimating national forest carbon storage by different scale models, regardless of the scale, the estimation difference of the independent model was higher than the simultaneous model. However, in general, the estimation differences at various scales were within 3%. Conclusion: 1) The volume-derived forest carbon storage model proposed in this paper from stand volume to stand carbon storage was effective and reliable, which can be used to directly estimate forest carbon storage. 2) Based on the simultaneous equations model of non-linear seemingly unrelated regressions with dummy variables, the scale-compatible and tree species-classified forest carbon storage model can be better established. 3) The average R² of the forest carbon storage model constructed in this paper was above 0.95, and MPE was less than 1%, which can be used to quickly and accurately estimate forest carbon storage in forestry practice. 4) According to the fitting accuracy of the model and the stability of the parameters, we recommend using the simultaneous-tree species model. 5) Under the accuracy requirement of 5%, the national scale model can be used to estimate the national forest carbon storage.

Objective: As one of the processes governing the dynamic changes in forests, tree recruitment is the basis to ensure the long-term maintenance of the structure and function of forest ecosystems. The recruitment model can predict the development dynamics of forest and quantify the future health and productivity of forest ecosystems which can provide the fundamental theoretical framework and data support for the conservation and restoration of natural forests. Method: Based on the 8th (2009), and 9th (2014) national forest inventory in Hunan Province, 784 natural Cunninghamia lanceolata forest sample plots were used to develop a tree recruitment model for natural secondary forests, incorporating stand factors, site factors, and climate factors. The basic model selected is the negative binomial (NB) model, taking into account the overdispersion in the recruitment data, zero-inflation model and Hurdle model are introduced to construct the zero-inflation Poisson (ZIP) model, zero-inflation negative binomial (ZINB) model, Hurdle-Poisson (HP) model and Hurdle-NB (HNB) model. Furthermore, to address potential autocorrelation and heteroscedasticity issues in the data due to repeated measurements and stratification, we introduced the county where the plots were located as a random effect in the five aforementioned models, constructing corresponding mixed-effects models. Finally, model validation was conducted using ten-fold cross-validation. Result: The basal area of the tree species (Bai), soil thickness (ST), elevation (EL) and mean annual precipitation (MAP) significantly influence the recruitment of C. lanceolata forests. The performance of the negative binomial composite models (NB, ZINB, and HNB) in simulating natural C. lanceolata forests recruitment is notably superior to that of the Poisson composite models (ZIP and HP). The fitting performance of ZINB and HNB outperforms NB, with ZINB showing a slight advantage over HNB. The introduction of county-level random effects resulted in likelihood ratio test outcomes that indicate improved goodness of fit for NB, ZIP, ZINB, and HP models compared to the base model, except for the HNB model. Among these, the ZINB mixed-effects model exhibited the best fitting performance, a conclusion supported by the results of ten-fold cross-validation. Conclusion: The climate-sensitive natural C. lanceolata forests recruitment model constructed in this research holds biological significance and statistical reliability. It can provide scientific guidance for the implementation of ecological restoration measures and silvicultural practices in the region’s natural secondary forests, thereby enhancing stand quality and contributing to the timely achievement of“carbon neutrality and peak”strategic goals.

Objective: This study aims to uncover the water adaptation strategies of desert shrubs by exploring their xylem anatomical traits, xylem functional trade-offs, and the impact of phylogenetic and meteorological factors on their anatomical structure. Additionally, this research also aims to establish a theoretical foundation for vegetation preservation and restoration in degraded desert ecosystems. Method: In this study, 18 typical desert shrubs were used as experimental objects, and their xylem anatomical characteristics were examined and compared with those of woody plants across the globe. The typical characteristics of desert shrub xylem were analyzed. The trade-offs between the“mechanical safety, storage, and hydraulic efficiency”of the xylem were assessed using a structural equation model (PLS-PM). The interspecific variability was investigated by integrating phylogenetic analysis and climate factors in the natural distribution areas. Result: 1) Compared with the average of woody plants around the world, desert shrubs displayed a higher vessel fraction, axial parenchyma fraction, and a lower fiber fraction. Compared with the global average of angiosperms, desert shrubs exhibited a higher vessel density and smaller vessel hydraulic diameter. The combination of increased vessel density and reduced hydraulic diameter resulted in the maximum theoretical hydraulic conductivity of desert shrubs being basically consistent with the global average. 2) There were significant variations in wood anatomical characteristics among 18 desert shrubs, and the anatomical traits of plants in the same family showed a certain degree of aggregation in principal component analysis. However, apart from the significant phylogenetic signal observed in vessel density, the phylogenetic signals of other traits were not significant. 3) There was a significant trade-off between mechanical safety and hydraulic efficiency and storage capacity, and there was no significant correlation between hydraulic efficiency and storage capacity. Vessel density was negatively correlated with mean annual temperature, mean temperature of wettest quarter, and mean temperature of warmest quarter, while vessel diameter and vessel wall thickness were positively correlated with those climate factors. On the other hand, annual precipitation did not have a significant effect on anatomical traits. Precipitation seasonality exhibited a significantly positive correlation with vessel wall thickness. However, no significant correlation was observed between annual precipitation, wettest quarter precipitation, warmest quarter precipitation, and anatomical anatomy. Conclusion: The xylem of desert shrubs exhibits drought adaptation features that contribute to reduced mechanical support, increased storage capacity, and maintained hydraulic efficiency. The vessel features of these shrubs are significantly influenced by phylogeny and meteorological factors, while other anatomical traits show no significant effects.

Objective: This study aims to explore frost fatigue and its relationships with freeze-thaw-induced embolism and xylem anatomical structure in different trees from temperate zones, which can improve knowledge of winter plant hydraulics and provide new theoretical basis for the selection of suitable tree species for afforestation in temperate and boreal regions. Method: Six common temperate trees [Acer truncatum, I-101 (Populus alba) × 84K (P. alba× P. glandulosa), Liriodendron chinense, Salix matsudana, Betula platyphylla, and Platanus orientalis] were used as study materials and their branches were collected in January of winter. A modified Cavitron freezing centrifuge was utilized for freeze-thaw treatments and constructed native vulnerability curves (NVCs) and frost fatigue vulnerability curves (FFVCs). The embolic areas (EAs) of these two vulnerability curves per species were calculated to assess the degree of frost fatigue (DFF). For each of species, the native percentage loss of hydraulic conductivity (NPLC), i.e., the degree of freeze-thaw-induced embolism, was determined by a low-pressure flow meter (LPFM) and xylem anatomical structure traits were measured, such as vessel diameter (D), vessel density (V_D), vessel lumen fraction (F), intervessel contact fraction (F_C), and wood density (WD). Result: After undergoing freeze-thaw treatment, the resistance of xylem embolism decreased for all tree species and frost fatigue occurred. For all tree species, the frost fatigue vulnerability curves were double S-shaped compared to the S-shape of the native vulnerability curves. Compared with the embolism area of NVC, the embolism area of FFVC of A. truncatum was slightly reduced with no significant difference, while the embolism areas of FFVCs of the other five tree species were significantly reduced. The degree of frost fatigue showed pronounced interspecific differences and ranked as I-101 (P. alba)×84K (P. alba×P. glandulosa) > S. matsudana > P. orientalis > L. chinense > B. platyphylla > A. truncatum. There were significant differences in the degree of freeze-thaw-induced embolism and xylem anatomical structure traits among different tree species. The degree of frost fatigue was significantly positively correlated with the degree of embolism induced by freeze-thaw, and only with vessel diameter in the xylem anatomical structure traits. The degree of freeze-thaw-induced embolism was also significantly positively correlated with vessel diameter. Conclusion: There are obvious differences in frost fatigue among the six tree species. A. truncatum has strong resistance to frost fatigue with the lowest degree of frost fatigue and is “resilient species”. The other five species have high vulnerability to frost fatigue and are “weakened species”. Tree species with wider vessel have higher degrees of freeze-thaw-induced embolism and frost fatigue. Vessel diameter thus is the key structural trait that determines the degree of freeze-thaw-induced embolism and frost fatigue of trees. Tree species with narrow conduits in the xylem are more resistant to freeze-thaw-induced embolism and frost fatigue, which would favor their survival and distribution in cold environments in temperate and boreal regions.

Objective: In this study, the genetic variation of growth and morphological traits among different half-sib families of Michelia macclurei was investigated. The purpose of the study is to explore the interactions between genotype and environment on the growth and development of M. macclurei, screen out half-sib families with excellent comprehensive traits, and provide important genetic information and breeding materials of M. macclurei. Method: In this study, seeds from 75 families were collected from 12 natural and secondary stands of M. macclurei in Guangdong and Guangxi. A random block design was used to establish a semi sibling pedigree test forest in Guangdong and Fujian. Indexes reflecting growth rates were measured at 2-year-old and 3-year-old, while both growth and morphological indexes were measured at 4-year-old and 8-year-old. The ASReml v3.0 software was utilized to analyze the mean and standard deviation of various indicators, as well as family heritability (narrow sense), and B-type correlation values for 75 families across two test sites. Based on the genetic correlation results of 8-year-old traits, the breeding value of volume traits and aggregate breeding value of morphology traits were used to selected superior families in Guangdong and Fujian respectively. Result: There were significant differences (P<0.01) in height (H), diameter at breast height (DBH), volume (VOL), straightness (SFS), trunk bifurcation (SFA), branch thickness (TPB), branch angle (APB), and stem height (HUB) among 75 families at different ages. The family heritability of H and DBH traits at 2–8 years old, SFA, TPB, APB and HUB at 8-year-old was all greater than 0.25, indicating that these traits are highly influenced by genetic factors and have potential for breeding improvement. However, the results of B-type correlation analysis showed that all traits were moderately or significantly affected by families and environment, indicating that the interaction of environment and genotype must be taken into account in character evaluation and genetic breeding of M. macclurei. Pearson correlation analysis revealed that H and DBH of the families were highly correlated with the VOL, but negatively correlated with SFA, SFS, TPB, and APB. By aggregate breeding values, one superior family (F44) was obtained from Guangdong experimental site and one superior family (F7) was obtained from Fujian experimental site. Conclusion: There are significant or extremely significant differences in all traits among the families of M. macclurei, and there are also significant differences among the traits among the sites, and the variation of growth and morphological indexes is greatly affected by the interaction of genotype and environment. Among them, volume traits have a large phenotypic variation coefficient (PVC) and genetic variation coefficient (GVC), and have a large breeding potential. One family with superior comprehensive traits has been selected in each of the two experimental sites, namely F44 from Guangdong and F7 from Fujian. This study provides important information for the genetic evaluation of the main traits of M. macclurei in the future, and provides core breeding materials for further multi-trait breeding.

Objective: The mechanism of quota water addition on the the aril cracking of Torreya grandis cv.‘Merrilii’ in the near mature period was discussed, and the theoretical basis for promoting the cracking rate of aril and reducing the harvesting cost was provided. Method: During the near maturity stage, by setting the quota water addition (the soil moisture content is approximately 26.5% at a depth of 25 cm) and control treatment (without water addition), then measuring the aril cracking rate, firmness of T. grandis cv.‘Merrilii’ in different periods, combined with paraffin sections observe the anatomic structure and analyzing the ethylene production volume and the cell wall components, and based on the transcriptome and RT-qPCR analysis to further reveal the intrinsic mechanism of water addition promotes the aril cracking. Result: 1) Water addition treatment significantly increased the cracking rate of the aril in T. grandis cv.‘Merrilii’ to 72.55%, decreased the firmness by 40.40% ( P ≤ 0.05 ), and increased the ethylene release by 1.32 times. The microstructure showed that the resin canals in the parenchyma cell layer of the aril treated with irrigation were obviously broken and separated, and the thickness of the parenchyma tissue layer increased significantly by 20.12%. 2) Water addition treatment significantly increased the water-soluble pectin (WSP) in aril, while the contents of CDTA soluble pectin (CSP), cellulose and hemicellulose decreased significantly. The cracking rate of aril was significantly positively correlated with WSP and significantly negatively correlated with CSP. 3) The expression levels of cell wall metabolism-related genes TgEXPs, TgPMEs and ethylene synthesis-related genes TgACOs were significantly up-regulated after irrigation treatment. Among them, the expression levels of TgEXP1, TgEXP2, TgPME1, TgPME2 and TgACO1 were significantly negatively correlated with firmness and CSP, but were significantly positively correlated with cracking rate, ethylene release and WSP. Conclusion: In the near mature period, quota water addition significantly promoted the cracking of the aril of T. grandis cv.‘Merrilii’ and shortened the cracking period by increasing the ethylene release and changing the cell wall components and related gene expression, which provided a reliable theoretical basis for the cultivation measures to improve the cracking rate.

Objective: To clarify the influence of landscape plant odor types and odor concentrations on human physical and mental health, explore the correlation between physiological responses and subjective perceptions under odor stimulation, provide indicators selection reference for subsequent studies on the effects of landscape plant odor on human health and theoretical basis for smellscape design and optimization. Method: This study utilized ginkgo sarcotesta and osmanthus flowers, common odorous materials in autumn, representing positive and negative odor types, respectively. Through pre-experiments, low and high odor concentration values were set, and COSMOS XP-329IIIR portable odor sensor was used to prepare four groups of odor materials: low-concentration osmanthus, high-concentration osmanthus, low-concentration ginkgo, and high-concentration ginkgo. Fifty-two university students were recruited for the experiment, and their physiological indicators were measured by ErgoLAB and Emotiv Epocx, while their subjective perceptions and emotional indicators were collected using pleasure rating scales, familiarity rating scales, odor intensity rating scales, and odor emotion scales(ScentMove? questionnaire). Compare the differences in the effects of odor types and concentrations on various physical and mental indicators through analysis of variance and non-parametric tests, and then use Spearman rank correlation analysis to test the correlation between physiological and psychological indicators. Result: 1) The pre-measured odor intensity was significantly affected by odor concentration and odor type (P<0.05, P<0.01), while the post-measured odor intensity was only significantly affected by odor type (P<0.05). 2) The six emotional indicators of the ScentMove? questionnaire (desire, peacefulness, happiness, energy, nostalgia, unpleasant feelings)were not significantly affected by odor concentration (P>0.05), but were significantly affected by odor type (P<0.01). Pleasantness was significantly positively correlated with positive emotions such as desire,peacefulness, happiness, energy, nostalgia (P<0.01) and significantly negatively correlated with unpleasant feelings (P<0.01). Familiarity was significantly positively correlated with emotions such as happiness, peacefulness, nostalgia, and energy (P<0.01), and significantly negatively correlated with unpleasant feelings (P<0.05); there was no significant correlation between odor intensity and the six emotional indicators. 3) Skin conductivity level(SCL), average heart rate(AVHR), standard deviation of NN intervals(SDNN), and root mean square of successive differences (RMSSD) were not significantly affected by odor concentration (P>0.05), but were significantly affected by odor type (P<0.01). α brain wave were not significantly affected by odor type or concentration (P>0.05). θ brain wave, low frequency of β (β_L) brain wave, and high frequency of β (β_H) brain wave were significantly affected by odor concentration (P<0.05, P<0.01), but not by odor type (P>0.05). γ brain wave are significantly affected by odor type, and the interaction between odor type and concentration (P<0.05, P<0.01). 4) Among the physiological indicators, low frequency to high frequency energy ratio of heart rate variability(LF/HF), θ brain wave, β_L brain wave, β_H brain wave, and γ brain wave showed the highest correlation with the psychological indicators. Conclusion: Subjectively, the perception threshold of odor intensity varies for different odor types, and the duration of olfactory stimulation can affect people’s ability to perceive odors. Emotional responses are not significantly affected by concentration, but the perception of pleasantness is a major factor influencing emotional experiences. Physiologically, the autonomic nervous system is not sensitive to odor concentration, but shows clear reactions to positive and negative odors; electroencephalogram is more sensitive to odor concentration, with high concentrations of odor causing significant inhibition of brain wave activity. Overall, θ brain wave, low frequency of β brain wave, high frequency of β brain wave, low frequency to high frequency energy ratio of heart rate variability(LF/HF) can serve as effective physiological indicators for studying emotional valence. This study further refines the variables of the impact of plant odors on human health benefits, validates the correlation of commonly used physiological and psychological indicators in olfactory health benefits research, and provides methodological references and theoretical basis for future related research.

Objective: This study aims to reveal the morphological adaptation mechanism and provide important information for phenotypic tracing of Bursaphelenchus xylophilus, by investigating the morphological characteristics and phenotypic variation of B. xylophilus under different terrain conditions in different infected areas. Method: Zhejiang Province, where the pine wood nematode invaded earlier, was selected as the sampling area. The pine wood nematode epidemic areas in Zhejiang Province were divided into 18 districts and 19 regions based on the invasion time and the topographic habitats of pine wood nematode, where the samples were collected and the nematode was isolated and purified. Seven morphological indices related to adult female and male nematodes, individual development, feeding, and reproduction were determined. These indices included body length, body width, median bulb width, stylet length, tail length, anus body width, and spicule length. The phenotypic variation of B. xylophilus was analyzed by hierarchical cluster analysis and variation analysis to identify distinct morphological indicators. Result: 1) There are abundant phenotypic variations in B. xylophilus adults in different regions of Zhejiang Province, and female nematodes were significantly larger than males in several morphological indices. The results of variation analysis showed that the morphological variation of B. xylophilus primarily occurred in feeding-related morphological indices. Among the morphological indicators of female and male nematodes, median bulb width and stylet length of male and female adults varied significantly, while the body length and tail length were relatively stable morphological indicators. The spicule length was a morphological feature with less variation in male pine wood nematodes. 2) Hierarchical clustering analysis with multiple indicators showed that the female and male adult pine wood nematodes from the 19 sampling regions were all divided into three different clusters, but the clustering results of female and male were inconsistent. The clustering results of male nematodes were related to individual reproductive indices, while those of female nematodes were related to individual growth and development indices. There was randomness in relation to the invasion time and colonization habitat of the pine wood nematodes. PLS-DA analysis indicates that body length, body width, and tail length were the main morphological indicators for clustering female nematodes, while body length, tail length, and spicule length were the main indicators for clustering male nematodes. 3) The morphology of B. xylophilus changed in environmental adaptation, with the nematode morphology of northern populations larger than that of southern populations, and the morphology of nematodes in colonized areas larger than that in invaded areas. Altitude had an impact on the morphology of female. 4) In environmental adaptation, the rate of morphological differentiation in females was greater than that in males. The morphological variation of females tended towards individual growth and development, while that of males tended towards reproductive development. Conclusion: Terrain and invasion time affect the morphology of pine wood nematode, and the significant phenotype variations of B. xylophilus mainly occur in the morphological characteristics related to feeding. Body length, tail length and spicule length may be key morphological features for phenotype tracing of B. xylophilus on a large scale. The degree and direction of variation in female and male adults are inconsistent.

Objective: This study aims to elucidate the role of Bxy-mix-1 gene in the growth and development of Bursaphelenchus xylophilus by analyzing the expression characteristics and biological functions of the gene associated with sex determination in B. xylophilus, so as to provide a theoretical foundation for exploring specific nematode population growth control measures from the perspective of sex ratio regulation. Method: Based on the genome data of B. xylophilus, primers were designed, by which the Bxy-mix-1 gene was cloned. Bioinformatics analysis of Bxy-mix-1 was performed. To elucidate the spatio-temporal dynamic expression characteristics of the Bxy-mix-1 gene, RT-qPCR and in situ hybridization techniques were employed to investigate its expression level and expression site in each age of B. xylophilus. Additionally, RNA interference technique was utilized to explore the role of this gene in the growth and development of B. xylophilus. Result: The results of bioinformatics analysis showed that the full-length CDS of Bxy-mix-1 gene was 2 163 bp, encoding 1 171 amino acids, belonging to the SMC protein family. Bxy-mix-1 gene was expressed in different developmental stages of B. xylophilus, with the lowest expression level in embryo stage, gradually increasing expression level in J2, J3 and J4 stages, and reaching the highest expression level in adult stage. Meanwhile, there was difference in gene expression level between female and male, showing a significantly higher expression level in the males than that in the females. The results of in situ hybridization showed that Bxy-mix-1 gene exhibited whole-embryo expression at embryonic stage, with expression concentrated in the middle and posterior parts of the body at J2 and J3 instars. At the J4 and adult stage, there were differential expressions of female and male in the gonads of female and male and in the mating spines of male. After silencing the Bxy-mix-1 gene, the statistical results showed a significant decrease in the male to female ratio of B. xylophilus. The results of mating experiment showed that the mislocalization rate of males increased significantly, and the average number of offspring of females decreased significantly. Conclusion: Bxy-mix-1 is a member of the SMC protein family which has sexual dimorphism in the expression level and location. This study indicates that Bxy-mix-1 plays an important role in regulating sex determination and reproductive behavior of B. xylophilus.

Objective: A new sawfly pest mining leaves of Pterocarya stenoptera in North China was reported and described. The systematic status of Fenusinae and Heterarthrinae as well as some genera and species of mining sawflies were clarified. Method: The classical comparative morphology was used to clarify the name and the systematic status of the pest. The whole genome of the new pest was sequenced by second-generation sequencing technology. Mitogenome was assembled and the phylogenetic trees of Fenusinae were inferred. Result: The pest was confirmed to be a new species of Fenusinae, Tenthredinidae: Sinoscolia fengyang Wei & Niu, sp. nov. This new species is similar to the type species, Sinoscolia brevicornis Wei & Nie, but differs from the latter by the following characteristics: the anterior margin of clypeus incised, labrum brownish black; the postocellar area not higher than top of ocelli, the middle furrow shallow; the middle fovea clearly smaller than frons, the frontal walls subquadrate; frons broader than distance between frons and inner margin of eye; antenna about 1.6 times as long as head breadth; the anal cell of hind wing more than 2 times as long as anal petiole, the anal petiole 1.5 times as long as cu-a. Sinoscolia Wei & Nie, 1998 is a genus endemic to China and is similar to Scolioneura Konow, but differs from it by the mandibles asymmetric, left mandible with 3 teeth and right one with 2 teeth; the cell R1 in hind wing broadly open; serrulae almost flat; penis valve with distinct ventral apical process. Based on mitochondrial genome data, a molecular phylogenetic relationship was established to briefly discuss the systematic status of Fenusinae as well as some genera and species. Conclusion: Sinoscolia fengyang is a new species of Fenusinae based on morphological study and the mitochondrial genomic analysis. Heterarthrinae is an ingroup of Fenusinae, so the former should be merged into Fenusinae. Both Kaliofenusa and Fenusa are valid and independent genera. Fenusella nana (Klug, 1816) is not a member of Fenusella, and Profenusa japonica Togashi, 1981 is not a member of Profenusa.

Objective: In this paper, impregnation modification utilizing melamine-urea-glyoxal (MUG) resin is proposed to improve the cracking defect of plantation grown Castanopsis hystrix wood and increase its value. Method: MUG resin with different mass fractions (10%, 15%, 20%, and 25%) was used to modify plantation C. hystrix wood (denoted as MUG10, MUG15, MUG20, MUG25). The changes in wood's physical and mechanical properties before and after modification were analyzed. The changes in pore structures were also investigated through nitrogen adsorption, mercury intrusion, and scanning electron microscopy methods. Result: The results showed that the dimensional stability and mechanical properties of resin-impregnated wood were significantly improved with the increasing mass fraction of MUG resin. When the mass fraction of MUG was 25%, the WPG (weight percent gain) of resin-impregnated wood was 21.1%, oven-dried density was 762 kg·m^?3, and the difference between the oven-dried density of earlywood and latewood was 42.0%, which was lower than that of untreated wood. The ASE (anti swelling efficiency) of tangential, radial, and volume of the resin-impregnated wood (MUG25) were 52.06%, 39.96%, and 44.30%, respectively. And the ratio of radial and tangential wet swelling was 0.70 indicating the anisotropy of modified wood decreased. Compared with the untreated wood, the modulus of elasticity (MOE), modulus of rupture (MOR), and compressive strength (CS) of resin-impregnated wood (MUG25) were increased by 35.59%, 30.01%, and 32.78%, respectively, and the hardness of radial section, tangential section, and cross section were increased by 37.13%, 13.46%, and 27.94%, respectively. Furthermore, the porosity of the resin-impregnated wood decreased and the pores such as wood vessels, fibers, and pits in wood cell were filled with resins. Conclusion: MUG resin-impregnated modification can effectively improve the dimensional stability of C. hystrix wood and expand its application scope.

Protecting forest ecosystems necessitates timely, accurate, and dynamic information on the status and changes in forest plant diversity, including an analysis and evaluation of the contributing factors. The development of remote sensing technology enables multi-scale monitoring, with optical remote sensing data based on the spectral variation hypothesis facilitating the monitoring of forest plant diversity. However, spectral diversity, while reflective of horizontal forest diversity, has a limited ability to monitor the vertical structure of forests. Despite the great potential of forest structural complexity for understanding biodiversity, comprehensive tools for measuring forest structure have been limited. The recent development of active remote sensing technologies, such as LiDAR, has expanded the detection of forest plant diversity from the spectral to the structural dimension, offering an opportunity to clarify the structure-function relationship of forests. The main objective of this review is to summarize the use of LiDAR data in biodiversity-related assessments of forests. We highlight topics related to forest structural parameters, structural diversity, species diversity, dead wood, understorey, forest type and successional stage. We found that different LiDAR structural metrics significantly explain various forest biodiversity indicators and are influenced by factors such as data acquisition, sensor type, sampling scale, forest type, and geographic location. The fusion of spectral information from optical images with structural information from LiDAR is highly advantageous in studies considering tree species and diversity. LiDAR remote sensing technology enables the monitoring and assessment of forest structure and diversity at different scales. The integration of spaceborne LiDAR and satellite images helps to understand the impacts of changes in the vertical structure of the canopy on ecosystem composition and function globally, offering broad applications in the conservation and management of biodiversity.

The intensification of climate change and human activities has led to a severe situation of frequent wildfires globally, posing a significant threat to forest ecosystems. Constructing effective firebreaks and firebreak systems is crucial for preventing and mitigating the spread of wildfires. This paper first outlines the mechanisms of biological firebreaks, including species selection, structural design, and fire environment regulation, and explores key factors such as site selection, width design, species configuration, and spatial layout for firebreaks. Secondly, the study reviews the types, functions, and methods of fuel removal for engineering firebreaks, with a focus on the planning and design of forest roads. Third, the study examines the key factors influencing the effectiveness of firebreaks and evaluates their practical efficacy, and further analyzing the applicability and limitations of different assessment methods. Finally, the study looks forward to future research directions in five specific areas: the multi-layered composite design of biological firebreaks; diversified planning and layout of engineering firebreaks; green, efficient, and low-cost fuel management technologies for firebreaks; assessment techniques for the fire-retardant effectiveness of biological firebreaks; methods for determining the optimal width and density threshold for firebreaks.