Objective: In order to provide theoretical foundation for desert steppe vegetation conservation, the spatial characteristics of soil water content and above-ground vegetation biomass and the appropriate soil moisture threshold in desert steppe-shrubland transition in eastern Ningxia were analyzed. Method: Spatial heterogeneity of soil moisture in 0-200 cm soil layer and the related above-ground biomass were investigated in 43 shrubland sites and 43 grassland sites of desert steppe in eastern Ningxia via GIS and geostatistics methods. Result: It was shown that soil moisture was higher in grassland (6.23%) than that in shrubland (5.47%), with the variation ranging from 1.37% to 25.36% in the former and 1.5% to 19.58% in the latter, especially in the 80-200 cm soil layer. The coefficient of variation (CV) of soil moisture moderately ranged from 28.94% to 62.30% in both vegetation types between which soil moisture in shrubland was generally higher than that in grassland. And the related above-ground biomass was higher in shrubland (0.56 kg·m^-2) than that in grassland (0.06 kg·m^-2), and the coefficients of variation were moderate for both. Geostatistical results showed that the structural variation ratio [C/(C₀+C)] of soil moisture in 0-120 cm soil layer was higher in grassland (0.75) than that in shrubland (0.64). The structural variation ratio of soil moisture between 0-120 cm soil layer gradually decreased along with the increase of soil depth. The range (A₀) in shrubland (45.84 km) was higher than that in grassland (18.56 km) (P < 0.05), and the soil moisture in 120-200 cm soil layer followed a pure nugget effect model. The structural variation ratio of above-ground biomass was higher in shrubland (0.76) than that of grassland (0.37), and the range (A₀) in grassland (43.91 km) was significantly higher than that of shrubland (12.77 km) (P < 0.05). We obtained the suitable soil moisture threshold 8.11%-14.19% in the transition from desert grassland to shrubland according to the response characteristics of above-ground biomass and soil moisture. Conclusion: During the transition from desert grassland to shrubland, accelerated deep soil water consumption accompanied with the increased above-ground biomass and related spatial heterogeneity and the decreased spatial heterogeneity of soil moisture in landscape scale. And the pure nugget effect model was found for deeper soil layer moisture in grassland and shrubland due to increased rainfall in the survey and previous years.

Objective: Different underlying surfaces in typical aeolian sand areas were selected in the dry-up Qingtu Lake to carry out the observation of sediment transport flux of wind-sand flow, the spatial differences of sediment transport flux and the particle size distribution characteristics of wind-sand flow were analyzed, in order to characterize sediment transport flux of saline alkali sediments and to provide a basis for the effective management of saline alkali desertification at the bottom of the lake. Method: Wind-sand flow meter was used to measure the sediment transport flux of wind-sand flow on the nine underlying surfaces in Qingtu Lake and its relationship with wind speed was studied, and the size distribution pattern of wind-sand flow particles was analyzed. Result: The average sediment transport flux of wind-sand flow in the range of 0-50 cm on different underlying surfaces showed as follows: lake shoal>Kalidium foliatum community in lake bed > moving Nitraria tangutorum shrub >Haloxylon ammodendron forest in saline sandy > K. foliatum community in the wasteland> semi-fixed N. tangutorum shrub >H. ammodendron forest in shifting sandy land> stable N. tangutorum shrub>fixed N. tangutorum shrub. The average sediment transport flux of wind-sand flow of different underlying surfaces were positively correlated with the average wind speed greater than 5.0 m·s^-1 in an exponential function with different extents of correlation. The particle size of wind-sand flow at the bottom of the lake was fine sand, the largest average particle size was the lake shoal, and the smallest was the K. foliatum community in the barren land. Conclusion: Among the 9 underlying surfaces, the sediment transport flux of lake shoal, K. foliatum community in lake bed and moving N. tangutorum shrub was larger, indicating that they are important area of wind sand movement at the bottom of the lake. Engineering and biological measures should be actively taken to control the flow of sand sources in the area. The particle size of wind-sand flow on the ground surface of K. foliatum community in the barren land was small, easier to be blown up by strong wind, increasing the content of air aerosol and pollution of the atmospheric environment. It was recommended to grow salt and alkali resistant shrubs to improve vegetation coverage, reduce surface wind speed and reduce dust emission. For the other 5 underlying surface types, the surface vegetation coverage was higher or the surface crust was relatively stable and the sediment transport flux was small, therefore closure of the sites can be adopted to allow natural restoration.

Objective: This paper aims to study the dynamic changes and driving factors of soil microbial diversity and community composition in Quercus aliena var. acuteserrata forests at different altitudes in Qinling Mountains. Method: This experiment was conducted in Mount Taibai of Qinling Mountains with four elevations of 1 361.6, 1 524.2, 1 630.5 and 1 769.3 m, at which three standard plots (20 m ×20 m) were set in Q. aliena var. acuteserrata forests with good drainage, gentle slope and moderate growth. In August 2016, mixed sampling was carried out in 0-10 cm soil layers by the "S" type method, and then the diversity and composition of soil microbial community were determined by high-throughput sequencing technique. Result: 1) In Q. aliena var. acuteserrata forest, diversity (α diversity and β diversity) of soil bacteria had significant changes at different elevational gradients, but there was no significant change in diversity of soil fungi. 2) In the composition of bacterial community, the relative abundance of Actinobacteria decreased significantly with the increase of elevation, while that of Proteobacteria and Verrucomicrobia increased significantly. The relative abundance of Chloroflexi, Gemmatimonadetes and Nitrospirae showed a trend of increasing first and then decreasing; and that of other bacterial taxa such as Acidobacteria and Planctomycetes showed a decreasing trend along the increase of elevation, but there was no significant difference between different elevations. In the composition of fungal community, the relative abundance of Basidiomycota and Ascomycota, two dominant phyla, did not change significantly with the increase of elevation. 3) Bacterial diversity was significantly positively correlated with soil organic carbon (SOC), total nitrogen (TN), C∶P and N∶P, and the response of bacterial community composition to elevational gradient was mainly determined by soil bulk density, soil temperature, SOC, C∶P and TN. Fungal diversity was only significantly negatively correlated with soil moisture, and its community composition was significantly correlated with pH, SOC, TN and N∶P. Conclusion: This study indicates that the changes in soil bacterial and fungal diversity along the altitudinal gradient are influenced by different soil environmental factors, and provides a comprehensive insight into the changing characteristics and influencing factors of soil microbial community structure and composition in the warm temperate forest ecosystems of the Qinling Mountains, thus providing a scientific basis for an in-depth understanding of the microbial mechanisms of soil organic carbon decomposition in forest ecosystems.

Objective: This study aimed to provide theoretical basis for the high yield management of Phyllostachys edulis forests for bamboo shoots in Mufu Mountain area by investigating the influence of bamboo forest density and the fertilizer types on the yield and quality of bamboo shoots and soil physicochemical properties. Method: A two-factor complete randomized block experiment with three levels of bamboo forest density (2 100-2 550, 2 700-3 150, 3 300- 3 750 stem·hm^-2) and three types of fertilizer (compound fertilizer, organic fertilizer and formula fertilizer) was conducted, and so there were 9 kinds of combination treatments in total. The natural bamboo forests which had not been managed and had no density regulation or fertilization during the study period were used as the control. The yield differences and changes of quality characteristics of bamboo shoots were analyzed. Based on principal component analysis, the effects of different management measures on soil physicochemical properties were evaluated, and then the redundancy analysis was used to explore the relationship between the quality of bamboo shoots and soil physicochemical properties and bamboo forest density. Result: 1) Within the range of bamboo forest density in this study, the bamboo shoot yield increased with the decreasing density, and reached the highest when the density was 2 100-2 550 stem·hm^-2. Fertilizer types significantly affected the bamboo shoot yield, and when compound fertilizer was applied the yield was the highest, when organic fertilizer was applied the yield was the lowest. 2) Fertilizer types obviously affected the nutritional quality of bamboo shoots, and the soluble sugar contents were the highest when organic fertilizer was applied, the protein contents were the highest when formula fertilizer was applied. The oxalic acid and tannin contents of bamboo shoots decreased with the decreasing bamboo forest density. The eating quality would be better with lower bamboo forest density. 3) After bamboo forest management measures were taken, the soil density decreased, but soil acidification was exacerbated at the same time. The soil pH-value did not significantly decrease only when organic fertilizer was applied. Regulation of bamboo forest density had no significant effects on the contents of total nitrogen and total potassium in the soil, but could significantly promote the content of hydrolytic nitrogen, available phosphorus and organic matter in the soil. Meanwhile, all types of fertilizers significantly increased the contents of hydrolytic nitrogen and available phosphorus in the soil. 4) The soil physicochemical properties improved with the decrease of bamboo forest density. The soil physicochemical properties were the best when formula fertilizer was applied, followed by organic fertilizer. Except the management of "3 300-3 750 stem·hm^-2 + compound fertilizer", all other management measures could improve soil physicochemical properties, among which, the most effective managements were "2 100-2 550 stem·hm^-2 + compound fertilizer", "2 100 -2 550 stem·hm^-2 + organic fertilizer" and "3 300-3 750 stem·hm^-2 + compound fertilizer". 5) Soil physicochemical properties and bamboo forest density explained the quality characteristics of bamboo shoots well, and the explanation for the nutritional quality and eating quality reached 74.7% and 69.1%, respectively. The soil pH-value was the main factor affecting the nutritional quality, and the bamboo forest density was the main factor affecting the eating quality. Conclusion: The measure of "2 100-2 550 stem·hm^-2 + compound fertilizer" can better increase the bamboo shoot yield. The measures of adopting lower bamboo forest density management, applying organic fertilizer or formula fertilizer, and adjusting the soil pH-value can not only improve the nutritional quality and eating quality of bamboo shoots, but also improve the soil physicochemical properties.

Objective: The objectives are to study the scenic beauty in four seasons of typical plant communities along the Winter Olympics expressway, to explore the factors affecting the landscape in four seasons, and to provide a scientific basis for improving the quality of road forest landscape. Method: Taking the urban expressway and expressway among the venues of Winter Olympics in Beijing as the research object, 34 typical sample plots were selected to evaluate the beauty in four seasons. A landscape photo was randomly selected as a reference, and the scenic beauty estimation(SBE) in four seasons was calculated by Daniel & Boster's method. Based on the quantitative theory I, the landscape evaluation model of landscape factor category and SBE value and the comprehensive evaluation model of four seasons were established by stepwise regression of qualitative variables. Result: 1) The comprehensive factors affecting the landscape of the four seasons include stand density, hierarchical structure, patterns of composition of color-leaf plants, plant color and trunk visibility. The patterns of composition of color-leaf plants has the greatest influence, with a contribution rate of 24.5%. 2) Among the factors affecting the landscape in the three seasons, the hierarchical structure and the patterns of composition of the color-leaf plants are the landscape factors affecting three seasons of spring, autumn and winter. The patterns of composition of the color-leaf plants have the greatest impact on the landscape in autumn and winter, and the contribution rates were 22.57% and 21.91% respectively. Plant color is the landscape factor affecting spring, summer and winter, which has the greatest impact on the landscape in summer, with a contribution rate of 24.31%. 3) Among the factors affecting the landscape in spring and autumn, plant growth and forest edge line are the landscape factors in spring and autumn. The contribution rates of tree species richness to spring and winter are 9.28% and 5.64% respectively. The proportion of evergreen tree species has a higher impact on the landscape in summer and winter than the tree shape richness, and the contribution rate of the proportion of evergreen tree species to the landscape in summer is 22.01%. The contribution rates of native tree species to the landscape in summer and autumn are 6.92% and 11.89% respectively. 4)Among the landscape factors affecting one season, the contribution rate of stand cleanliness to spring landscape is 10.77%, the contribution rate of trunk display to autumn landscape is 9.12%, and the contribution rate of stand density to winter landscape is 6.5%. Conclusion: According to the contribution rate of different landscape factors to the landscape in four seasons, when improving the landscape quality, it is necessary to focus on the factors such as the existence mode, hierarchical structure, plant color, tree arrangement mode, proportion of evergreen tree species, branch color, plant growth status and so on. However, in addition to considering the selected landscape factors, it still needs to be optimized and improved according to the actual situation.

Objective: Linalool is the flavor with the widest uses and the largest consumption in the present world. Artificial cultivation of Cinnamomum camphora var. linaloolifera in dwarf form is an important way to solve the shortage of raw materials for extraction of essential oil. To reveal the dynamic changes of the contents of essential oil and nutrient in branches and leaves in the growing season and their correlation is of great significance for the establishment of high yield and high efficiency nutrient management and cultivation model of dwarf forest. Method: Dynamic changes of essential oil content and nitrogen, phosphorus and potassium in leaves and branches were measured for 3 clones in different months and ANOVA and correlation analysis were conducted to detect the patterns of accumulation of essential oil and nutrients and their dynamic relation. Result: 1) The content of leaf essential oil of C. camphora var. linaloolifera showed a bimodal curve, which peaked in May and August, and the difference between maximum and minimum values was more than 45%. However, the content of essential oil in branches showed a "V" type change, with a low content in the period of vigorous growth. The difference between the maximum value and the minimum value is more than 35%. The content of essential oil was significantly larger in leaves than in branches, and the fluctuation range of leaf/branch ratio of essential oil was 4.74 to 15.33. The changes of essential oil content in leaves and branches were significant among different clones. 2) As the growth process progresses, the change of total nitrogen content in growing season showed a "W" pattern in leaves and a "V" pattern in branches. All reached the lowest value in July or August. The fluctuation range of total nitrogen content in leaves and branches was 1.56 to 3.84; The total phosphorus content of leaves was similar to that of total nitrogen for a "W" pattern, which reached the minimum value in May or July. The content of total phosphorus in branches increased gradually. The change of total potassium content in leaves showed an inverted "V" pattern, reaching the maximum in June or August. While the change of total potassium content in branches showed a "W" pattern, reaching the lowest value in May or July. The contents of nitrogen, phosphorus and potassium in C. camphora var. linaloolifera was larger in leaves than in branches, and the contents of nitrogen, phosphorus and potassium in branches and leaves were nitrogen > potassium > phosphorus. Changes of nitrogen, phosphorus and potassium content in different clones in different months reached a significant level (P < 0.05). The correlation of nitrogen, phosphorus and potassium content in each organ reached a significant or very significant level. 3) In different months of growing season, the nitrogen, phosphorus and potassium in leaves and branches showed different degrees of synergistic or antagonistic relationship with the content of essential oil. There was a negative correlation between leaf essential oil content and nutrients in leaves of C. camphora var. linaloolifera, and the correlation between total nitrogen content and essential oil content reached a very significant level. There was a positive correlation between branch essential oil content and nutrient content in branches, but the correlation was not significant. Conclusion: The essential oil content in leaves of C. camphora var. linaloolifera was relatively high in the period of vigorous growth, while the essential oil content of branches showed an opposite trend. The nutrient content was lower in the vigorous growth period and higher in the late growth period. In order to further explore the formation mechanism of essential oil, comprehensive effects of variety, growth month and nutrients should be taken into account.

Objective: Micropropagation protocols have been developed for more than 20 varieties of tree peony(Paeonia Sect. Moutan), but not applied to industrial use due to the high contamination rate, low multiplication rate, rooting difficulties and low transplanting survival rate. Therefore, it is an important issue to improve the micropropagation protocols of tree peony. Method: This study was performed to optimize the micropropagation protocol of Paeonia × lemoinei 'High Noon' through selection of explants, light-emitting diodes(LED) illumination culture and improvement of rooting methods. Result: Etiolated shoots were explants superior to scale buds which showed lower contamination rate(19.59%), higher survival rate(80.41%), and no browning during initial culture. Compared with traditional fluorescent lamp, the optimal LED illumination(light quality 70%Red+30%Blue, light intensity 50 μmol·m^-2s^-1) significantly promoted the multiplication and growth of the in vitro shoots. The multiplication rate was 3.79, and the in vitro shoots grew well. Based on the reactivity that vitamin B₂ (VB₂) can coexist with IBA under dark conditions and decompose IBA under light conditions, an efficient one-step rooting method was developed. The shoots were firstly cultured in the dark on medium supplemented with IBA 1.0 mg·L^-1 and VB₂ 1.0-5.0 mg·L^-1 for 30 days to induce rooting, and then transferred to light culture for 20 days to accelerate IBA decomposition which will help eliminate the inhibition of IBA on root elongation. The rooting percentage(71.07%-74.23%) and root number(3.17-3.34) of one-step rooting method were similar to those of two-step rooting method. Compared with two-step rooting method, the one-step rooting protocol improved the transplanting survival rate by optimizing the quality of rooted shoots, and its proportion of first grade plantlet was up to 75.00%, which produced 85.00% survival after transplanting. Conclusion: Etiolated shoots are explants superior to scale buds in initiation and establishment of in vitro culture. LED illumination(light quality 70% Red+30% Blue, light intensity 50 μmol·m^-2s^-1) can significantly promote the multiplication and growth of in vitro shoots. An efficient one-step rooting method was established in P. × lemoinei 'High Noon' micropropagation both by addition of vitamin B₂ in the rooting medium and by the control of light conditions(30 days of dark culture, and then 20 days of light culture), which produced simpler technical process, lower rooting cost, better quality of rooted shoots and higher transplanting survival rate than two-step rooting method. This study has developed an optimized micropropagation protocol for P. × lemoinei 'High Noon', greatly promoting the micropropagation of the variety, and providing a basis for the micropropagation of other tree peony varieties.

Objective: The bark beetles in the genus Ips (Coleoptera: Scolytinae) are severe stem borers of conifers, and widely distributed in the Northern Hemisphere. The purpose of this paper is to identify the species in genus Ips in China and provide DNA data based on a nationwide investigation. Method: In this study, a total of 12 062 Ips adult specimens were collected from 39 sites in the coniferous forests in 9 provinces (autonomous regions) in Northeast, Northwest and Southwest China. Based on the first preliminary identification of species level with the morphological characters recorded in literature, fifty-two representative samples were selected for mtDNA COⅠ gene sequencing and sequence alignment. Phylogenetic trees containing all species in the genus and Chinese samples were constructed based on maximum likelihood, maximum parsimony and Bayesian methods. Result: A total of 10 Ips species were identified based on their morphological characteristics. The molecular identification based on sequence comparisons further verified the morphological identification results, namely I. chinensis, I. duplicatus, I. hauseri, I. nitidus, I. schmutzenhoferi, I. sexdentatus, I. shangrila, I. stebbingi, I. subelongatus and I. typographus. In the phylogenetic analysis of all known 37 Ips species worldwide, the Chinese samples were clustered in the same branch with the same reference species, which further supported the results of morphological and molecular identifications. At the same time, phylogenetic analysis further showed that I. duplicatus and I. hauseri were sibling species. There was obvious genetic differentiation between the samples of I. chinensis and the known northern and southern populations of the species, and the samples were independently classified into the third subclade within the species. The I. typographus samples from Xinjiang, Northeast-Far East and Europe were divided into three separate subbranches. The I. schmutzenhoferi samples from China and those from Nepal and Pakistan were divided into two subbranches. The I. duplicatus and I. sexdentatus samples were divided into two subclades with their corresponding European samples. There was no genetic differentiation in I. subelongatus from Xinjiang and northeast China. Conclusion: The species of Ips are abundant and widely distributed in China. The morphological characteristics of many sibling species are very similar, and difficult to distinguish solely based on morphology. Joint methods based on morphological characters and mtDNA COⅠ gene sequence alignment and phylogenetic analysis can accurately identify Ips species. Among the 10 Ips species in this study, I. schmutzenhoferi is a new record species in China. In addition, the identification of I. chinensis was amended, and seven Ips species were found with subspecific genetic differentiations.

Objective: This study aimed to investigate the effect of the cry1Ac transgenic Populus nigra (Shijion) on the growth, reproduction and enzyme activity of the earthworm Eisenia foetida, a soil indicator organism. Method: In this study, the leaves of the cry1Ac transgenic and non-transgenic poplar were added to the soil for continuously feeding to the earthworm E. foetida for 140 days in the laboratory. The survival of earthworm, the change of earthworm weight, and the number of the cocoons and their hatching were investigated every 14 days. The total protein, and the activities of acetylcholinesterase (Ache), glutathione peroxidase (GST), and superoxide dismutase (SOD) in earthworm were determined after 7 days of cocoon incubation and 140 days of adult exposure. Cry1Ac concentrations in the soil, casts and guts of earthworm were also detected by ELISA. Result: Over the 140 d experimental period, there were no significant differences in survival rate, and weight of earthworms fed with the transgenic and non-transgenic poplar leaves. Both the transgenic and non-transgenic poplars treatments began to breed at the 28^th day. There was no significant difference in the number of cocoons produced by a single earthworm between the transgenic poplar and non-transgenic poplar treatments in the whole experimental period. In the 8 investigations of 42-140 days, the average number of cocoons in non-transgenic poplar treatment was significantly higher than that in the transgenic poplar treatment only at the 70^th d, and there was no significant difference at the other 7 investigation periods. There was no significant difference in the hatching rate of earthworm cocoons and the average number of newborn earthworms per cocoon between transgenic poplar and control poplar treatments. There were no significant differences in the total protein content, and the activities of AchE, GST, and SOD in adult E. foetida after 140 days of exposure between transgenic and non-transgenic poplar treatments. On the 7^th d, SOD activity of new worm increased under two poplar treatments, compared with the fermented cow dung treatment. ELISA determined a sharp decrease of Cry1Ac in mixed soil along with the experimental time. No Cry1Ac was detected in the earthworm tissue under long-term feeding. Conclusion: The results suggests that transgenic poplar does not have significant adverse effects on the survival, growth and reproduction of E. foetida.

Objective: Based on the survey of utilization of artificial nest boxes in different habitats in Beijing Songshan National Nature Reserve by secondary cavity-nesting birds, the attraction effect of various bird species and selection preference of ecological factors were analyzed, and the habitat requirements of secondary cavity-nesting birds during breeding were revealed, so as to provide reference for selecting sites to hang the artificial nest boxes. Method: The 10 m×10 m experimental plots were set up respectively around occupied nest boxes and non-occupied nest boxes, and in the plots, sixteen ecological factors, such as slope aspect and number of trees were recorded. Kruskal-Wallis H was used to test the selection differences of ecological factors between nest-boxes of different species. The generalized linear model (GLM) was used to choose the best model of artificial nest box selection for secondary cavity-nesting birds in different habitats. Result: In 2017 and 2019, six species of birds were attracted by artificial nest boxes in Beijing Songshan National Nature Reserve, including cinereous tit (Parus cinereus), willow tit (Poecile montanus), daurian redstart (Phoenicurus auroreus), Chinese nuthatch (Sitta villosa), Eurasian nuthatch (S. europaea) and yellow-rumped flycatcher (Ficedula zanthopygia). The success rate of attraction was 52.9% and its number of being used by cinereous tits was the largest (n=81). The cinereous tits, willow tits and daurian redstarts had significantly different preference of height of nest boxes set out (P=0.009) and average tree height (P=0.017). The hanging height of nest boxes used by daurian redstarts was the lowest and was significantly lower than that used by cinereous tits (P=0.015) and willow tits (P=0.024). The average tree height in the plots where the nest boxes were used by cinereous tits was the lowest and significantly lower than that of willow tits (P=0.013). The best model showed that the probability of nest boxes being used by cinereous tits was positively correlated to the number of trees (P=0.003), and negatively correlated to the DBH of trees (P=0.016) and the number of dead trees (P=0.007). The probability of nest boxes being used by willow tits was positively correlated to the average tree height (P < 0.001), and negatively correlated to the DBH of trees (P < 0.001). The probability of nest boxes being used by daurian redstarts was negatively correlated to the height of nest boxes set out (P=0.024), the DBH of nest boxes fixed trees (P < 0.001), the number of dead trees (P=0.009) and understory canopy density at 3 m from the ground (P=0.013). Conclusion: Artificial nest boxes have the best attraction effect on cinereous tits. Cinereous tits and willow tits prefer more vegetation coverage to hide while daurian redstarts prefer more vegetation coverage and illumination during breeding period. We suggest to set out artificial nest boxes in the dense forest with tall trees, and make the nest entrance toward sun to have more solar radiation. The distance between nest boxes can be set to 50 m apart in order to improve utilization rate.

Objective: Ancient wooden-structure building is a valuable material for the study of Chinese ancient history,culture,art,science and technology and economy. This study aimed to investigate the selection principle of wood species and the relationships between the principle and biological diseases of wooden components in ancient wooden-structure buildings in severe wood biological diseases area,to understand the wood species allocation pattern and biological disease regulation. It was expected to provide scientific basis for the repair and protection of ancient wooden-structure buildings and for the study of ancient architectural history. Method: A total of 30 old wooden components replaced when 12 ancient wooden-structure buildings were repaired,were used as objects to detect the types,locations and degrees of biological diseases. Wood samples were taken from wooden components and embedded in carbon wax. 15-20 μm thick microsections were prepared from embedded wood samples by sliding section microtome. The microstructure and biological diseases characteristics were observed by optical microscope. Wood identification and the grade of biological diseases were determined,according to the identification characteristics list of IAWA softwood and hardwood and the relevant national standards. Result: The species in wooden components of 12 ancient buildings involved 14 genera and 12 families. The proportion of softwood and hardwood was 43.3% and 56.7%,respectively. Cunninghamia sp., Betula sp., Populus sp. and Pinus sp. were commonly used species. Zhejiang Province was the most abundant in wood species used,Henan and Guizhou provinces were mainly hardwood,whereas Hunan Province was dominated by softwood. Among the 10 kinds of wooden components,the wood species of load-bearing and large volume wooden components were mainly composed of Cunninghamia sp., Larix sp., Ginkgo sp., Pinus sp. Betula sp., Castanopsis sp., Phoebe sp., Quercus sp., Ulmus sp., Populus sp., Pometia sp. and Temstriemia sp.,but the wood species of non-essential load-bearing structure,small volume or decorative wooden components were mainly composed of Cunninghamia sp., Betula sp., Populus sp., Tilia sp., Ulmus sp. and Ailanthus altissima. Among the wood physical and mechanical strength of 14 wooden components, Quercus sp. had the largest air-dry density and bending strength,while Cunninghamia sp. was the smallest. There were 9 kinds of wood with strong resistance to decay and 4 kinds of wood easy to crack. Wooden components were damaged by various degrees of decaying fungi,carpenter bees,beetles and termites. The wood species vulnerable to carpenter bees were Cunninghamia sp., Betula sp. and Pinus sp.. Pinus sp., Betula sp. and Populus sp. were the most vulnerably attacked by beetles,while Cunninghamia sp., Ulums sp., Quercus sp. and Castanopsis sp. were susceptibly attacked by termites. All wood species were vulnerable to the damage of decaying fungi,of which Cunninghamia sp., Betula sp. and Populus sp. accounted for a large proportion. Conclusion: In terms of wood utilization,there are obvious differences among areas with severe wood biological diseases. There are also differences in wood utilization among different types of wooden components,as well as the same type of wooden components. The selection principle of wood species is as follows: 1) Considering the safety performance of buildings,the physical and mechanical properties of wood are the primary factors in the selection of wood species. 2) Considering the economic convenience of material sawing and transportation,local common native wood species should be selected. 3) "Local species" is an important principle of wood utilization,which leads to great differences in different regions. 4) To some extent,the selection principle of wood species is affected by the use of wooden components. 5) To some extent,the selection principle of wood species is affected by the location and function of ancient buildings. Wood biological diseases are closely related to wooden components selection: 1) Although the natural decay resistance of wood species is different,fungal decay is still the primary biological disease factor of wood quality deterioration of 12 ancient buildings. It shows that the decay is more closely related to the climate and environment where ancient buildings were located. 2) Carpenter bees and beetles are the main insects of wooden components. The selection of wood species for nest building is related to the species of carpenter bees,the kinds of wooden components and building region.

Objective: To realize the on-site identification of wood species in wooden ancient buildings, the micro-destructive curves of common wood species of wooden components were quantitatively studied, and the relevant comparison method based on micro-destructive curves was also discussed. Method: In this paper, the commonly used wood species, larch, Chinese fir, pine and poplar in wooden components of ancient buildings were taken as the research objects. The resistograph test curves of the related wood species were obtained by using resistograph detector. The identification method and idea of wood species information of wooden components in ancient buildings based on micro-destructive testing were proposed through quantitative research on mean value, ratio, trend of micro-destructive curves of relevant wood species. Result: The results indicated that the commonly used wood species, larch, Chinese fir, pine and poplar in wooden components of ancient buildings can be preliminarily identified through similarity comparison between on-site testing curves and multiple wood micro-destructive curves database. The next step research should be focused on improving the micro-destructive parameter design, basic database expansion and comparison method. The identification of wood species was carried out by the comparison the micro-destructive curves. When the density of wood species varies greatly, the identification can be obtained directly from the height of the curves. When the density of wood species is similar, but the peak and valley of curves have large differences, the identification can be obtained through curves ratio and curves trend. Furthermore, when the density of wood species and the curves ratio are similar, the identification should be confirmed through historical information of ancient buildings, wood sampling information and other features of the curves. At last, the identification accuracy in actual application can be improved by combining the traditional identification results and by adding the micro-destructive curves of wooden components to database. Conclusion: The wood species of on-site identification technology of wooden components in ancient buildings is a proper protection identification technology based on the characteristics of historical and cultural relics. The technology can be used to identify wood species by similarity comparison of wood micro-destructive curves under certain rules and constraints, which can be used as an effective complemental way to the traditional identification method.

Objective: In order to provide a theoretical basis for further improving the accuracy of wood long-term life prediction, the applicability of the commonly used Gerhards model in wood life prediction research was analyzed, the influences of the selection of model parameters on the life prediction results were discussed, and an interval model that can better reflect the distribution characteristics of test data based on the Gerhards model also proposed. Method: Firstly, the Gerhards model was theoretically deduced to clarify the relationships between the failure time of the wood specimen and the ramp loading speed or constant stress level. Then, by comparing the real values of coniferous wood loading test data in the literature with the predicted values of 8 groups of Gerhards models, the pros and cons of each model for wood life predictions of different loading conditions were analyzed. Finally, aiming at the problem that the predicted value is higher than the true value in wood life prediction, an interval prediction model analysis method based on Gerhards model was proposed. Result: When the Gerhards model is used to predict the life of wood specimens under linear loading conditions, the predicted values are relatively close, and the deviation from the experimental values is small; when predicting the life of wood specimens under constant loading conditions, the difference between each predicted values is large, and some of the predicted value are very different from the experimental values. When the constant stress level on the Northern Douglas fir sample is between 60% and 95%, it is recommended to use the Gerhards model 6 for life prediction. When the stress level on the Norway spruce sample is between 55% and 105%, it is recommended to use the Gerhards model 7 for life prediction. When the stress level on the wood sample is lower than 50%, it is recommended to use the Gerhards model 1 for life prediction. The difference between the loading condition of the data used in the fitting model and the loading condition of the predicted object has a great influence on the model prediction accuracy. Compared with the traditional prediction models, the interval model can reflect the distribution characteristics of the test data more completely, and the interval prediction model fitted by percentiles can cover more test data than that fitted by the data based on T distribution hypothesis. Conclusion: It is necessary to discuss the applicability of the Gerhards model in the study of wood life prediction. The model could have a better prediction effect when the loading condition of the data used in the fitting model is similar to the loading condition of the predicted object. The quantile model proposed in this paper can make most of the test data points fall within the interval, which can provide a reference for improving the long-term life prediction accuracy of wood.

Objective: The aim of this study was to investigate the effects of antibacterial agent treatment processes on the anti-blue stain bamboo scrimber and to provide technical support for its outdoor applications. Method: In the paper, the 3-iodo-2-propynyl butylcarbamate(IPBC) was used as an antibacterial agent. The anti-blue stain properties of bamboo scrimber manufactured by the soaking IPBC/soaking process, the soaking IPBC/coating process, and bamboo scrimber soaking in the IPBC process were studied through the indoor laboratory method and outdoor exposure test. Meanwhile, the scanning electron microscope(SEM), laser scanning confocal microscope(LSCM) and computed tomography(CT) were applied to investigate the distribution of IPBC in the bamboo fiber bundles and bamboo scrimber manufactured by the soaking IPBC/coating process. Result: The indoor experimental results showed that the grade of infected blue stain of the control sample and the bamboo scrimber manufactured by soaking IPBC/soaking process reached 4 level, while those of the bamboo scrimber manufactured by the soaking IPBC/coating process and bamboo scrimber soaking in the IPBC process reached 1 and 0 level, respectively. The outdoor exposure test was carried out in high humidity environments of Chengdu, Sichuan Province. The results indicated that the blue stain occurred on the surface of the control sample, the bamboo scrimber manufactured by soaking IPBC/soaking process and bamboo scrimber soaking in the IPBC process for about two months. Whereas, no blue stain occurred on the surface of the bamboo scrimber manufactured by the soaking IPBC/coating process for a duration of 12 months. The antibacterial agent was found in the cracks, parenchyma cells, vessels, intercellular cracks et al., which was confirmed by CT and LSCM result. The anti-blue stain efficiency of the bamboo scrimber manufactured by the soaking IPBC/coating process was due to the uniform distribution of IPBC in the bamboo fiber bundles, the formation of phenol-formaldehyde resin film on the bamboo fiber bundles enclosed the IPBC in the bamboo scrimber, which formed an effective fixation system of the PF resin during the curing process at high temperature, and then it acted as an antibacterial agent inhibitor and decreased the loss of antibacterial agent. Conclusion: The bamboo scrimber manufactured by soaking IPBC/coating process could be efficient for the prevention and amelioration of the blue stain and could be wildly used in outdoor environments.

Objective: The traditional manual identification methods of wood species have some problems, such as strong professionalism, heavy task, long cycle and non-real-time performance and so on. A wood identification algorithm based on improved residual neural network was proposed to meet the requirements for real-time and efficiency of wood supervision. Method: Polished cross section images from thirty-two species of wood were processed. Firstly, a total of 8 975 cross-section images of wood were collected by mobile phone with external micro-lens. The gain coefficients were calculated by the means of average gray values of R, G and B channels. The product of each component gray value and the corresponding gain coefficient was used to replace the original gray values of three channels for eliminating the influences of color deviation caused by different image acquisition equipments and environments. Secondly, based on the self-similarity of wood cross-sectional macro structure, more training samples and image features were obtained by horizontal flipping, vertical flipping, addition of impulse noise and image block to ensure the relative balance quantity of different wood images. Then, the bilinear interpolation method was used to scale each sub-image to the same image size of 224×224 pixels. The improved residual convolutional neural network ResNet101 model based on block gradient weighting was used to extract the features of each sub-image, and the final identification score of each image was calculated. Finally, the average accuracy and recall rate were used to evaluate the identification results of different block processing strategies, different models and the improved residual convolutional neural network model. Result: On the same test set, VggNet16, GoogleNet, DenseNet, MobileNetv3, ResNet50, ResNet101 and ResNet152 models were used to identify the original cross-sectional images of 32 similar wood species, and the average identification accuracy rates were 71.3%, 81.3%, 83.2%, 66.4%, 87.9%, 92.1% and 90.5%, respectively. The ResNet101 model was selected to extract wood image features and identify wood species. Based on the ResNet101 model with 5×5, 7×7 and 10×10 blocks in the original images, the average identification accuracies of 94.8%, 96.5% and 95.3% were obtained respectively. The block gradient weighting strategy was applied to the ResNet101 model, and the average identification accuracy of 98.8% and the average recall rate of 99.1% were obtained. Compared with the ResNet101 models based on the original images and 7×7 blocks, the average identification rate of the ResNet101 model improved by using the block gradient weighting method was increased by 6.7% and 2.3%, and the average recall rate was increased by 7.4% and 2.8%, respectively. The block gradient weighting method can effectively improve the identification accuracy of woods. Conclusion: The 32 similar wood species were identified based on the ResNet101 model with block gradient weighting method, and the average identification accuracy was 98.8%. Wood cross-sectional images can be used to identify wood species, and the block gradient weighting strategy can improve the model identification rate.

Objective: Both Dinochloa orenuda and Bonia levigata are climbing bamboos distributed in the tropical lowland rainforest of Hainan Island. The former species is a heliophiles distributed in forest edges and forest gaps while the latter one is a skiophyte in the low light environment. This paper aimed to explore the survival strategies of the two bamboo species in the tropical lowland rainforest, so as to provide a knowledge for the protection and utilization of climbing bamboo resources. Method: D. orenuda and B. levigata were sampled from Ganshiling, Hainan Island in June, September, December 2019, and March 2020. The leaf anatomical structure, leaf gas exchange parameters, leaf area, leaf dry-matter content, and specific leaf area were studied by using paraffin section, leaf epidermis isolation, and LI-6400 portable photosynthesis system, respectively. Result: 1) The net photosynthetic rate (P_n), stomatal conductance (Cond), intercellular carbon dioxide concentration (C_i), and transpiration rate (Tr) of D. orenuda were higher in June and September than those in December. In contrast to these characteristics, the water use efficiency (WUE) of D. orenuda had an opposite trend in these months. The net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate of B. levigata were the highest in September and lower in March and June, but water use efficiency was the highest in March and the lowest in September. Except for the intercellular carbon dioxide concentration in December, the net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration, and transpiration rate of D. orenuda were higher than those of B. levigata in each month, respectively. 2) The leaf thickness (LT), number of bulliform cells (NBC), sectional area of bulliform cells (SABC), diameter of second-order vascular bundle (DSVB), sectional area of second-order vascular bundle (SASVB), distance between second-order vascular bundle (DBAVB), and percent of stomata area (AP) of the two bamboos were the higher in the rainy season (June, September) than those in the dry season (December, March). Besides, the LT, stomata width (SW), single stomata area (AS), and AP of D. orenuda were higher than those of B. levigata in each month. Whereas the mastoid process thickness (MPT), upper epidermal thickness (UET), DBAVB, and stomata density(SD) of D. orenuda were lower than those of B. levigata in the same time periods, respectively. 3) There were significant differences (P < 0.05) in the maximum and minimum of single leaf area (LA), leaf dry-matter content (LDMC), and specific leaf area (SLA) between D. orenuda and B. levigata in each month, but there was no significant difference(P > 0.05) in SLA between D. orenuda and B. levigata. 4) The plasticity of various indicators of D. orenuda was higher than that of B. levigata, which reflected that D. orenuda had higher adaptability to the environment than B. levigata. Conclusion: With its relatively large photosynthetic capacity, LT, AS, and relatively lower LA, SLA, and DBAVB, D. orenuda can adapt to forest canopy strong light environment, canopy water deficit, and dry season stress. However, B. levigata can adapt to drought stress and weak light environment under the forest with higher LA, SLA, UET, and MPT, thinner leaf thickness, and small and dense stomata. Our results have revealed that the functional traits of leaves determine different survival and adaptive strategies of the two climbing bamboos.

Objective: Lindera setchuenensis has important medicinal value. Researches of chloroplast genome possess essential theoretical and practical significance for species identification, analysis of genetic diversity and resource protection of the genus Lindera. Method: The complete chloroplast genome of L. setchuenensis was sequenced based on Illumina HiSeq 2000 platform, and was assembled through de novo. The genome structure, gene composition, repeats and phylogeny were analyzed. Result: The chloroplast genome of L. setchuenensis exhibited a typical quadripartite structure. A total of 125 functional genes were detected, including 81 protein coding genes, 36 tRNA genes, and eight rRNA genes. Frequency of guanine and cytosine bases(GC3s) of the genome encoding genes was 27.96%, 20 codons were ended with A/U(T) among 21 optimal codons. Among the 27 pairs of long repeats, forward repeats and palindromic repeats accounted for 44% and 41% respectively, and the length of 30 bp and 33 bp accounted for 44% and 30% respectively. Among the 181 SSRs, 68% were A/T repeats and 55% were located in the intergenic regions. Comparing the chloroplast genomes of the genus Lindera, it was indicated that six hyper-variable loci, petA-psbJ, trnH-psbA, petK-psbI, ccsA-ndhD, rpl32-trnL, and ycf1, could potentially be used as DNA barcodes candidates for species identification. Phylogenetic analysis revealed that the genus Lindera was divided into five clades. L. setchuenensis presented the closest relationship with L. megaphylla. Conclusion: The structure of chloroplast genome of L. setchuenensis is conservative and prefers codons ending with A or U(T). The hyper-variable regions and SSR loci can be used as DNA barcoding for species identification. The results provide a basis for the development of molecular markers, phylogeny and breeding of elite varieties of Lindera plants.