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Windbreak effect of shelterbelts in oases of the ulan buh desert base on analysis of wind flow distribution
Bao Yanfeng, Hao Yuguang, Zhao Yingming, Xin Zhiming, Dong Xue, Li Yonghua
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190122
[Abstract](0) [FullText HTML](0) [PDF 1145KB](0)
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  Objective   This research compared the windbreak effect of five shelterbelt with different structures and configurations based on the methods of wind flow analyses and proposed that use the fixed parameter “wind protection area” to compare windbreak effect of different shelterbelts, to obtain the characteristic of wind flow field and wind statistical parameters, to provide the theoretical bases and practice patterns about shelterbelt construction in arid lands.   Method   This paper take five shelterbelt with different structures and configurations as object (The structure of shelterbelt No. 1 has closely spacing of 0.13 and comprised of only trees; shelterbelt No. 2 has more widely spacing of 0.24 and comprised of only trees; shelterbelt No. 3 has sparse spacing of 0.27 and comprised of trees and bushes; shelterbelt No. 4 has passable spacing of 0.39 and comprised of only trees; shelterbelt No. 5 has sparse spacing of 0.27 and comprised of only trees) in oases of the Ulan Buh Desert. Through synchronization observation to obtain wind speed data and analyze the characteristic of wind flow field, wind statistical parameters and windbreak effect in five different shelterbelts based on the methods of geographical and statistical analyses.   Result   The results showed that range of wind protection efficiency in different shelterbelt is different. Shelterbelt No.1 range from 65% to 95%, shelterbelt No.2 range from 67% to 85.4%, shelterbelt No.3 range from 46% to 82%, shelterbelt No.4 range from 44% to 67%, shelterbelt No.5 range from 56% to 72%. Shelterbelt No.2 composed of two-line one tree belt presents high wind protection efficiency above 67%. Shelterbelt No.2 is also conductive to save and conserve soil and water. Shelterbelt No.3 is composed of two line bushes and two-line trees presents 2.47 times “wind protection area” to shelterbelt No.4 composed of two-line tress when the wind protection efficiency is 60%. Shelterbelt No.3 has a wide application prospect with good windbreak effect.   Conclusion   Shelterbelt has more widely spacing and composed of two-line one tree belt and “small grid with narrow auxiliary forest belt” shelterbelt composed of two line bushes and two-line trees both presents good windbreak effect in oases of the Ulan Buh Desert.
Response of Soil Nutrients and Their Stoichiometric Ratios to Stand Density in Two Plantations in the Loess Region of Western Shanxi Province
Wang Yansong, Ma Baoming, Gao Haiping, Wang Baitian, Li Sha, Dong Xiuqun
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190287
[Abstract](0) [FullText HTML](0) [PDF 887KB](0)
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  Objective  To study the changes and differences of soil nutrient and stoichiometry of Pinus tabuliformis and Robinia pseudoacacia under different densities to strengthen the stand management and ecological restoration of artificial forests in the Loess Plateau.  Methods  Pinus tabuliformis and Robinia pseudoacacia plantations were taken as research objects, and they were divided into three groups of stand density: high (2000 ~ 2700 plant·hm−2), medium (1100 ~ 1600 plant·hm−2) and low (800 ~ 1100 plant·hm−2). Four kinds of stands with different stand densities were selected for each group, and soil samples were taken in layers respectively to measure the physical and chemical properties of soil.  Results  (1) Two-factor analysis of variance shows that the stand type has a significant effect on total P, C:P, N:P, the stand density only has a significant effect on total P, and the stand type and the stand density has a jointly significant effect on organic carbon, total N, total P, C:P, N: P. (2) The organic carbon and total N of Pinus tabuliformis and Robinia pseudoacacia forests with different stand densities are as follows: Pinus H (high density Pinus tabuliformis forests) > Pinus M (medium density Pinus tabuliformis forests) > Robinia L (low density Robinia pseudoacacia forests) > Robinia H (high density Robinia pseudoacacia forests) > Pinus L(low density Pinus tabuliformis forests) > Robinia M (medium density Robinia pseudoacacia forests), and the total P is as follows: Robinia M > Pinus H > Robinia L > Robinia H > Pinus M > Pinus L; With the increase of stand density, the contents of organic carbon and total N in all soil layers of Pinus tabulaeformis forest show gradual increase, while the changes of total P content are relatively stable and have no significant difference. The contents of organic carbon and total N in all soil layers of Robinia pseudoacacia forest first decrease and then slightly increase, while the contents of total P first increase and then decrease. Under the same density and different stand types, the soil nutrient content of Pinus tabuliformis forest is better than Robinia pseudoacacia forest at high density and medium density, but it is opposite at low density. (3) The C:N ratios of Pinus tabuliformis and Robinia pseudoacacia forests with different stand densities are as follows: Pinus H > Robinia H > Robinia L > Pinus M > Robinia M > Pinus L and the C:P and N:P ratios are as follows: Pinus H > Pinus M > Robinia L > Robinia H > Pinus L > Robinia M; With the increase of stand density, the soil C:P and N:P in Pinus tabulaeformis forest gradually increased, the availability of phosphorus gradually decreased, while the soil C:P and N:P in Robinia pseudoacacia forest decreased first and then increased, the availability of phosphorus first increased and then decreased. The availability of phosphorus in Pinus tabuliformis forest soil was lower than that in Robinia pseudoacacia forest with the same density under high and medium density, but the opposite was true under low density. Soil organic carbon and total N determine the levels of C:P and N:P respectively to a great extent. Under different stand densities, soil C:N is relatively stable, soil nitrogen content is relatively deficient, and growth process is limited by nitrogen. (4) The soil nutrient content of Pinus tabuliformis and Robinia pseudoacacia under different forest densities showed an “ surface aggregation phenomenon ” and soil organic carbon, total N, total P, C:P, N:P gradually decreased with the increasing of soil depth. C:N has no obvious law; With the increase of stand density, the variation intensity of soil properties of Pinustabuliformis forest firstly decreased and then increased, while that of Robinia pseudoacacia forest increased slowly. Compared with Pinus tabuliformis forest, stand density has less influence on the vertical variation of soil nutrients and stoichiometry of Robinia pseudoacacia forest, and the vertical variation tends to be more stable. (5) The change of stand density will change the influence of soil physical properties on soil nutrient and its stoichiometric ratio to different extent. The effect of soil bulk density on soil nutrient content and stoichiometric ratio is the greatest under different stand density, followed by non capillary porosity.  Conclusion  Generally speaking, under different densities of the same stand type, Pinus tabuliformis forest is at a better level in soil nutrient content and its vertical variation, phosphorus availability and nitrogen limitation at medium density, while Robinia pseudoacacia forest is at low density in comparison. Under the same density and different stand types, the comprehensive performance of Pinus tabuliformis forest in high density and medium density is better than that of Robinia pseudoacacia forest with the same density, but it is opposite in low density.
Quantitative assessment on the effects of vegetation changes on runoff changes based on Budyko theory in the Kuye River Basin of northern China
Bi Zaoying, Li Yanzhong, Lin Yixue, Bu Tianhui, Huang Rong
Corrected proof  doi: 10.12171/j.1000-1522.20190330
[Abstract](41) [FullText HTML](36) [PDF 993KB](11)
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  Objective  Significant restoration of vegetation in arid areas can affect the underlying surface conditions of the basin and change the hydrological process, which in turn affects the sustainable use of water resources in the basin. Assessing the spatial and temporal variation pattern of vegetation and clarifying its contribution to the runoff change is the premise of water resources management. This will also be helpful for evaluating the implementation effect of the vegetation restoration project.  Method  Based on the normalized difference vegetation index (NDVI), hydrological and meteorological data, this paper analyzes the impact of vegetation change on runoff change during 1982−2015 based on the Budyko framework of the Fu’s model.  Result  (1) The break point of observed runoff occurred around year 1998, and the changing rates of runoff and human water consumption reached − 55.5% and 92.3%, respectively before and after the break point, with a significant difference (P < 0.05); while the precipitation and dryness index increased by 2.6% and 1.9%, respectively, without significant difference (P > 0.05). (2) The basin NDVI was significantly different before and after the break point. Approximately 88.7% of basin area showed a significant increase trend (P < 0.001), especially in the downstream, indicating that the vegetation was greatly restored. The optimal solution of the watershed parameter was 2.37, and the fitted parameter and constant term were 20.407 and − 1.868, respectively (P < 0.05), demonstrating that the fitting effect was good, and the applicability was strong. (3) The contribution rate of vegetation change to runoff reached 84.9%, while the contribution rates of climate change and human activity impact to runoff were 9.3% and 5.8%, respectively.  Conclusion  It shows that the vegetation in the basin has been greatly restored; the greening of vegetation becomes the dominant factor determining the change of runoff, followed by climate change and human activities. The long-term ecological hydrological effects of vegetation changes need to be further investigated. The results of this study can provide a reference for the implementation of ecological restoration projects and decision-making.
Dynamics of chlorophyll fluorescence parameters under drought condition for three typical desert shrubs
Jin Chuan, Zha Tianshan, Jia Xin, Tian Yun, Zhou Wenjun, Yang shuangbao, Guo Zifan
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190316
[Abstract](56) [FullText HTML](33) [PDF 1151KB](5)
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Knowledge on the response process of physiological parameters of desert plants to natural environment fluctuations can better understand and predict the impact of climate change on desert ecosystems. We conducted in-situ field measurements of chlorophyll fluorescence for three desert shrubs (Artemisia ordosica, Salix psammophila and Hedysarum mongolicum). The objectives were to explore the responses of photosystem II(PSII) Maximum quantum yield(Fv/Fm), photochemical efficiency(ΦPSII) and non-photochemical quenching(NPQ) to environmental factors, understand the PSII photosynthetic physiology and its photoprotection mechanism of desert shrubs in arid environment. As a result, under water stress(soil water content < 0.08 m3·m− 3), three typical desert shrubs’ Fv/Fm and ΦPSII were reduced and NPQ increased (p < 0.01). The Fv/Fm of Salix psammophila was lower than that of Artemisia ordosica and higher than that of Hedysarum mongolicum(p < 0.01). The ΦPSII of Hedysarum mongolicum was lower than that of both Artemisia ordosica and Salix psammophila (p < 0.01). The ΦPSII and NPQ for three typical desert shrubs presented a clear daily variation with photosynthetic active radiation (PAR), and also affected by air temperature (Ta), relative humidity (RH) and vapor pressure difference (VPD). Three shrub species resist drought stress through heat dissipation machnism, but have different degrees. The Fv/Fm of Artemisia ordosica can be restored to a appropriate value of ~ 0.75 through self-regulation of heat dissipation, and its reaction center damage was recoverable. Hedysarum mongolicum was greatly affected by drought stress, and its photoprotective response of heat dissipation was sensitive. According to the conclusion, Artemisia ordosica can be considered as the first choice for vegetation restoration in arid areas, Salix psammophila is the second and Hedysarum mongolicum is not recommended. The activity of PSII reaction center was characterized by changes in chlorophyll fluorescence parameters, which can fully reflect the response strategy of desert shrubs to environmental fluctuations, and can be used as an important means to explore the response of desert plants in arid and semi-arid areas to environmental changes.
The effects on the quality of cuttings of Juniperus chinensis ‘Plumosa Aurea’ caused by light intensity
Zhao Xiaozhi, Gao li, Jia Guixia
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200007
[Abstract](10) [FullText HTML](7) [PDF 872KB](1)
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ObjectiveIn order to find an effective method to improve the quality and rooting rate of the cuttings and expand the reproduction coefficient by researching the effect of different light treatments on the quality of cuttings produced by J. chinensis ‘Plumosa Aurea’.MethodThe five-year-old J. chinensis ‘Plumosa Aurea’ stock plants were treated with full light condition, 30% of shading, and 50% of shading for 90 days. Statistics and analysis of the differences in plant morphology, growth changes, and cutting yield were carried out. The cuttings under different treatments were used for cutting under full light, combined with the rooting rate and rooting quality, comprehensive evaluation of the effects of different light treatments on cutting quality.ResultLight treatment had a great influence on the morphology, physiology and anatomical structure of the J. chinensis ‘Plumosa Aurea’ stock plant and cutting. Under full light condition, the stock plant had a weak photosynthetic capacity, it could produce a large number of cuttings, while the cutting rooting rate was 0.0% due to high lignification degree of the cuttings. Photosynthetic capacity of stock plants under 30% shading treatment was the strongest in the three groups. The yield of the stock plant was medium, the phloem of cutting was developed with strong differentiation ability, so that the cutting rooting rate could reach to 76.3%. Under the 50% shading treatment, the stock plant had very weak photosynthesis and produced less number of cuttings. Although the formation layer of the cutting strips was developed, the moisture content of the leaf and stem cortex was too high, and the nutrient content was low, resulting in a cutting rooting rate of only 28.4%. Among the three groups, the 30% shading treatment significantly increased the cutting rooting rate of cuttings and the roots were healthy.ConclusionThe change of light intensity had an important effect on the growth and development of plants, especially for the golden leaf plants, shading treatment can affect the biomass distribution of plants, change the nutrient accumulation and tissue structure of new shoots. Different light treatments had a greater impact on the growth state of the J. chinensis ‘Plumosa Aurea’ stock plant and the quality of the cutting. After 30% of shading treatment of for 90 days, J. chinensis ‘Plumosa Aurea’ stock plants had stronger photosynthetic capacity and the abundant accumulation of nutrients, which can effectively improve the quality of cuttings and increase the rooting rate.
Research on Forest Fire Smoke Detection Technology Based on Video Region Dynamic Features
Liu Changchun, Liu Pengju, Ji Yeyun
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200049
[Abstract](59) [FullText HTML](85) [PDF 1047KB](2)
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ObjectiveVideo surveillance is increasingly applied to the early detection of forest fire smoke. The existing video forest fire smoke detection methods are mostly based on pixel extraction of smoke characteristics for analysis and detection, but when the smoke is early or the smoke is far from the camera, the smoke only appears in a small area on the video image. Moreover, the diffusion of smoke is irregular, and the background environment is complex and changeable, resulting in insignificant pixel-based features, which makes it more difficult to automatically detect pixel-based smoke. Based on the principle of visible light video image processing, this paper proposes a forest fire video smoke detection method based on local area image dynamic characteristics to improve the accuracy and sensitivity of forest fire video smoke detection.MethodThe video images are selected as the research object. One frame per second is taken to generate an image sequence, and the image sequences are divided into multiple levels and different scales; using the principle of image signal-to-noise ratio, we calculate the signal-to-noise ratio of continuous image sequences after blocking; the adaptive threshold is obtained according to the signal-to-noise ratio of the background image, and the image block whose brightness changes in the image sequence to be detected is determined to be the suspected smoke block; the LBP texture feature of the suspected smoke block is extracted, and the support vector machine is used to distinguish the smoke area.ResultUsing the Value component of the HSV color space, smoke areas can be effectively extracted. The videos with forest fire smoke are selected to verify the proposed smoke change detection method. The analysis results show that the method can determine the image block where the smoke occurs and exclude some non-smoke interference factors.ConclusionThis paper proposes a video forest fire smoke detection technology based on brightness characteristics and LBP texture features of local area, which can accurately locate the smoke occurrence area and exclude some interference factors. The average detection recognition rate reaches more than 92%, which is helpful for real-time forest fire smoke automatic detection and improving the detection rate of forest fire smoke. It has a strong practicality.
The soil compactness and litter adjust the water holding and Mseepage capacity of urban forest soils
Lü Jiao, Mustaq Shah, Cui Yi, Xu Chengyang
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190476
[Abstract](50) [FullText HTML](36) [PDF 1209KB](18)
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ObjectiveThis study analyzed the effects of human interference on physical properties such as soil bulk density, porosity, and compactness, and reveal that compactness and litter return to forest determine the water-holding and seepage capacity of urban forest soils, with a view to providing scientific reference for scientific management of urban forest litter and trampled extent.MethodTaking the forest in the Olympic Forest Park, a typical urban forest park in Beijing, as the research object, by measuring different trample levels (mild, moderate, severe) and different litter accumulations (0 ~ 4 t/hm2、4 ~ 8 t/hm2、8 ~ 12 t/hm2), different grass coverage (0, 0 ~ 50%, 50% ~ 100%) related properties of water holding and seepage in the lower soil layer. The effects of compactness and litter restoration on soil water holding capacity and water seepage ability were analyzed.Results(1) Different trample levels and litter accumulations had significant effects on soil water holding capacity (P < 0.05), and weed coverage had no significant effect (P > 0.05). The trampling degree weakened, and soil aeration, water holding capacity, and infiltration capacity increased significantly. (2) Soil water holding capacity and soil infiltration rate are significantly positively correlated with soil porosity, and significantly negatively correlated with soil bulk density, indicating that human disturbance affects the water holding and seepage capacity by changing the degree of soil aeration and compaction. (3) As soil compactness increases, the water holding and seepage capacity of urban forest soils decreases significantly, the accumulation of litter increases, and soil water holding and seepage capacity changes are insignificant: rise first, than decrease. (4) Soil water holding capacity increases with decreasing compactness and increasing litter accumulation, both of which have a synergistic effect. Soil water seepage capacity increases with decreasing compactness, and litter has little effect.ConclusionThe soil compactness and litter return to forest determine the water holding and seepage capacity of urban forest soils, reducing human trampling, and proper retention of litter can improve soil water holding and seepage capacity and reduce surface runoff. The related results laid the foundation for urban forest and sponge city management.
Tobacco over-expression Populus tomentosa mitochondria ascorbate peroxidase improving stress resistance
Wang Bing, Cheng Ziyi, Zhang Lei, Zhao Zhijing, Lu Hai, Liu Di
Corrected proof  doi: 10.12171/j.1000-1522.20190390
[Abstract](87) [FullText HTML](63) [PDF 975KB](13)
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ObjectiveIn order to study the role of Populus tomentosa mitochondrial APX (PtomtAPX), the stress resistance of overexpression PtomtAPX transgenic tobacco was studied in this study.MethodOverexpression PtomtAPX transgenic tobacco and wild-type tobacco were treated with drought, salt and oxidative stress. Relative water content, chlorophyll content, malondialdehyde content, APX activity, AsA consumption, NADP/NADPH ratio, SOD activity were measured.ResultIn this study, comparing with wild-type plants, overexpression PtomtAPX, under oxidative stress, salt stress and drought stress, the APX activity, relative water content, chlorophyll content, AsA consumption, and NADP/NADPH ratio increase of the tobacco over-expression PtomtAPX gene were significantly higher than those of wild type, of which the APX activity of PtomtAPX transgenic tobacco was 1.77 times of wild type, the average relative water content was 1.15 times of wild type, the chlorophyll content was 1.6 times of wild type, AsA consumption was 1.11 times of the wild type, and the ratio of NADP to NADPH was 1.18 times of the wild type. It suggested that the tobacco overexpressed PtomtAPX harbored stronger ROS scavenging ability.ConclusionThese indicate that mitochondrial APX acts a crucial role of abiotic stress tolerance in plants by eliminating H2O2 and preventing cell damage under abiotic stress.
Seasonal dynamics of functional diversity of soil microbial communities in Castanopsis kawakamii forest gaps
Wang Xuelin, Liu Jinfu, He Zhongsheng, Wu Zeyan, Jiang Lan, Zhu Jing, Xing Cong, Gu Xinguang
Corrected proof  doi: 10.12171/j.1000-1522.20200052
[Abstract](86) [FullText HTML](49) [PDF 736KB](10)
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Objective As a small-scale disturbance in the forest ecosystem, the forest gap plays an important role in nutrient cycling and functional diversity of microbial community in the soil of forest. Clarifying the seasonal dynamic response mechanism of soil nutrients and functional diversity of microbial community to the forest size will help to improve the soil ecological environment of Castanopsis kawakamii forests. Method The gaps of C. kawakamii natural forests were used as research objects, and the Biolog micro-plate method was used, combining the regularity of soil physical and chemical properties, carbon source utilization capacity and metabolic characteristics with different size of forest gaps during growing season and non-growing season. Result (1) The soil temperature (ST), available potassium (AK) content in the growing season of the gaps were significantly higher than those in the non-growing season, and pH value, available phosphorus (AP) content were significantly lower than those in the non-growing season. The formation of forest gaps promoted the increase of soil pH value and the accumulation of available potassium (AK), and accelerated the absorption and utilization of alkali-hydrolyzable nitrogen (HN) and available phosphorus (AP) by microorganisms. (2) The average well color development (AWCD) of soil microorganisms in the growing season of the forest gaps was significantly higher than that in the non-growing season in the middle and late cultivation periods. The soil microorganisms of the forest gaps mainly used carboxylic acid, polymer, and amino acid carbon sources in the growing season, and mainly used the carbon sources as amino acid and carboxylic acid carbon sources in the non-growing season. (3) In soil microbial functional diversity indexes of forest gaps, Shannon-Wiener and Pielou indices in the growing season of the forest gaps were significantly higher than those in the non-growing season, and the Simpson index was significantly lower than in the non-growing season. Gap size had no significant effect on the functional diversity index of microbial community during the growing season. The Simpson index of the soil microbial community in the non-growth small forest window was the highest. The Shannon-Wiener index and Pielou index of the medium gaps were the highest. (4) Generalized linear model (GLM) analysis showed that increasing soil temperature (ST) and soil available potassium (AK) in the growing season of the forest gaps were conducive to increasing the dominance of common soil microorganism species. The reduction of soil alkaline nitrogen (HN) content and the increase of available potassium (AK) content in non-growing seasons were conducive to the increase of microbial diversity and uniformity. Conclusion Functionaldiversity of soil microbial community of the forest gaps during the growing season is maintained at a high level, and the soil nutrient cycling efficiency is high. The soil environment of non-gaps during the non-growing season is conducive to the growth and metabolism of soil microorganisms and maintains the function of the soil ecosystem. Heterogeneity of soil temperature and available nutrient content caused by the formation of forest gaps is the main factor affecting the metabolic characteristics and functional diversity of soil microbial communities.
Height Extraction Method of Multiple Standing Trees based on Monocular Vision of Smart Phones
Chen Xiangwu, Xu Aijun
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190345
[Abstract](99) [FullText HTML](46) [PDF 1060KB](2)
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Objectiveto propose a method for extracting height of multiple standing trees based on monocular vision of smart phones.MethodFirst of all, with the smart phone as the acquisition device, this method segments and locates the input images of standing trees by Graph Cut algorithm, so as to realize the automatic outline acquisition of multiple standing trees in a single image. Then, the camera is calibrated by the camera of smart phones to acquire the depth of the camera image of smart phones based on the geometry analogue method. Next, targets are taken from different angles to optimize the accuracy of depth extraction model and further determine the optimal orientation of information extraction. Meanwhile, combined with high-precision gyroscope, the depression angle of camera can be acquired, and the height measurement of multiple standing trees under non-contact condition can be realized according to the extracted depth information and depression angle of camera.ResultIn this method, the height measurement model of standing trees has good stability with smart phone MI 2S as the experimental equipment. Moreover, the maximum relative error is 2.45% and the accuracy of tree height measurement can reach 97.55%.ConclusionThe height extraction method of multiple standing trees based on monocular vision of smart phones has the characteristics of high accuracy and easy operation, which can effectively meet the accuracy requirements of tree height measurement in national forest resource survey II.
Species Distribution and Diversity Characteristics of Lao Mountain’s Secondary Plant Communities in Qingdao
Jiang Xiaolei, Hao Qing, Li Wei, Sun Zhenyuan
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190414
[Abstract](63) [FullText HTML](47) [PDF 1276KB](6)
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ObjectiveIn order to clarify the composition structure and diversity characteristics of forest communities in Laoshan area of Shandong Province and their relationship with environmental factors, so as to provide theoretical basis for forest management,MethodUsing a cumulative species curve to verify the adequacy of sampling. according to the species importance matrix, the forest community was divided into different types. The relationship between the distribution of different community types and topographic and soil conditions was studied by canonical correspondence analysis (CCA). The relationship between species diversity and terrain and soil conditions was analyzed by Pearson correlation, and the regression curve was fitted by the local weighted regression distribution point smoothing method (Lowess).Result50 standard sample plots were adequate.The species composition of forest community in Laoshan Mountain was complex, and it could be divided into 10 community types by WARD clustering method according to the important value matrix of species. Altitude, slope position, slope direction and soil’s pH value were the main factors affecting community distribution, in which altitude factor had significant effect on the distribution of trees, shrubs and herbs as well. Among the 11 topographic and soil factors studied in this paper, altitude and soil available phosphorus content were significantly correlated with the overall species diversity of the community. With the increase of altitude, the Shannon-Wiener index of trees, shrubs and herbs increased at first and then decreased. The Pielou index of trees and shrubs increased slightly with the increase of altitude. When the content of available phosphorus reached 30 mg/kg, the Shannon-Wiener index and Pielou index decreased significantly, and then remained stable.ConclusionTerrain and soil conditions had a certain influence on the distribution of Laoshan community types, which proves the role of habitat filtration. Altitude and soil available phosphorus content might be the most important limiting factors for species diversity in Laoshan forest community.
Effects of styrene-acrylic emulsion doping on the properties of geopolymer wood adhesives
Ma Su, Zhen Jin, Wang Jiayu, Zhang Derong, Yu Zhiming, Tang Ruilin, Zhang Yang
Corrected proof  doi: 10.12171/j.1000-1522.20200019
[Abstract](1506) [FullText HTML](123) [PDF 1469KB](10)
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ObjectiveGeopolymer has great research potential in wood adhesive industry due to its high mechanical properties and weather resistance. But the high brittleness and low interfacial compatibility of the inorganic network limit its bonding strength with wood. In order to increase the toughness and the shear strength, the study used geopolymer as raw material of wood adhesives to explore the application possibility of geopolymer in the field of wood adhesives and solve the harm of formaldehyde emission from wood-based panel products from the perspective of raw materials.MethodIn this experiment, the geopolymer adhesive was composed of styrene-acrylic emulsion as the adulterant, metakaolin (MK) as the raw material and silane (KH-550) as the coupling agent, activated by alkali and then cured to solid. Though adjusting the content of styrene-acrylic emulsion and curing process, the characteristics of geopolymer matrix and its effect on shear performance of geopolymer-based wood adhesive were obtained.ResultCompared with pure geopolymer, adding styrene-acrylic emulsion decreased the compressive strength and the flexural strength of the geopolymer matrix, reduced the compression-flexure ratio to 6.09, improved the shear strength to 2.6 MPa, decreased the contact angle by 4.1% as well as increased roughness of the surface of geopolymer by creating more plastic cavities and microcracks. The addition of KH-550, though decreased the compressive strength and the flexural strength, significantly promoted the modification. The compression-flexure ratio was reduced to 5.96; the shear strength was increased to 3.6 MPa; the contact angle was decreased by 25.7%; the surface’s cavities were smaller and the microstructure was more tight. The silane played a coupling role in the matrix, which makes the styrene-acrylic emulsion chemically link with the geopolymer.ConclusionStyrene-acrylic emulsion organic doping and silane coupling work synergistically to form a tough film in metakaolin-based geopolymer which improves geopolymer’s brittleness and achieve a toughening effect, and to improve the interfacial compatibility of the geopolymer and wood, thus enhancing the shear strength of the geopolymer-based wood adhesive.
Tamarix ramosissima changes the responses of root morphology of annual Populus euphratica seedlings to various soil water and salinity conditions
Lei Shanqing, Wang Wenjuan, Xu Yixin, Wang Yuchen, Chen Lijun, Du Zhiqiang, Li Jingwen
Corrected proof  doi: 10.12171/j.1000-1522.20190441
[Abstract](151) [FullText HTML](159) [PDF 828KB](27)
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Objective Root is the key organ for Populus euphratica to colonize and regenerate in the field. In this study, we investigated the responses of root growth to soil conditions and biological factors to provide support for further study on adaptive strategy of Populus euphratica seedlings and provide a theoretical basis for protection management of Populus euphratica forests in northwestern arid area of China. Method Here, a controlled pot experiment was conducted to study the responses of root morphological features of annual Populus euphratica seedlings to interspecific competitor under 3 levels of water and salinity and their interactive effects. Result (1) Under various levels of water and salinity, roots mainly for absorption (diameter under 5mm) and for anchoring (above 5mm) maintained stable proportions, indicating a conservative root morphology of annual Populus euphratica seedlings. But interspecific competition with Tamarix ramosissima changed this property. (2) Annual Populus euphratica seedlings had larger special root length and special root area while growing with Tamarix ramosissima seedlings, which meant higher absorbing ability in mixed planting pattern. However, total root volume, root surface area and basal diameter significantly dropped compared with those grew with intraspecific individuals, demonstrating neighboring Tamarix ramosissima seedlings could intensively restrict root growth of annual Populus euphratica seedlings. (3) Water condition and neighbor had more significant effect on root growth of Populus euphratica seedlings instead of salinity condition. Neighboring Tamarix ramosissima seedlings could change root plastic responses of Populus euphratica seedlings to water and salinity, making Populus euphratica seedlings more vulnerable to salinity stress. Conclusion In summary, root morphology of annual Populus euphratica seedlings shows adaptive strategy while competing with neighboring Tamarix ramosissima seedlings, but still interspecific competition leads to harmful outcomes for growth of Populus euphratica. For seedlings growing on floodplain, interspecific competition may also be a major threat to their survival.
Genetic structure of populations and introgression of three Quercus species in mountainous area of Beijing
Gao Jipeng, Qin Ling, Cao Qingqin, Fang Kefeng, Tian Yelin
Corrected proof  doi: 10.12171/j.1000-1522.20190402
[Abstract](91) [FullText HTML](69) [PDF 764KB](7)
Abstract:
ObjectiveInterspecific hybridization and introgression often occur among species of Quercus, especially among sympatric Quercus more frequently. In this paper, the genetic structure and genetic variation of three species of Quercus in the mountainous area of Beijing were studied. It will provide effective data for gene introgression, germplasm resources and management of Quercus species naturally distributed in Beijing.Method304 natural oak samples of Quercus mongolica, Quercus dentate and Quercus aliena from Yunmeng Mountain, Shangfang Mountain and BUA (Beijing University of Agriculture) Forest Farm were selected as the material, and six pairs of SSR primers were used to study the genetic diversity, genetic structure and introgressive hybridization among populations.ResultA total of 105 alleles were detected, the average number of alleles (Na) of each locus was 17.5, the expected heterozygosity (He) was 0.660 − 0.911, the polymorphism information content index (PIC) was 0.632 − 0.903. The three oaks had high genetic diversity at the overall level. At the species level, the average allele number (Na) of the three oaks was 12.667−14.167, the expected heterozygosity (He) was 0.743−0.849, the polymorphism information content index (PIC) was 0.725−0.826, the genetic diversity level of the three species of oaks was Q. mongolica > Q. dentate > Q. aliena. The genetic structure analysis of 7 populations of Quercus showed that most of the genetic variation was in local populations. The genetic introgression analysis by structure software found that the gene introgression occurred among three pairs of Q. mongolica, Q. dentate and Q. aliena.ConclusionThere is a common and complex phenomenon of introgression hybridization among Q. mongolica, Q. dentate and Q. aliena in Beijing mountainous area.
Film properties of waterborne paint based on Fraxinus mandshurica substrate
Huang Quanfei, Huang Yanhui, Zhang Wei, Lin Xinyu, Wang Xuecong
Corrected proof  doi: 10.12171/j.1000-1522.20200088
[Abstract](54) [FullText HTML](22) [PDF 1198KB](6)
Abstract:
ObjectiveFraxinus mandshurica, as a kind of excellent hard wood, is often used to make medium and high grade furniture. The waterborne paint is a very environmentally friendly paint, and it is of great practical significance to study the coating properties of Fraxinus mandshurica for improving the performance of waterborne paint and optimizing the coating process. In this paper, the film properties and adhesion mechanism of waterborne paint on the surface of Fraxinus mandshurica were systematically studied, which can provide theoretical support and scientific basis for the application and research of waterborne paint on wood.MethodIn this paper, commercial waterborne paint was used to paint Fraxinus mandshurica and the film properties were measured according to the corresponding standards. SEM and FTIR were used to explore the adhesion mechanism of waterborne paint on the substrate.ResultThe film thickness of cured waterborne paint on substrate was 96.63 μm, the hardness was H, the adhesion was up to level 0, the water resistance was up to grade 1, the color difference value ΔE before and after coating was 9.86, which could keep the wood color of the substrate. Because the priming paint evenly covered the surface of the substrate, sealed the hydrophilic hydroxyl in the substrate, and improved the hydrophobic property of the substrate surface, the contact angle of the substrate surface increased by about 10°. The surface glossiness of the coated substrate was significantly improved, and the glossiness in parallel texture direction was 40.4% higher than that in the vertical direction. This is mainly due to the fact that most of the cells that make up the wood are arranged in an axial direction, and the waterborne paint is mainly filled in the large cell cavities arranged longitudinally, but it is difficult to penetrate into the cell walls with nano level pores. The combination of waterborne paint and substrate was mainly in the physical form of mechanical interlocking, and chemical reactions also occurred. The increase of the intensity of the peak of1 148 cm− 1 indicated that the carboxyl group in the waterborne paint had esterified with the hydroxyl group in the substrate; the appearance of the peak 1 063 cm− 1 showed that the cellulose in the substrate had etherified with the hydroxyl group in the waterborne primer.ConclusionThe waterborne paint has good adhesion on the surface of Fraxinus mandshurica, has a good protective performance and can effectively improve the visual effect of the substrate, so as to improve its commercial value.
Extraction technology of flavonoids from pine shell and its antioxidant activity
Fu Qun, Kuai Bin, Li Lu, Liu Lei, Wang Mengli
Corrected proof  doi: 10.12171/j.1000-1522.20190452
[Abstract](357) [FullText HTML](98) [PDF 1514KB](20)
Abstract:
Objective Pinus koraiensis is an important economic tree species in northeastern China. The chemical components in its pine shell have many biological activities, especially the content of flavonoids is very rich. It is a kind of natural antioxidant, and the pine shell is regarded as the waste which is sent to the landfill or burned, resulting in the waste of resources. Therefore, in-depth study on flavonoids in pine shell has practical significance for the development and utilization of Korean pine. Method Response surface methodology was used to optimize the extraction process of flavonoids from Korean pine shell by ultrasonic assisted low eutectic solvent, and the antioxidant activity of the extract was studied. Result The best extraction parameters of flavonoids were The moisture content of DES is 40%, ultrasonic power 200 W, extraction time 30 min, extraction temperature 60 ℃, solid-liquid ratio 1∶55. Under this condition, the yield of flavonoids was 9.838% ± 0.211%, 69% higher than that of alcohol extraction. The IC50 of DPPH·, ABTS+·and·OH scavenging rate of flavone extracted by DES were (5.195 ± 0.039) μg/mL, (9.528 ± 0.132) μg/mL, (151.860 ± 0.238) μg/mL, respectively, which were 40.98%, 52.94% and 11.59% lower than that of flavone extracted by alcohol extraction. When the concentration of flavone was in the range of 0.1−0.5 mg/ml, it had a protective effect on HepG2 damaged cells, and the protective effect of flavone extracted by DES was better than that extracted by alcohol. Conclusion In conclusion, the green and environment-friendly DES can be used to extract flavonoids from pine shell, and the extract can maintain good antioxidant activity.
Crown width prediction models for Larix olgensis and Fraxinus mandshurica mixed plantations
He Mengying, Dong Lihu, Li Fengri
Corrected proof  doi: 10.12171/j.1000-1522.20190250
[Abstract](356) [FullText HTML](271) [PDF 1969KB](69)
Abstract:
ObjectiveBased on the data of 3 164 Larix olgensis sample trees and 3 574 Fraxinus mandshurica sample trees from 24 sample plots in mixed plantations from Maoershan Mountain Forest Farm and Yimianpo Forest Farm in Shangzhi City, Heilongjiang Province of northeastern China, the crown width models for Larix olgensis and Fraxinus mandshurica were developed.MethodBy analyzing the variation rules of crown width of Larix olgensis and Fraxinus mandshurica in different mixed stands and the relationship between crown width with forest competition factors, the best model was selected from the basic models of six commonly used linear and nonlinear crown width models. The mixed proportion Si and the tree position P in the mixed strip were taken as dummy variables, and other tree variables and stand variables were added. The crown width models of Larix olgensis and Fraxinus mandshurica were developed, and the fitting effects of the models were evaluated.ResultThe crown width of Larix olgensis and Fraxinus mandshurica was different in different mixed proportion Si and different position P in the mixed strip. The results showed that the ratio of tree DBH to dominant tree diameter (DDH) and the ratio of tree height to dominant tree height (HDH) were positively correlated with crown width, and the basal area of larger trees (BAL) was negatively correlated with crown width. Distance independent competition factors can reflect the competitive pressure of trees and have effect on crown width. The results showed that the crown ratio (CR) was positively correlated with crown width of Larix olgensis, the ratio of total tree height to DBH (HD) was negatively correlated with crown width of Larix olgensis, the dominant tree height of Fraxinus mandshurica (H0Fra) was positively correlated with crown width of Fraxinus mandshurica, the HD was negatively correlated with crown width of Fraxinus mandshurica. For the crown width models of Larix olgensis and Fraxinus mandshurica with the dummy variable P and Si, the Ra2 was 0.564 2 and 0.545 9, and for the crown width models of Larix olgensis and Fraxinus mandshurica with the tree variables (CR and HD) and stand variable (H0Fra), the Ra2 was 0.6745 and 0.5896.ConclusionThe crown width models of Larix olgensis and Fraxinus mandshurica, including the dummy variable Si and P, tree variables (CR and HD) and stand variable (H0Fra), have good fitting effects and prediction accuracy. Therefore, the crown width models established in this study can well predict the crown width of Larix olgensis and Fraxinus mandshurica in mixed plantations, and provide a basis for further study on the crown structure in mixed plantations.
Predicting model construction of single tree DBH of Picea schrenkiana in Xinjiang based on mixed effects model
Chen Guodong, Ding Peiyan, Yin Zhongdong
Corrected proof  doi: 10.12171/j.1000-1522.20190236
[Abstract](279) [FullText HTML](120) [PDF 883KB](28)
Abstract:
ObjectiveThis paper aims to establish a DBH growth model of Picea schrenkiana in Xinjiang Autonomous Region of northwestern China in order to predict the DBH growth of Picea schrenkiana and provide a theoretical basis for the forestry department to manage P. schrenkiana forest.MethodTaking Picea schrenkiana as the research object, based on the 70 pieces of Tianshan Mountain pure forest re-testing plots in Xinjiang, a total of 1 914 viable standing trees were measured in the sample plots, and 1 531 sets of data were randomly selected for training data, 383 sets of data for test data. Contrasting and analyzing the application of traditional single-tree DBH model and mixed-effect model in the spruce single-tree DBH model, considering the density level effect, plot effect and nesting two-level effect when using the R language nlme module to construct the mixed effect model, and using the average absolute error \begin{document}$ (\left|\bar {E}\right|) $\end{document}, root mean square error\begin{document}$\rm (RMSE)$\end{document}, average prediction error (\begin{document}$\rm MPE$\end{document}), total relative error (\begin{document}$\rm TRE$\end{document}), to test the fitting effect of the model.ResultThe mixed effect model (\begin{document}${R}_{\rm adj}^{2}$\end{document}=0.762) was superior to the traditional breast diameter model (\begin{document}${R}_{\rm adj}^{2}$\end{document}=0.505). In the mixed-effects model, based on the nested two-level mixed-effects model, the adjustment decision coefficient, the average absolute error\begin{document}$ (\left|\bar {E}\right|) $\end{document}, the root mean square error\begin{document}$(\rm RMSE)$\end{document}, the average prediction error (\begin{document}$\rm MPE$\end{document}), the total relative error (\begin{document}$\rm TRE$\end{document}), and the adjustment decision coefficient \begin{document}$({R}_{\rm adj}^{2})$\end{document} were 0.589 cm, 0.804 cm, 0.966%, − 0.042%, 0.899, respectively. The mixed effect model fitting effect from high to low was: nested two-level mixed effect model (\begin{document}${R}_{\rm adj}^{2}$\end{document}=0.899) > mixed effect model (\begin{document}${R}_{\rm adj}^{2}$\end{document}=0.766) > density horizontal effect mixed model (\begin{document}${R}_{\rm adj}^{2}$\end{document}=0.762). The power function can effectively eliminate the influence of heteroscedastic structure. The first-order autoregressive matrix AR (1) can effectively eliminate the time-dependent effect of the data.ConclusionThe mixed model of DBH growth of Picea schrenkiana can be used as the main model for the prediction of DBH diameter in the Picea schrenkiana of Xinjiang, in which the mixed effect model of nesting density level effect and plot effect is the best for predicting the DBH diameter (\begin{document}${R}_{\rm adj}^{2}$\end{document}=0.899). This study shows that the mixed effect model is an effective method for predicting the DBH diameter of the Picea schrenkiana in Xinjiang, and provides a theoretical basis and a new method for predicting the DBH diameter of the large-scale Xinjiang Picea schrenkiana.
Establishment of remote sensing based model to estimate the aboveground biomass of Pinus densata for permanent sample plots from national forestry inventory
Zhang Jialong, Xu Hui
Corrected proof  doi: 10.12171/j.1000-1522.20190394
[Abstract](159) [FullText HTML](160) [PDF 1360KB](32)
Abstract:
ObjectiveThis study aims to establish a remote sensing based parametric model for estimation of aboveground biomass (AGB) of Pinus densata for permanent sampling plots, which can be used for rapid and accurate biomass estimation in the future with previous sampling plots, or obtaining biomass quickly with less field work.MethodBased on the change of remote sensing images and permanent sampling plots, linear mixed model was used to improve the accuracy of biomass estimation. Based on the permanent sampling plots in the 7 years of 1987, 1992, 1997, 2002, 2007, 2012, 2017 from the national forest inventory and corresponding years of Landsat TM and OLI images, firstly the images were preprocessed including radiometric correction, atmospheric correction, geometric correction and topographic correction. The original bands, ratio factors, vegetation indices, image enhancement information, textures, fraction after spectral mixture analysis, leaf area index were extracted. Then, the changes of remote sensing spectral variables were derived. According to the distribution of Pinus densata from the forest management inventory, the topographic factors were selected as the fixed and random effects for the linear mixed model. The multiple linear regression, non-linear regression, geographically weighted regression, and linear mixed model were used to establish the static models of the AGB estimation for Pinus densata. The change models with and without tree height participation were developed based on the change of remote sensing spectral variables. Finally, the different modeling and validation results were compared and validated, and the optimal results were selected as the estimation model and validated.Result(1) Comparing the static data for modeling and validation, the linear mixed model with the plot number as fixed effect and the slope grade as random effect got the highest R2 of 0.75. The prediction result showed that either using the remaining 20 training datasets or the observed data in the year of 2017 for validation, the prediction accuracy was low. (2) Comparing the change data for modeling and validation, the linear mixed model with the plot number as fixed factor, slope grade as random factor and remote sensing change factors as independent variables performed the best with R2 of 0.70, the predicted P value was (68.86 ± 11.93)%. When increasing the change of average tree height, the fitting R2 was 0.79, the P value was (73.39 ± 6.18)%. (3) The change model with or without the participation of tree height got a fitting and prediction accuracy of 80%, and its prediction accuracy reached the prediction accuracy of non-parametric models.ConclusionThe accuracy of fitting and prediction based on the change variables is improved compared with the static model. The accuracy for estimating AGB of Pinus densata has been greatly improved with linear mixed model, remote sensing and topographic factors. The developed model of estimating the AGB of Pinus densata with remote sensing change factors has effectively compensated the deficiency of the static optical images, and it can be used for estimation of other years after validation.
Fertility analysis and 2n gametes induction of Lilium FA hybrids ‘Jiaoyang’ in short growth period
Piao Meiling, Jia Guixia, Zhang Dongmei
Corrected proof  doi: 10.12171/j.1000-1522.20190425
[Abstract](123) [FullText HTML](88) [PDF 790KB](8)
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ObjectiveThis paper aims to explore the fertility of pollen and female gametes of Lilium FA hybrids ‘Jiaoyang’, and to improve and restore the fertility of gametes by artificial induction, so as to apply it in polyploid introgression breeding.MethodThe pollen fertility of L. FA hybrids ‘Jiaoyang’ was observed by the method of acetic acid magenta staining, and the process of meiosis of its pollen mother cells was observed. 2n gametes were induced by colchicine injection, and 2n pollen fertility was verified by hybridization with L. davidii var. unicolor. In order to explore the fertility of female gametes, L. FA hybrids ‘Jiaoyang’ was used as female parents crossed with L. davidii var. unicolor through direct pollination and cut-style method. The fertility of female gametes was measured by the expansion rate of ovary, the number of embryo seeds and the germination rate.ResultDuring the meiosis of pollen mother cells, there were unequal segregation of chromosomes and cytoplasm in L. FA hybrids ‘Jiaoyang’, which produced a large number of aneuploid microspores, could not develop into fertile pollen, resulting in no fertility. After colchicine treatment, some 2n pollen was produced. The optimum concentration of colchicine was 0.1%, and the highest induction rate was 86.00%. The female gametes were fertile and produced aneuploidy gametes. By cut-style method, the ovary expansion rate increased from 11.91% to 65.02%.ConclusionColchicine can induce 2n pollen production and restore certain fertility in the pollen of L. FA hybrids ‘Jiaoyang’, while the female gametes can be fertile, and the embryo seeds can be obtained and germinated crossed as the female parent. The study on the fertility of L. FA hybrids ‘Jiaoyang’ is helpful for further introgression among different groups of lilies, and is of great value for cultivating new varieties with excellent comprehensive characters.
Wind resistance of 25 landscape tree species in coastal area of Shanghai
Zhang Deshun, Li Keke, Li Linglu, Zhang Liyao, Liu Ming
Corrected proof  doi: 10.12171/j.1000-1522.20190253
[Abstract](1323) [FullText HTML](1073) [PDF 1260KB](36)
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ObjectiveTyphoon is one of the main meteorological disasters in the east coast of China. The frequency and intensity of wind damage caused by climate change have been increasing in recent years. The study on wind resistance of landscape tree species is directly related to the ecological stability of urban green space system.MethodThe comprehensive evaluation was taken for the wind resistance of 25 tree species by the static tension test, morphological stability evaluation, timber property determination and soil compactness measurement.ResultThere was a logarithmic function relationship between the tensile torque and the tensile angle of each species; the stability index decreased with the increase of tree height, crown width/crown height, canopy size and asymmetry; there was a linear relationship between the compressive strength and the bending strength of tree cores.ConclusionFinally, 25 species were categorized into two groups: the first was a rigid tree with a large static tension and a small bending angle like Magnolia grandiflora, Firmiana simplex, Catalpa bungei ‘Jinsi’ and Liquidambar formosana. Another group was toughness trees with small static tension and large bending angle like Ginkgo biloba.
Dynamics of water use efficiency of Artemisia ordosica leaf in growing season in response to environmental factors in Yanchi, Ningxia Province of northwestern China
Zhou Wenjun, Zha Tianshan, Jia Xin, Tian Yun, Wei Tengzhou, Jin Chuan
Corrected proof  doi: 10.12171/j.1000-1522.20190206
[Abstract](79) [FullText HTML](51) [PDF 1035KB](10)
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Objective We aimed to understand the seasonal dynamics of leaf water use efficiency and its response to environmental factors in Artemisia ordosica, a typical sandy plant in the semi-arid ecosystem of northwestern China for the purpose of ecosystem process modeling. Method The leaf stomatal conductance (gs), net photosynthetic rate (Pn) and transpiration (E) of Artemisia ordosica were measured using Li-6 400 portable photosynthetic analyzer from May to September, 2018. Water use efficiency (WUE, WUE = Pn / E) was analyzed in relation to soil water content (SWC), saturated water vapor pressure deficit (VPD), photosynthetically active radiation (PAR) and leaf surface temperature (Tl). Result The gs, Pn, E and WUE were more sensitive to VPD when SWC ≤ 0.08 m3/m3. When SWC > 0.08 m 3/m3, the gs, Pn, E and WUE were more sensitive to the response of PAR and Tl. Conclusion The results of this study further prove that Artemisia ordosica acclimates to drought conditions through changing gs and relative magnitude of Pn and E, and thus changing WUE. And WUE is lower during drought, indicating that soil drought stress restricts leaf photosynthesis and WUE. It is concluded that Artemisia ordosica acclimats to dry environmental conditions through conservative strategy of water resource.
Effects of rainfall reduction on litter leaf decomposition of Pinus tabuliformis plantations
Du Linyao, Liu Qianhui, Shen Xuanxuan, Wang Qitong, Wang Yilin, Zhang Feng, Yu Haiqun, Jia Xin
Corrected proof  doi: 10.12171/j.1000-1522.20190211
[Abstract](87) [FullText HTML](47) [PDF 993KB](13)
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ObjectiveLitter decomposition plays an important role in carbon and nutrient cycles of forest ecosystems. The effects of rainfall reduction on leaf litter decomposition of Pinus tabuliformis were examined in order to understand the response of carbon (C) and nitrogen (N) turnover dynamics of P. tabuliformis plantations to future changes in precipitation, and to improve the prediction and assessment of ecosystem functions of plantation forests under climate change.MethodA field rainfall exclusion experiment was performed in a plantation forest at Badaling Forest Farm, about 50 km north of Beijing from May to October, 2018. Losses of mass, C and N dynamics of P. tabuliformis leaf litter were measured and compared among three growing-season rainfall levels, i.e. 100% rainfall exclusion, 50% rainfall exclusion and control.ResultAfter five months of decomposition, no litter mass loss was detected for the 100% rainfall exclusion treatment and slight increase in litter mass wase actually observed. The percentages of remaining litter mass, C and N for the 50% rainfall exclusion treatment were 75.75%, 49.31% and 71.00%, respectively, while those for the control were 73.18%, 51.92% and 75.50%, respectively. There were no significant differences in remaining litter mass, C and N between the 50% rainfall exclusion treatment and control. The annual decomposition coefficients (k) for the 50% rainfall exclusion treatment and control were 0.64 and 0.92, respectively. There was a significant positive correlation between the monthly decomposition rate and soil water content. For the 50% rainfall exclusion treatment and control, N immobilization was observed in June and N release was observed from July to October.ConclusionIn the P. tabuliformis plantation, the effects of rainfall reduction on leaf litter decomposition depend on the magnitude of rainfall reduction. The decomposition dynamics of P. tabuliformis leaf litter may be relatively insensitive to mild and moderate droughts, but severe droughts can strongly restrict the decomposition rate and the turnover of C and N.
Forest carbon-timber compound management planning of Pangu Forest Farm in Great Xing’an Mountains, northeast China
Dong Lingbo, Lin Xueying, Liu Zhaogang
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190331
[Abstract](44) [FullText HTML](25) [PDF 890KB](6)
Abstract:
ObjectiveTo provide the optimal forest management paradigm for various forest types, the research of forest management in our country have mainly been performed on the scale of forest stand (or plot), however the importance of the temporal and spatial configuration of alternative thinning treatments has been ignored for a long term. Therefore, a spatial explicitly forest management planning model was developed by integrating forest carbon increments objective into traditional timber harvest scheduling problem, which can provide some new theories and technologies for the multi-objective management of forest resources in our country.MethodWith the guidance of forest category management theory, a practical forest multi-objective spatial management planning model (FMS), including the forest timber production and the carbon increments of aboveground tree-layer, was developed for the Pangu Forest Farm in Great Xing’an Mountains using the simulated annealing algorithm. To improve the practicality of the planning model, FMS subjected to the even-flow constraints of harvest volume, the inventory constraint of forest carbon stocks, and the spatial constraints of different thinning treatments. Based on FMS and the constraints of carbon trading and timber market in our country, the optimal forest management plans for a 50-years planning horizon of Pangu Forest Farm was optimized. Then, the amount of timber harvest, the amount of carbon increments, and the temporal and spatial configuration of alternative thinning treatments for each period was quantificationally analyzed.ResultThe joint net present values (NPV) of timber production and carbon increments during the 50-years planning horizon for Pangu Forest Farm was as large as 1.54 × 108 CNY, in which the NPVs of timber production and carbon increments were 1.37 × 108 CNY and 0.17 × 108 CNY respectively, when the carbon price was assumed as 120 CNY/t. The amount of harvest timber and carbon increments during the planning horizon were estimated as 1.78 × 106 m3 and 1.68 × 106 t, and the carbon stocks of aboveground tree biomass was 5.99 × 106 t, in which the carbon stocks of aboveground tree biomass at the ending of planning horizon increased by 38.98% with respect to that at the beginning of planning horizon. Within the optimal management plan, the protected area, thinned area and no-thinned area accounted for 44.36%, 48.01% and 7.63% respectively, in which the thinned area with high intensity accounted for 41.78% of the total forest area in this region. In addition, some significant differences were observed among the configuration of alternative management activities for each period, in which the amount of harvest volume and thinned area, as well as the number of thinned sub-compartments, all accounted for approximately 90% of their gross for each period. The distributions of thinning treatments presented significantly spatial characteristics for the optimal management plans, however the pattern was all conformed with the constraints.ConclusionThe outputs of FMS have some significant advantages: (1) forest managers always can obtain some pediocratic economic benefits for each period due to the even-flow constraints of harvest volume; (2) the forest resources can be protected from over-harvesting due to the inventory constraints of carbon stocks, which are meaningful to promote the function of forest carbon sequestration; (3) the forest planning model can provide the optimal temporal and spatial configuration of forest management activities. Obviously, all these advantages are helpful for the multi-objective management of forest resources in our country. However, the values of some key constraint parameters still need further research to improve the practicality of the proposed planning model in future.
The spatial and temporal distribution characteristics and discoloration of Fraxinus mandshurica knot
Guan Zhuizhui, Zhang Yandong
Accepted Manuscript  doi: 10.12171/j.1000-1522.20200004
[Abstract](53) [FullText HTML](44) [PDF 998KB](7)
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ObjectiveThe study aimed to know the spatial and temporal distribution characteristics and discoloration of Fraxinus mandshurica knot and establish the predictable model of discoloration length of knot.MethodThe study selected 16 Fraxinus mandshurica from artificial mixed forest of 49-year-old Fraxinus mandshurica and Larix olgensis, and dissected knots with a chainsaw and measured the knot properties by using a 20x magnifying glass in the laboratory.Result(1)The number of formed knots from 1st to 5th year accounted for 98.1%; The number of dead knots from 6th to 15th year accounted for 94.1%; The number of completely occluded knots from 11th to 20th year accounted for 73.6%. (2)89.5% of the knots located below 10.0 m, and 10.5% of the knots located between 10.0 m and 14.0 m in the vertical distribution. (3)The discoloration length of knot increased with the increase of knot diameter. When the knot diameter was greater than 15.0 mm, the discoloration length of knot increased significantly. (4)The discoloration length of knot significantly decreased with the increase of the insertion angle of knot(P < 0.05), but significantly increased with the increase of the radius of dead knot and the occlusion time of knot(P < 0.05). (5)The study filtered three key factors(KD,TRK and OT) to establish a multiple regression model of the discoloration length of knot by the stepwise regression method: YDL = 1.557XKD + 0.382XTRK + 1.140XOT - 7.523. The correlation reached a significant level.ConclusionFraxinus mandshurica knot discolored easily during the natural pruning. Knot diameter, total radius of the knot and occlusion time of the knot were key factors which affected the discoloration length of knot. When the knot diameter exceeded 15.0 mm, the discoloration length of knot increased significantly. Therefore, the branch diameter should be controlled within 15.0 mm when pruning.
Analysis on phenotypic variation and germplasm resource selection of wild Amygdalus mira (Koehne) in Tibet
Wei Liping, Han Yanying, Da buqiong, Gong Wenfeng, Deng Gongfu, Hu Jie
Corrected proof  doi: 10.12171/j.1000-1522.20190422
[Abstract](120) [FullText HTML](73) [PDF 776KB](18)
Abstract:
ObjectiveThis study aims to explore the variation of fruit phenotypic traits of the wild Amygdalus mira (Koehne) populations in Tibet of northwestern China and to screen the good germplasm resources by the principal component analysis, and also to ascertain the effects of ecological factors on phenotypic traits of fruits for fine breeding and generalizing of Amygdalus mira.MethodThe 18 populations (SYD, AR, LD, JT, DB, QD, MX, LK, BM, GY, SZ, BJ,ZR,PZ, QN, BH, LZ, CN) in 5 regions were surveyed and sampled according to the concentration distribution area combined with the differences in altitude, climate and maturity of wild A. mira in Tibet. In each population, 13 trees with good growth potential were selected, and the spacing of each individual plant was greater than 50 m. The ripe fruits were collected from the dark, sunny and the upper, lower four directions of each plant, 5 fruits were randomly selected from each direction, 20 in total, and then the phenotypic traits were measured.ResultThe fruit phenotypic traits were highly significantly different in population and among populations of A. mira. The mean of phenotypic differentiation coefficient was 67.99%, and the fruit phenotypic variations were mainly derived from populations. According to the results of PCA analysis and the use of pulp and core, the representative populations with large fruit, small nut, thick pulp and low nuclear rate were selected as the Jiangtang Township, Qiangna Township and Lang Township, and the representative populations with small fruit, large nut, thin pulp and high nuclear rate were the Guyu Township, Shangyadong Township and Qudeng Township. The 5 ecological factors explained 56.00% of the fruit character variation through RDA analysis, and only the annual average temperature had a significant effect on the overall variation of fruit traits (P = 0.049). The multiple regression equation of the two characteristics of the pulp thickness and the nuclear rate with the ecological factors were all significant (P < 0.01), and the adjusted R2 was 0.5993 and 0.7981, respectively. The thickness of pulp was negatively correlated with longitude, altitude and average annual rainfall, and was positively correlated with latitude and average annual temperature. The nuclear rate was positively correlated with longitude, altitude, average annual rainfall and annual temperature, and was negatively correlated with latitude. The effects of longitude, latitude and altitude on the thickness of pulp and the nuclear rate were highly significant.ConclusionThe phenotypic variation of A. mira mainly comes from populations. According to the phenotypic traits, fruit type and nut type of A. mira and its representative populations were screened. The effects of longitude, latitude and altitude of 5 ecological factors on the thickness of pulp and the nuclear rate were the most significant.
Spatial and temporal response of soil moisture to different fire intensities in Larix gmelini forests
Zhang Yun, Yu Yue, Cui Xiaoyang, Wang Haiqi
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190182
[Abstract](44) [FullText HTML](31) [PDF 891KB](3)
Abstract:
ObjectiveThe sequential quantification of soil moisture was in the mild-, moderate-, severe-burned areas of the Larix gmelini forests, the spatial and temporal change laws and the responses to the different fire intensities were analyzed by the fixed monitoring points, to understand the effects of soil moisture on vegetation restoration and provide reference to artificial regulation in the early years after forest fire.MethodThe sequential monitoring was conducted by the latticed co-coupled sampling method, and soil moisture content was determined by the oven drying method.ResultThe results showed that: (1) Soil moisture immediately decreased in the mild-, moderate-, severe-burned areas following the burning, further declined sharply in the arid spring, and rose again in the rainy season; (2) Soil moisture was less in the severe burned area than the mild-, moderate burned area before the rainy season, and no difference was between the three areas in the rainy season; (3) Significant negative correlation of spatial pattern was between soil moisture or its relative change and fire intensity before the rainy season.ConclusionSoil moisture in the severe burned area maybe affect vegetation regeneration in the early years of post-fire coniferous forest ecological restoration in the cold temperate zone.
Effect and influence factors of Taxus cuspidata in the process of reintroduction
Xu Chao, Long Ting, Wu Xinlei, Chen Jie, Liang Yanjun, Li Jingwen
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190423
[Abstract](33) [FullText HTML](25) [PDF 692KB](3)
Abstract:
ObjectiveReintroduction is an important method for endangered species conservation and population restoration. With Taxus cuspidata, a critically endangered wild plant with extremely small population, as the research object, this study chooses three different forest types and two groups of different age of Taxus cuspidata seedling for field regression tests, studies the reintroduction forest type suitable for Taxus cuspidate and the main factors influencing seedling growth and survival during reintroduction process. It is hopefully to provide scientific evidence for the conservation of Taxus cuspidata.MethodBetula platyphylla-Populus cathayana forest, Pinus koraiensis-spruce-fir forest and Pinus koraiensis-Tilia amurensis forest were selected as the reintroduction transplanting, indexes such as soil factors and topographic factors were investigated, and indexes such as seedling livability, seedling height, basal diameter and crown breadth were investigated month by month. Difference significant analysis and multiple comparison were conducted for each growth index of seedlings, and the impact factors of reintroduction seedling growth were studied through grey correlation analysis and other methods.ResultThe very year survival rate of the regression seedling of Taxus cuspidata is more than 86%. The ground diameter, seedling height and crown width all increased, except for the seedling height growth of Taxus cuspidata in 1 ~ 2 years, the growth indexes of Taxus cuspidata seedlings of all forest types showed no significant variation. The 1 ~ 2 year Taxus cuspidata seedlings of Korean pine linden forest were significantly higher than that of poplar birch forest and Korean pine-spruce-fir forest. As it was during the overwintering period, 4 ~ 5 year old Taxus cuspidata seedlings were eaten by roe deer, their survival rate decreased significantly, and the growth rate was very poor; The growth of 1 ~ 2 year old seedlings was also effected to some extent by long - term low temperature stress. The survival and growth of regression seedling of Taxus cuspidata are affected by diversified environmental factors, among which, the most relevant is forest type, followed by aspect, gradient and canopy density, while the association degree of soil chemical property index is lesser.ConclusionThe reintroduction of 4 ~ 5 year old Taxus cuspidata seedlings failed due to predation of animals. 1 ~ 2 year old seedlings adapt to the three habitats of Betula platyphylla-Populus cathayana forest, Pinus koraiensis-spruce-fir forest and Pinus koraiensis-Tilia amurensis forest and the optimum forest type for the seedling reintroduction of 1 ~ 2 year old is Pinus koraiensis-Tilia amurensis forest.. Forest type, Slope aspect, slope and light are the primary environmental factors influencing the reintroduction of Taxus cuspidata.
Effect of cutting methods on natural regeneration of Mytilaria laosensis plantation
Tang Jixin, Jia Hongyan, Zeng Ji, An Ning, Li Hongguo, Lei Yuancai
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190281
[Abstract](92) [FullText HTML](40) [PDF 896KB](7)
Abstract:
ObjectiveTo provide a scientific basis with utilization of natural regeneration and sustainable management of Mytilaria laosensis plantation, effect of cutting methods on natural regeneration of the plantation was explored, based biological characteristics of Mytilaria laosensis tree species.MethodUsing one–factor completely random design, three kinds of cutting treatment and one kind of control (CK treatment) was conducted with the plantation in the south subtropical area of China, the three kinds of cutting treatment was respectively TA treatment (strip clear-cutting, width of strip clear-cutting land was about 100 m, length of slope was more than 100 m, width of each reserve belt was not less than 30 m), TB treatment (strip shelter wood cutting, width of strip shelter wood cutting was about 50 m, the reserve density of the stand was during 120-150 plants per heater), TC treatment (clear-cutting,cutting area was 4.0 heater), and CK treatment (along the slope direction, the plantation was with no cutting, which width of reserve belt was during 50-100 m). Each kinds of cutting treatment was surveyed with three plots. The differences in regeneration density, regeneration frequency and growth of natural regeneration sapling of the tree species of the plantation with different cutting methods were analyzed, by using one factor analysis of variance (One way AVOVA) and least significant difference method (LSD) with data processing system (DPS14.5).Result(1) In the cutting land, after 2 years forest tending, the effect of natural regeneration sapling (tree hight > 1.3 m) in any cutting treatment could reach good grade standard of natural regeneration in cutting land (regeneration density was greater than 3 000 trees per heater, and regeneration frequency was more than 60%), but only the regeneration effect of seed regeneration saplings of TC treatment could reach the good grade standard of natural regeneration. (2) In the strip clear-cutting land, the effect of natural regeneration of the species decreased with the increasing of forest edge distance, and which could reach the good grade standard of natural regeneration only within 18 m with forest edge (distance was the unilateral distance range from the forest edge). (3) The effect of the natural regeneration in the cutting treatment was much better than the CK treatment. (4) During the scale of 0-10 m, the spatial distribution of natural regeneration saplings in the plantation and its cutting land, mostly was non-single distribution type, and presented regular change (at the first was aggregation distribution, and then was random distribution, or uniform distribution).ConclusionThere was no significant effect with different cutting methods and forest tending on the spatial distribution of seed regeneration saplings in the cutting land, but had an extremely significant effect on promoting the density and frequency of seed regeneration saplings (P < 0.01), and had an obvious effect on changing the diameter distribution of seed regeneration saplings in the cutting area. (2) If strip-cutting operation was not in peak period of seed rain of the plantation (the seed rain peaks was during November and December), the width of strip clear cutting should be controlled within 36 m. (3) Light was the key factor affected the establishment of natural young trees in the plantation. Any kinds of cutting methods (clear-cutting, strip shelter wood cutting and strip clear-cutting) could effectively realize good grade standard of natural regeneration on the cutting land, by taking advantage of falling period of seed rain and natural regeneration characteristics of the plantation, which falling seed was easy to germinate at open ground, and sprout of the stump was easy to germinate.
Comparation in essential oil components of different altitudes and varieties of Paeonia rockii
Wu Yi, Hu Jianzhong, Han Xue, Yin Liqiang, Yuan Weiqiong, Zhao Qianlong, Lv Zhaolin
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190304
[Abstract](0) [PDF 0KB](0)
Abstract:
ObjectiveThe composition of essential oil which was extracted from different altitudes and varieties of Paeonia rockii were studied, and the differences and similarities of the composition of compounds were also explored.MethodIn this experiment, Paeonia rockii essential oils were prepared from different altitudes of the same species and different varieties at same altitudes. The essential oil content and composition of Paeonia rockii were analyzed.ResultThe study has shown that different oils of different varieties of Paeonia rockii essential oil have different oil content, white Paeonia rockii essential oil has the highest oil content, reaching 10.94%, purple Paeonia rockii is the next, which is 10.31%, while the No. 3 pink Paeonia rockii essential oil has the lowest oil content, 7.47%. A total of 70 compounds were detected in three different altitude gradients (1, 2, and 3), and 54 species, 53 species, and 57 compounds were detected in the first, second, and third grounds, respectively. The ingredients were geraniol (5.07%、13.87%、13.74%), tetradecane (5.99%、9.86%、7.25%),7-dodecen-1-ol-acetate (35.16%、29.16%、25.01%), dodecane (7.26%、6.29%、7.32%) and tricosane (8.00%、6.36%、8.11%); A total of 75 compounds were detected in three different varieties (white, pink, purple) of Paeonia rockii essential oil, and 59, 54 and 62 species were detected in white, pink and purple Paeonia rockii. The main components were geraniol (3.91%、5.07%、9.52%), tetradecane (15.93%、5.99%、8.96%), 7-dodecen-1-ol-acetate (19.79%、35.16%、22.91%), dodecane (12.40%、7.26%、6.60%) and tricosane (7.83%、8.00%、6.37%). Although the five kinds of Paeonia rockii essential oils of different varieties at different altitudes are mainly composed of the above five components, the content varies greatly. At the same time, the other components in the essential oils also have large differences in species, quantity and content.ConclusionThis study can provide basic theoretical support for the selection of growth conditions, identification of species and the wide application of essential oil of Paeonia rockii.
Comparation in essential oil components of different altitudes and varieties of Paeonia rockii
Wu Yi, Hu Jianzhong, Han Xue, Yin Liqiang, Yuan Weiqiong, Zhao Qianlong, Lv Zhaolin
Corrected proof  doi: 10.12171/j.1000-1522.20190304
[Abstract](163) [FullText HTML](22) [PDF 984KB](7)
Abstract:
ObjectiveThe composition of essential oil which was extracted from different altitudes and varieties of Paeonia rockii were studied, and the differences and similarities of the composition of compounds were also explored.MethodIn this experiment, Paeonia rockii essential oils were prepared from different altitudes of the same species and different varieties at same altitudes. The essential oil content and composition of Paeonia rockii were analyzed.ResultThe study has shown that different oils of different varieties of Paeonia rockii essential oil have different oil content, white Paeonia rockii essential oil has the highest oil content, reaching 10.94%, purple Paeonia rockii is the next, which is 10.31%, while the No. 3 pink Paeonia rockii essential oil has the lowest oil content, 7.47%. A total of 70 compounds were detected in three different altitude gradients (1, 2, and 3), and 54 species, 53 species, and 57 compounds were detected in the first, second, and third grounds, respectively. The ingredients were geraniol (5.07%、13.87%、13.74%), tetradecane (5.99%、9.86%、7.25%),7-dodecen-1-ol-acetate (35.16%、29.16%、25.01%), dodecane (7.26%、6.29%、7.32%) and tricosane (8.00%、6.36%、8.11%); A total of 75 compounds were detected in three different varieties (white, pink, purple) of Paeonia rockii essential oil, and 59, 54 and 62 species were detected in white, pink and purple Paeonia rockii. The main components were geraniol (3.91%、5.07%、9.52%), tetradecane (15.93%、5.99%、8.96%), 7-dodecen-1-ol-acetate (19.79%、35.16%、22.91%), dodecane (12.40%、7.26%、6.60%) and tricosane (7.83%、8.00%、6.37%). Although the five kinds of Paeonia rockii essential oils of different varieties at different altitudes are mainly composed of the above five components, the content varies greatly. At the same time, the other components in the essential oils also have large differences in species, quantity and content.ConclusionThis study can provide basic theoretical support for the selection of growth conditions, identification of species and the wide application of essential oil of Paeonia rockii.
Construction of Urban Ecological Network in Yanqing District of Beijing based on MSPA Model
Kong yang, Wang siyuan
Corrected proof  doi: 10.12171/j.1000-1522.20190271
[Abstract](178) [FullText HTML](128) [PDF 1562KB](20)
Abstract:
ObjectiveWith the rapid development of Beijing's urbanization, Beijing's ecological environment tends to deteriorate and urban ecological security faces enormous challenges. The construction of ecological network can mitigate the damage caused by the rapid urbanization and the fragmentation of urban and rural landscapes and is great significance for the protection of urban biodiversity.MethodsThis paper selected Yanqing District of Beijing as the research area. Based on the ArcGIS software platform, the remote sensing image of Yanqing District of Beijing was interpreted to obtain the land cover type. The land cover type was divided into foreground and background by the ArcGIS. The analysi method (MSPA) obtains seven types of landscape types and identifies the core area as an important ecological source. The Accumulative Cost Distance Model and the Network Analysis are used to obtain the best. Based on the ecological network under the threshold, the ecological network optimization proposal of Yanqing District is proposed.ResultsThe results showed that: (1) the overall fragmentation degree in Yanqing District was low, the material and energy migration between different types was relatively smooth and the overall landscape diversity was higher, but the number of habitat patches in the city was less and the corridor was scarce; (2) The distance threshold which was most suitable for the current structure of the ecological network in Yanqing District was 20 000 m and the network closure degree α was 0.73. (3) Woodland and cultivated land were important landscape types of potential ecological corridors in the study area and forest area was the largest, it was 17 452.9 hm2, accounting for 81.1% of the total corridor area.ConclusionsThe MSPA method has the advantages of accurate and detailed evaluation of geometric connectivity, small amount of data required and visualization of analysis results. The network analysis method could optimize the ecological network. Therefore, based on the MSPA method and network analysis method, the accuracy of the ecological network construction in Yanqing District is more detailed and accurate. The research results have important guiding and practical value for the construction of ecological network and biodiversity protection in Yanqing District. The ecological network construction in Yanqing District could provide a reference for the other areas.
Core germplasm construction of Populus tomentosa Carr. based on the fluorescent SSR
Mao Xiuhong, Zhu Shili, Li Shanwen, Hua Hui, Tian Shuyong, Zhong Weiguo, Dong Yufeng, An Xinmin
Accepted Manuscript  doi: 10.12171/j.1000-1522.20190413
[Abstract](798) [FullText HTML](70) [PDF 576KB](9)
Abstract:
ObjectiveTo study the sampling proportion and to determine the sampling strategy on the basis of corresponding genetic analysis, analyze the genetic diversity, and construct the core germplasm of P. tomentosa Carr.. It can provide molecular foundation for the introduction, genetic breeding, collection and preservation of Leuce germplasm resources. It also can provide reference for the core germplasm construction of other tree species.MethodBased on 16 pairs of fluorescent SSR primers, the genetic diversity of 272 accessions of P. tomentosa Carr. and poplar hybrid was analyzed by capillary electrophoresis. Based on expected heterozygosity data, all samples were ranked according to their contribution to the overall genetic diversity. The sampling ratios was the top 50%, 45%, 40%, 35%, 30%, 25%, 20% and 15%. The representativeness of core germplasm was analyzed by comparing the average effective allele number Ne, the average Shannon information index I and the average expected heterozygosity He, et al. Then the appropriate sampling proportion was determined.ResultWith the decrease of sampling proportion, the values of Ne, I and He are all increasing, which are all greater than the corresponding values of the original germplasm. The values of He are all greater than 0.5, indicateing abundant genetic diversity, while the values of the original germplasm are less than 0.5. According to 25% sampling ratio, the first 68 germplasm were obtained, including 18 hybrid germplasm and some excellent germplasm selected by all provinces. The Ne, I and He values are 2.761, 1.094 and 0.539, respectively, which are all higher than the corresponding values of the original germplasm 2.075, 0.825 and 0.432. It was showed by the t-test that there was no significant di?erence between the genetic diversity of the core germplasm and the original germplasm resources, indicating that these 68 germplasm have a very reliable representation in terms of genetic diversity and can be used as the core germplasm. The genetic consistency between Beijing germplasm and Hebei germplasm was 0.997, followed by Shanxi at 0.990.ConclusionThe best sampling proportion of core germplasm of P. tomentosa Carr. is 25%, and the best sampling range is 20%-40%. If the number of germplasm resources is large, it can be reduced to 15%; if the base is small, it can be increased to 45%. He, Ne, I, etc. all indicated that the above core germplasm had abundent genetic diversity. The genetic variation of hybrid germplasm is rich, which aggregates the good alleles of the parents. It is proved at the molecular level that hybrid germplasm is an important breeding resource for genetic improvement of P. tomentosa Carr.. We suggest that relevant departments or breeders should attach great importance to the collection, preservation and reuse of poplar hybrid germplasm.
Spatial layout of biological fuelbreaks in Jiangle County, Fujian Province of eastern China
Yuan Shuo, Li Chao, Chen Hao, Muhammad Amir, Liu Xiaodong
Corrected proof  doi: 10.12171/j.1000-1522.20190365
[Abstract](392) [FullText HTML](211) [PDF 1031KB](27)
Abstract:
ObjectiveSanming area of Fujian Province, eastern China is a forest fire-prone area. This study aims to reduce losses caused by fires and cutting off fire sources through the overall layout of biological fuelbreaks in the research area of Jiangle County, Sanming City of Fujian Province.MethodIn order to comprehensively plan the biological fuelbreaks in Jiangle County, we obtained the minimum control area by analyzing the spatial and temporal distribution of forest fires in Jiangle County over the past 12 years, determined the location of biological fuelbreaks through spatial analysis, hydrological analysis, and object-oriented spatial feature extraction and other methods and finally calculated the fire belt network density after selecting optimal fire-resistant tree species and determining the biological fuelbreak width based on statistics of the current status of biological fuelbreaks in Jiangle County.ResultThe density of biological fuelbreaks was finally determined to be 19.04 m/ha and the minimum control area was finally determined to be 10 ha. The final biological fuelbreaks need to be built were 3 591.67 km, including 1 846. 64 km in ridges, 384.21 km in valleys and 1 360.83 km in forest edges. The width of biological fuelbreaks of ridges was 12 m, and valleys and forest edges were both an average value, i.e. 9 m. Thus, the total area of the planned biological fuelbreaks was 3 786.49 ha. Choosing Schima superba as the major species, and Camellia oleifera and Phyllostachys heterocycla as subsidiary species after comparing the fire-resistant ability of main tree species in Jiangle County not only achieved a better result of fire prevention but also had economic benefits.ConclusionBased on the previous studies on fuelbreak construction in Fujian Province, and taking its density, minimum control area, construction location, and appropriate width into consideration, as well as the choose of fire-resistant tree species, this study has managed to optimize the spatial layout of fuelbreaks in Jangle County. This economical and pragmatical engineering, which is adaptative to local conditions will play an important role in fire prevention in Jiangle County of Fujian Province, eastern China.
Effects of nitrogen, phosphorus addition and drought on leaf stoichiometry in dominant species of alpine meadow
Fu Yiwen, Tian Dashuan, Niu Shuli, Zhao Kentian
Corrected proof  doi: 10.12171/j.1000-1522.20190469
[Abstract](489) [FullText HTML](427) [PDF 1004KB](40)
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ObjectiveGlobal change has substantially changed soil nitrogen (N), phosphorus (P) and water availability, which further impacts plant growth and physiological processes. However, so far few studies have been conducted to analyze the interaction effects of soil N, P and water on plant growth and physiological traits, especially for alpine meadow plants. This study aims to reveal the impacts of N addition, P addition, drought and their interactions on plant growth, leaf N and P content and N:P ratios in dominant species of alpine meadows, providing scientific evidence for grassland management.MethodBased on an experiment of N addition (10 g/(m2· year)), P addition (10 g/(m2· year)) and drought (50% rainfall reduction) in an alpine meadow of northwestern Sichuan, we measured aboveground biomass, leaf N, P content and their ratio in Elymus nutans, Deschampsia caespitosa and Anemone rivularis. Then we analyzed the influence of different treatments and their interactions on plant biomass and leaf nutrient.ResultFor plant growth, N addition significantly increased plant biomass of three species, but the impacts of P addition, drought, and the interactions among different treatments were not significant. For leaf nutrient, N addition significantly enhanced leaf N content and N:P ratio of three species, and P addition also promoted leaf P content but reduced N:P ratio. Drought raised leaf N content of E. nutans and D. caespitosa, but had no significant effect on leaf P content and N:P ratio. The interaction of N addition and drought promoted leaf N content and N:P ratio of E. nutans and D. caespitosa. Nevertheless, the interaction of N and P addition was not significant for leaf nutrient of all species.ConclusionThis study indicates that alpine species have quite different responses of plant growth versus nutrient traits to nutrient enrichment, drought and their interactions. N input mainly facilitates plant growth, but the complex impacts of soil N, P, drought and their interactions all affect plant nutrient and stoichiometric balance. These results imply that more future studies are needed to detect the mechanisms underlying alpine plant physiological responses to the interactions of various global changes.
Diurnal variations of stand transpiration of Larix principis-rupprechtii forest and its response to environmental factors in Liupan Mountains of northwestern China
Ma Jing, Guo Jianbin, Liu Zebin, Wang Yanhui, Zhang Ziyou
Corrected proof  doi: 10.12171/j.1000-1522.20190468
[Abstract](760) [FullText HTML](541) [PDF 1799KB](54)
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ObjectiveThis paper aims to examine the diurnal variations of stand transpiration and its response to environmental factors in a Larix principis-rupprechtii plantation, and to further explain the regulation mechanism of environmental conditions to the stand transpiration in short time scale.MethodA field experiment was conducted in a Larix principis-rupprechtii plantation stand located in the Xiangshuihe Watershed within the Natural Reserve of Liupan Mountains, Ningxia of northwestern China. The sap flow of sample trees was continuously monitored in the growth season (from May to October) in 2018. The meteorological and soil moisture conditions were continuously measured simultaneously. The response of hourly stand transpiration (T) to environmental factors was analyzed, and a T model coupling the effects of multiple influencing factors was established.ResultIt was shown that: (1) the response of T to solar radiation (Rs) and vapor pressure deficit (VPD) followed a binomial equation. The T firstly increased with rising Rs and VPD till to peak at the thresholds of 666.7 W/m2 and 1.86 kPa, and then gradually decreased afterwards. (2) The T response to relative extractable water (REW) of the 0-60 cm soil layer followed a saturated exponential growth function. The T increased firstly with rising REW, and then became stable when the REW was above 0.3. (3) The response functions of T each individual driving factors (Rs, VPD and REW) were determined using the upper boundary line method, and then were coupled to form the frame of T model. Thereafter, the observed data of odd-days and even-days were used for model fitting and validation. The fitted model is: T = (− 6.347 0 × 10− 5\begin{document}${R_{\rm{s}}^2}$\end{document} − 0.637 0Rs − 208.734 8) × (− 0.003 2VPD2 + 0.013 8VPD + 0.001 7) × (− 0.008 1 − 0.004 6(1 − exp(− 12.469 6REW))). The model was well calibrated (R2 = 0.74, Nash coefficient (NSE) = 0.82) and validated (R2 = 0.77, NSE = 0.84).ConclusionThe T variation can be well predict by the T model coupling the effects of solar radiation, vapor pressure deficit, and soil moisture conditions. This model can accurately predict the variation of T of Larix principis-rupprechtii plantation under changing environment. Meanwhile, the model establishment approach used here can be a reference for developing the stand transpiration model in other regions and for other tree species.
Extraction of tree crown parameters from high-density pure Chinese fir plantations based on UAV image
Sun Zhao, Pan Lei, Sun Yujun
Corrected proof  doi: 10.12171/j.1000-1522.20190386
[Abstract](3422) [FullText HTML](663) [PDF 9380KB](60)
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ObjectiveCrown width is an important characteristic factor of canopy structure, which directly affects the productivity and vitality of trees. The forest canopy density is one of the important indexes to reflect forest canopy structure and density and to evaluate forest management and logging intensity. UAV has the advantages of easily getting high-resolution remote sensing images with high precision and low cost. Studying the method of extracting canopy parameters using UAV images is of great significance for improving the accuracy and efficiency of forest resource inventory and monitoringMethodTaking Chinese fir plantation in Jiangle Forest Farm of Fujian Province as the research object, using the quadrotor UAV CCD image data as the data source, based on the object-oriented classification method, the canopy parameters of the Chinese fir plantation were extracted from the UAV image. Then the canopy objects were grouped into one group according to the segmentation results of the image, and the number of raster pixels of each canopy object was counted to calculate the canopy width area and canopy density.ResultThe object-oriented classification effectively extracted the canopy of high canopy density stand. When the segmentation scale was 70, the segmentation of single tree had the best effect. Some single trees were lost during the segmentation process because of over-segmentation and under-segmentation. After the segmentation was completed, optimizing the feature space of the segmented object and selecting appropriate classification features, finally the study area was divided into two types: crown and gap. By counting the number of grid points of each object, the calculated stand factors included canopy density and crown area. With the measured data on the ground as reference, the crown area extraction accuracy was 0.829 1, and the forest canopy density measurement accuracy was 0.973 1.ConclusionThe results show that the canopy parameter extraction based on high-resolution image of UAV is also applicable in high-canopy closed forest stands, which can effectively improve the efficiency and accuracy of forest resource survey.
Determination and analysis of the relationship between microclimate elements and greening structures in the city streets of Shanghai: taking Xuhui District and Yangpu District as examples
Zhang Deshun, Xue Kaihua, Wang Zhen, Cao Wei, Ma Chundong
Corrected proof  doi: 10.12171/j.1000-1522.20170359
[Abstract](1182) [FullText HTML](847) [PDF 1088KB](86)
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ObjectiveThis paper aims to explain the corresponding relationship between the microclimate elements and the street greening layout, guide the adaptability design of urban street green space.MethodBased on the field survey, the correlation between the microclimate factors and the street greening layout was elaborated, and the influence of several factors as solar radiation, air temperature and wind speed on vertical structure of street greening was explored in this study.Result(1) The relationship between street shade coverage and microclimatic factors: The higher the shade coverage, the better the reduction efficiency of solar radiation, The effect is most pronounced when coverage reaches more than 90 percent, And the rule characteristic of its cooling effect is more obvious, However, the excessive shade coverage makes the street space closed, resulting in a reduced cooling effect. The efficiency of wind speed reduction is more than 21% higher than that of 50% ~ 70% for the street greening with a green coverage rate of more than 90%. (2) Relationship between street greening cladding structure and microclimatic elements: In the multi-layer vertical structure, the more complex the structure is, the greater the greening amount will be, and the higher the solar radiation reduction efficiency will be. Its overall average reduction efficiency of solar radiation is 88.78%. The average daily cooling efficiency of the layered vertical structure is 8.69%. In the natural cycle of one day, the weakening efficiency of the wind speed is the best, followed by that of the tree-shrub-grass, the tree-shrub next, tree-grass third, shrub-grass is the last. The average daily wind speed reduction efficiency of the laminated structure is about 77.61%. (3) Relationship between vertical green ratio and microclimatic elements: The ratio of total green content of trees and shrubs was positively correlated with the solar radiation reduction efficiency. The higher the proportion of trees and shrubs, the higher the average cooling efficiency. During the natural cycle of a day, the closer the ratio of trees and shrubs to grass, the better the weakening effect on wind speedConclusionBased on the relationship between the layout of street greening and microclimate elements, the technical countermeasures for improving the comfort of microclimate by regulating the composition of street greening are proposed: (1) To build comfortable street summer microclimate, appropriate maintains 70 ~ 90% green shade coverage rate. (2) Shade and ventilation should be increased through a moderate greening cladding structure, but it should be avoided that it is too complicated to affect the normal ventilation. (3) According to the scientific proportion of vertical green quantity, taking into account the requirements of green shade coverage in summer and temperature increase in winter, planting deciduous trees and keeping trees and shrubs account for more than 50% of the street greening.
Display Method:
2020, 42(6): 1-2.  
[Abstract](30) [FullText HTML](34) [PDF 301KB](2)
Abstract:
Forest Sciences
Differential expression of miRNA and function of target genes in heteromorphic leaves of Populus euphratica
Zeng Ming, He Shuhang, Li Wenhai, Feng Jun, Zhao Yuanyuan, Zheng Caixia
2020, 42(6): 1-13.   doi: 10.12171/j.1000-1522.20190464
[Abstract](241) [FullText HTML](138) [PDF 1110KB](18)
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ObjectiveHeterophylly is the phenomenon that plants form multiple types of mature leaves on the same plant to adapt to the environment. Populus euphratica is a typical woody heterophyllous plant, and previous research found that there were differences between heteromorphic leaves of P. euphratica in physiological characteristics and enironmental adaption. In this study, to reveal the molecular regulation of morphological and physiological characteristics in heteromorphic leaves of P. euphratica, we analyzed the differential expression of miRNAs and functions of target genes in heteromorphic leaves of P. euphratica.MethodIn this paper, using high-throughput sequencing, comparative study for miRNA expression patterns and functions of target genes was conducted in lanceolate leaves and dentate broad-ovate leaves.ResultTotal of 6 high-quality sRNA libraries were obtained, and the valid sequence of each library accounted for 56%−81% of the raw data. Total 517 known miRNAs and 127 predicted novel miRNAs were identified, the length of which was mainly distributed in 20−22 nt. Besides, 389 of the identified miRNAs were mapped to 54 known miRNA families, and there were 369 miRNAs detected in both two types of leaves. Compared with lanceolate leaves, 7 miRNAs were up-regulated and in dentate broad-ovate leaves, while 15 miRNAs were down-regulated. Based on the prediction of target genes and function annotation, differentially expressed miRNAs were involved in stress-resistant pathways in Populus euphratica, such as cellular response to salt stress, inositol phosphate metabolism, cutin, suberine and wax biosynthesis, base excision repair, and RNA degradation pathways. Moreover, expression levels of 5 differentially expressed miRNAs and their corresponding target genes were examined by quantitative real-time PCR, which could confirm the expression profile of the sRNA-sequencing and the negative regulation of miRNAs on their target genes.ConclusionOur study reveales that the expression patterns of miRNA between the heteromorphic leaves of P. euphratica are different. The miR167 and miR166 involved in growth and development of plant and miR172 associated with stress resistance of plant are up-regulated in dentate broad-ovate leaves. Besides, the miR169 and miR396 involved in stress resistance of plant are down-regulated in dentate broad-ovate leaves in comparison to lanceolate leaves. We speculate that the differential expression of miRNA may induce the morphological difference between heteromorphic leaves, and could increase the resistance of dentate broad-ovate leaves to adverse environments, this is consistent with our previous results of morphological and physiological characteristics in heteromorphic leaves of P. euphratica.
Overexpression of PeAnn1 from Populus euphratica negatively regulates drought resistance in transgenic Arabidopsis thaliana
Wu Xia, Zhang Yinan, Zhao Nan, Zhang Ying, Zhao Rui, Li Jinke, Zhou Xiaoyang, Chen Shaoliang
2020, 42(6): 14-25.   doi: 10.12171/j.1000-1522.20200031
[Abstract](185) [FullText HTML](100) [PDF 1603KB](17)
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ObjectiveAnnexins is a large class of annexin families common in prokaryotes and eukaryotes, and participates in many stress response processes such as oxidative stress, heat stress, drought stress and salt stress. However, the role of Populus euphratica annexin family genes in adapting to adverse conditions is still less known. This paper studies the role of P. euphratica Anneixn1 in osmotic stress and drought resistance.MethodThe mannitol-induced expression of PeAnn1 was examined in P. euphratica leaves. PeAnn1 sequence was compared with annexin genes from P. tomentosa, Arabidopsis thaliana, Glycine soja, and Oryza sative. Phylogenetic tree of annexins was constructed using MEGA 6 software. PeAnn1-overexpressed A. thaliana (PeAnn1-OE1 and PeAnn1-OE2), Annexin1 mutant (atann1) and wild-type A. thaliana (WT) were used in this study. Plants of each genotype were subjected to increasing osmotic stress caused by different concentrations of mannitol (0, 150, 200, 250, 300 mmol/L), drought, and subsequent water recovery. During the period of water stress, the germination rate, root length, chlorophyll content, and fluorescence parameters, H2O2, activity of antioxidant enzymes and expression of encoding genes were examined.ResultThe short-term mannitol treatment up-regulated the expression of PeAnn1 in P. euphratica leaves. The PeAnn1 sequence displayed higher similarity to P. tomentosa Ann1 (PtAnn1) than other plant species. Phylogenetic analysis revealed that the PeAnn1 was highly homologous to the PtAnn1. The survival rate and root growth of A. thaliana plants were inhibited with increasing concentrations of mannitol, and the inhibition was more pronounced in PeAnn1-overexpressing lines as compared to the WT and mutant (P < 0.05). All the measured photosynthesis parameters, such as chlorophyll content, the maximum photon efficiency of PSⅡ (Fv/Fm), the actual photosynthetic quantum yield (ΦPSⅡ), and the relative electron transfer rate (ETR) were lower in the transgenic plants than in the WT and mutant (P < 0.05). After rehydration, the recovery degree of photosynthetic parameters of PeAnn1-transgenic A. thaliana was also lower than the WT. Under osmotic stress, the activities of antioxidant enzymes, such as SOD, POD, and CAT were significantly lower in PeAnn1-overexpressed plants than those of the WT and mutant. In accordance, the expression of these antioxidant enzyme genes showed a same trend as the activities, which could not remove reactive oxygen species, causing oxidative damage.ConclusionThe above results indicate that overexpression of PeAnn1 decreases the capacity of A. thaliana in the adaptation to water deficit conditions.
Genetic transformation of Populus alba × P. glandulosa ‘84K’ with AtDME1 and its chemical-inducible expression analysis
Wu Xiaojuan, Lu Junqian, Chang Yingying, Zhong Shanchen, Su Xiaohua, Zhang Bingyu
2020, 42(6): 26-32.   doi: 10.12171/j.1000-1522.20190068
[Abstract](1145) [FullText HTML](137) [PDF 737KB](26)
Abstract:
ObjectiveDNA methylation is an important epigenetic modification that plays an essential role in plant growth and development. In this study, the chemically-induced promoter and the Arabidopsis thaliana demethylation transferase gene AtDME1 were introduced into the genome of Populus alba × P. glandulosa ‘84K’, and the expression of AtDME1 was effectively induced by 17-β-estradiol treatment. The expression characteristics of AtDME1 in transgenic poplar plants were investigated. This study laid a foundation for the establishment of poplar methylation-induced variation system and genetic improvement of poplars.MethodThe chemically-induced promoter and AtDME1 were transformed into genome of P. alba × P. glandulosa ‘84K’ using Agrobacterium-mediated transformation. Traditional PCR and DNA sequencing were used to identify the transgenic plants in hygromycin resistant plants. The chemical inducer 17-β-estradiol was used to induce expression of AtDME1 in in vitro leaves of a transgenic clone for 0, 3, 6, 12, 24, 48, 96 and 144 hours, and the expression of AtDME1 gene was detected by quantitative real-time PCR (qRT-PCR).ResultA total of 224 hygromycin resistant buds were obtained, among them six hygromycin resistant plants were screened. Finally, six transgenic plants were identified by molecular methods, which were named as AD-1−6. Results of qRT-PCR showed that the expression of AtDME1 reached its highest level after 3 hours treatment of 17-β-estradiol, and its expression gradually decreased after12 hour’s treatment.ConclusionThe chemical inducer 17-β-estradiol can rapidly and efficiently induce the expression of AtDME1 gene in transgenic poplar, which lays a solid foundation for further study on the mechanism of DME1 gene in the regulation of poplar genome methylation. It lays a solid foundation for the study of the chemical expression characteristics of poplar.
Genetic structure variation of Pinus tabuliformis plantations in Beijing and the differences with Shanxi mountain populations
He Kuaikuai, Wu Wenbin, Zhang Zijie, Hu Xiange, Han Fangxu, Niu Shihui, Li Yue
2020, 42(6): 33-42.   doi: 10.12171/j.1000-1522.20190399
[Abstract](1026) [FullText HTML](1169) [PDF 592KB](21)
Abstract:
ObjectiveThe purpose of this study was to reveal the genetic diversity, genetic structure and genetic relationship of Pinus tabuliformis populations in Beijing, and to explore the impact of introduced land on population genetic structure and growth, and to provide references for the cultivation and germplasm resource management of P. tabuliformis in Beijing.MethodBased on 7 pairs of highly and stable polymorphically nuclear genomic EST-SSR primers, the population genetic diversity, genetic structure and genetic distance were analyzed among 8 P. tabuliformis populations planted in last century in Beijing, 3 ancient P. tabuliformis populations and 5 mountain populations from Shanxi Province of northern China.ResultThe genetic structure difference ( FST = 0.066) was the maximum among Beijing plantation populations, the second was population from Shanxi Province (FST = 0.033), and the lowest was ancient populations (FST = 0.023). Both of the Beijing populations and ancient populations deviated from Hardy-Weinberg equilibrium and showed heterozygote excess, and the maximum heterozygote excess was in ancient P. tabuliformis populations. All of the populations could be clustered into 3 categories when genetic distance was 0.020 based on genetic distance analysis, showing near genetic distances among different populations, the level of evolutionary divergence and genetic differentiation were relatively low. The EST-SSR loci site amplification frequency of J10, J20, J42 and J50 in Beijing populations, ancient P. tabuliformis and Shanxi populations showed significant differences, which could be used for source tracing for unknown provenances.ConclusionThe Beijing populations of P. tabuliformis have richer genetic diversity and higher genetic differentiation than ancient P. tabuliformis; some introduced provenances eventually phased out because of the difference in fitness under stress environment, resulting in the genetic structure has a certain amount of change for the retained population. Our study provides important theoretical foundation for the follow-up studies on the evaluation, cultivation and germplasm management of P. tabuliformis populations in Beijing.
Establishment of an effective protocol for cultivation of tissue cultured seedlings in Pinus massoniana superior provenance
Wang Yin, Yao Ruiling
2020, 42(6): 43-51.   doi: 10.12171/j.1000-1522.20190396
[Abstract](278) [FullText HTML](90) [PDF 1127KB](22)
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ObjectivePinus massoniana is a main tree species for ecological construction and timber in southern areas of China. However, the productivity of plantation is generally low resulting from the limitation of improved varieties, which leads to the slow development of industrialization in P. massoniana. It is necessary to develop an effective propagation system of elite germplasm for P. massoniana in order to promote the use of improved varieties, accelerate the industrial development, and enhance the competitiveness of industry.MethodIn this study, ‘Tongmiansong’ (TM), the backbone of P. massoniana breeding resources was used as the research object, zygotic embryos excised from immature cones were applied to explants, and mature somatic embryos (SE) obtained via somatic embryogenesis were used for testing materials. Concerning the technical bottlenecks of P. massoniana tissue culture, including low germination rate, poor shoot growth, and recalcitrance to rooting, effects of active charcoal (AC), basal media, and plant hormones on SE germination as well as reinvigoration and adventitious rooting of shoots were investigated in the present study.Result(1) AC significantly improved germination of TM mature SE, while a high level of AC was able to weaken their germination effects, and the best effect was observed at the 0.83 mol/L AC treatment. Based on the application of AC in the medium, the basal medium composed of high N, low ratio of NH4+/NO3, and moderate K and Ca furtherly enhanced the germination of SE, reaching 94.1% of germinating rate. (2) 0.42 mol/L AC effectively promoted the elongation of germinated SE. Under the treatment of 4 μmol/L TDZ, induction of axillary buds was better, achieving effective bud proliferation coefficient of 5.6/35 d, and shoot height of 9.2 cm/50 d. (3) After 60 days of 1.2 μmol/L NAA + 2 μmol/L PBZ application in the rooting medium, rooting rate was 94.3%, root number was 6.4, and survival rate was 95.8% after 3-month transplanting.ConclusionThe effective breeding system by tissue culture for TM was firstly established via a combined approach of somatic embryogenesis and organogeneis in this study, which would be used for the rapid propagation of elite germplasm for P. massoniana as well as for the research on genetic transformation, providing solid foundation for industrialization of improved varieties and molecular breeding in P. massoniana.
Study on forest structure diversity based on the neighbourhood trees
Bai Yu, Yang Hua, Wen Jing, Wang Quanjun
2020, 42(6): 52-58.   doi: 10.12171/j.1000-1522.20190120
[Abstract](741) [FullText HTML](229) [PDF 735KB](63)
Abstract:
ObjectiveStand is an important part of forest biodiversity. Due to its complexity or lack of ecological relevance, the typical diversity index cannot be analyzed on a spatial scale and therefore cannot reflect the internal changes of species and spatial structure.MethodTaking the spruce-fir forest in Jin’gouling Forest Farm in Wangqing County of Jilin Province, northeastern China as an example, two 60 m × 60 m typical sample plots were set by contiguous grid quadrat method, and a new index describing the diversity of spatial structural units-neighbourhood diversity index was evaluated.Result(1) The diameter structure curve of spruce-fir forest in the study area is multi-peak anti-J-shaped curve. The proportion of forests with small and medium-order diameter was higher, the trees with large diameter were less, and the distribution of diameters was continuous and reasonable. (2) The species diversity and tree diameter of the spruce-fir forest were high, tree species and the diameter distribution were relatively uniform, the degree of mixing was strong, the horizontal structure was highly variable, and the stand structure was complex. (3) Results of the analysis of three neighbourhood diversity indices (species diversity, structural diversity by diameter distribution, and structural diversity by diameter variation) were consistent with the results of the Shannon diversity index, and the close index values were obtained for stand with similar structure.ConclusionThe neighbourhood diversity index can describe the diversity of forest stands and spatial structure characteristics, and reflect the spatial variation of species and structure diversity, and has obvious ecological significance. It can be applied to the structural adjustment of forest stands and provide a theoretical basis for rational forest management.
Simulating study on tree recruitment of Quercus mongolica based on zero-inflated model and mixed effect model methods
Li Chunming, Li Lixue
2020, 42(6): 59-67.   doi: 10.12171/j.1000-1522.20190216
[Abstract](481) [FullText HTML](107) [PDF 611KB](33)
Abstract:
ObjectiveTree recruitment is the basis to ensure forest long-term maintenance, and the recruitment model can predict the development of forest and quantify the future health and productivity of forest ecosystem.MethodAbout 295 permanent sample plots were established across the natural range of Quercus mongolica in the Jilin Province of northeastern China in 1995. Stand factor, site factor, and climate factor were selected to construct recruitment model of Quercus mongolica. The basic forms of model include Poisson distribution and negative binomial distribution. The zero-inflated model was added to these basic models because of the existence of a large number of zero values in the sample plots. The sample plot’s random effect was taken into account in order to solve the problem of nested and longitudinal data in the model. Finally, the validation data were used to verify the fitness of model.ResultStand arithmetic mean diameter and the number of trees per hectare were the most important factors, and both were negatively correlated with the probability and quantity of tree recruitment. Both site and climate factors had no significant effect on tree recruitment. The accuracy of the negative binomial distribution model was higher than that of the Poisson distribution due to the over-dispersion of the data. After considering sample plot’s random effect, all the models obviously improved the simulation accuracy of the model except for the standard negative binomial distribution model. The simulation effect of the negative binomial distribution model was the best when considering random effect and zero-inflated model.ConclusionIn order to ensure the occurrence of tree recruitment, it is very important to determine science management and initial planting density in forest management.
Characteristics analysis of quantity and spatial structure of standing live and dead trees in Tilia amurensis secondary forest on the west slope of Zhangguangcailing, northeastern China
Liu Yue, Xu Liying, Wang Yujiao, Yu Jiangbo, Yang Lixue
2020, 42(6): 68-79.   doi: 10.12171/j.1000-1522.20190305
[Abstract](269) [FullText HTML](164) [PDF 1163KB](31)
Abstract:
ObjectiveThe aim of this study was to provide a basis for the growth, protection and management of Tilia amurensis secondary forest by analyzing the quantity and spatial structure characteristics of standing live and dead trees and exploring the growth state, succession process and the main causes of standing dead trees under two disturbance modes (non-cutting and selective cutting).MethodThe research was conducted by analyzing the species composition, diameter structure, height structure and spatial structure of standing live and dead trees.Result(1) Tilia amurensis, Acer mono, as well as other dominant tree species in living trees also had a dominant position in dead trees in selective cutting stand, while only Tilia amurensis was dominate among the living trees and standing dead trees in non-cutting stand, but Acer mono was only dominate in the living trees, and it was rare in dead standing trees. (2) The standing live and dead trees of the small diameter were dominant in all two stands, and the diameter distribution was roughly inverted J type. The height class distribution of living trees was roughly left-skewed distribution in two stands, while the standing dead trees were inverted J type, meanwhile, the small standing dead trees accounted for a large proportion. Therefore, it could be analyzed that the main reason for the formation of dead trees in the two stands was the competition among trees. (3) The trivariate distribution of spatial structure parameters had shown that there were more dominant living trees, which were randomly distributed, highly mixed and dominant in two stands. Whereas, most of the standing dead trees were randomly distributed, in disadvantaged state, and the surrounding trees were all other tree species or only one was the same tree species. (4) The quadrivariate distribution of spatial structure parameters showed that the standing dead trees of the two stands were randomly distributed in general with good mixture of species and obvious size differentiation. There were three or four standing live trees around one standing dead trees in that state. ConclusionIt further indicates that inter-species competition is the main reason for the formation of standing dead trees. This study analyzed the spatial structure and quantitative characteristics of standing live and dead trees in the secondary forest of Tilia amurensis. Therefore it is not only exploring the formation of dead standing trees in the secondary forest, but also provides a theoretical basis for its protection and management.
Prediction models and changing rules of dead fuel moisture content of 8 forest species in Beijing area
Zhan Hang, Niu Shukui, Wang Bo
2020, 42(6): 80-90.   doi: 10.12171/j.1000-1522.20190370
[Abstract](1584) [FullText HTML](115) [PDF 1100KB](22)
Abstract:
ObjectiveThe forest fuel moisture content has great impact on the occurrence and spread of forest fire, particularly important on the fire behavior, and its prediction forecast models have significant effects on predicting forest fire and forest fire behavior.MethodThrough the continuous determination of dead fuel moisture content of 8 kinds of forest trees in Beijing area during the period of fire prevention, we researched the relationship between fuel moisture content and the current and previous meteorological data, and established the prediction models by selecting the meteorological factors, which has great influence on the fuel moisture content. On this basis, we quantitatively analyzed the diurnal variation and fire protection period variation of the fuel moisture content.ResultThe fuel moisture content of different tree species was significantly different, from descending order was Quercus variabilis, Q. aliena, Ulmus pumila, Robinia pseudoacacia, Acer truncatum, Platycladus orientalis, Pinus tabuliformis, Larix principis-rupprechtii. And the fuel moisture content of different types was also significantly different. Generally the broadleaf tree’s fuel moisture content was higher than that of coniferous trees, and the fuel moisture content of dead leaves and 1 hr dead branches were higher than 10 hr and 100 hr. That of 1 hr of dead branches was mainly affected by the current meteorological factors, while that of 10 hr and 100 hr of dead branches were affected by the early meteorological factors. The test indexes of 32 linear prediction models showed that the fitting effect was perfect. The diurnal variation of the fuel moisture content was higher and more stable at night, lower and varied greatly during the day, which peaked at 06:00−08:00, then dropped sharply, and later reached the lowest value at about 12:00−14:00. During the fire protection period, the fuel moisture content showed a trend of rising first, then decreasing. It was low in November but increased slowly and reached a high level from December to January of the following year. From early March to the end of April, the fuel moisture content kept a very low level.ConclusionHigh-precision prediction methods of different tree species and among different fuel types could offer theoretical support for forest fire prevention, which can be used in practice. In March and at noon time in Beijing, it,s windy, drying and hot and the fuel moisture content is low, so the fire management should be reinforced in such a fire danger period.
Object-oriented tree species classification with multi-scale texture features based on airborne hyperspectral images
Wu Yanshuang, Zhang Xiaoli
2020, 42(6): 91-101.   doi: 10.12171/j.1000-1522.20190155
[Abstract](88) [FullText HTML](42) [PDF 1441KB](14)
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ObjectiveBased on the classification of airborne hyperspectral imagery, the method of combining different scale texture features with object-oriented classification was less applied to the classification of tree species, and the related research was mainly for single tree species identification without considering multiple tree species, therefore, the ability to identify tree species in complex forests needs further study. However, the study in such research was scanty, so this study intended to explore the application of different scale texture features and object-oriented classification techniques in the fine classification of tree species.MethodWe used airborne hyperspectral data with object-oriented classification to classify tree species. According to the type of land cover in the study area, we used stratified classification method to distinguish non-forest land, other forest land and forested land, and finely classify tree species in forest land. Feature variables were extracted from airborne hyperspectral images, including independent component analysis (ICA) transformation images and spatial texture features, analyzed the spectral reflectance and the suitable texture scale of each tree species. The tree species were classified according to different scale texture features, and compared tree species classification results of different features by support vector machine (SVM).ResultConcerning the object-oriented tree species classification combined with texture features, the overall accuracy of single-scale texture features was 87.11%, and the Kappa coefficient was 0.846. Combined with different scale texture features, the overall accuracy was 89.13%, and the Kappa coefficient was 0.87. Compared with the accuracy based on spectral features, the classification accuracy was improved by 4.03% and 6.05%, respectively. It showed that in object-oriented classification, the addition of texture features had a significant effect on improving the accuracy of tree species classification. The classification accuracy of tree species combined with different scale texture features was higher than single scale texture features, especially in the classification of other broadleaved tree species and Masson pine (Pinus massoniana), the producer accuracy was higher than single texture scale by 5.48% and 6.12%, respectively.ConclusionDifferent scale texture feature is more advantageous than single-scale texture feature, which improves the contribution of texture features in tree species classification. The spectrum of integrated airborne hyperspectral imagery and object-oriented classification of different scale texture features make the tree species identification more precise and accurate. It is effective for tree species classification in complex forest, and meets the application requirements in fine tree species identification based on airborne hyperspectral images.
Vegetation coverage information extraction of mine dump slope in Wuhai City of Inner Mongolia based on visible vegetation index
Li Pengfei, Guo Xiaoping, Gu Qingmin, Zhang Xin, Feng Changdong, Guo Guang
2020, 42(6): 102-112.   doi: 10.12171/j.1000-1522.20190252
[Abstract](265) [FullText HTML](167) [PDF 1620KB](29)
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ObjectiveThis paper aims to use visible vegetation index to get the slope vegetation coverage of mine dump quickly and accurately, and to provide an effective method for the vegetation investigation of slope in Wuhai mining area, Inner Mongolia of northern China.MethodThis study selected one of the typical mine dumps in the Wuhai City to choose a suitable visible vegetation index for local research, estimate the dump vegetation coverage, and furthermore try to provide a new method for extracting the dump slope vegetation coverage by means of Quadrat survey, UAV remote sensing and visible vegetation index.Result(1) Different visible vegetation indexes had varied vegetation extraction effects. Among them, the darker part of red-green ratio index (RGRI) and blue-green ratio index (BGRI) represented the larger vegetation index, while the brighter part of other common visible vegetation indexes represented the larger vegetation index. (2) Gray image feature values of different visible vegetation indexes mainly distributed in range of [− 1, 1] in the research area. There was a big overlap of pixel value between vegetation and land in the gray image of normalized green-blue difference index (NGBDI) and BGRI constructed from blue and green bands, which means some partial confusion between them. (3) Visible-band difference vegetation index (VDVI) can extract slope vegetation quickly and accurately among common visible vegetation indices. The average recognition accuracy of VDVI vegetation index was 93.4% by manual visual interpretation and error matrix, showing that VDVI vegetation index could be more suitable for the vegetation extraction on the mine dump in Wuhai City, and was better than the vegetation index of other common visible light. The vegetation coverage of the study area was approximately 20.4% by this method.ConclusionVisible vegetation index, an unsupervised classified method, could be a new method for investigating vegetation coverage of mine dump slope without selecting reference features by people but extract slope vegetation coverage directly and has a broad application prospect. The study also indicates that VDVI shows higher extraction accuracy of extracting vegetation coverage of mine dump slope in the Wuhai City, which means a practical significance to guide the vegetation restoration in local mine dump.
Vegetation type distribution in nature reserve based on CART decision tree
Bai Ying, Hu Shuping
2020, 42(6): 113-122.   doi: 10.12171/j.1000-1522.20190269
[Abstract](1809) [FullText HTML](88) [PDF 888KB](11)
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ObjectiveIn order to meet the needs of nature reserve monitoring, improve the precision of remote sensing inventory on vegetation types, an object-oriented classification method and machine learning algorithms were developed in vegetation classification by GF-1 WFV remote sensing data.MethodThe study site is located in Baishuijiang National Natural Reserve, Gansu Province of northwestern China. The GF-1 WFV multispectral data, Landsat-8 OLI remote sensing data, DEM data and field survey data were employed as the key data sources. Firstly, the multiresolution segmentation of GF-1 WFV data was carried out, and the research area was divided into many polygon objects. Then spectral features, geometric features and texture features from polygon objects were extracted to vegetation classification using CART decision tree. Finally, the accuracy of classification was analyzed by error matrix based on TTA mask.ResultIn the multiresolution segmentation process, the shape factor and compactness were set to 0.2 and 0.5, respectively, the boundary of the polygon objects was identical with ground objects. When the shape factor and compactness were fixed, the optimal segmentation scale was 40. The accuracy results showed that the overall accuracy and Kappa coefficient were exceed of 83% and 0.80 in three CART decision trees, which was superior to KNN algorithm and SVM algorithm. Overall accuracy and Kappa coefficient of CART decision tree reached 85.18% and 0.832 2 by spectral, geometric and texture features, which was better than CART decision tree by spectral features or spectral combined with geometric features.ConclusionThe image classification based on CART decision tree algorithm and object-oriented classification method were suitable for vegetation classification in nature reserve by GF-1 WFV image, which could effectively assist the nature reserve monitoring.
Effects of converting years from farmland to forestland on soil physical properties in the loess area of western Shanxi Province, northern China
Zhang Hengshuo, Zha Tonggang, Zhang Xiaoxia
2020, 42(6): 123-133.   doi: 10.12171/j.1000-1522.20190087
[Abstract](240) [FullText HTML](136) [PDF 1543KB](16)
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ObjectiveThis paper aims to evaluate the effects of converting time from cropland to forestland on soil physical properties, and provide a basis for the construction of soil and water conservation forests in the region.MethodThe 23 years positioning continuous monitoring was taken on soil physical properties under five typical forests, including one natural restoration Populus davidiana plantation, two mixed plantations of Platycladus orientalis and Robinia pseudoacacia, Pinus tabuliformis and Robinia pseudoacacia, two pure plantations of Robinia pseudoacacia and Pinus tabuliform, and taking the corn farmland as control.Result(1) With the increase of converted years, the soil bulk density (BD) under the four plantations increased first and then decreased to a stable value, which was lower than initial value at about 10−15 years. In the natural restoration forest (NF), BD showed a downward tendency with the highest decreasing range of 11.21% at 0−20 cm soil depth. (2) The soil total porosity (TP) under the 4 plantations decreased first and then increased to a stable value, which was higher than initial value at about 10−15 years. The cumulative changing rates of TP at the soil depths of 0−20 cm and 20−40 cm were 1.4% and 0.6%, respectively under NF. (3) The capillary porosity (CP) under the five typical forests all showed an increasing trend with the increase of converting time. The CP at 0−20 cm changed more than at 20−40 cm in the plantations; the cumulative changing rates of CP at 0−20 cm and 20−40 cm were 2.5% and 1.5%, respectively under NF.Conclution The converted years showed a significant effects on soil physical properties (P < 0.05) under the typical forests, while for the plantations, the change of BD and TP mostly occurred in the first 10−15 years. The mixed forests of Pinus tabuliformis and Robinia pseudoacacia should be the prioritized for the artificial vegetation restoration in the research area based on its remarkable improvement effects on soil physical properties.
Response of litter decomposition to warming of Artemisia ordosica in Mu Us Desert of northwestern China
Mu Yu, Jia Xin, Zheng Jiajia, Huang Songyu, Yuan Yuan, Bai Yuxuan, Qin Shugao
2020, 42(6): 134-141.   doi: 10.12171/j.1000-1522.20190092
[Abstract](690) [FullText HTML](107) [PDF 878KB](18)
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ObjectiveThe response of litter decomposition rate of Artemisia ordosica to warming is helpful to understand and predict the carbon cycle and nutrient cycling of the Mu Us Desert of northwestern China under the background of climate change.MethodThe Open Top Chamber (OTC) was used to simulate the warming, and plant decomposition was put into the mesh bags to explore the effects of warming on the decomposition of Artemisia ordosica litter.ResultThe residual rate of litter quality of each part under the warming treatment was higher than that of control, simulated warming reduced the rate of litter decomposition. (1) From May to October in 2017, under the warming treatment, the residual rates of the twig and letters were 91.07% and 71.73%, respectively, but under control, the two indicators were 86.08% and 60.74%; (2) different types of litter decomposition rates were different under varied treatment conditions at different time periods, and there were significant interactive effects between each influening factor; (3) the Olson negative index model showed that under the warming treatment, the decomposition coefficient k of the twigs and leaves of Artemisia ordosica litter was lower than that of control. (4) Warming didn’t affect the bacterial diversity and structure of litter.ConclusionWarming may slow down the decomposition of plant litter in arid and semi-arid areas, and the inhibition of warming on litter decomposition is related to decomposition time and litter types.
Forestry Engineering
Preparation of lignin-based carbon aerogel under hypersaline template and its electrochemical applications
Liu Jiaran, Guo Siqin, Zhao Tianchang, Xu Feng
2020, 42(6): 142-148.   doi: 10.12171/j.1000-1522.20200096
[Abstract](918) [FullText HTML](97) [PDF 1368KB](11)
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ObjectiveThe porous carbon aerogel was prepared by hydrothermal reactions of industrial lignin, formaldehyde and salt undercarbonization process. The structure, physicochemical and electrochemical properties were tested to explore its possible applications in supercapacitor electrode materials.MethodAlkali-lignin (2 g) was mixed with three different salts (ZnCl2, NaCl and Na2CO3) following the addition of 1.5 mL of formaldehyde. The mixture was stirred into a thick paste and transferred to the reactor. The temperature was raised to 160 ℃ for 2 hours to produce a series of lignin carbon aerogel (LCA) precursors. In a tube furnace filled with nitrogen, the temperature was raised to 900 ℃ at a rate of 3 ℃/min, and the temperature was kept warm for 3 hours for carbonization. Then the product was washed and cooled to obtain LCA. The structure and physicochemical properties of carbon aerogel were characterized by specific surface area (SSA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). After being grounded, the carbon aerogel was made into supercapacitor electrodes. Electrochemical energy storage was characterized by cyclic voltammetry, cyclic charge-discharge test and open-circuit impedance test.ResultThe maximum specific surface area of LCA prepared with ZnCl2 as template was 711 m2/g. The gelatinous structure observed under SEM and XRD results revealed that the bulk of LCA was composed of amorphous carbon. Furthermore, at a current density of 0.2 A/g, the specific capacitance reached 124 F/g, however, increasing the current density up to 10 A/g, the specific capacitance remained 60 F/g, with a capacitance retention rate of about 48%, which had the best multiplier performance.ConclusionFinally, LCA was directly prepared by hydrothermal and carbonization process under hypersaline condition with cheap industrial lignin as raw material. LCA dominated by amorphous carbon can be prepared under ZnCl2 salt template. It has high specific surface area and excellent electrochemical performance, which can be used as an electrode material for supercapacitor. This method has the advantages such as environmental friendliness, simple operation and low cost with possible industrial applications.
Forestry Engineering
Effects of Penicillium griseofulvum’s biological dyeing on the properties of Phyllostachys heterocycla
Wang Haowei, Yu Zhiming, Zhang Yang, Tang Ruilin, Liu Yuansong, Wang Xiaoqian, Huang Siqi, Zhao Boshi
2020, 42(6): 149-156.   doi: 10.12171/j.1000-1522.20200150
[Abstract](1084) [FullText HTML](367) [PDF 1015KB](18)
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ObjectiveDiscoloration of bamboo is common. However, the functional development for this feature is still insufficient. The discoloration of bamboo affects the use value and economic value of bamboo and its products. At present, the research on biological discoloration of bamboo is mainly aimed at prevention and control. In this study, the biological dyeing of bamboo was realized by inducing Penicillium griseofulvum to infect bamboo, which is easy to change color.MethodThe bamboo infected by P. griseofulvum was prepared by fungal culture, inoculation, infection, sterilization and drying; the effects of P. griseofulvum infection on the micromorphology, chemical components, surface properties, physical and mechanical properties of Phyllostachys heterocycla were analyzed by SEM, ATR-FTIR, surface color difference test, surface contact angle test, surface roughness test, mass loss rate and 24 hours water absorption, mechanical strength test.ResultThe red exudate secreted by P. griseofulvum accumulated and permeated to the surface of Phyllostachys heterocycla. P. griseofulvum entered, spread, grew and produced pigment in the interior of bamboo through vessel cells in bamboo vascular bundles. The degradation of cellulose, lignin and hemicellulose mainly occurred in the early stage of infection. The infection behavior made the surface color difference value of Phyllostachys heterocycla increased continuously, the color changed to dark red gradually, forming a unique decorative effect. At the same time, the surface contact angle became smaller, and the surface roughness had no obvious change. The influence of infection behavior on the physical and mechanical properties of Phyllostachys heterocycla was small, the mass loss rate was slightly increased, the water absorption rate decreased in 24 hours, and the decrease of mechanical properties mainly occurred in 10−20 days of infection.ConclusionThis study proves that the biological dyeing of bamboo can achieve better dyeing effect and has no serious adverse effects to bamboo properties, which provides the theoretical basis for further research of biological dyeing technology of bamboo.

Establishment Time:1979

CN 11-1932/S

ISSN 1000-1522

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