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Kinetics analysis and strategy of compensation control study for feeding platform of curve saw for wood
Meng Zhaoxin, Cao Jiajia, Zhu Li, Ma Jingyao, Shi Jinsong
Corrected proof  doi: 10.12171/j.1000-1522.20190234
[Abstract](194) [FullText HTML](70) [PDF 1385KB](8)
ObjectiveFeeding platform is a mechanism designed by imitating manual feeding when sawing wood board. The posture of platform end is the key to ensure sawing quality. A compensation control strategy was proposed in this paper to enhance the accuracy of end posture as the error of platform cannot be simply and efficiently compensated just through hardware.MethodFirstly, Lagrange method was used to establish the dynamic transfer function of the platform. Through dynamic analysis, the motion characteristics of the key components of the platform were analyzed. By simulation and other methods, according to mathematical solution, the error and its characteristics of the end posture were studied, thus a simple error model was established. Secondly, based on the traditional PID control and the parameter optimization function of RBF neural network, a single neuron PID controller suitable for the feeding platform was designed to compensate the driving displacement relation of each branch chain and to carry out real-time compensation control on the mechanism. Finally, the compensation control strategy was verified and analyzed by the joint method of Matlab and Adams, and the algorithm was transplanted to the controller of the feeding platform successively.ResultAfter compensation by the single neuron PID algorithm, the offset error of the end trajectory curve of the feeding platform in X and Y directions was reduced from 3 mm to less than 1.5 mm, and the angle error was reduced from 3.5° to 1.5°, and in most curve segments, the end trajectory curve of the platform completely coincides with the command curve.ConclusionThe SN-PID proposed by this paper can effectively improve the accuracy of the end posture of the woodworking saw feeding platform, and the feeding platform after compensation control can realize the precise cutting task of the wood plate.
Above-ground Biomass Distribution of Quercus aliena var. acuteserrata Forest in Taibai Mountain
Yu Wen, Pang Rongrong, Peng Jieying, Zhang Shuoxin, Yan Yan
Corrected proof  doi: 10.12171/j.1000-1522.20190440
[Abstract](23) [FullText HTML](26) [PDF 782KB](7)
ObjectivesBiomass estimation is critical for carbon stock assessment under global climate change. Taibai Mountain is the main peak in the Qinling Mountains. The forest biomass distribution in Taibai Mountain would provide the basis for the dynamics of forest carbon sequestration during the vegetation restoration in the Qinling Mountains.MethodsWe analyzed the differences of above-ground biomass in different habitats, sampling scales and DBH classes. The significance of difference was determined by ANOVA based on the field measurements of environmental factors and trees with DBH ≥ 1 cm in two 1.5 ha permanent plots in the primary and secondary Q. aliena var. acuteserrata forests.ResultsThe results showed that the average above-ground biomass of the primary and secondary forest plots were 279.50 t/ha and 217.81 t/ha, respectively. Significant differences were found in above-ground biomass in different habitats. In the primary forest, the above-ground biomass was larger in the habitat with low total nitrogen, while the above-ground biomass in the secondary forest was larger in habitat with lower available phosphorus. Moreover, the above-ground biomass was larger in the habitat with a higher degree of concavity in the primary forest. At the same sampling scale, the above-ground biomass in the primary forest was larger than in the secondary forest. No significant difference in the above-ground biomass was found at different sampling scales in each forest. However, in the primary forest, the average above-ground biomass showed a unimodal trend along the increase of DBH class. And the above-ground biomass was the largest at the Ⅵ DBH class. The above-ground biomass increased along the increase of the DBH class in the secondary forest. The above-ground biomass in the primary forest was higher than that in the secondary forest at the Ⅳ ~ Ⅶ DBH classes, while smaller than that in the secondary forest at the Ⅸ DBH class.ConclusionsTherefore, disturbance, habitat heterogeneity and DBH class can affect the above-ground biomass allocation in Q. aliena var. acuteserrata forests.
Dyeing process and mechanism of eucalyptus veneer with Dalbergia bariensis heartwood pigment as dye
Zhang Qingshuo, Yang Yutong, Fu Yunlin, Sun Jing
Corrected proof  doi: 10.12171/j.1000-1522.20190270
[Abstract](315) [FullText HTML](245) [PDF 1171KB](13)
ObjectiveIn order to make full use of the processing residues of Dalbergia bariensis and improve the added value of eucalyptu, natural dye has been extracted from the Dalbergia bariensis heartwood.MethodThe main components of Dalbergia bariensis heartwood content were analyzed by ultra-high performance liquid chromatography with quadrupole-electrostatic field orbitrap high resolution mass spectrometry. The best dyeing process and color fastness were measured. The binding mechanism of Dalbergia bariensis dye and eucalyptus veneer was analyzed by Fourier transform infrared spectroscopy (FTIR).The distribution characteristics of the dye in eucalyptus veneer were observed by the field emission scanning electron microscope (FESEM).ResultNine flavonoids were identified from the pigment of Dalbergia bariensis heartwood by UPLC-Q-EXACTIVE-MS: malvidin, rhamnetin, butein, sakuranetin, alizarin, luteolin, hemotoxylin, pinocembrin, taxifolin. The optimal dyeing process of eucalyptus veneer was: dyeing temperature 90 ℃, dyeing time 12 hours, pigment mass fraction 4%, NaCl mass fraction 2%. The order of influence factors of dyeing test was: temperature > pigment mass fraction > dyeing time > NaCl mass fraction. The order of influence factor of color fastness was: temperature > pigment mass fraction > dyeing time > NaCl mass fraction. It was preliminarily determined as physical adsorption and intermolecular hydrogen bonding through the analysis of FTIR’s and FESEM’s reaction to the dyeing mechanism.ConclusionNatural dye extracted from Dalbergia bariensis heartwood was used to imitate the precious rosewood by dyeing eucalyptus veneer, which blazes a trail in the full utilization of precious rosewood and explores the high value-added utilization of fast-growing wood.
Optimization of induction conditions for embryogenic callus of somatic embryogenesis in Cunninghamia lanceolata
Wu Xialei, Han Chao, Sun Yuhan, Cao Sen, Hu Ruiyang, Xu Jinliang, Zheng Huiquan, Li Yun
Corrected proof  doi: 10.12171/j.1000-1522.20190196
[Abstract](27) [FullText HTML](18) [PDF 956KB](5)
ObjectiveTo optimize the induction culture of embryogenic callus in the somatic embryogenesis process of Cunninghamia lanceolate and explore the effects of basic medium, maternal genotype and exogenous additives on the induction of Cunninghamia lanceolate somatic embryo.MethodFemale gametophyte (the immature zygotic embryo is in the multi-embryo stage) of three parental genotypes (Z1, Z2, Z3) were used as explants, and used six basic media, different concentrations of exogenous additives of TDZ and MeJA, cytological observation during the induction culture.ResultWith DCR as the basic medium, the induction culture was best, the callus induction rate was 70.74%, and the induction rate of embryogenic callus was 17.36%, which was the best choice for the induction of immature embryo culture of Cunninghamia lanceolate; The maternal genotype has a greater impact on embryogenic callus induction, and the female gametophyte of the Z1 genotype tree is most suitable for inducing embryogenic callus; With DCR as the basic medium, adding sucrose 30 g/L, activated carbon 1 g/L, plant gel 5 g/L and adding plant growth regulator 2,4-D 1.5 mg/L, KT 0.4 mg/L, MeJA 1.2 μmol/L and TDZ 0.004 mg/L, the embryogenic callus of Cunninghamia lanceolate The induction rate is the highest, reaching 19.83%; Embryogenic callus can be induced in only 4 days, and the structure and polarity characteristics of the Proembryogenic masses in different stages are significantly different.ConclusionThe basic medium, maternal genotype and exogenous additives all significantly affected the induction culture of Cunninghamia lanceolate somatic embryos. Female gametophyte with Z1 donor parental genotype as explants, DCR as the basic medium and adding MeJA and TDZ in combin 4ation can significantly improve the somatic embryos induction rate of Cunninghamia lanceolate.
Study on soil enzyme activities and physicochemical properties of typical woodlands in karst faulted basins
Sun Yonglei, Lu Zeyang, Zhou Jinxing, Pang Danbo, Liu Yuguo, Guan Yinghui
Corrected proof  doi: 10.12171/j.1000-1522.20180328
[Abstract](17) [FullText HTML](15) [PDF 705KB](10)
ObjectiveSoil enzymes are involved in all soil biochemical processes and are closely related to soil physicochemical properties. In this paper, three typical woodlands in karst faulted basins were studied, and the relationships between soil enzyme activities and physicochemical properties of forest lands were explored, which provides a reference for vegetation ecological restoration in this area. MethodIn this study, the Pinus yunnanensis, Eucalyptus maideni and natural secondary forest in the karst faulted basin were used as research objects. The relationship between soil enzyme activities and physicochemical properties was studied by using the methods of redundancy analysis.Result(1) The soil pH values of the three forest lands ranged from 5.47 to 6.03, and the soil bulk densities of the 10−20 cm and 20−30 cm soil layers in the Pinus yunnanensis forest were significantly higher than those of the Eucalyptus maideni forest and the secondary forest (P < 0.05). The contents of TN in 0−10cm and 10−20cm layers of Eucalyptus maideni forest were significantly higher than those in Pinus yunnanensis forest and secondary forest (P < 0.05). The AP content in 0-10cm soil layer of secondary forest was significantly higher than that in Pinus yunnanensis forest and Eucalyptus maideni forests (P < 0.05). The contents of SOC and AN showed the law of secondary forest > Pinus yunnanensis forest > Eucalyptus maideni forest. (2) The activity of acid phosphatase and urease in the 0−10 cm soil layer of three woodlands was in order of secondary forest > Eucalyptus maideni forest > Pinus yunnanensis forest, while the 10−20 cm soil layer showed the opposite law. The highest activities of amylase, cellulase and invertase in 0−10 cm and 10−20 cm soil layers were obtained from secondary forest, followed by Pinus yunnanensis forest and the lowest in Eucalyptus maideni forest. In addition, the soil enzyme activities in the soil layers of the forests were significantly different (P < 0.05), and the soil enzyme activities showed a trend of decreasing with the increase of soil depth. (3) Through the redundancy analysis of soil physicochemical properties and enzyme activities in the three forest lands, the results showed that SOC, AN, AP and pH all had a significant positive correlation with invertase activity. However, total N was significantly negatively correlated with invertase activity. Soil bulk density was negatively correlated with urease and acid phosphatase activities. (4) the Monte Carlo test showed that the order of importance of soil physicochemical properties on soil enzyme activities was: SOC (41.4%) > AN (32.9%) > AP (24.3%) > bulk density (12.6%) > TN (7.9%) > pH (5.5%).ConclusionComprehensive analysis showed that SOC and AN were the main indicators affecting the changes of soil enzyme activity in the study area. The secondary forest is the best in the restoration of soil fertility and enzyme activity in karst faulted basins, while the advantage of Pinus yunnanensis forest is higher than that of Eucalyptus maideni forest.
Relationships between leaf functional trait variation of Cotinus coggygria under drought stress and location geographical-climatic factors
Li Jinhang, Zhu Jiyou, Catherine Mhae B. Jandug, Zhao Kai, Xu Chengyang
Corrected proof  doi: 10.12171/j.1000-1522.20190079
[Abstract](13) [FullText HTML](10) [PDF 859KB](2)
ObjectiveThis study aims to identify leaf functional variation patterns and differences of Cotinus coggygria seedlings from different locations and to analyse the influences of different geographic-climatic factors on leaf functional variation under continuous drought environment.MethodA standard continuous drought stress experiment was carried out using one-year-old C. coggygria seedlings from five different locations within China. Three levels of water regimes were set: control (CK, 75% ~ 80% of soil field capacity), moderate stress (MS, 55% ~ 65% of soil field capacity) and severe stress (SS, 35% ~ 45% of soil field capacity). ANOVA was used to identify the effects of drought, location and their interaction on leaf functional traits. On the other hand, the Principal Component Analysis (PCA) and the Redundancy Analysis (RDA) were used to measure the relationship between location distribution of the species and the geographical-climatic factors and the influences of geographical-climatic conditions on leaf functional trait variation degree (TVD), respectively.Result1) Drought stress had significant effects on all the leaf functional traits. Seedlings under SS had lower leaf function traits in terms of leaf chlorophyll content (LChl, 17.61%, P < 0.001), relative water content (RWC, 3.71%, P < 0.001), specific leaf area (SLA, 10.89%, P = 0.002), and leaf area ratio (LAR, 17.22%, P = 0.001) compared to the seedlings under CK. However, seedlings under SS had higher leaf dry matter content (LDMC) and leaf density (LD) by 9.04% (P < 0.001) and 14.52% (P = 0.009), respectively. 2) Correlations among leaf functional traits became stronger in drought environment which showed that SLA had significantly (P < 0.01) negative links with LDMC and LD, LDMC and LD had a significant (P < 0.01) and positive relation, and RWC had significantly positive correlations with LChl (P < 0.01), SLA (P < 0.01) and LAR (P < 0.05). 3) The leaf functional traits showed significant differences among C. coggygria locations under drought treatments. SLA (P = 0.002), LChl (P = 0.025) and LD (P = 0.026) were significantly different under MS treatment, and LChl (P < 0.001), LAR (P < 0.001) and RWC (P = 0.005) were significantly different under SS treatment. 4) Among the five different locations, C. coggygria seedlings from Yanqing County in Beijing had the highest average trait variation degree (the mean values of all trait variation degrees) by 17.57% while the lowest was from Jiang County of Yuncheng City in Shanxi Province by 6.97%. 5) After the screening of RDA, precipitation of the driest month (DMP, P = 0.002), growing season mean monthly precipitation difference (GSPD, P = 0.008), max. temperature of the warmest month (WMT, P = 0.016) and average annual precipitation (ANP, P = 0.036) had significant effects on leaf functional trait variation degree. Particularly, DMP had negative relationships with all trait variation degree, but more significant with the variation degree of LDMC and LD. GSPD and ANP had significantly negative relationships with the variation degree of SLA and LAR. WMT was closer to the variation degree of LChl.ConclusionSignificant differences were found for leaf functional traits of C. coggygria among different drought treatments and different locations. The local climate (especially DMP, GSPD, WMT and ANP) was the main cause of leaf functional trait variation of C. coggygria from different locations under drought stress. Among seedlings from the five locations explored in our study, seedlings from Jiang County of Yuncheng City in Shanxi Province were more suitable to introduce to the arid areas in Northern China, as a result of a relatively high DMP, a proper GSPD and ANP, a relatively low WMT, and a low average leaf functional trait variation degree under drought stress.
Experimental research on mechanical performance of damaged bracket set joints
Chen Jiuzhang, Chen Xueyao, Dai Lu
Corrected proof  doi: 10.12171/j.1000-1522.20190278
[Abstract](375) [FullText HTML](105) [PDF 1266KB](27)
ObjectiveThe bracket set is an important component of the wooden structure in Chinese ancient architecture system, which plays a vital role in maintaining the mechanical properties of the whole structure reliable. There are different degrees of damage of bracket set joints in existing ancient structures. While at present, most of the researches on the mechanical properties of bracket set joints are based on intact bracket sets, and little consideration is given to the mechanical properties and deformation rule of damaged bracket sets, especially under the condition of decaying and volume loss caused by worm moths. Therefore, it is of great practical significance to study the effect of damage on the mechanical properties of bracket set joints or even the whole structure, which can also help provide scientific basis for the repair and protection of ancient timber structures.MethodThis research took a typical second-story bucket arch on columns in supporting platform of Yingxian Wooden Tower, Shanxi Province of the northern China as the object, and made four groups of bracket set models with the 1/3.5 scale. One group of model kept in perfect condition, while the remaining three groups were drilled with holes in different positions artificially to weaken the stress-bearing section of components of the bracket set joints, so as to simulate the real damage to them. By adopting the vertical loading test, the load-displacement curves of four groups of bracket set joints were obtained, and the mechanical characteristics and deformation performances of bracket set joints were clarified combining the test result.ResultThe test result and data analysis showed that under certain vertical loads, the failure of bracket joints was mainly reflected in the fracture, bending deformation of the second-story Hua-Gong and cracks on the connection block. The failure mode of damaged bracket set joints was similar to that of the intact one. While pre-drilled groups sufferred from worse damage as their ultimate load and stiffness decreased, and the negative effect caused by the former damage was more obvious on the stiffness of bracket set joints.ConclusionWhen the damage type is the same and the overall damage condition of the structure is similar, the damage on the first story of a bracket set joint would exert greater influence on stiffness, which means it is easier to deform when bearing vertical loads.
Growth of Lasiodiplodia theobromae and its effect on the surface properties of rubber wood
Zhao Boshi, Yu Zhiming, Zhang Yang, Qi Chusheng, Tang Ruilin, Liu Yuansong, Wang Haowei, Han Yiyun
Corrected proof  doi: 10.12171/j.1000-1522.20190382
[Abstract](93) [FullText HTML](54) [PDF 1038KB](17)
ObjectiveLasiodiplodia theobromae is one of the main fungi that causes the blue stain of rubber wood, and most researches focused on prevention of blue stain. This paper uses the diversity of blue stain from prevention to induction, to improve the utilization value of blue phenomenon.MethodBy analyzing the effects of different proportions of czapek-dox medium on the growth rate of Lasiodiplodia theobromae on the culture medium and the surface of rubber wood, the optimum environment was optimized, and we investigated the effects of Lasiodiplodia theobromae on the surface properties of rubber wood.ResultThe results showed that optimum environment was yeast extract 9 g/L, glucose 20 g/L, pH weak acidity, MgSO4 1.0 g/L, FeSO4 0.03 g/L, KCl 0.2 g/L. With the increase of time, the dyeing area of surface color gradually increased, and the color changed from red and yellow to blue and green, and the light fastness gradually increased, and static state contact angle was improved by 13.04%, and the dynamic state contact angle inproved prominently, and surface roughness and wear resistance gradually decreased.ConclusionIn this study, Lasiodiplodia theobromae dyed rubber wood was prepared, and the surface texture and color of rubber wood were controlled by different time gradients, which verified the feasibility of biological wood processing and expanded the utilization value of microorganisms in wood processing.
Country park planning and design based on bird habitat construction—a case study of Longquan Lake Park east district, Shijiazhuang
Yan Jialun, Dong Yuxiang, Ye Kemo, Suo Yunbo, Yan Na, Han Li, Lin Chensong
Corrected proof  doi: 10.12171/j.1000-1522.20190372
[Abstract](25) [FullText HTML](25) [PDF 1593KB](10)
ObjectivePut species diversity protection as the goal, bird habitat construction as the breakthrough point, recommend methods and strategies for promoting country park landscape quality.MethodAfter the survey of bird species was conducted in Longquan Lake area, some target species of birds were selected. Through the study and analysis of the ecological habits of the target species, the need for habitat was clarified. Construct vertical and horizontal space of bird habitat suitability index system, including water type, habitat area, water bank form, waterfront buffer zone, plant coverage, terror distance,water depth and plant height. These index were analyzed and summarized to draw a scientific and rational country park landscape plan.ResultA total of 23 target species of birds were identified and their habitats were about 20.3 hectares, including 11.4 hectares of water area habitats and 8.9 hectares of land area habitats. Water area habitats has six zones: the surface area of water in each zone is between 2.6 and 5.8 hectares. The coverage of aquatic plants is between 30% and 65%. The flush distance is 50 meters; The average water depth is between 0.8 and 2.5 meters. The average height of aquatic plants is 0.3 and 1.8 meters. Land habitat also has six zones: Arbor coverage of the waterfront buffer area in each zone is between 10% and 16%, shrub coverage is between 35% and 44% and herb coverage is between 40% and 55%.The average plant height is 8.6 to 22.5 meters. Herb ranges from 12 to 31 species; The flush distance is 50 meters too.Conclusion(1) The index system of bird habitat suitability was constructed and the construction strategy was proposed, which could provide theoretical support and practical guidance for the planning and design of country parks. (2) Country parks should have different sizes, rich functions, winding natural slope revetment and a certain depth of water space; Plant landscape should not only meet birds' requirements for water area, near-shore buffer zone, vegetation coverage, community composition and height, but also enhance the richness of ground cover. Park roads and sites should adopt a strategy of near-natural materials and low bird disturbance. (3) During the planning and design of country parks, attention should be paid not only to the demand of birds for habitat and the relationship between different species of birds, but also to meet the needs of human leisure and recreation, so as to realize the harmonious coexistence of man and birds.
Exploring the Strategy of Scenic Forest Construction in Cultural Heritage Corridor—Taking a scenic forest special plan of the ancient Great Wall cultural heritage corridor in Datong as an example
Shui Jialing, Yao Guanggang, Feng Xiao
Corrected proof  doi: 10.12171/j.1000-1522.20190307
[Abstract](44) [FullText HTML](25) [PDF 3153KB](2)
ObjectiveEcological corridor is an important component of cultural heritage corridor, and vegetation restoration is the core of ecological corridor construction. Vegetation restoration in cultural heritage corridors should not only meet the requirements of ecological restoration, but also meet higher demands, e.g., inheriting historical features and presenting characteristic landscapes. Scenic forest is an artificial or natural community with ornamental, recreational and tourism function under the premise of ecological stability, which has high ecological, aesthetic and tourism value, and can realize the balanced development of natural ecological and cultural landscape in the cultural heritage corridor. Therefore, the study of scenic forest construction strategies in cultural heritage corridors is very important and urgent.MethodThis study takes the "Special Planning of Scenic Forest in the Ancient Great Wall Cultural Heritage Corridor of Datong City" as an example, and explores the strategy of constructing scenic forest in the heritage corridor. The specific methods are as follows: First, according to laws and regulations, the buffer zones of heritage protection are decided. Outside the buffer zone, after collecting and analyzing the digital information, the scopes of afforestation are determined. Then the afforestation classes are resolved according to the specific conditions of the land. Next, according to the specific situation of the corridor, the vegetation landscape control and afforestation intensity control are formulated. Finally, the selection of varieties, vegetation community construction and planting method design are determined based on the local native plant community.ResultThis research breaks through the traditional afforestation method and guides the construction of cultural heritage corridors along the length of the ancient Great Wall in Datong City with a length of about 250 km and a surface area of nearly 186 km2.ConclusionThe successful implementation of this case fully proves the effectiveness of the above-mentioned scenic forest construction strategy in the heritage corridor.
Changes of inorganic nitrogen in the leachates of urban forest soil and its soil nitrogen under the irrigation of different mass concentrations of ammonium nitrogen——taking Harbin as an example
Duan Wenjing, Duan Wenbiao, Chen Lixin, Shen Hailong, Mu Yu, Han Donghui
Corrected proof  doi: 10.12171/j.1000-1522.20180193
[Abstract](39) [FullText HTML](20) [PDF 988KB](7)
ObjectiveIn order to ascertain the change of soil nitrogen and ammonium nitrogen, nitrate nitrogen in the urban forest soil leachate were irrigated with different mass concentrations of ammonium nitrogen.MethodThis paper selected 3 typical forest types in the demonstration base of urban forest in Harbin (Quercus mongolia plantation, Fraxinus mandshurica plantation, Phellodendron amurense plantation) as the object of this study. Bare ground without vegetative growth was used as a control. Through the method of field collecting soil column and indoor soil column simulation, the different mass concentration of ammonium nitrogen solutions (100, 50, 25, 0 mg/L) were prepared by using ammonium sulfate for indoor simulation irrigation, ammonium nitrogen and nitrate nitrogen in soil column leachate and soil nitrogen in column after treatment were measured and analyzed.ResultThe effects of three forest types on the removal of ammonium nitrogen were significant, the removal rate was above 95%; There was no significant difference in the removal of ammonium nitrogen by different forest types under the load of different mass concentration of ammonium nitrogen; The mass concentration of nitrate nitrogen in original soil column leachate for three forest types and a control was higher, it ranged for 4.41 to 5.53 mg/L; When the influent ammonium nitrogen mass concentration was 100 mg/L, except for the control, the content of ammonium nitrogen in soil columns for the three forest type was increased; when it was lower than 100 mg/L, except for the Quercus mongolia plantation, the content of ammonium nitrogen in the soil columns for the other two forest type was reduced; the content of nitrate nitrogen in soil column for each forest type and the control was significantly increased, but the difference in total nitrogen content between them was not significant; After irrigation with different mass mass concentration of ammonium nitrogen, the change of ammonium nitrogen in soil column leachate was not significantly affected by the forest type, influent water amount and their interaction. But their effect on nitrate nitrogen reached a significant level. The change of nitrogen in the soil column after irrigation was significantly influenced by the above three factors.ConclusionFor the original soil column in three forest types and bare soil, ammonium nitrogen removal and nitrate nitrogen leaching loss in the soil in Quercus mongolia plantation were most significant, followed by the soils in Phellodendron amurense plantation, Fraxinus mandshurica plantation soil and bare soil.
Applications of Machine Learning Algorithm in Forest Growth and Yield Prediction
Lei Xiangdong
Corrected proof  doi: 10.12171/j.1000-1522.20190356
[Abstract](57) [FullText HTML](68) [PDF 809KB](15)
Forest growth and yield prediction is an important field of forest management science, and modelling forest growth and yield is key to forest management decision-making. The traditional statistical growth models such as linear and nonlinear regression model, mixed-effect model, quantile regression, variable-in-error model are often applied under certain statistical assumptions, such as the data are independent, normally distributed and homoscedastic. The above requirements are usually difficult to be met for forest data with repeated observation and hierarchy. With the development of AI techniques, machine learning provided a new way for forest growth modeling, with the advantages of no requirements on data distribution, extracting deep knowledge from the data, and high accuracy. The applications in forest growth and yield are still less than other domains. We reviewed the main machine learning algorithms including classification and regression tree (CART), multivariate adaptive regression splines (MARS), bagging regression, boosted regression tree (BRT), random forest (RF), artificial neural networks (ANN), k-nearest neighbors (k-NN), and support vector machine (SVM), parameter tuning, software, advantages and challenge. We concluded that machine learning would be widely applied with great potential and its combination with traditional statistical methods would become a trend in forest growth and yield prediction.
Effects of soil physical properties under the influence of the Conversion of the Cropland into Forestry in Loess Plateau of Western Shanxi province
Liu Junting, Zhang Jianjun, Sun Ruoxiu, LI Liang
Corrected proof  doi: 10.12171/j.1000-1522.20180376
[Abstract](304) [FullText HTML](203) [PDF 1025KB](12)
ObjectiveIn order to discuss the " Grain for Green Project” on improving the soil physical property, we did an analysis about the change of soil physical property in different age.MethodThe paper selected three kinds of land uses (grass, pure plantation, mixed plantation) in the Shanxi west loess area, contrasting with farmland, to discuss the effects of the various ages in the Grain-for-Green Program on soil physical properties such as soil bulk density, soil total porosity and capillary porosity.ResultThe soil bulk density increased significantly with soil depth. The mean soil bulk density of 0−60 cm soil layer was farmland (1.38 g/cm3) > grass (1.27 g/cm3) > pure plantation (1.20 g/cm3)> mixed plantation (1.18 g/cm3). There were significant differences in the soil bulk density of woodland and grass, farmland (P < 0.05). Besides the soil bulk density decreased as the increasing year since abandoned. The value of it has been stable in 1.16 g/cm3 after 23 years old. The best improvement effect was the topsoil, but faded away with the with increasing soil depth. The total porosity was inversely proportional to the age and tended to vary gently with increasing age of stand. The value of total porosity of topsoil was the biggest which was 50.8%−57.6%, and the periods of greatest change is 5−10 years old The value of it has been stable in 55.61% after 25 years old. The mean in the layers of 0−60 cm was mixed plantation (53.67%) > pure plantation (52.87%) > farmland (47.82) > grass (45.97%). There were significant differences between the grass, farmland and woodland in the total porosity (P < 0.05), and the pure plantation was significantly different from the mixed plantation. With the growth of forest age, the capillary porosity also increases. The value of the mixed plantation and the pure plantation is 52.21% and 50.37%, which is significantly different from the farmland (45.62%).ConclusionThe project of the Grain for Green can obviously improve soil physical properties, and the effect of mixed plantation on soil improvement is better than pure plantation.
Screening Study of Fire Resistant Tree Species in Jianshui County, Yunnan Province
Gu Wangming, Lu Zeyang, Huang Chunliang, Li Yifan, Guan Yinghui
Corrected proof  doi: 10.12171/j.1000-1522.20190378
[Abstract](360) [FullText HTML](149) [PDF 737KB](14)
Objective According to the characteristics of forest fires and afforestation species in Jianshui County, Yunnan Province, 18 major afforestation species were selected as research objects, aiming to screen out fire-resistant tree species suitable for forestry development in Jianshui County, and in order to provide a certain theoretical basis for forest fire prevention in this area. Method Using 16 indicators (the physicochemical properties and combustion properties of tree species such as water content, crude fat and ash, the biological and ecological characteristics of tree species such as thick and thin canopy, leaf thickness and bark thickness, and the natural regeneration ability of tree species, seedling source and afforestation) as evaluation factors, and the fire performance of 18 species was comprehensively evaluated by typical sampling, point selection survey, experimental measurement and analytic hierarchy analysis. Result According to the assessment results, the tree species were divided into four categories, Category I (optimal fire- resistance trees): Michelia macclurei, Pistacia chinensis Bunge, Camellia OleiferaAbel, Pittosporum brevicalyx are the preferred species for fire-resistant forest belts; Category II (secondary fire-resistance trees): Ternstroemia gymnanthera, Photinia serrulata Lindl, Ligustrum lucidum, Cyclobalanopsis glauca, Symplocos sumuntia, Sapiumdiscolor, can be used as a fire-resistant tree species to create a biological fire-fighting forest belt;Category III (ordinary fire-resistance trees): Quercus acutissima Carruth, Quercus variabilis, Pistacia weinmannifolia J. Poisson ex Franc, difficult to plant as a fire tree species, but can be used for forest fire prevention; Category IV (non fire-resistance trees): Pinus yunnanensis, Fraxinus malacophylla, Eucalyptus globulus, Pinus massoniana, Platycladus orientalis, have poor fire performance and should not be used as fire tree species and should be protected. Conclusion In view of the current characteristics of forest stand structure with single forest structure and large forest area in Jianshui County, it is suggested that Class I and Class II fire tree species can be built as the main bio-fire forest belt in the future to achieve the purpose of blocking the spread of forest fires; The fire performance of the Class III tree species is general, and the field can be planted in combination with Class I and Class II fire tree species according to site conditions and regional characteristics.
Thoughts on Tree Breeding Strategies
Kang Xiangyang
Corrected proof  doi: 10.12171/j.1000-1522.20190412
[Abstract](35) [FullText HTML](15) [PDF 626KB](3)
The low level of plantation cultivation in China is due to insufficient investment in manpower and financial resources in the field of tree breeding, and insufficient attention and implementation of breeding strategies. It leads to the difficulty of maintaining the basic breeding cycle of tree genetic improvement, and can not sustain the continuous improvement of the genetic improvement level of trees and the improvement of plantation productivity. This article comprehensively analyzed the development experience, theory and technology achievements of tree breeding at home and abroad, and put forward several issues that need to be paid attention to in the formulation and implementation of tree breeding strategies. Varieties have regionality, temporality and economic attributes. Ecological value belongs to the subsidiary benefits of planting improved varieties. It is necessary to formulate breeding objectives and breeding cycles that are scientific, specific and have certain market competitive advantages. On this basis, the construction and management of base population, selected population and breeding population of tree species should be strengthened. Scientific experimental design and analysis methods should be adopted to ensure accurate and efficient genetic testing and selection. We should continuously push on the construction of advanced-cycle breeding population, and rationally adopt techniques such as promoting flowering and fruiting, related selection or marker assisted selection to accelerate the process of mating and selection, continuously improve the genetic quality of base populations and selected populations, and even achieve the production and application of distant hybrid varieties with super-strong advantages. For the species that can reproduce asexually, physical and chemical mutagenesis and chromosome doubling can be applied at a certain stage of genetic improvement to further increase the accumulation and utilization of beneficial mutations. For the excellent varieties that have been applied to production but still have insufficient, further optimization can be carried out by molecular breeding such as genetic transformation and gene editing. Mating, genetic testing and selection are the core of the breeding cycle and the basis for further implementation of other breeding techniques, which need to be given more attention.
Characterization and distribution rule of quebrachitol in Hippophae rhamnoides L.
Tao Cui, Wang Jie, Yao Yujun, Han Xue, Lü Zhaolin
Corrected proof  doi: 10.12171/j.1000-1522.20190200
[Abstract](84) [FullText HTML](47) [PDF 846KB](10)
ObjectiveBased on an efficient and accurate characterization method, we accurately quantify quebrachitol and explored the change rules of its content in seabuckthorn, providing references for the development and utilization of seabuckthorn resources.MethodAfter the comparison of the two methods, HPLC was selected for the determination of content of quebrachitol in three different parts of seabuckthorn, including the flesh, seed and leaf.ResultsThis method showed a good linear relationship (R2 = 0.998 5), with high precision (RSD ≤ 0.53%), high accuracy (RSD ≤ 1.16%) and good repeatability (RSD ≤ 1.71%). The results showed that there was a significant difference in the content of alcohol in different parts of seabuckthorn (P < 0.01), and the content in the leaves of seabuckthorn was the highest (59.73 mg/g dry leaves), followed by the flesh of seabuckthorn (2.19 mg/g fresh flesh) and the seeds of seabuckthorn (0.39 mg/g fresh seeds). The leaves of seabuckthorn at different growth stages from May to September were collected, and the results showed that the content of quebrachitol increased gradually with the growth of leaves, and the growth rate was the largest from July to August, and the content accumulated to the highest in September (64.79 mg/g dry leaves).ConclusionLiquid chromatography-evaporative light scattering detector was found easy operating, accurate, and repeatable for the determination of quebrachitol content. The quebrachitol content in the leaves of seabuckthorn was more abundant than that in the fruits, and it reached the highest in September. This study can provide effective data support for the development and application of quebrachitol in seabuckthorn resources.
Study on regeneration of Pinus tabulaeformis burned area in Liaoheyuan Nature Reserve
Wang Bo, Gu Xinghan, Han Shuwen, Zhang Jianan, Niu Shukui, Liu Xiaodong
Corrected proof  doi: 10.12171/j.1000-1522.20190315
[Abstract](237) [FullText HTML](151) [PDF 627KB](28)
ObjectivesFrom the four aspects of tree species composition, density, growth character (base diameter, plant height, crown diameter) and spatial distribution pattern, the forest characteristics of Pinus tabulaeformis plantation in Liaoheyuan Nature Reserve were discussed, which could provide reference for vegetation restoration and forest management.MethodsTo reserve the burns community slightly into the research object, according to different renewal methods (natural renewal and artificial promotion of natural renewal) under natural renewal, 3 20 × 20 m sample plots were set up under natural renewal with different fire intensity (severe fire, moderate fire and light fire) and control (not burned), the natural renewal sample land under severe fire is the same as that under severe fire land under natural fire, there are 15 sample lands in total, survey to update the amount and type of trees, measurement update forest base diameter, plant height, crown diameter, for each wood gauging sample and record the information such as the geographic coordinates and site factor. Single factor variance analysis was used to analyze the difference of tree regeneration density and growth character, and variance/mean method was used to analyze the spatial distribution pattern of tree regeneration.Result(1) The tree species of tree regeneration in the burned area of Pinus tabulaeformis are mainly Quercus mongolica and Populus davidiana, accounting for 38.1% and 42.3% of all tree regeneration respectively, in addition to that of Pinus tabulaeformis, Ulmus laciniata, Ulmus macrocarpa Hance, Ulmus pumila, Acer mono Maxim and so on. Under severe fire, there was a significant difference in the density of tree regeneration between different regeneration methods (P < 0.05), there was no significant difference in the density of tree regeneration between different fire intensities under natural renewal (P > 0.05). (2) There was no significant difference in the growth traits and characteristics of all tree regeneration in different regeneration modes under severe fire (P > 0.05), there was an extremely significant difference in the growth characters and characteristics of all tree regeneration under natural renewal with different fire intensity (P < 0.01). (3) The spatial distribution pattern of tree regeneration was different with different fire intensity, regeneration mode and tree species.ConclusionsAfter 4 years of fire, the regeneration tree species in the burned area of Pinus tabuliformis were mainly Quercus mongolica and Populus davidiana. Moderate and low intensity surface fire could promote the natural regeneration of stands. Adopting salvage logging and other management measures to artificially promote natural renewal can speed up the restoration of vegetation in fire marks.
The morphology, distribution, dynamic characteristics of poplar roots and its water uptake habits
Xi Benye
Corrected proof  doi: 10.12171/j.1000-1522.20190400
[Abstract](482) [FullText HTML](401) [PDF 947KB](17)
Root is the link between plants and soil, and also the organ for plants to absorb water and nutrients. It plays a vital role in the physiological activities of plants. Poplar is widely planted in North China Plain, and the wood output accounts for 30% of the total wood output in China. Therefore, understanding the characteristics of poplar root is conducive to the in-depth understanding of its survival and growth mechanism, ecological adaptation strategies in various environments, so as to provide a theoretical basis for the optimization of efficient management technology of poplar plantation and the improvement of forest quality and forest yield. In this paper, based on the existing studies, the contents of poplar root morphology, distribution, dynamic characteristics, water absorption characteristics and some research methods are reviewed. Firstly, various root classification methods used in previous studies were discussed, then their shortcomings and merits and more suitable methods for poplar root classification are pointed out. Secondly, the various architecture, morphology, distribution and growth dynamics of poplar root found in existing studies were summarized, and the causes of various characteristics and their effects on the absorption efficiency of poplar root are discussed. Finally, the water absorption characteristics and mechanism of poplar root under various conditions are summarized, the deficiencies of existing research on poplar root and the future research direction were also put forward.
Clogging processes of permeable paver systems under different maintenance methods in Beijing
Li Meiyu, Zhang Shouhong, Wang Yunqi, Xie Chaoshuai, Li Ruixian
Corrected proof  doi: 10.12171/j.1000-1522.20190062
[Abstract](232) [FullText HTML](97) [PDF 1035KB](11)
ObjectivesAs one of the promising stormwater management practices, permeable paver systems are more and more widely used in the Sponge City constructions. However, due to the lack of long-term monitoring data, the clogging processes of permeable paver systems and the recovery effects of maintenance methods are not clear. Based on the laboratory experiments, the clogging processes of permeable paver systems under different maintenance methods were measured and analyzed.MethodsBased on inflow-infiltration experiments, long-term changes in permeable pavement permeability and grain size distributions of bedding layers are measured and analyzed for three permeable pavement systems maintained with different methods including non-cleaned, vacuum suction and high pressure washing.ResultsThe results showed that the permeabilities decayed exponentially in the permeable paver systems, the infiltration rates of permeable paver systems were 26, 229, and 19 mm/h respectively, which attenuated 99.6%, 96.3% and 99.7% of the newly-installed systems, vacuuming is preferable to pressure washing in the long-term performances of permeable paver systems. The removal efficiencies of suspended solids of permeable paver systems were between 95%−98%, which performed similarly (P < 0.05, n = 7). The contents of fine particles (0−200 μm) in the upper layers of old bedding layers increased 15.6%−29.2% compared with the new bedding layers. The infiltration rates of " new paver + old bedding layer + old geotextile” were 28.3%−32.4% of the newly-installed systems for the replacement of old bedding layers and geotextiles in permeable paver systems. While the infiltration rates could recovery to 63.8%−72.6% in the " old paver + new bedding layer + new geotextile” systems.ConclusionsTherefore, the measures of periodic maintenance of vacuuming and the renewal of bedding layers and geotextiles can be considered to obtain better permeability and recovery effect of permeable paver systems.
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](511) [FullText HTML](371) [PDF 1087KB](39)
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.
Estimation of above-ground carbon density of arbor forest based on ZY-3 satellite image
Zheng Dongmei, Wang Haibin, Xia Chaozong, Chen Jian, Hou Ruiping, Hao Yuelan, An Tianyu
Corrected proof  doi: 10.12171/j.1000-1522.20180351
[Abstract](77) [FullText HTML](69) [PDF 1250KB](8)
ObjectiveBased on the ZY-3 satellite imagery and the LULUCF carbon sink monitoring plot data covering Zhejiang Province, the study attempts to construct a technical method for automatically extracting the above-ground carbon density of arbor forest in Zhejiang Province.Methodtaking the carbon density of arbor forest in Zhejiang Province as the research object, relevant research tests were carried out in the aspects of vector sign constructing, extraction of spectral information, purification of interpretation sign, ZY-3 satellite image classification, optimization of independent variables, optimization of modeling methods, production of carbon density map, etc.ResultThe results show that the accuracy of classification of ZY-3 imagery after purification of interpretation signs is higher than that of image classification before purification. The accuracy of classification of ZY-3 images by kNN method (average total accuracy is 80.31%, average Kappa coefficient is 0.69, the average user accuracy of arbor forest is 91.86%, and the average producer accuracy of arbor forest is 80.85%), which is higher than the maximum likelihood classification method (average total accuracy is 78.56%, average Kappa coefficient is 0.62, the average user accuracy of arbor forest is 89.68%, and the average producer accuracy of arbor forest is 77.79%). Among the selected modeling methods, the model accuracy constructed by the kNN method (average RMSE is 15.64 t/hm2, average RRMSE is 23.53%) is better than the robust estimation method (average RMSE is 17.63 t/hm2, average RRMSE is 25.11%). Finally, the above-mentioned carbon density distribution map of arbor forest in Zhejiang Province was generated.ConclusionThis study provides a new path for arbor forest or forest carbon density estimation at the provincial or larger scale, providing a reference for automated estimation of carbon density and other forest parameters.
Effect of mixing sand on unconfined compressive strength of soil in collapsing gully
Huang Qiannan, Zhang Xiaoming, Wei Jie, Zhang Ziyou, Hu Jie
Corrected proof  doi: 10.12171/j.1000-1522.20180235
[Abstract](78) [FullText HTML](52) [PDF 903KB](4)
ObjectiveIn order to study the mechanics characteristic of colluvial deposits of collapsing gully, soil simulation of the collapsing have been made and the unconfined compressive strength was measured.MethodTwo methods to mix the sand and soil and different sand content are taken.ResultThe result shows that: unconfined compressive strength reduction along with the reduction of sand content because of the lesser axial stress. From 0% to 100% of sand content, unconfined compressive strength reduction from 71.1 kPa to 14.6 kPa. The specimen mixed sand to soil with separated layer destroys serious and the strength is smaller result to the unstable substratum. The highest strength occurs to the specimen which is low sand content and mixed uniformly.ConclusionMixing sand dramatically reduces the unconfined compressive strength of soil in collapsing gully. Under the same sand content circumstances, specimen mixed uniformly has a high strength and brittle failure at end of test.
Flame retardant properties of phytic acid and melamine treated wood
Wu Yuhui, Zhang Shaodi, Ren Zizhong, Wang Mingzhi
Corrected proof  doi: 10.12171/j.1000-1522.20190406
[Abstract](48) [FullText HTML](31) [PDF 1309KB](5)
ObjectiveBased on the environmental considerations, the research of biomass flame retardant have drawn widespread attention recently. As a biomass extracted from plant seeds, phytic acid can be used as acid source in the intumescent flame retardant (IFR) system, and melamine is commonly considered as gas source in the system thanks to its feature of non-halogen, low toxicity and high flame retardant efficiency. In this study, an IFR system of phytic acid and melamine was prepared and used as a flame retardant of wood, the flame retardancy of the treated wood was then investigated.MethodTwo-step impregnation method was conducted to assemble the phytic acid-melamine flame retardant in the interior of Populus cathayana. The weight percent gain, bulking, pyrolysis and combustion behavior of the modified wood was assessed. The morphology of the residue of treated wood after combustion was analyzed in order to discuss the mechanism of phytic acid-melamine IFR system.ResultThe first peak of heat release rate and the total heat release of 15% phytic acid and 5% melamine treatment group (PM2) were reduced by 91.24% and 79.05% compared with that of Control, respectively. The PM2 group showed stronger smoke suppression performance, and reduced the total smoke emission by 52.94% compared with the control group. The mean carbon monoxide released by PM2 group is reduced by 70.47% compared with the P15% group. The amount of carbon residue of PM2 group was significantly increased, which was 69.58% higher than that of P15% group and 278.4% higher than that of the control group. The PM2 group has the optimum effect on promoting the residue and reducing the heat release.ConclusionThe phytic acid and melamine flame retardant system can penetrate into the wood. The phytic acid takes part in catalyzing the formation of charcoal and the melamine plays a role in reducing toxic gases during the combustion. The synergistic effect between phytic acid and melamine can enhance the carbon residue and decline the fire toxicity of wood.
Effects of Syringa pinnatifolia var. alanshanica on soil physicochemical properties, enzyme activities and microbial diversity
Wang Tao, Guo Yang, Su Jianyu, Xu Chunyan
Corrected proof  doi: 10.12171/j.1000-1522.20180365
[Abstract](115) [FullText HTML](80) [PDF 1167KB](17)
ObjectiveThe purpose of this study was to investigate the effect of S. pinnatifolia var. alanshanica on the soil nutrients, soil enzymes, and soil microorganisms.MethodsFive-point sampling method was employed to collect three soil samples (treatment group) under the S. pinnatifolia var. alanshanica shrub and three control samples (control group) from the naked land near the plant. After the physicochemical properties and enzyme activities determination, the microbial community structure was further analyzed via high-throughput sequencing technique.ResultsResults showed the soil pH value remained unchanged, while the contents of water, organic matter, total nitrogen, available potassium and nitrogen were increased significantly (P < 0.05), and the available phosphorus content was decreased significantly (P < 0.05) by S. pinnatifolia var. alanshanica. At the same time, the activities of sucrase, urease, and laccase were increased significantly (P < 0.05). Under the S. pinnatifolia var. alanshanica shrub, the diversity of soil bacteria was decreased with the richness of bacteria being almost unchanged, but both the diversity and abundance of ffungi were increased significantly. The numbers of Bacillus in bacteria and Saccharomycopsis, Clonostachys, Trichoderma, Paranamyces in fungi were increased by S. pinnatifolia var. Alanshanica. However, the numbers of Sphingomonas and Flavobacterium in bacteria, Lentinula, Fusarium, Gibberella, Lycogalopsis, Ilyonectria, Aspergillus, Synchytrium, and Acremonium in fungi were decreased significantly. All the alterations of microorganisms were closely associated with the changes of nutrients and enzymes.ConclusionsS. pinnatifolia var. alanshanica increased the activities of soil enzymes by altering the community structure of soil fungi, and enhanced the contents of soil nutrients and water and promoted the cycling of carbon, nitrogen, phosphorus and potassium by increasing the richness of functional bacteria.
The responses of PSII photochemical parameter to a snowfall event in early growing season in Artemisia ordosica
Ren Cai, Jia Xin, Wu Yajuan, Ma Jingyong, Tian Yun, Zha Tianshan
Corrected proof  doi: 10.12171/j.1000-1522.20190058
[Abstract](1573) [FullText HTML](131) [PDF 1439KB](16)
ObjectivesThe aim is to examine the impact of a snow event in the early growing season on photosynthetically physiological status of a typical shrub, and to understand photosynthetically physiological mechanism to acclimate to the snow stress.MethodsWe monitored the variations in chlorophyll fluorescence and calculated energy partitioning parameters continuously in situ by a multi-channel monitoring fluorometry during a snow event which covered a period of prior- and post-snowing days, in relation to environmental factors.ResultsActual photosynthetic quantum yield (ΦPSII) was lowest on snow day. The daytime mean value of ΦPSII on snow day was 40% and 33% lower than that of prior and post snow. Regulatory energy dissipation (ΦNPQ) and non-photochemical quenching (NPQ) were highest on snow day, with daytime mean value of ΦNPQ being 95% and 48% higher than that of prior and post snow, respectively. The daytime mean value of NPQ on snow day was 94% and 76% higher than that of prior and post snow. Maximal quantum yield of PSII photochemistry (Fv/Fm) was 0.69 on snow day, smaller than that of prior snow, and smaller than stress line of 0.73. Fv/Fm recovered back within 3−4 days. There were opposite response trends at PAR threshold of 900 μmol/(m2·s)and at air temperature of 10 ℃, indicating different controlling environmental factors around the thresholds. Water availability was always one of the most common limitations during the stress recovery.ConclusionsThere was a stress for Artemisia ordosica during the snow event. The stress was mainly induced by the synergy of low temperature and high radiation. A. ordosica acclimated to the stress by mechanism of increasing ratio of regulatory thermal energy dissipation of energy partitioning in PSII reaction center. The 3−4 days were needed for A. ordosica to recover from the snow stress. The recovery period could be shortened by condition of low radiation, moderate high temperature and high moisture.
Anatomical structure characteristics and growth ring analysis of underground rhizome of herbaceous peony
Zhang Jianjun, Chen Liqi, Li Jianguang, Sun Miao, Fan Yongming, Yu Xiaonan
Corrected proof  doi: 10.13332/j.1000-1522.20190096
[Abstract](530) [FullText HTML](459) [PDF 886KB](34)
ObjectiveBy observing and analyzing the rhizome structure and development characteristics of different varieties of peony, the anatomical study on the rhizome was conducted to preliminarily analyze the secondary structure and growth ring characteristics of the rhizome of herbaceous peony, so as to provide theoretical basis for judging the plant age of peony and optimizing the asexual reproduction and cultivation management technology, and promote the development and utilization of resources.MethodThe underground rhizomes of different developmental stages of six varieties of different peony groups were studied, and their development and renewal characteristics were observed and analyzed. Paraffin sections and freehand slicing techniques were used to observe and analyze the secondary structural characteristics of rhizomes of different cultivars and different cultivars with different growth years.ResultThe underground rhizome structure of different varieties was basically the same, that is, the underground organs of the peony were composed of rhizome, rhizome buds and roots growing on the rhizome. The rhizome was updated regularly every year, and the age grading characteristics were obvious; the developmental characteristics of the tetraploid cultivar ‘Cream Delight’ were significantly different from the other five varieties.The rhizomes of 6 varieties of peony were composed of peridermis, cortex, secondary phloem, cambium, secondary xylem and central pith. The large and small conduits of the secondary xylem of the rhizomes of diploid variety ‘Zhongshengfen ’, diploid variety ‘Fenyunu’, triploid variety ‘Coral Sunset’ and tetraploid variety ‘Cream Delight’ were arranged sequentially.The larger diameter catheter and the surrounding small catheter gathered to form a cluster, and the catheter group was sparsely distributed. The spacing between the two catheter groups was significant. The interval between the catheter clusters of ‘Coral Sunset’ was smaller than ‘Cream Delight’.The large and small ducts in the secondary xylem of the rhizomes of the two triploid Itoh varieties ‘Prairie Charm’ and ‘Going Bananas’ were evenly distributed and formed a relatively continuous ring zone, and they don't clump together. After dehydration, the vascular structure of the rhizome of the peony was white or yellowish, with intermittent distribution of the ring, and the central medullary tissue was concave.Vascular tissues located in different rings were radially arranged from the pith to the cortex. The larger diameter catheters in the secondary xylem and the small ones around them were clustered in clumps in the rhizomes of different growth years.The catheter group was tangentially intermittently arranged in a sequence parallel to the cambium to form a clear growth ring, and the number of growth ring was consistent with the actual growth age of the rhizome of the peony.ConclusionThe structural characteristics of underground rhizome of different varieties of peony are basically the same, and there are obvious grading characteristics.The rhizome development characteristics of diploid and triploid are similar, but different from tetraploid. The secondary structural characteristics of rhizome of varieties belonging to lactiflora and hybrid groups are similar, but are significantly different in the varieties of Itoh group. There are significant differences in secondary structure of the rhizomes between triploid and tetraploid varieties of hybrid peony, and there is no direct correlation between the secondary structure characteristics of root growth ring and chromosome ploidy of herbaceous peony. The growth rings in the rhizome of peony are its annual rings, and the number of growth rings can reflect the actual growth years of peony.
Forest management method originated by China since the 21st century
Zhao Zhonghua, Hui Gangying
Corrected proof  doi: 10.13332/j.1000-1522.20190325
[Abstract](629) [FullText HTML](96) [PDF 684KB](25)
China’s forestry development has entered a new stage and the ecological construction has been a main task of forestry construction. Cultivating healthy, stable, high-quality and efficient forest ecosystems has become the goal to meet the overall requirements of the construction of ecological civilization in the new era. The key to achieving this goal is to improve the structure of forests, accelerate forest growth and forward succession, improve the productivity and quality of forests by adopting scientific and rational management measures. Based on a brief review of the forest management objectives and techniques in different stages of forestry construction in China, this paper reviews the theories and techniques of forest management independently developed in China since forestry construction entered the stage of ecological construction, focusing on the technical system of " ecological harvesting and regeneration”, " natural forest conservation and restoration” and " structural-based forest management” summarized from three aspects: theoretical basis, core technology and application practice, in order to provide a basis for precise upgrading of forest quality currently being implemented in China.
Numerical simulation of the safety influence of defects on Qijia-beams of ancient timber building
Ou Zina, Zhang Houjiang, Guan Cheng
Corrected proof  doi: 10.13332/j.1000-1522.20190328
[Abstract](52) [FullText HTML](42) [PDF 2055KB](15)
ObjectiveThe Qijia-beams are used as the main load-bearing members for Chinese ancient timber building. The safety performance of whole wood structure is directly affected by the bearing capacity safety of Qijia-beam. Factors, such as surrounding environment and load for a long period, lead to different degrees of the defects in the wooden beam. These defects will affect the tensile stress and shear stress distribution, as well as the bearing capacity safety of the wooden beam. Therefore, it is necessary to study the influence of different defect types, sizes and locations on the safety of bearing capacity of the Qijia-beam.MethodAbaqus finite element software was used to simulate the stress state of the beam with different defects such as crack, decay and hole. By quantifying the size and location of the defects, the single parameter numerical simulation analysis of different damage factors was carried out to determine the maximum working stress location of the wood beam with defects, analyze the sensitive location of the damage of the wood beam, and investigate the variation patterns of the bearing capacity of wood beams.ResultThe results showed that the types of different defects had different influence on the safety of the Qijia-beam. External decay had the greatest influence on the bearing capacity of the Qijia-beam, followed by hole defect, and the impact of crack defect was relatively minimal. For the bending beams in the elastic stage, the defects had the greatest influence on the bearing capacity safety of the Qijia-beam when it was located in the tension zone between two under Jiagua-columns. The influence of different defect sizes on the bearing capacity of the Qijia-beam was different. With the increase of the crack depth, the decay depth, and the hole size, the safety of the wooden beam was gradually reduced.ConclusionDue to the existence of local defects, the bearing capacity of the Qijia-beams would be decreased. The research of this paper provided numerical simulation, which could accurately determine the maximum tensile stress of the wooden beam. It was a good method to quantitatively study the influence of defect on the safety of Qijia-beam and to determine the location of Qijia-beam safety monitoring.
Progress and perspective of quantitative remote sensing of forestry
Huang Huaguo
Corrected proof  doi: 10.13332/j.1000-1522.20190326
[Abstract](284) [FullText HTML](240) [PDF 760KB](41)
Forestry remote sensing has entered the stage of quantitative inversion of parameters after air-photo interpretation, satellite visual interpretation and quantitative estimation of forest volume. Under the background of strong demands of remote sensing from forestry on operational monitoring and accuracy improvement, quantitative remote sensing is gradually integrated with forestry remote sensing. It has gradually matured in talent teams, theoretical models, data sources and application methods for the quantitative studies in forestry remote sensing. This paper puts forward the concept and framework of quantitative remote sensing of forestry (QRSF), and points out the key scientific problems: (1) how to adapt remote sensing interpretation, modeling and inversion to complex forest conditions; (2) how to improve the accuracy of parameter inversion; (3) how to enrich forestry remote sensing data sources; (3) how to develop highly intelligent and automated information extraction algorithm on remote sensing data. On the basis of introducing quantitative remote sensing models and general inversion methods suitable for forestry, the application methods of hyperspectral, thermal infrared, lidar and microwave remote sensing data sources in forestry are expounded. In the future, QRSF will make breakthroughs in the unified modeling of full-band data, information fusion mechanism, physical model inversion and large-scale data fusion.
Effects of different filter algorithms on deriving leaf area index (LAI)
Liang Yongqi, Li Mingze, Yang Ruixia, Geng Tong, Li Huan
Corrected proof  doi: 10.13332/j.1000-1522.20180268
[Abstract](147) [FullText HTML](143) [PDF 1412KB](27)
ObjectiveFiltering is an important part of data preprocessing when using discrete-return LiDAR to derive leaf area index (LAI). Laser penetration index (LPI), which responses to the canopy’s gap fraction, is a pivotal argument, and can be defined by echoes intensity or count, and is directly influenced by filter precision. So, filter algorithms can affect deriving LAI indirectly.MethodIn this paper, we used the open source filter algorithms without manual operation to filter the error points. Using the LPI defined on count, we built model in larch forest and elm forest, Maor Mountain National Park, based on Beer-Lambert law. We compared the filter algorithm of adaptive triangulated irregular network, morphology, local slope, using hybrid filtering as standard. In order to avoid the subjective influence during modelling, we built 100 models by choosing samples randomly.ResultIn larch forest, the models’ R-squared under larch was 0.900 3, 0.876 3, 0.892 5,0.877 0, root mean squared error (RMSE) was 0.105 6, 0.134 5, 0.109 7,0.133 2; in elm forest, the models’ R-squared was 0.914 4, 0.903 0, 0.887 2, 0.900 0, root mean squared error (RMSE) was 0.269 0, 0.201 7, 0.189 4, 0.207 0, respectively.ConclusionConsidering the sample’s topography, when using discrete-return LiDAR data derive LAI based on LPI, the hybrid algorithm has a better performance on deriving LAI. II error has more influence on deriving LAI than I error.
Experimental study on in-situ monitoring of the evolution law of cracks in wood components with transverse cracks based on acoustic emission and image correlation
Tu Juncheng, Zhao Dong, Zhao Jian
Corrected proof  doi: 10.13332/j.1000-1522.20190276
[Abstract](198) [FullText HTML](88) [PDF 1060KB](15)
ObjectiveThe defects of the wood component with transverse cracks will cause fracture damage under bending load. It is important to study the law of crack initiation and propagation to predict and evaluate the fracture damage of the timber-containing members.MethodThis paper was performed on Chinese fir and damage was monitored in-situ in real time based on acoustic emission (AE) and digital image technology (DIC) during three-point bending failure of wooden beams with prefabricated transverse cracks. The AE parameter analysis method was used to study the characteristics of AE signals during the crack initiation and propagation of Chinese fir. The strain characteristics of the surface of the wooden beam are also analyzed according to the strain and displacement changes of the crack tip region.ResultThe results showed that the crack initiation and propagation laws reflected by the AE and DIC measurements during the damage evolution of prefabricated cracks in wood beam specimens were consistent, the digital images of damage evolution from monitoring the crack tip region of wooden beams verify the prediction of AE signals, and AE ring count, energy and amplitude were effective indicators to predict the crack initiation of wooden beams. The strain of the wooden beam surface can effectively observe the evolution of crack initiation and extension.ConclusionThe results of this study establish the relationship between wood microcrack initiation, propagation behavior and acoustic emission parameters and surface strain, and it successfully construct the evolutionary measurement and evaluation system for in-situ monitoring of cracks in wood components with transverse cracks based on acoustic emission technology and digital image correlation method. The experimental results provide a reference for the further study of the damage mechanism and in-situ monitoring methods for the crack evolution behavior of wood components with transverse cracks.
The quantitative characteristics of natural protected areas in northeast China
Zhang Fangling, Pu Zhen, Liang Xiaoyu, Gu Yuanyang, Xing Shaohua
Corrected proof  doi: 10.13332/j.1000-1522.20190139
[Abstract](225) [FullText HTML](159) [PDF 633KB](20)
ObjectiveAn in-depth analysis of the quantitative characteristics of national natural protected areas in large geographical units of China is crucial for reforming the protected area system and establishing an effective national park system.MethodBased on the data collected from 594 national natural protected areas in Northeast China, this paper examines their quantitative characteristics on the basis of three aspects: construction categories, construction periods and natural ecosystem, We also identified and calculated national natural protected areas that have overlapping boundaries.ResultThe results show that the establishment of national natural protected areas in Northeast China experienced three stages, namely the stage of stagnation, the initial develop stage and the stage of rapid development, suggesting the overall upward trend from 1956 to 2016; Affected by natural environmental and social factors, the distribution of national natural protected areas in the study area is uneven and patchy. There are as many as 108 national natural protected areas with overlapping scope, especially nature reserves and forest parks. According to ecosystems in the research area, it can be roughly classified into six categories, among which forest ecosystems and inland wetland ecosystems dominate in terms of quantity and area, grasslands and meadows, desert, ocean and coasts was overlooked, some parts of areas were not protected.ConclusionWe suggest that the future development of natural protected area in Northeast China can take into account both diversification and systematization. In regard to the planning and establishment of natural protected areas, we should focus on the spatial distribution of natural ecosystems and pay more attention to the consistency of natural protected area catigories with ecosystem types, in order to provide the convenient for construction and management. Optimize and integrate hot spots that natural protected areas gathered according to main natural ecosystem by construct national park, merge natural protected areas that spatial proximity, protected objects has association. This research will provide scientific data support for the establishment and management of national parks and natural protected areas in Northeast China.
Variation of microscopic morphology and chemical composition of marigold stalk
Yang Guochao, Wang Nan, Huang Xinxin, Geng Yaru, Liu Jing, Zhang Qiuhui
Corrected proof  doi: 10.13332/j.1000-1522.20190311
[Abstract](150) [FullText HTML](85) [PDF 1368KB](6)
ObjectiveThe variation of micromorphology, chemical composition and functional groups of marigold straw was studied to provide scientific and reasonable technical basis for the utilization of crop straw at the micro-scale and molecular level.MethodField emission scanning electron microscopy (FE-SEM) and energy dispersive spectrometer (EDS) were used to characterize the microstructural variation and chemical element composition difference of the cross section of marigold straw. The cell wall percentage of marigold straw was measured by color image computer analysis system. And the functional group distribution rule of marigold straw along the direction of height was characterized by Fourier transform infrared spectrometer (FTIR), second derivative infrared (SDIR) and two-dimensional correlation infrared (2DIR).ResultThe results showed that: 1) the radial size of marigold straw had a small variation in the upper part (range 7.3), but a large variation in the middle and root (range 10.0 and 10.7, respectively). 2) The upper structure of marigold straw was " sparse”, but the diameter and distribution of tube holes in the middle and lower segments were not significantly different. The type of catheter was mainly single-tube or complex tube. The carbon and oxygen ratio of marigold straw was 0.73, 0.79 and 0.83 from tip to root, showing an increasing trend. The content of nitrogen atom percentage also had the same trend. 3) The cell wall ratio showed an increasing trend from the inside to outside and the height direction from the tip to root. 4) FTIR spectra corresponding to different heights were significant changes in 2 816−2 972, 1 651, 1 461 and 800−849 cm− 1. 1 700, 1 280 cm− 1 of the SDIR curve and 3 240−3 409, 2 921, 2 850, 1 619 cm− 1 of the 2DIR. The results indicated that the species and quantity of corresponding functional groups were correlated with the variation of straw height, it could infer changes of three kinds of basic units of straw.ConclusionThrough the analysis of Micromorphology and functional groups of marigold straw, the corresponding relationship between radial size, internal structure, percentage of carbon and oxygen atoms, cell wall percentage and height direction of marigold straw were revealed. The variation of the types and quantities of functional groups contained in the main chemical constituents of straw in the direction of straw height was deduced.
Coupling of landscape patter and water use efficiency with different amplitudes: a case study of Qianyanzhou in eastern China
Wen Yongbin, Han Hairong, Cheng Xiaoqin, Li Zuzheng
Corrected proof  doi: 10.13332/j.1000-1522.20190081
[Abstract](360) [FullText HTML](189) [PDF 757KB](21)
The landscape pattern, which could exert critical impacts on the carbon and water distribution and their coupling in the ecosystem, is the product of integrated actions of ecological processes on a time-spaced scale.ObjectiveThe objective of this study is to explore the interaction law between landscape pattern and water use efficiency at multiple scales, and to provide a theoretical basis for studies of the coupling relationship between landscape pattern and ecological process, and regional ecological planning.MethodWe used the Biome-BGC model optimized by the PEST model to simulate water use efficiency (WUE) of Qianyanzhou forest ecosystem from 2000 to 2014, and analyzed the correlations between landscape pattern index (LPI) and WUE, landscape pattern and total primary productivity (GPP), and their trends.ResultThe results showed that: (1) the landscape fragmentation index (NP and PD) and WUE had a significantly negative correlation in the buffer range of 10−80, while there was a significantly positive correlation between AREA-MN and WUE in this range; (2) The landscape shape index (SHAPE and FRAC) was significantly positive correlatied with WUE in the range of 50−100; (3) The positive correlation between landscape polymerization index (PLADJ and AI) and WUE was significant in the range of 10−50; (4) Both landscape diversity and uniformity index (SIDI and SIEI) showed a significantly negative correlation with WUE when the buffer was between 10 to 20, while a significantly positive correlation in the buffer range of 70−100; (5) The correlation between landscape pattern index and water use efficiency showed a conspicuous scale effect; (6) The change law of the correlation between GPP and LPI was consistent with the correlation between WUE and LPI.ConclusionThis indicates that the coupling of landscape pattern and ecological process is affected by the scale effect. We suggest that the scale effect should be fully considered into regional ecological planning so that the coupling effect of landscape pattern and ecological process could be maximized.
Effects of waterlogging stress on growth, physiological and piochemistry characteristics of Magnolia wufengensis
Wang Yanshuang, Fang Wen, Wang Xintong, Zhao Xiuting, Liao Guoli, Duan Jie, Ma Lüyi
Corrected proof  doi: 10.13332/j.1000-1522.20190225
[Abstract](412) [FullText HTML](165) [PDF 1162KB](33)
ObjectiveMagnolia wufengensis has fleshy roots, which are very sensitive to water. In this paper, the waterlogging stress test of Magnolia wufengensis was carried out to investigate the effects of waterlogging environment on its growth, physiological and biochemical characteristics, which provided a theoretical basis for determining the suitable water environment for the growth of Magnolia wufengensis and its promotion work.MethodOne-year-old Magnolia wufengensis seedlings were used as experimental materials, and potted waterlogging method was utilized for 5 treatments: control (CK), waterlogging for 4 days (W4), 7 days (W7), 11 days (W11) and 15 days (W15). The growth, physiological and biochemical indexes of seedlings on days 1, 4, 7, 11, 15 after waterlogging and on the 2nd (R2), 5th (R5), and 8th (R8) days after stress relief were measured to analyze the response of Magnolia wufengensis seedings to waterlogging stress and self-recovery ability after waterlogging stress.ResultWith the increase of waterlogging stress time, the survival rates of W4, W7, and W11 decreased to 95.00%, 70.00%, and 60.00%, respectively, and all W15 seedlings died after 2 days of stress relief; the growth of seedling height and ground diameter decreased, and the growth of W11 seedlings restored to a basic standstill after stress relief; the content of chlorophyll showed a downward trend, and the difference between treatment and CK was not significant; Net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) showed a downward trend. Net photosynthetic rate and stomatal conductance were significantly lower than CK in all treatments; the transpiration rate was significantly different from CK except W4. Soluble protein content and malondialdehyde content gradually increased. The malondialdehyde content was significantly different from CK in all treatments, and soluble protein content was significantly different from CK except for W4. Superoxide dismutase(SOD), peroxidase(POD)and catalase(CAT) activities showed the same trend, which increased first and then decreased. SOD and POD under W11 and W15 treatments were significantly different from CK, and CAT activities were significantly different from CK except W4.ConclusionWith the increase of waterlogging stress time, the growth and physiological activities of Magnolia wufengensis seedlings were inhibited to extent, but they had certain recovery ability after the relief of waterlogging stress, and the shorter the stress time was, the stronger the recovery ability was. The waterlogging stress lasts for about 11 days. And it can basically reduce the damage by regulating the activity of the protective enzyme system and the content of osmotic adjustment substance, and maintain the normal physiological and metabolic functions of the plant body. Thus, the result indicates that Magnolia wufengensis has a certain tolerance to waterlog. When the waterlogging stress lasts for 15 days, it exceeded the regulation capacity of the plant itself, which will lead to its death.
2019, 41(11).  
[Abstract](40) [FullText HTML](26) [PDF 330KB](4)
Forest Sciences
Physiological and growth variations of Quercus mongolica saplings along an elevational gradient in Changbai Mountain Nature Reserve, northeastern China
Fan Ying, Qiao Xuetao, Zhao Xiuhai
2019, 41(11): 1-10.   doi: 10.13332/j.1000-1522.20190095
[Abstract](965) [FullText HTML](341) [PDF 973KB](78)
Objective This paper aims to reveal the inner mechanisms of vegetation growth to elevational gradient and provide scientific basis for predicting the impact of climate change on vegetation growth of Quercus mongolica in Changbai Mountain Nature Reserve, northeastern China. Method We used the Quercus mongolica saplings under the canopy to evaluate leaf physiological characteristics, leaf morphological characteristics and plant growth characteristics of Quercus mongolica at different elevations. Result The results were as follows: (1) there were no significant differences (P > 0.05) between the average needle leaf mass per area (LMA) and leaf dry mass content (LDMC) from various elevations. The apparent quantum yield, the saturation light intensity, the light saturated net photosynthesis, the water use efficiency and apparent CO2 use efficiency were negatively correlated with elevation, i.e. the ability to utilize low light, the ability to adapt to strong light and the maximum photosynthetic potential decreased with elevation, while the consumption of water and intercellular CO2 required for the production of organic matter increased with elevation. (2) Leaf biomass, new branch biomass, one year old branch biomass, leaf biomass proportion, new branch biomass proportion and one year old branch biomass proportion were also negatively correlated with elevation, i.e. the annual growth of Quercus mongolica saplings decresed with elevation. (3) All leaf factors in this study explained 12.03% of total growth variation, while all environmental factors in this study explained 19.31% of total growth variation of Quercus mongolica saplings. Conclusion The elevational responses of leaf physiological characters and whole plant growth characters of Quercus mongolica reflect that this species has strong plasticity in heterogeneous habitats. There is no significant difference in leaf mass per area and leaf dry mass content of Quercus mongolica from different elevations, but the photosynthetic rate and annual growth decrease with elevation, namely environmental variations may affect the growth of saplings by affecting the photosynthetic characteristics rather than the morphological characteristics of the leaves, in turn, affect the growth of Quercus mongolica saplings. This paper is of certain significance to predict the physiological and ecological response of Quercus mongolica under the future climate change.
Effects of stand age and climate change on the volume of Pinus massoniana forests in the Three Gorges Reservoir Area of central China
Feng Yuan, Xiao Wenfa, Zhu Jianhua, Huang Zhilin, Yan Xuxin, Wu Dong
2019, 41(11): 11-21.   doi: 10.13332/j.1000-1522.20190184
[Abstract](153) [FullText HTML](123) [PDF 1246KB](45)
ObjectiveBoth stand age and climate change are crucial factors influencing forest volume dynamics, and it is important to investigate their effects on forest volume on a regional scale.MethodBased on an ecological process model (3-PG), data from a forest resource planning and design survey and three future climate scenarios (BS, RCP4.5, and RCP8.5), this study quantified the effects of stand age and climate change on the volume growth of Pinus massoniana forests in the Three Gorges Reservoir Area (TGRA) of central China.ResultStand age was predicted to increase the annual average volume of the Pinus massoniana forests by 2.60 × 106 m3/year or 2.60 m3/(ha·year) in the TGRA during 2009 to 2050. While the effect of climate change was less pronounced than that of stand age, an annual volume increment of 1.70 × 105−2.00 × 105 m3/year or 0.17−0.20 m3/(ha·year) only accounted for 6.55%−7.67% of the effect of stand age. The effects of both stand age and climate change on volume growth in Pinus massoniana forests were predicted to be the strongest in the central part and the weakest in the southern part of the TGRA. The Wanzhou District was predicted to present the highest annual average increment of volume per hectare (4.54 m3/(ha·year)) owing to stand age; while Banan District, the lowest value (1.17 m3/(ha·year)). The promoting effects of climate change on volume growth were predicted to be the highest in Kaizhou District (0.40 m3/(ha·year)); the lowest in Fuling District (0.03 m3/(ha·year)).ConclusionBoth stand age and climate change are predicted to enhance the volume growth of the Pinus massoniana forests, and their combined effects would most increase the annual average volume increment per hectare in Wanzhou and Kaizhou Districts and least in Banan District. Studies are required to focus on the growth of Pinus massoniana forests in Banan District in the future through strengthening of forest management and adjustment of the forest age structure to maintain the development of regional forest resources.
Characteristics analysis of surface runoff for three types of forests in Hainan Island, southern China
Wang Hua, Xiang Yangzhou, Yang Zengjiang, Guo Junyu
2019, 41(11): 22-30.   doi: 10.13332/j.1000-1522.20190275
[Abstract](133) [FullText HTML](109) [PDF 645KB](19)
ObjectiveThe aim of this study was to provide a scientific basis for the accurate evaluation of water conservation benefits in three forest types and sustainable management of plantations. We discussed the monthly dynamics of surface runoff from eucalyptus plantations, rubber plantation and secondary forest and the surface runoff laws of different rainfall levels.MethodRunoff fields were established in different forests in Limu Mountain, Hainan Province, southern China, including four fields in eucalyptus plantations (F1, F2, F3, F4), one field in rubber plantation (F5), and one field in secondary forest (F6). Surface runoff observation was carried out from April 2010 to March 2011 and the surface runoff characteristics of three forest types were compared and analyzed. The monthly ground runoff coefficient was predicted by the basic idea of G(2,1) model and sigmoid model.Result(1) The annual surface runoffs of F1−F6 fields were 230, 49, 170.1, 84.2, 340, 396.4 mm, of which the rainy season accounted for 90.28%, 91.61%, 87.89%, 92.74%, 91.86%, 90.88%. (2) The monthly surface runoff was all ordered as F6 > F5 > F1 > F3 > F4 > F2. (3) The total runoff of the secondary forest in the rainy season was 1.75−8.11 times of the eucalyptus plantations, and the rubber plantation was 1.49−6.89 times of the eucalyptus plantations. Surface runoff occurred when the rainfall exceeded 10 mm, and the surface runoff increased with the rainfall level. The rainfall greater than 60 mm accounted for 57.95% of the total annual rainfall, while the surface runoff from F1 to F6 fields accounted for 84.92%, 89.08%, 82.14%, 87.75%, 79.56%, 83.49% of the annual surface runoff. (4) The sigmoid model predicted that the surface runoff coefficient of the rainy season was higher than the dry season, but the surface runoff prediction of each field in August 2010 was more biased.ConclusionOur results indicate that the surface runoff of 5-year-old eucalyptus and 6-year-old rubber plantations in the region are not always larger than that of secondary forests. It is necessary to consider the forest age and geographical location when evaluating the water conservation capacity of plantations.
Reproductive allocation and compensation mechanism for reproductive costs of dioecious shrub Rhamnus davurica
Huang Yunhao, Xin Benhua, Wang Juan
2019, 41(11): 31-36.   doi: 10.13332/j.1000-1522.20180425
[Abstract](175) [FullText HTML](127) [PDF 649KB](21)
Objective The trade-offs between reproductive and vegetative processes have an important role in the life-history theory. Dioecious species afford an excellent opportunity to detect the trade-offs in resource allocation. Method This research selected the dioecious shrub Rhamnus davurica to examine trade-offs between reproduction and vegetative growth, and determine whether females reduce vegetative growth with the higher reproductive allocation. If female hadn’t showed less vegetative growth than male, whether compensation mechanism led to that or not. The investigated R.davurica was divided into 4 groups based on genders and DBH. The differences of reproductive allocation between genders were compared by ANOVA and multiple comparisons. We did photosynthetic experiment of R.davurica on early June 2012 using LI-6400 portable photosynthesis system. Result The main results were showed as: diameter level was positively correlated with reproductive biomass and foliage biomass (P < 0.05). In the same diameter level, the reproductive biomass (including flower and fruit biomass) was significantly different between genders (P < 0.05), but there was no significant difference between genders regarding the foliage biomass (P > 0.05). Photosynthetic capacity and the estimated light photosynthetic curves were different between the male and female. Conclusion We conclude that the relationship between vegetative growth and reproductive growth does not agree with trade-off theory, this is a result of difference in the total available resources, R.davurica in large diameter-class has more total available resources. Although in the same diameter level, females do not show less vegetative growth than males. It is due to their higher photosynthetic efficiency and carbon fixation capacity. This higher photosynthetic capacity is a compensatory mechanism for females whit higher reproductive pressure.
Enhancement of embryogenic callus proliferation in Chinese pine (Pinus tabuliformis) by airlift bioreactor
Li Yixuan, Zhao Jian, Fu Shuangbin, Dong Mingliang, Yang Shuo, Li Shanshan, Kong Lisheng, Zhang Jinfeng
2019, 41(11): 37-43.   doi: 10.13332/j.1000-1522.20190221
[Abstract](130) [FullText HTML](45) [PDF 790KB](16)
ObjectiveThe proliferation of a great number of active embryogenic callus can provide sufficient materials for somatic embryogenesis and plant regeneration of Pinus tabuliformis. However, the yield of flask suspension proliferation is limited and easy acidification necrosis. The establishment of airlift bioreactor system for embryogenic callus multiplication of P. tabuliformis can promote the proliferation of embryogenic callus of P. tabuliformis.MethodIn this study, P. tabuliformis callus was used as material, and L9 (34) orthogonal design was used to investigate the effects of three factors on callus proliferation in bioreactor, including inoculation volume, ratio of old and new media and hormone concentration. Then the suspension culture in conical flask was compared with that in conical flask under the same conditions.ResultThe highest embryogenic callus proliferation rate, 216.18% was obtained using 10 g embryogenic callus, 0.2 mg/L 2,4-D and 20% old culture medium inoculated in 100 mL liquid medium in the ALB.ConclusionCompared with conical flask suspension culture, the growth rate of embryogenic callus in ALB system was 2.15 times faster in a week. Microscopic observation shows that the proliferated embryogenic callus is stable and high quality. This study provides technical support for large-scale propagation of P. tabuliformis based on somatic embryo system.
Comprehensive evaluation of salt tolerance of clones of Fraxinusin spp. seedling stage under salt stress
Yan Wenhua, Wu Dejun, Yan Liping, Wang Yinhua, Ren Fei, Yan Lin, Liu Jie, Yu Linlin
2019, 41(11): 44-53.   doi: 10.13332/j.1000-1522.20180438
[Abstract](115) [FullText HTML](75) [PDF 922KB](24)
ObjectiveThis paper aims to explore the salt tolerance of ash tree clones, breed excellent salt tolerant of clones, and improve land productivity through biological measures.MethodCutting potted seedlings of 1-year-old ash clones were taken as materials, and their growth and physiological index of 9 clones under different salt stress conditions (0, 2, 4, 6, 8 g/L) were studied.ResultUnder salt stress, the growth of clones was significantly inhibited, and with the increase of NaCl concentration, the growth indicators (seedling height increment, ground diameter increment, biomass accumulation) of clones showed a decreasing trend, and the decline of ‘YL’ of clones was the slowest; the chlorophyll content of nine clones also decreased with the increase of salt concentration, and there was significant difference between saline wax and other clones (P < 0.05). Under salt stress, the cell membrane permeability and MDA content of clones increased, but at the same salt concentration, ‘YL’ and ‘Y3’ of clones were lower than those of other clones; when salt stress increased gradually, the contents of proline and soluble sugar showed different trends according to different varieties. Among them, osmotic regulators in ‘YL’,‘L5’, ‘QB’, ‘L2’ and ‘Y3’ had been increasing, the content of the other four clones showed a single peak curve, and the highest value reached 6 g/L. SOD activity increased first and then decreased. Its value of ‘YL’ was the highest, which was significantly different from that of other clones (P < 0.05).ConclusionPrincipal component analysis was used to evaluate the salt tolerance of nine ash tree clones. The salt tolerance of nine ash tree clones was ordered as follows: ‘YL’, ‘Y3’, L5’, QB, JJ, JN11, HX, ‘L2’ and‘J10’. The results provided are not only theoretical basis but also breeding materials for the breeding of ash tree salt tolerant clones.
Object-oriented multi-index integrated vegetation change analysis based on WorldView2 and GF-2
Zhu Fangyan, Shen Wenjuan, Li Mingshi
2019, 41(11): 54-65.   doi: 10.13332/j.1000-1522.20180435
[Abstract](200) [FullText HTML](130) [PDF 1236KB](28)
ObjectiveUsing high spatial resolution satellite images to capture accurate information on vegetation change is of great significance for the rational use of vegetation resources and sustainable management. Traditional pixel-based direct change detection methods are easy to cause salt-and-pepper noises and the results of object-oriented classification methods depend heavily on the classification accuracy. After investigating the advantages and weaknesses of the existing algorithms for vegetation change analysis, the major objective of this study was to develop a relatively objective algorithm for vegetation change detection by high spatial resolution remote sensing data, and to verify its effectiveness.MethodAn object-oriented multi-index integrated change analysis (MIICA) algorithm was proposed in the analysis based on a existing MIICA. First, bi-temporal cross-sensor high spatial resolution images were segmented uniformly with the optimal segmentation parameters, which were determined by examining the precision (P) and recall (R) indices, followed by the extraction of feature parameters of the segmented objects. Then the appropriate thresholds objectively determined by ROC (receiver operating characteristic) curves were integrated to derive vegetation change positions and directions (vegetation gain or loss) finally.ResultResults showed that compared with the pixel-based MIICA and the object-oriented classification method, the producer’s accuracy of our method was higher than that of the pixel-based MIICA, meanwhile the user’s accuracy was higher than that of the object-oriented classification method. And our method had higher overall accuracy and Kappa coefficient, estimated at 0.880 and 0.805, respectively. The detection results of our method could better reflect the positions and shapes of the vegetation change areas, with some subtle vegetation changes clearly detected.ConclusionObject-oriented MIICA can improve the shortcomings of pixel-based MIICA and object-oriented classification method, and improve the detection accuracy. The proposed method is essential for the analysis of vegetation changes, the reasonable utilization and sustainable management of vegetation resources in forest parks or natural reserves, where heavy anthropogenic disturbances frequently exist.
Comparison of individual tree crown extraction method and suitability of airborne and spaceborne high-resolution remote sensing images
Sun Zhenfeng, Zhang Xiaoli, Li Niwen
2019, 41(11): 66-75.   doi: 10.13332/j.1000-1522.20180446
[Abstract](486) [FullText HTML](193) [PDF 1659KB](27)
ObjectiveThis method applies high resolution remote sensing image to extract individual tree crown information quickly and accurately, which can have important significance for modern forest management. Object-oriented multi-scale image segmentation method can effectively solve the limitations of pixel feature analysis and is an important technical approach to individual tree crown extraction. This paper compares and analyzes the tree crown segmentation accuracy of different remote sensing platforms and artificial forest species, explores the advantages and applicability of the experimental methods for different scale image data and tree species, and provids reference for the assortment of image data combined with the purpose of investigation.MethodTaking Gaofeng Forest Farm of Guangxi Zhuang Autonomous Region as the research area, the UAV CCD, airborne CCD and spaceborne GF-2 remote sensing image data were selected. Aiming at the poor contrast effect between the crown area and the background area, the image enhancement processing was firstly performed by wavelet transform to remove the image noise, enhance the contrast between the crown and the background, and then apply the object-oriented multi-scale segmentation method to eliminate the interference of the background area. Rapid extraction of single tree crown for canopy areas was taken. Finally, the process and method of extracting single tree crown of Eucalyptus robusta and Cunninghamia lanceolata plantation under three kinds of images, and the accuracy of crown extraction were studied and analyzed.ResultWavelet transform is effective in enhancing UAV and airborne images. The individual tree crown segmentation accuracy of Eucalyptus robusta and Cunninghamia lanceolate in UAV platform was 87%, 93.3%, with tree crown estimation accuracy of 84.2%, 85.1%, respectively. The individual tree crown segmentation accuracy of Eucalyptus robusta and Cunninghamia lanceolate in airborne platform was 89%, 91.1%, with tree crown estimation accuracy of 83.9%, 84.4%, respectively. However, wavelet transform is not appropriate for image enhancement of spaceborne platform. The crown segmentation accuracy of Eucalyptus robusta and Cunninghamia lanceolata in spaceborne platform was 82%, 89%, with tree crown estimation accuracy of 72.3%, 73.3%, respectively.ConclusionIn UAV and airborne platform, the precision of tree crown extraction by multi-scale segmentation is close. In spaceborne platform, the extraction accuracy of the individual tree crown is lower than that of the former two platforms because of the limitation of spatial resolution of the image, and the direct application of multi-scale segmentation to single tree crown extraction. But it can also meet the basic needs of forest survey.
Image recognition of tree species based on multi feature fusion and CNN model
Liu Jiazheng, Wang Xuefeng, Wang Tian
2019, 41(11): 76-86.   doi: 10.13332/j.1000-1522.20180366
[Abstract](306) [FullText HTML](215) [PDF 1513KB](52)
ObjectiveThere are intra-class differences and inter-class similarities in tree species image recognition, which makes it difficult for traditional methods based on single artificial features to achieve ideal recognition results. In order to solve these problems, a tree image depth learning recognition method based on convolution neural network was proposed, which combines deep features of the image with artificial features.MethodSix kinds of common tree species, including Pinus sylvestris var. mongolica, Populus davidiana, Betula platyphylla, Larix gmelinii, Cedrus deodara and Pinus alba, were studied. Firstly, the original tree species image set was expanded by clipping, horizontal flipping, rotation and other operations, and was divided into training set and test set to establish the image database of this tree species recognition experiment; secondly, the model was designed as three parallel channels. The network selected RGB image, HSV image and LBP-HOG image, respectively, and recognized the above tree image from the point of view of pixel value, color, texture and shape. On the one hand, a CNN depth learning model suitable for this experiment was constructed. The RGB image and the corresponding HSV image in the training set were used as the input of the first and second CNN models to extract the deep features of tree image. On the other hand, the training set was de-noised by Gaussian filtering, and LBP-HOG features were extracted artificially to represent texture and shape features as the input of the third CNN model. Finally, the features obtained by each of the three models were summarized in the last layer of the fully connected layer as the final classification basis of the soft Max classifier. Finally, in order to verify the feasibility of the proposed method, the SVM classifier, BP neural network, the existing depth learning LeNet-5 model and VGG-16 model were trained by the above features and training set, and the test set was identified and verified to compare the final recognition effect.ResultThe training accuracy of the multi-feature fusion CNN model was 96.13%, and the average recognition accuracy was 91.70%. In the CNN tree species recognition model based on one-way training, the recognition rate of RGB image as training input value was the highest, which was 75.21%, followed by HSV feature recognition rate, and LBP-HOG feature was the worst; in the case of multi-feature fusion, the combination recognition rate of RGB + HSV + LBP + HOG was the highest, which reached 93.50%; in the case of RGB + H channel + LBP + HOG, the recognition rate of RGB + HSV + LBP + HOG was the highest. The recognition rate was 89.50%. Under the same condition of feature or feature combination, the recognition rate of SVM, BP neural network, LeNet-5 model and VGG-16 model was lower than that of the model in this paper.ConclusionBased on RGB + H channel + LBP feature fusion, the three-way parallel CNN model is used to get the highest recognition rate for the six types of tree images in this paper, which overcomes the problem of low recognition rate in the case of a single feature, and the recognition effect is also very ideal. It realizes automatic recognition of specific categories from a large number of different tree images.
Analyses on water use characteristics of Salix psammophila based on sap flow and leaf water potential
Yang Ruizhi, Ma Jingyong, Liang Chunxuan, Tian Yun, Jia Xin, Zha Tianshan
2019, 41(11): 87-94.   doi: 10.13332/j.1000-1522.20180241
[Abstract](297) [FullText HTML](113) [PDF 975KB](22)
ObjectiveIn arid and semi-arid areas, water transfer process of plants is regulated by a set of effective mechanisms. Understanding the mechanisms of responses of xerophytic plants to soil drought is important for predicting the structure and functioning of dryland ecosystems under changing climate.MethodThe stem sap flow of Salix psammophila was monitored continuously using five heat balance sensor, and the leaf water potential of the plant was measured at predawn and midday in nineteen sunny days during 1 May to 10 October, 2017. The photosynthetic active radiation above canopy, air temperature, air relative humidity, and soil moisture content were monitored simultaneously.ResultThe results were that the sap flux density and soil water potential were highly correlated in short term (May to June, July to September). The sap flux density and the water potential drop (ΨLΨS) were positively correlated during the growing season. Leaf transpiration rate increased with leaf water potential and vapor pressure deficit (VPD), respectively, saturating at −3.7 MPa and 1.9 kPa, leaf conductance for water vapour increased positively with VPD, saturating at 0.9 kPa, then decreasing with these variables when greater than their respective threshold. The vulnerability curve was " r” shape for Salix psammophila. The water potential, at which 50% of hydraulic conductivity was lost as a result of xylem embolism (P50), was 0.72 MPa. The whole-branch hydraulic conductance per unit basal sapwood cross-sectional area (Ks) increased with soil water potential (ΨS) and leaf conductance (gL). The correlation between gL and ΨS was low because of the influence of VPD on gL. The relative sensitivity of stomata and plant hydraulic conductance to declining soil water potentials (ϭ) was 1.035.ConclusionThe results show that as water stress develops, Salix psammophila controls the water loss by reducing the Ks and certain level of xylem embolism does not induce the closure of the stomata. This mechanisms may be advantageous in terms of maximizing transpiration and assimilation rates. It has obvious theoretical significance to understand the water use characteristics of plants in arid areas, and lays a foundation for further study on the mechanism of the compensation for hydraulic limitation of Salix psammophila.
Characteristics of soil C, N, P and their relationship with litter quality in natural Pinus massoniana forest
Xiang Yunxi, Pan Ping, Chen Shengkui, Ouyang Xunzhi, Ning Jinkui, Wu Zirong, Ji Renzhan
2019, 41(11): 95-103.   doi: 10.13332/j.1000-1522.20190029
[Abstract](447) [FullText HTML](519) [PDF 728KB](45)
ObjectiveAnalyzing the carbon, nitrogen and phosphorus characteristics in forest soil and their relationship with litter quality can provide references for the accurate improvement of forest quality.MethodThis paper takes natural Pinus massoniana forest in southern Jiangxi Province, eastern China as the research object and obtains data based on the investigation of standard plots and sample measurement, it extracted the variables which reflect the litter quality characteristics by principal component analysis and set up a regression model with the litter quality and the soil organic carbon (C), total nitrogen (N), total phosphorus (P), respectively to analyze the relationship between the content of C, N and P in soil and litter quality.Result(1) With the increase of soil depth, soil C, N, P gradually decreased, and C and N contents in 0−10 cm soil layer were significantly higher than that in other layers (P < 0.05), while P content in each soil layer had no significant difference (P > 0.05). In general, the contents of C, N, P in soil changed from the state of moderate to extremely low. With the increase of forest age, the contents of C, N and P in all soil layers showed an upward trend, among which the content of C in 0−10 cm soil layer was significantly different in varied age groups (P < 0.05). (2) The existing amount of semi-decomposed layer and undecomposed layer of litter increased first and then decreased and the maximum value of each age group achieved in near-mature forest; the contents of C, N and P in each decomposition layer did not show significant changes in different age groups, but the contents of C and C/N in the semi-decomposition layer were significantly lower than those in the undecomposed layer (P < 0.05), while the contents of N and P in the semi-decomposed layer were higher than those in the undecomposed layer, and the differences were not significant (P > 0.05). (3) The principal components reflecting the quality characteristics of semi-decomposed layer and the undecomposed layer of litter were significantly correlated with soil C and N contents, but were not significantly correlated with soil P contents, showing that the contents of C, N and P in soil were positively correlated with the contents of C, N and P in the semi-decomposed layer of litter, and negatively correlated with the contents of C, N and P in the undecomposed layer of litter.ConclusionIn natural Pinus massoniana forest, the soil nutrient contents totally were low. When the contents of C, N and P of litter decreased in undecomposed layer and increased in semi-decomposed layer, the contents of soil nutrients increased. Therefore, promoting the decomposition of litter in the management can improve the soil nutrient content, which is conducive to the growth of trees.
Spatial distribution characteristics of soil organic carbon and total nitrogen stocks across the different typical vegetation types in Nangunhe National Nature Reserve, southwestern China
Ren Yulian, Lu Mei, Cao Qianbin, Li Cong, Feng Jun, Wang Zhisheng
2019, 41(11): 104-115.   doi: 10.13332/j.1000-1522.20180319
[Abstract](308) [FullText HTML](142) [PDF 1056KB](27)
ObjectiveThe change in vegetation types along the elevation gradient induces the alterations in site, microclimate and soil properties, thus in turn forms the variations of soil carbon and nitrogen stocks along the elevation gradient. We aimed to explore the variation characteristics of soil organic carbon and total nitrogen stocks along the elevation gradient in Nangunhe Nature Reserve, Yunnan Province of southwestern China and its coupling relationship with environmental factors.MethodThree typical vegetation types (i.e., ravine rainforest, semi-evergreen monsoon rainforest, mid-montane humid evergreen broadleaved forest) in Nangunhe Nature Reserve were applied to investigate the variation rules of soil organic carbon and total nitrogen stocks along the elevation gradient. The association of soil organic carbon and total nitrogen stocks to environmental factors was also analyzed through the general linear regression and RDA redundancy.ResultSoil organic carbon and total nitrogen stocks increased along the elevation gradient (P < 0.05). Soil organic carbon and total nitrogen stocks were ranked as ravine rainforest (89.10 t/ha, 11.94 t/ha) < semi-evergreen monsoon rainforest (190.30 t/ha, 25.34 t/ha) < mid-montane humid evergreen broadleaved forest (508.05 t/ha, 56.55 t/ha). The order was consistent with the variations in litter thickness, average annual precipitation, soil water content, total organic carbon and nitrogen. Soil organic carbon stocks of three vegetation types showed a vertical change of increasing first and then decreasing along the soil layers. However, total nitrogen stock decreased with increasing soil depth. Soil organic carbon and total nitrogen stocks were positively related with altitude, average annual precipitation, soil water content, litter thickness, total organic carbon and total nitrogen (P < 0.01), while average annual air temperature, soil temperature, soil pH and bulk density had negative correlation with soil organic carbon and total nitrogen stocks (P < 0.01). Redundancy analysis showed that litter thickness and soil water content were the dominant factors of soil organic carbon and total nitrogen stocks.ConclusionThe results indicated that change of vegetation types along the elevation gradient affected the variations in microclimate (i.e., temperature and water), litter input (litter thickness), and soil physicochemical properties (i.e., soil bulk density, and C and N concentration), which contributed to significant effects on the soil carbon and total nitrogen stocks in tropical area.
Effects of simulated different cooking temperatures on the quality of Korean pine seed oil and principal component analysis
Wang Fengjuan, Tong Xinyu, Xia Xiaoyu, Fu Qun, Guo Qingqi
2019, 41(11): 116-124.   doi: 10.13332/j.1000-1522.20190115
[Abstract](189) [FullText HTML](170) [PDF 921KB](33)
ObjectiveIn order to explore the changes of fatty acid composition and physicochemical properties, Korean pine seed oil was heated at simulated cooking temperatures, and to reveal comprehensive evaluation by the principal component analysis method.MethodTo determine the fatty acid composition of Korean pine seed oil pre-treated at different cooking temperatures, gas chromatography-mass spectrometry (GC-MS) was used. The physical and chemical properties of Korean pine seed oil before and after heat treatment were measured according to the national standard, and the fatty acid composition of Korean pine seed oil treated at different temperatures was analyzed by SPSS19.0 software.ResultWith the increase of heat treatment temperature, the carbonyl value and acid value of Korean pine seed oil increased significantly (P < 0.05), the peroxide value increased firstly and then decreased, reaching the maximum value of 9.79 mmol/kg at 180 ℃, and the iodine value and saponification value decreased respectively by 31.78% and 22.86% compared with control. The types and contents of fatty acids in Korean pine seed oil changed significantly after high temperature heating. The contents of unsaturated fatty acids, linoleic acid and pinolenic acid decreased, while the types and contents of trans fatty acids increased with cooking temperature. Five fatty acids (9t-C18∶1, (9c, 11t)-C18∶2, (10t, 12c)-C18∶2, 14-methyl-C16∶0, 10c-C17∶1) were synthesized during heating. Two principal components were extracted when analyzing the fatty acid composition of Korean pine seed oil treated at different temperatures through principal component analysis. The variance contribution rates were 83.80% and 10.43%, respectively.ConclusionIt is suggested that raising temperature can reduce the quality and fatty acid composition of Korean pine seed oil. The physical and chemical indexes and fatty acids of Korean pine seed oil do not change significantly during low temperature heat treatment.With the increase of temperature, the content of polyunsaturated fatty acids decreased, and the types and contents of trans fatty acids increased in Korean pine seed oil.
Landscape Architecture
Construction of green space planning framework based on ecosystem service function simulation: a case study of shallow mountain area in Beijing
Li Fangzheng, Liu Yang, Shi Yao, Hu Kaifu, Zheng Xi
2019, 41(11): 125-136.   doi: 10.13332/j.1000-1522.20190149
[Abstract](591) [FullText HTML](228) [PDF 1279KB](58)
ObjectiveIn the context of rapid urbanization and global climate change, the deterioration of the ecological environment has brought tremendous impact on human life and health. Ecosystem service function assessment has been promoted as a method to cope with climate change and build a green and livable living environment. Establishing a green space planning framework based on ecosystem service function simulation calculus has scientific guiding significance for objectively evaluating the service function of green space and building a sustainable green space network.MethodOn the basis of summarizing the relevant research of scholars at home and abroad, this paper takes the shallow mountain area of Beijing as an example to construct a green spatial planning framework based on the assessment of ecosystem service function. Six functional indicators, namely, heat island mitigation, soil and water conservation, carbon sequestration and oxygen release, climate regulation, biodiversity conservation and cultural recreation, were selected, and runoff was adopted. Coefficient formula calculation, MaxEnt model simulation and other methods were used to evaluate, identify the location of key green spaces of different service types in the region and propose suitable green space types. Finally, through the construction of recreational greenways and ecological corridors, green space links were strengthened and the layout of green space was improved.ResultThe results showed that the spatial distribution of ecosystem service benefits of different types showed some differences. According to the service differences provided by different regions, seven types of green space were delimited, including wetland park, forest park, country park, urban park, geological park, scenic spot and ecological conservation green space. Six new green roads were added. In plain and shallow mountainous area, ecological corridors were constructed in villages and towns such as Hot Spring Town, Yanshou Town, Shisanling Town and Yukou Town, and linear green space for the purpose of protecting target animals was established.ConclusionThe aim is to strengthen the implementation of ecological priority development strategy in shallow mountain areas and promote the formation of sustainable green development mode.
Forestry Engineering
Connection characteristics and parameter optimization of plastic-wood insert joint
Wang Anzheng, Guan Huiyuan
2019, 41(11): 137-145.   doi: 10.13332/j.1000-1522.20190226
[Abstract](139) [FullText HTML](128) [PDF 1383KB](14)
ObjectiveThe insert connection mode between plastic and wood is a common joint form in plastic chair furniture. Optimal design of joint parameters can effectively improve joint strength, thus enhancing the reliability of products.MethodPP plastic and beech jointed by round tenon was put forward as an example, the wall thickness of plastic part, inserting length and interference fit were selected as the observing factors, and the tensile strength and bending strength were taken as evaluation indexes. A three-factor and three-level Box-Behnken response surface design method was used to establish a mathematical model between joint strength and matching parameters. The significance and interaction of each factor were analyzed by analysis of variance, and the optimal assembling and matching parameters of the joint were obtained by solving the regression equation. On this basis, the comparative analysis of the withdrawal forces of joints was carried out between three different assembly forms interference assembly, gluing assembly and wood screw assembly.ResultThe results showed that the three design factors had significant effects on the tensile strength of the joints, but only the wall thickness of plastic parts and the depth of insertion had significant effects on the bending strength of the joints, and had nothing to do with the interference fit. The optimum matching parameters of 40 mm round tenon-wood joints were as follows: the wall thickness of plastic parts was 3.2 mm, the depth of joints was 50 mm, and the interference fit was 0.14 mm. Under this condition, the ultimate withdrawal force and the load of bending of joints were 2 139.3 N and 1 306.4 N. In addition, the withdrawal force of the joints with three different assembly methods was as follows: the interference assembly (type I joint) was 966.5 N < the glued assembly (type II joint) was 1 251.4 N < the wood screw connected assembly (type III joint) was 1 607.6 N.ConclusionThe matching parameters of the plastic-wood insert joint can be optimized by the response surface method to obtain the best mechanical properties. In practical application, it is easy to obtain the maximum joint strength when the design factors are close to the upper limit in the design domain. In addition, the use of wood screws can greatly increase the tensile strength of the joints.
Mechanical properties of CLT shear connections between self-tapping screws and mortise tenons
Lin Qinyu, Wen Chengsheng, Diao Yue, Yan Lirong, Gao Ying
2019, 41(11): 146-154.   doi: 10.13332/j.1000-1522.20190209
[Abstract](245) [FullText HTML](164) [PDF 2900KB](23)
ObjectiveThe appearance of CLT (cross-laminated timber) enables wooden buildings to break through height limitation, yet the current use of metal connectors reduces the efficiencies of CLT and wastes the mechanical capacities of CLT. Thus, the study of CLT connections becomes a vital issue. In order to provide scientific basis for the engineering application of mortise-tenon connection in CLT building, this paper makes a study of the shear performance of the mortise-tenon connection, and compares it with self-tapping screws (STS) used for wall-to-wall joints.MethodH-type CLT specimens connected with STS and mortise tenons were subjected to monotonic and cyclic loading test. Load-displacement curve, hysteretic curve and skeleton curve under pure shear loads were obtained. Mechanical properties such as initial stiffness, peak load, energy dissipation, stiffness degradation and strength degradation were investigated combining failure mode.ResultIt was shown that STS connections failed before the damage of CLT material appeared, and the damages also occurred on the wood around connections. While mortise-tenon connections failed after the damage appeared of CLT. In monotonic loading tests, mortise-tenon connections presented lower ductility than STS connections, but maximum load, ultimate displacement, yield load, yield displacement and energy dissipation were higher than STS connections by 313.50%, 35.38%, 370.80%, 92.76%, 459.64%, respectively. In cyclic loading tests, the ductility of STS connections deteriorated, but that of mortise-tenon connections became better. Meanwhile, the maximum load of pushing and pulling phase of mortise-tenon connections were respectively 455.54% and 234.74% higher than STS connections, and its ability to maintain stiffness, strength and consume energy were all better than STS connections.ConclusionCompared with the STS connections, mortise-tenon connections can allow full use of the strengths of CLT material and promote engineering application of CLT building.
Research Methods
A simple method for estimating runoff sediment concentration
Wen Wenjie, Zhang Jianjun, Li Yixuan, Huang Xiaoqing, He Pei
2019, 41(11): 155-162.   doi: 10.13332/j.1000-1522.20180246
[Abstract](115) [FullText HTML](117) [PDF 656KB](17)
ObjectiveRunoff sediment concentration is an important variable in monitoring hydrological processes and quantifying soil erosion. Methodological improvements in measuring sediment concentration are critical to the automatic, efficient and accurate estimation of soil losses, and could also guide soil and water conservation practices.MethodWe collected and analyzed soil samples from different provinces in China, and developed a weighing-based empirical model for estimating sediment concentration. We also investigated factors(specific gravity of sediment, volume of sample, water temperature)which may influence the accuracy of the method.ResultThe results showed that measured data agreed well with true values, and the method for estimating sediment concentration was accurate enough for practical use. When the sediment concentration was between 5 g/L and 20 g/L, the average relative error is less than 20%; when the sediment concentration was between 20 g/L and 200 g/L, the average relative error is less than 5%. Both specific gravity of sediment and temperature (P > 0.05) had no significant effect on the accuracy of the method, it is therefore reasonable to use the average specific gravity of the top-layer soil in the calculations, and the range of variation was between 2.50 and 2.70. However, the accuracy was significantly influenced by the measurement of the sample’s volume, how to accurately measure the volume of sample is the key to invent automatic monitoring machine for estimating sediment concentration in surface runoff.ConclusionThe weighing method has simple operation and high accuracy. It has a good application prospect in the study of inventing automatic monitoring machine for estimating sediment concentration in surface runoff.

Establishment Time:1979

CN 11-1932/S

ISSN 1000-1522

Supervisor:Sinopec Research Institute of Petroleum Engineering

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