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RSS2017 Vol. 39, No. 8
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2017, 39(8): 1-8.
doi:10.13332/j.1000-1522.20160418
Abstract:
Small watershed management is a sophisticated and arduous mission, it is important to take into overall consideration of economy, society, ecology, environment and other elements. Based on the present management theory, management planning and management requirement of small watershed management in China, this paper has given a detailed introduction to the development process of small watershed management at home and abroad and mainly elaborated the idea, technology and pattern of small watershed management in some developed countries (United States, Europe, Japan) and developing countries (India, Nepal, Africa), analyzed the characteristics and key experiences; on the other hand, some questions are raised, so the author gave the outlook and thinking of the current small watershed management: we should attach great importance to combine economic, political cultural and social construction with watershed management; for the ecological and economic characteristics of different regions, we should follow the principle of adjusting measures to local conditions and suitable administration; it should be adapted to the development of social economy and has to constantly adjust the objectives and measures of comprehensive watershed treatment.
Small watershed management is a sophisticated and arduous mission, it is important to take into overall consideration of economy, society, ecology, environment and other elements. Based on the present management theory, management planning and management requirement of small watershed management in China, this paper has given a detailed introduction to the development process of small watershed management at home and abroad and mainly elaborated the idea, technology and pattern of small watershed management in some developed countries (United States, Europe, Japan) and developing countries (India, Nepal, Africa), analyzed the characteristics and key experiences; on the other hand, some questions are raised, so the author gave the outlook and thinking of the current small watershed management: we should attach great importance to combine economic, political cultural and social construction with watershed management; for the ecological and economic characteristics of different regions, we should follow the principle of adjusting measures to local conditions and suitable administration; it should be adapted to the development of social economy and has to constantly adjust the objectives and measures of comprehensive watershed treatment.
Abstract:
In order to explore the mechanism of marginal cleavage inBetula pendula'Dalecarlica', the research tookBetula pendula'Dalecarlica' andBetula pendulaas research projects, based on leaf morphological characters and anatomical feature, we conducted qRT-PCR of leaf cleavage relating genes in apical buds, leaf tips, lobes, sinuses and other tissues, and also measured the endogenous IAA content and analyzed the GUS dyeing of IAA living tag(DR5). It turned out thatBetula pendula'Dalecarlica' blades owned three or four lobes from base to tip in both leaf sides, the veins on the back showed obvious tubular uplift, leaf width, mean distance between secondary veins, cross sectional areas of main veins were respectively bigger, namely 21.12%, 12.64%, 21.46%. Tissue expression characteristic analysis ofBpmiR164sand target genes demonstrated thatBpmiR164-2 andBpCUC2 played an important role in the formation of lobes, which was the major regulating gene in producing lobes; tissue expression characteristic analysis ofBpPINsindicated that onlyBpPIN2 andBpPIN5 in six auxin efflux carriergenes presented up-regulated expression; living tag of endogenous IAA manifested that IAA content enriched in apical buds and spires, meanwhile, the tissues of leaf tips, teeth and lobes in leaf expressed more IAA, we also got the IAA distribution features from results of LC-MS in above-mentioned tissues. Above all, the formation of lobes was bound up with polar transportation of hormone in the veins and some related gene regulation.
In order to explore the mechanism of marginal cleavage inBetula pendula'Dalecarlica', the research tookBetula pendula'Dalecarlica' andBetula pendulaas research projects, based on leaf morphological characters and anatomical feature, we conducted qRT-PCR of leaf cleavage relating genes in apical buds, leaf tips, lobes, sinuses and other tissues, and also measured the endogenous IAA content and analyzed the GUS dyeing of IAA living tag(DR5). It turned out thatBetula pendula'Dalecarlica' blades owned three or four lobes from base to tip in both leaf sides, the veins on the back showed obvious tubular uplift, leaf width, mean distance between secondary veins, cross sectional areas of main veins were respectively bigger, namely 21.12%, 12.64%, 21.46%. Tissue expression characteristic analysis ofBpmiR164sand target genes demonstrated thatBpmiR164-2 andBpCUC2 played an important role in the formation of lobes, which was the major regulating gene in producing lobes; tissue expression characteristic analysis ofBpPINsindicated that onlyBpPIN2 andBpPIN5 in six auxin efflux carriergenes presented up-regulated expression; living tag of endogenous IAA manifested that IAA content enriched in apical buds and spires, meanwhile, the tissues of leaf tips, teeth and lobes in leaf expressed more IAA, we also got the IAA distribution features from results of LC-MS in above-mentioned tissues. Above all, the formation of lobes was bound up with polar transportation of hormone in the veins and some related gene regulation.
2017, 39(8): 17-23.
doi:10.13332/j.1000-1522.20160428
Abstract:
Unmanned aerial vehicle (UAV) remote sensing technology plays an important role in the acquisition of tree parameters. In order to explore the feasibility of using high-resolution imagery of UAV to extract tree height, the Qiuji Coal Mine Forest Park of Shandong Province of eastern China was selected as the study area in this paper, the Pix4D software was used to process high-resolution imagery collected by UAV to generate the orthomosaic and 3D point cloud. The OTSU method was used to divide the 3D point cloud into two parts: the tree point cloud and the ground point cloud, then the top height of tree and the mean height of the ground were extracted according to the two parts of the point cloud. And the tree height was computed when the average ground height was taken as the height of tree root. The results showed that the tree point cloud and the ground point cloud could be accurately divided by OTSU method. And it was feasible that high resolution UAV imagery was used to extract the tree height, the absolute error of tree height was less than 80cm, the relative error was 16.2%, and the mean square error (RMSE) was 36.3cm. At the same time, the measurement of tree height was affected by the shape of crown. The height RMSE ofPlatanus acerifoliawith broadly ovate crown was 29.2cm, the height RMSE ofSabina chinensiswith conical crown was 50.9cm, the coefficient of determinationR2of the measured height and the real height of the two kinds of trees were respectively 0.9920 and 0.8894, the accuracy of measured height of thePlatanus acerifoliawas significantly higher than that of theSabina chinensis.
Unmanned aerial vehicle (UAV) remote sensing technology plays an important role in the acquisition of tree parameters. In order to explore the feasibility of using high-resolution imagery of UAV to extract tree height, the Qiuji Coal Mine Forest Park of Shandong Province of eastern China was selected as the study area in this paper, the Pix4D software was used to process high-resolution imagery collected by UAV to generate the orthomosaic and 3D point cloud. The OTSU method was used to divide the 3D point cloud into two parts: the tree point cloud and the ground point cloud, then the top height of tree and the mean height of the ground were extracted according to the two parts of the point cloud. And the tree height was computed when the average ground height was taken as the height of tree root. The results showed that the tree point cloud and the ground point cloud could be accurately divided by OTSU method. And it was feasible that high resolution UAV imagery was used to extract the tree height, the absolute error of tree height was less than 80cm, the relative error was 16.2%, and the mean square error (RMSE) was 36.3cm. At the same time, the measurement of tree height was affected by the shape of crown. The height RMSE ofPlatanus acerifoliawith broadly ovate crown was 29.2cm, the height RMSE ofSabina chinensiswith conical crown was 50.9cm, the coefficient of determinationR2of the measured height and the real height of the two kinds of trees were respectively 0.9920 and 0.8894, the accuracy of measured height of thePlatanus acerifoliawas significantly higher than that of theSabina chinensis.
Abstract:
Neighborhood search techniques have become one of the most important strategies to improve the resolution efficiency of heuristics in forestry, however a drastically debate on the resolution efficiency of this search strategy has been put forward recently. Simulated annealing algorithm, as an example of heuristics, has been employed in a wide set of forestry planning problems. Therefore, the overall goals of this research were to evaluate the performances of different neighborhood search techniques of simulated annealing in forest spatial planning problems. The objective function was to maximize the harvest volume over ten 5-year planning periods, which mainly included timber volume flow constraints, ending inventory constraints, unit restriction model and green-up constraints. The tested neighborhood search techniques were 1-opt moves, and 2-opt moves of simulated annealing which have been widely used in forestry planning, in which the candidate solutions of 1-opt moves were generated by randomly changing the treatment of just one unit, however the candidate solutions of 1-opt moves were generated by randomly changing the treatments of two units simultaneously. The planning problems were applied to three hypothetical datasets, which encompassed 3293 (forest?, 29536 (forest?and 81625 (forest ? binary decision variables. The results showed that the 2-opt technique of simulated annealing can locate the maximum solutions for all the three planning problems, however increasing the number of units for changing the treatment schedule simultaneously in more than one unit did not improve the performance of simulated annealing if the combinatorial problems were very large (i.e., the number of management units within a forest was larger than 3600). Since the planning results highly depend on the sizes of planning problems, thus forest managers and planners should pick up the optimization techniques carefully when they plan to make forest plans in practices.
Neighborhood search techniques have become one of the most important strategies to improve the resolution efficiency of heuristics in forestry, however a drastically debate on the resolution efficiency of this search strategy has been put forward recently. Simulated annealing algorithm, as an example of heuristics, has been employed in a wide set of forestry planning problems. Therefore, the overall goals of this research were to evaluate the performances of different neighborhood search techniques of simulated annealing in forest spatial planning problems. The objective function was to maximize the harvest volume over ten 5-year planning periods, which mainly included timber volume flow constraints, ending inventory constraints, unit restriction model and green-up constraints. The tested neighborhood search techniques were 1-opt moves, and 2-opt moves of simulated annealing which have been widely used in forestry planning, in which the candidate solutions of 1-opt moves were generated by randomly changing the treatment of just one unit, however the candidate solutions of 1-opt moves were generated by randomly changing the treatments of two units simultaneously. The planning problems were applied to three hypothetical datasets, which encompassed 3293 (forest?, 29536 (forest?and 81625 (forest ? binary decision variables. The results showed that the 2-opt technique of simulated annealing can locate the maximum solutions for all the three planning problems, however increasing the number of units for changing the treatment schedule simultaneously in more than one unit did not improve the performance of simulated annealing if the combinatorial problems were very large (i.e., the number of management units within a forest was larger than 3600). Since the planning results highly depend on the sizes of planning problems, thus forest managers and planners should pick up the optimization techniques carefully when they plan to make forest plans in practices.
2017, 39(8): 33-41.
doi:10.13332/j.1000-1522.20170002
Abstract:
Climate change influences biodiversity by altering the habitat of species in ecosystem.Toona sureniis a timber plant with high ecological, economic and medicinal value. It is called "Chinese mahogany" in China with other species inToona. Understanding the habitat requirements, evaluating habitat quality and predicting the species' potential habitat are significant for protectingT.sureni, as well as for its protection introduction and plantation. Because of the advantages of using presence-only data and performing well with small sample sizes, incomplete data and gaps, MaxEnt model was employed to simulate the habitat suitability distribution, and the area under the receive operating characteristic curve(AUC)was used to examine the model's accuracy, the larger the AUC is, the more accurate the prediction is. So, based on the distribution ofT. sureniin Yunnan Province of southwestern China, the MaxEnt model was used to set up its distributional model of potential habitat. The results showed that the mean training AUC and mean test AUC were 0.959 and 0.818, respectively. It is illustrated that the prediction ofT.sureni's suitable habitats was reliable. Five variables, namely standard deviation of temperature seasonal change, minimum temperature of the coldest month(?, mean temperature of the driest quarter(?, precipitation of the coldest quarter (mm), range of annual temperature were significant factors determiningT. sureni's suitable habitat. Habitat suitability for current and future climate warming(2050s, 2070s) under scenario RCP2.6 in Yunnan Province and China was calculated. The study reports the intuitive and quantitative predictions of climate change onT. surenispecies' suitable habitats. The habitat suitability ofT.sureniin Yunnan Province and China is predicted to deteriorate with global warming.
Climate change influences biodiversity by altering the habitat of species in ecosystem.Toona sureniis a timber plant with high ecological, economic and medicinal value. It is called "Chinese mahogany" in China with other species inToona. Understanding the habitat requirements, evaluating habitat quality and predicting the species' potential habitat are significant for protectingT.sureni, as well as for its protection introduction and plantation. Because of the advantages of using presence-only data and performing well with small sample sizes, incomplete data and gaps, MaxEnt model was employed to simulate the habitat suitability distribution, and the area under the receive operating characteristic curve(AUC)was used to examine the model's accuracy, the larger the AUC is, the more accurate the prediction is. So, based on the distribution ofT. sureniin Yunnan Province of southwestern China, the MaxEnt model was used to set up its distributional model of potential habitat. The results showed that the mean training AUC and mean test AUC were 0.959 and 0.818, respectively. It is illustrated that the prediction ofT.sureni's suitable habitats was reliable. Five variables, namely standard deviation of temperature seasonal change, minimum temperature of the coldest month(?, mean temperature of the driest quarter(?, precipitation of the coldest quarter (mm), range of annual temperature were significant factors determiningT. sureni's suitable habitat. Habitat suitability for current and future climate warming(2050s, 2070s) under scenario RCP2.6 in Yunnan Province and China was calculated. The study reports the intuitive and quantitative predictions of climate change onT. surenispecies' suitable habitats. The habitat suitability ofT.sureniin Yunnan Province and China is predicted to deteriorate with global warming.
2017, 39(8): 42-49.
doi:10.13332/j.1000-1522.20160193
Abstract:
The impact of nitrogen (N) on net primary productivity (NPP) of forest ecosystem has become focus of the researchers since N deposition is increasingly serious. A six-year field experiment was conducted in the typical mixed broadleaf-Korean pine forest in Xiaoxing'an Mountains, northeastern China, to explore the effects of N addition on carbon (C) density and NPP of forest ecosystem and its components. Urea was selected as N source and four levels of N addition were control (N0, 0kg/(ha·a), low N (N1, 30kg/(ha·a), medium N (N2, 60kg/(ha·a) and high N (N3, 120kg/(ha·a). Results showed that N addition had no significant effects on C density of vegetation C pool, detritus C pool and soil organic C pool (P>0.05). N addition had no significant effects on the NPP of whole forest ecosystem, however, it inhibited NPP of coniferous tree leaf but promoted that of broadleaved trees (P< 0.05). Soil total N concentration had no significant difference among different N addition treatments, but it had a highly significantly positive correlation with soil organic C concentration (P< 0.01). We suggest that soil total N concentration has a significant influence on soil organic C in forest ecosystem, rather than N addition amount.
The impact of nitrogen (N) on net primary productivity (NPP) of forest ecosystem has become focus of the researchers since N deposition is increasingly serious. A six-year field experiment was conducted in the typical mixed broadleaf-Korean pine forest in Xiaoxing'an Mountains, northeastern China, to explore the effects of N addition on carbon (C) density and NPP of forest ecosystem and its components. Urea was selected as N source and four levels of N addition were control (N0, 0kg/(ha·a), low N (N1, 30kg/(ha·a), medium N (N2, 60kg/(ha·a) and high N (N3, 120kg/(ha·a). Results showed that N addition had no significant effects on C density of vegetation C pool, detritus C pool and soil organic C pool (P>0.05). N addition had no significant effects on the NPP of whole forest ecosystem, however, it inhibited NPP of coniferous tree leaf but promoted that of broadleaved trees (P< 0.05). Soil total N concentration had no significant difference among different N addition treatments, but it had a highly significantly positive correlation with soil organic C concentration (P< 0.01). We suggest that soil total N concentration has a significant influence on soil organic C in forest ecosystem, rather than N addition amount.
Abstract:
Nitrogen deposition is much heavier in the north of China, which exerts a great influence on forest ecological system dynamics. To improve our understanding about the effects of elevating N deposition on the growth and the biomass allocation pattern ofPinus tabuliformisseedlings, a nitrogen addition experiment with three provenances ofP. tabuliformisseedlings was carried out on Lingkong Mountain in Shanxi Province, northern China. Three-year-oldP. tabuliformisseedlings of three different provenances, Beijing (BJ), Shanxi (SX) and Neimenggu (NMG), were planted in a common garden, and five nitrogen treatments with three replications were designed, including: control (N0, 0kg/(hm2·a), in N, similarly hereinafter), low nitrogen level(N1, 15kg/(hm2·a)), middle nitrogen level (N2, 25kg/(hm2·a)), high nitrogen level (N3, 50kg/(hm2·a)) and the supersaturated nitrogen level (N4, 150kg/(hm2·a)). The base diameter, plant height, monthly growth amount, biomass and the biomass allocation pattern ofP. tabuliformisseedlings under different nitrogen addition levels were measured. The results showed that: 1) Adding nitrogen had remarkable effect on plant height for BJ provenance seedlings (P< 0.05), but there was no significant impact on the average base diameter. The base diameters of SX and NMG provenance seedlings were influenced by nitrogen addition treatments, but these effects were not significant. 2) The height growth of BJ provenance seedlings increased under adding nitrogen treatments, while their base diameter growth decreased, but these effects were not significant; The month base diameter growth of NMG provenance seedling decreased significantly under the N4 treatments (P< 0.05). 3) The growth of BJ provenance was affected by nitrogen addition, with dry biomass, dry biomass of the whole plant, the aboveground part and stem increasing significantly under the N1 nitrogen treatment (P< 0.05). Leaf dry biomass of SX provenance seedlings decreased significantly under different nitrogen addition treatments, while there was no significant changes of the whole plant biomass of NMG provenance seedling. 4) Leaf mass ratio of SX provenance seedlings increased significantly under the N3 level nitrogen addition treatments (P< 0.05); The root mass ratio of NMG provenance seedlings reduced significantly with the incensement of concentration of nitrogen addition. while stem mass ratio showed inversed trend; 5) The analysis of sources of variation showed that the variation of base diameter was related closely with both nitrogen treatment and provenance, but those of month growth of base diameter, leaf mass ratio and root-leaf ratio were only associated with the provenance. In conclusion, continuous nitrogen added has affected the internal stability ofPinus tabuliformispopulations.
Nitrogen deposition is much heavier in the north of China, which exerts a great influence on forest ecological system dynamics. To improve our understanding about the effects of elevating N deposition on the growth and the biomass allocation pattern ofPinus tabuliformisseedlings, a nitrogen addition experiment with three provenances ofP. tabuliformisseedlings was carried out on Lingkong Mountain in Shanxi Province, northern China. Three-year-oldP. tabuliformisseedlings of three different provenances, Beijing (BJ), Shanxi (SX) and Neimenggu (NMG), were planted in a common garden, and five nitrogen treatments with three replications were designed, including: control (N0, 0kg/(hm2·a), in N, similarly hereinafter), low nitrogen level(N1, 15kg/(hm2·a)), middle nitrogen level (N2, 25kg/(hm2·a)), high nitrogen level (N3, 50kg/(hm2·a)) and the supersaturated nitrogen level (N4, 150kg/(hm2·a)). The base diameter, plant height, monthly growth amount, biomass and the biomass allocation pattern ofP. tabuliformisseedlings under different nitrogen addition levels were measured. The results showed that: 1) Adding nitrogen had remarkable effect on plant height for BJ provenance seedlings (P< 0.05), but there was no significant impact on the average base diameter. The base diameters of SX and NMG provenance seedlings were influenced by nitrogen addition treatments, but these effects were not significant. 2) The height growth of BJ provenance seedlings increased under adding nitrogen treatments, while their base diameter growth decreased, but these effects were not significant; The month base diameter growth of NMG provenance seedling decreased significantly under the N4 treatments (P< 0.05). 3) The growth of BJ provenance was affected by nitrogen addition, with dry biomass, dry biomass of the whole plant, the aboveground part and stem increasing significantly under the N1 nitrogen treatment (P< 0.05). Leaf dry biomass of SX provenance seedlings decreased significantly under different nitrogen addition treatments, while there was no significant changes of the whole plant biomass of NMG provenance seedling. 4) Leaf mass ratio of SX provenance seedlings increased significantly under the N3 level nitrogen addition treatments (P< 0.05); The root mass ratio of NMG provenance seedlings reduced significantly with the incensement of concentration of nitrogen addition. while stem mass ratio showed inversed trend; 5) The analysis of sources of variation showed that the variation of base diameter was related closely with both nitrogen treatment and provenance, but those of month growth of base diameter, leaf mass ratio and root-leaf ratio were only associated with the provenance. In conclusion, continuous nitrogen added has affected the internal stability ofPinus tabuliformispopulations.
2017, 39(8): 60-67.
doi:10.13332/j.1000-1522.20160172
Abstract:
Using Levins, MacArthur-Levins and Pearson index methods, niche breadth, niche overlap and canonical correspondence analysis (CCA) of top 20 tree and shrub species were studied inThuja sutchuenensiscommunity of Dabashan Mountain, southwestern China. Results showed that:1)Thuja sutchuenensiswas a dominant species in the tree layer of the community with the maximum important value (0.225 1) and niche breadth (6.704 2), and had larger niche overlap than other species (Oij>0.123 7). It indicates thatThuja sutchuenensishas stronger ability to adapt to the environment, to compete and utilize resources in the tree layer. 2) The living conditions ofThuja sutchuenensisin shrub layer was far from optimistic. Although owning the maximum important value (0.170 1), while its niche breadth only ranked 19th (1.853 0). Also,Thuja sutchuenensishad smaller niche overlap degree(Oij< 0.482 3) than other species, but the other species had larger niche overlap degree withThuja sutchuenensis. Consequently, theThuja sutchuenensishad a weaker competition ability in the shrub layer. 3) Based on the advantage species CCA sequences in the tree layer, species (Thuja sutchuenensis,Cyclobalanopsis myrsinifolia) with broad niche breadth distributed in the center of the sequence diagram; individuals (Pinus armandii,Juglans cathayensis) with narrow niche breadth located in the periphery of the sequence diagram. Combined with the niche overlap, those species (Thuja sutchuenensis-Cyclobalanopsis multinervis,Thuja sutchuenensis-Lithocarpus fangii,Thuja sutchuenensis-Rhododendron sutchuenense, etc.) with high niche overlap degree usually close to each other in the sequence diagram. Concerning the 9 sequencing environmental factors, slope degree, pH and soil water content had great influence on the survival ofThuja sutchuenensis. 4) Habitat specialized and artificial destruction are two significant reasons to result in the narrow distribution range, patchlized shape, population renew difficulty and endangerment ofThuja sutchuenensis.
Using Levins, MacArthur-Levins and Pearson index methods, niche breadth, niche overlap and canonical correspondence analysis (CCA) of top 20 tree and shrub species were studied inThuja sutchuenensiscommunity of Dabashan Mountain, southwestern China. Results showed that:1)Thuja sutchuenensiswas a dominant species in the tree layer of the community with the maximum important value (0.225 1) and niche breadth (6.704 2), and had larger niche overlap than other species (Oij>0.123 7). It indicates thatThuja sutchuenensishas stronger ability to adapt to the environment, to compete and utilize resources in the tree layer. 2) The living conditions ofThuja sutchuenensisin shrub layer was far from optimistic. Although owning the maximum important value (0.170 1), while its niche breadth only ranked 19th (1.853 0). Also,Thuja sutchuenensishad smaller niche overlap degree(Oij< 0.482 3) than other species, but the other species had larger niche overlap degree withThuja sutchuenensis. Consequently, theThuja sutchuenensishad a weaker competition ability in the shrub layer. 3) Based on the advantage species CCA sequences in the tree layer, species (Thuja sutchuenensis,Cyclobalanopsis myrsinifolia) with broad niche breadth distributed in the center of the sequence diagram; individuals (Pinus armandii,Juglans cathayensis) with narrow niche breadth located in the periphery of the sequence diagram. Combined with the niche overlap, those species (Thuja sutchuenensis-Cyclobalanopsis multinervis,Thuja sutchuenensis-Lithocarpus fangii,Thuja sutchuenensis-Rhododendron sutchuenense, etc.) with high niche overlap degree usually close to each other in the sequence diagram. Concerning the 9 sequencing environmental factors, slope degree, pH and soil water content had great influence on the survival ofThuja sutchuenensis. 4) Habitat specialized and artificial destruction are two significant reasons to result in the narrow distribution range, patchlized shape, population renew difficulty and endangerment ofThuja sutchuenensis.
2017, 39(8): 68-76.
doi:10.13332/j.1000-1522.20170137
Abstract:
The sand transport and aeolian-sand structure of the array in 0-50 cm with different wind speeds, wind direction, power station array spacing, and whether or not there are the wheat straw sand barrier were analyzed by wind tunnel simulation, which aimed to investigate the effect of photovoltaic array on drifting sand with different allocation of wind field and photovoltaic DC field. The results showed that: 1) the sand transport rate of the array was proportional to the wind speed, and inversely proportional to the sand collection height in 0-50 cm. And the polynomial simulation of the sand transport rate under 3 kinds of wind speed was optimal. 2) The sand transport rate of the array and its characteristic value (λ) of aeolian-sand flow were the highest when the wind was south. And the best simulation of the south wind (180°), northeast wind (45°) and northwest wind (315°) were polynomial, logarithmic and exponential function, respectively. 3)The sand transport rate of the array in 20 cm (reduced in equal proportion to electric field) was the highest. 4) The characteristic value of aeolian-sand flow structure was 1.75 when the wheat straw sand barrier was laid at the front of the array, indicating unsaturated status and sand carrying capacity of aeolian-sand flow at this time.
The sand transport and aeolian-sand structure of the array in 0-50 cm with different wind speeds, wind direction, power station array spacing, and whether or not there are the wheat straw sand barrier were analyzed by wind tunnel simulation, which aimed to investigate the effect of photovoltaic array on drifting sand with different allocation of wind field and photovoltaic DC field. The results showed that: 1) the sand transport rate of the array was proportional to the wind speed, and inversely proportional to the sand collection height in 0-50 cm. And the polynomial simulation of the sand transport rate under 3 kinds of wind speed was optimal. 2) The sand transport rate of the array and its characteristic value (λ) of aeolian-sand flow were the highest when the wind was south. And the best simulation of the south wind (180°), northeast wind (45°) and northwest wind (315°) were polynomial, logarithmic and exponential function, respectively. 3)The sand transport rate of the array in 20 cm (reduced in equal proportion to electric field) was the highest. 4) The characteristic value of aeolian-sand flow structure was 1.75 when the wheat straw sand barrier was laid at the front of the array, indicating unsaturated status and sand carrying capacity of aeolian-sand flow at this time.
2017, 39(8): 77-86.
doi:10.13332/j.1000-1522.20170126
Abstract:
To better understand the role of precipitation and slope discharge on hydrodynamic characteristics of overland flow, the simulated rainfall experiments were carried out at a steep slope (slope gradient was 20°) flume in Jinyun Forest Ecological Station, Chongqing of southwestern China. Velocityvand flow depthhwere measured under different conditions of 5 unit dischargesq(ranged from 0.486×10-3to 1.736×10-3m3/(s·m)), 4 typical rainfall intensitiesP(0, 30, 60, 100 mm/h) and 4 different surface roughnessks(0.009, 0.180, 0.250, 0.425 mm). Furtherly, the hydraulic parameters, i.e., the mean velocityu, the velocity correction factor, flow-state indicatorm, flow regime and overland flow resistance coefficientfwere calculated. The results showed that: 1) mean velocity increased with increasingqin power function andvdecreased with the increase ofks. The velocity correction factor ranged from 0.04 to 0.37 in rainfall condition while ranged from 0.42 to 0.98 without rainfall. The overland flow was disturbed by rainfall. 2) The flow-state indicator ranged from 0.291 to 0.538. Without rainfall, flow-state indicator was mainly affected by roughness which was negatively correlated withm. The reduction rate was 21%, 28% and 39%, respectively. With medium-low rain intensity, no obvious variation pattern existed. When the rain intensity was 30 mm/h, the variation rate was 18%, -29% and 12%, respectively. When the rain intensity was 60 mm/h, the variation rate was 12%, -17% and -16%. With high rain intensity, the flow-state indicator significantly decreased with increasing roughness. The reduction rate was -6%, 1% and -11%, respectively. 3) TheReranged from 500 to 2 000, therefore the flow regime of overland flow was mainly transition flow. In most cases, flow pattern was supercritical flow. Without rainfall, the roughness was obviously related with the flow regime, that the overland flow tended to be supercritical with smaller roughness value, but this trend was not detecte with rainfall because of its disturbance effect. 4) Darcy resistance coefficient was positively related toks, while negatively correlated with unit discharge. Comparing the calculation formula of resistance coefficient with rainfall intensity to condition of without rainfall intensity, the correlation coefficient declined by 0.01%, showing that rainfall had no significant influence on resistance coefficient.
To better understand the role of precipitation and slope discharge on hydrodynamic characteristics of overland flow, the simulated rainfall experiments were carried out at a steep slope (slope gradient was 20°) flume in Jinyun Forest Ecological Station, Chongqing of southwestern China. Velocityvand flow depthhwere measured under different conditions of 5 unit dischargesq(ranged from 0.486×10-3to 1.736×10-3m3/(s·m)), 4 typical rainfall intensitiesP(0, 30, 60, 100 mm/h) and 4 different surface roughnessks(0.009, 0.180, 0.250, 0.425 mm). Furtherly, the hydraulic parameters, i.e., the mean velocityu, the velocity correction factor, flow-state indicatorm, flow regime and overland flow resistance coefficientfwere calculated. The results showed that: 1) mean velocity increased with increasingqin power function andvdecreased with the increase ofks. The velocity correction factor ranged from 0.04 to 0.37 in rainfall condition while ranged from 0.42 to 0.98 without rainfall. The overland flow was disturbed by rainfall. 2) The flow-state indicator ranged from 0.291 to 0.538. Without rainfall, flow-state indicator was mainly affected by roughness which was negatively correlated withm. The reduction rate was 21%, 28% and 39%, respectively. With medium-low rain intensity, no obvious variation pattern existed. When the rain intensity was 30 mm/h, the variation rate was 18%, -29% and 12%, respectively. When the rain intensity was 60 mm/h, the variation rate was 12%, -17% and -16%. With high rain intensity, the flow-state indicator significantly decreased with increasing roughness. The reduction rate was -6%, 1% and -11%, respectively. 3) TheReranged from 500 to 2 000, therefore the flow regime of overland flow was mainly transition flow. In most cases, flow pattern was supercritical flow. Without rainfall, the roughness was obviously related with the flow regime, that the overland flow tended to be supercritical with smaller roughness value, but this trend was not detecte with rainfall because of its disturbance effect. 4) Darcy resistance coefficient was positively related toks, while negatively correlated with unit discharge. Comparing the calculation formula of resistance coefficient with rainfall intensity to condition of without rainfall intensity, the correlation coefficient declined by 0.01%, showing that rainfall had no significant influence on resistance coefficient.
Abstract:
Global warming has seriously affected the structure and function of global ecosystems. In urban tree species selection, resistance evaluation system of tree pests and disease is one of the rational and effective approaches in the context of climate warming. According to the three levels of resistance screening, resistance evaluation and resistance management, an evaluation system of tree pests and disease resistance was constructed. Based on the explored literature, 32 urban tree species in Shanghai were evaluated by the evaluation system under climate warming. The evaluation system includes two aspects of disease resistance and pest resistance, among which, the disease resistance is catogorilized into four levels: non-lethal leaf disease, branch disease, root disease and lethal disease, and the pest resistance contains trunk borer pests, leaf-eating pests, sucking pests and underground pests.The results showed that 6 specices (Albizzia julibrissin,Phonex canariensis,Platanus acerifolia,Cinnamomum camphora,Rhododendron simsii,Cerasus serrulata) were in high fection level, 6 species (Cycas revoluta,Bischofia polycarpa,Salix babylonica,Euonymus japonicus,Osmanthus fragrans,Pittosporum tobira) were susceptible, 8 species (Ligustrum lucidum,Metasequoia glyptostroboides,Pterocarya stenoptera,Koelreuteria paniculata,Acer buergerianum,Malus hallian,Hibiscus syriacus,Ilex cornuta) were in low resistance, 10 pieces (Melia azedarach,Ginkgo biloba,Magnolia grandifolia,Cedrus deodara,Elaeocarpus decipiens,Distylium racemosum,Berberis thunbergii,Chimonanthus praecox,Fatsia japonica,Photinia serrulata) were in medium resistance, 2 species(Magnolia denudata,Camellia japonica) were in high resistance. Therefore, the evaluation system provides an effective method to evaluate the resistance of landscape trees from a case study of single or few pests and diseases to the multi-holistic research. Meanwhile, it has a certain reference value for the occurrence and development of tree pests and diseases in response to climate warming, and it is helpful for reasonable tree species selection and sustainable management.
Global warming has seriously affected the structure and function of global ecosystems. In urban tree species selection, resistance evaluation system of tree pests and disease is one of the rational and effective approaches in the context of climate warming. According to the three levels of resistance screening, resistance evaluation and resistance management, an evaluation system of tree pests and disease resistance was constructed. Based on the explored literature, 32 urban tree species in Shanghai were evaluated by the evaluation system under climate warming. The evaluation system includes two aspects of disease resistance and pest resistance, among which, the disease resistance is catogorilized into four levels: non-lethal leaf disease, branch disease, root disease and lethal disease, and the pest resistance contains trunk borer pests, leaf-eating pests, sucking pests and underground pests.The results showed that 6 specices (Albizzia julibrissin,Phonex canariensis,Platanus acerifolia,Cinnamomum camphora,Rhododendron simsii,Cerasus serrulata) were in high fection level, 6 species (Cycas revoluta,Bischofia polycarpa,Salix babylonica,Euonymus japonicus,Osmanthus fragrans,Pittosporum tobira) were susceptible, 8 species (Ligustrum lucidum,Metasequoia glyptostroboides,Pterocarya stenoptera,Koelreuteria paniculata,Acer buergerianum,Malus hallian,Hibiscus syriacus,Ilex cornuta) were in low resistance, 10 pieces (Melia azedarach,Ginkgo biloba,Magnolia grandifolia,Cedrus deodara,Elaeocarpus decipiens,Distylium racemosum,Berberis thunbergii,Chimonanthus praecox,Fatsia japonica,Photinia serrulata) were in medium resistance, 2 species(Magnolia denudata,Camellia japonica) were in high resistance. Therefore, the evaluation system provides an effective method to evaluate the resistance of landscape trees from a case study of single or few pests and diseases to the multi-holistic research. Meanwhile, it has a certain reference value for the occurrence and development of tree pests and diseases in response to climate warming, and it is helpful for reasonable tree species selection and sustainable management.
2017, 39(8): 98-103.
doi:10.13332/j.1000-1522.20160265
Abstract:
Taking essential oil fromPinus koraiensisneedles as the research object, its antioxidant and antimicrobial activities were evaluated. The antioxidant activity of the essential oil was explored with DPPH free radicals, ABTS free radicals, super-oxide anion free radical (O2-·) and total reducing power as indicators. Antibacterial activity of the essential oil was studied withEscherichia coli,Bacillus subtilisandStaphylococcus aureusas the test strain against typical food-borne microorganisms, with minimum inhibitory concentration. Pine needle essential oil showed remarkable antioxidant activity in scavenging DPPH free radical, ABTS free radicals, super-oxide anion free radical (O2-·), and in reducing power assays. Essential oils of half of the clearance IC50value concentration were 4.24, 4.46, 3.26 mg/mL. The diameters ofEscherichia coli,Bacillus subtilisandStaphylococcus aureusinhibition zone were (15.20±0.12) mm, (13.30±0.15) mm, and (9.50±0.21) mm, and the minimum inhibitory concentration(MIC) was 1.26, 2.50, and 5.00 μL/mL. These results suggest that the essential oil from pine needles has potential to be used as a natural antioxidant and antimicrobial agent in food processing.
Taking essential oil fromPinus koraiensisneedles as the research object, its antioxidant and antimicrobial activities were evaluated. The antioxidant activity of the essential oil was explored with DPPH free radicals, ABTS free radicals, super-oxide anion free radical (O2-·) and total reducing power as indicators. Antibacterial activity of the essential oil was studied withEscherichia coli,Bacillus subtilisandStaphylococcus aureusas the test strain against typical food-borne microorganisms, with minimum inhibitory concentration. Pine needle essential oil showed remarkable antioxidant activity in scavenging DPPH free radical, ABTS free radicals, super-oxide anion free radical (O2-·), and in reducing power assays. Essential oils of half of the clearance IC50value concentration were 4.24, 4.46, 3.26 mg/mL. The diameters ofEscherichia coli,Bacillus subtilisandStaphylococcus aureusinhibition zone were (15.20±0.12) mm, (13.30±0.15) mm, and (9.50±0.21) mm, and the minimum inhibitory concentration(MIC) was 1.26, 2.50, and 5.00 μL/mL. These results suggest that the essential oil from pine needles has potential to be used as a natural antioxidant and antimicrobial agent in food processing.
Abstract:
The leaves ofAquilaria sinensiswere extracted by ethanol solution, with rutin as reference substance and nitrate as chromogenic agent, the absorbance of the extract in the 510 nm wave was determined. In the single factor experiment, the effects of ethanol concentration, extraction temperature, solid-liquid ratio and extraction time on the extraction rate of total flavonoids were studied. On the basis of single factor experiment, the optimum conditions were studied by the response surface methodology. The total flavonoids in leaves ofAquilaria sinensiswere separated and purified by macroporous adsorption resin. By comparing the saturated adsorption capacity, adsorption rate and desorption rate of three kinds of resins D101, AB-8, and S-8, the resin with the best separation and purification effect was obtained, and the relationship between the adsorption time and the adsorption rate was studied. The results showed that: 1) the optimal extraction conditions were 80% ethanol, 65 ? liquid to solid ratio of 20:1 (mL/g) and 3 hours as extraction time. Under this condition, the yield of total flavonoids was 4.83%. 2) Non-polar and low- polar macroporous adsorption resin were more suitable for the separation and purification of total flavonoids from the leaves ofAquilaria sinensis. 3) D101 macroporous adsorptive resin had best adsorption ability. The purity of flavones increased to 2.8 times.
The leaves ofAquilaria sinensiswere extracted by ethanol solution, with rutin as reference substance and nitrate as chromogenic agent, the absorbance of the extract in the 510 nm wave was determined. In the single factor experiment, the effects of ethanol concentration, extraction temperature, solid-liquid ratio and extraction time on the extraction rate of total flavonoids were studied. On the basis of single factor experiment, the optimum conditions were studied by the response surface methodology. The total flavonoids in leaves ofAquilaria sinensiswere separated and purified by macroporous adsorption resin. By comparing the saturated adsorption capacity, adsorption rate and desorption rate of three kinds of resins D101, AB-8, and S-8, the resin with the best separation and purification effect was obtained, and the relationship between the adsorption time and the adsorption rate was studied. The results showed that: 1) the optimal extraction conditions were 80% ethanol, 65 ? liquid to solid ratio of 20:1 (mL/g) and 3 hours as extraction time. Under this condition, the yield of total flavonoids was 4.83%. 2) Non-polar and low- polar macroporous adsorption resin were more suitable for the separation and purification of total flavonoids from the leaves ofAquilaria sinensis. 3) D101 macroporous adsorptive resin had best adsorption ability. The purity of flavones increased to 2.8 times.
2017, 39(8): 111-118.
doi:10.13332/j.1000-1522.20170022
Abstract:
Based on standard parameters of modular components and construction module, this study aims to establish the standardized system of modern light wood frame house in order to promote the change of industry from extensive to intensive: establishing 18 kinds of modular walls and 8 kinds of floor components to complete the database; establishing a design method which was determined by modular parameters, and come up with the basic module (1 M=610 mm). By theoretical calculation and model manufacture of a single-storey modern light wood frame house, the feasibility of this system is verified.
Based on standard parameters of modular components and construction module, this study aims to establish the standardized system of modern light wood frame house in order to promote the change of industry from extensive to intensive: establishing 18 kinds of modular walls and 8 kinds of floor components to complete the database; establishing a design method which was determined by modular parameters, and come up with the basic module (1 M=610 mm). By theoretical calculation and model manufacture of a single-storey modern light wood frame house, the feasibility of this system is verified.
