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RSS2016 Vol. 38, No. 2
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2016, 38(2): 1-9.
doi:10.13332/j.1000-1522.20150268
Abstract:
Wind disaster is one of the main disasters causing damage to forest. Study of structural characteristics and mechanical abilities of trees can help us understand more about the stress state of single trees and the area most likely to break when destroyed by wind, so as to take measures to enhance the safety and stability of the forest. In this study, we used the linear filtering method to simulate the fluctuating wind model which is close to actual conditions. The finite element method was employed to simulate the tree under wind load, and then the stress state and structural displacement of different parts of the tree under the effect of dynamic wind loads were obtained. The process of building the model is divided into two parts: the first is the simulation of wind by applying the linear filtering method, and we calculate the wind field in a specific area; the second part is to construct the finite element model of the tree. Then the tree model is set in this wind field. The variables such as density and elastic module could be controlled by variables related to tree height. Macro file of the model building could be obtained by changing some specific variables of the command stream file. After applying the load, we collect the data and analyze the wind resisting ability of the tree. In this simulation, we choose Pinus thunbergii in the coastal protection forest as our research object. Through simulation, we can know more about the tree’s reaction to the fluctuating wind load and the weakness of the tree in response to the wind load, so as to take appropriate measures such as frequent thinning or reinforcement to enhance the tree’s stability.
Wind disaster is one of the main disasters causing damage to forest. Study of structural characteristics and mechanical abilities of trees can help us understand more about the stress state of single trees and the area most likely to break when destroyed by wind, so as to take measures to enhance the safety and stability of the forest. In this study, we used the linear filtering method to simulate the fluctuating wind model which is close to actual conditions. The finite element method was employed to simulate the tree under wind load, and then the stress state and structural displacement of different parts of the tree under the effect of dynamic wind loads were obtained. The process of building the model is divided into two parts: the first is the simulation of wind by applying the linear filtering method, and we calculate the wind field in a specific area; the second part is to construct the finite element model of the tree. Then the tree model is set in this wind field. The variables such as density and elastic module could be controlled by variables related to tree height. Macro file of the model building could be obtained by changing some specific variables of the command stream file. After applying the load, we collect the data and analyze the wind resisting ability of the tree. In this simulation, we choose Pinus thunbergii in the coastal protection forest as our research object. Through simulation, we can know more about the tree’s reaction to the fluctuating wind load and the weakness of the tree in response to the wind load, so as to take appropriate measures such as frequent thinning or reinforcement to enhance the tree’s stability.
2016, 38(2): 10-19.
doi:10.13332/j.1000-1522.20150214
Abstract:
The Daxing’an Mountain, located in Heilongjiang Province of northeastern China, is the largest natural forest area of China. It is of great significance to estimate its forest biomass and further study the characteristics of spatial pattern of forest biomass regionally. Based on the data of TM remote sensing images from Landsat5 series during late 20th century to 2010s, we constructed a remote sensing information model in order to estimate the forest biomass of the Daxing’an Mountain. Morans I coefficient from the direction of 0°, 45°, 90°, 135° and overall direction, and five parameters of semivariagram (namely, nugget value, sill value, variation value, ratio of nugget to sill value, ratio of arch rise to sill) were selected to analyze the heterogeneity and spatial self-correlation of forest biomass separately during three periods of 1994--1997, 2006--2007 and 2010--2011. Results showed that: the integrity of forest biomass in the three periods was good and all continuously distributed without any broken observation. The semivariagram models of biomass of different periods were linear with C/(C0 + C) approaching to 1. Using remote sensing inversion method to estimate forest biomass could provide reliable data source for geostatistics with an estimation precision higher than 75%. Meanwhile, heterogeneity and self-spatial correlation analysis of forest biomass according to geostatistics is a useful supplement to spatial relations of forest biomass by simply using GIS tool. Therefore, combination of remote sensing and geostatistics is confirmed to perform better in spatial-temporal variation analysis of forest biomass.
The Daxing’an Mountain, located in Heilongjiang Province of northeastern China, is the largest natural forest area of China. It is of great significance to estimate its forest biomass and further study the characteristics of spatial pattern of forest biomass regionally. Based on the data of TM remote sensing images from Landsat5 series during late 20th century to 2010s, we constructed a remote sensing information model in order to estimate the forest biomass of the Daxing’an Mountain. Morans I coefficient from the direction of 0°, 45°, 90°, 135° and overall direction, and five parameters of semivariagram (namely, nugget value, sill value, variation value, ratio of nugget to sill value, ratio of arch rise to sill) were selected to analyze the heterogeneity and spatial self-correlation of forest biomass separately during three periods of 1994--1997, 2006--2007 and 2010--2011. Results showed that: the integrity of forest biomass in the three periods was good and all continuously distributed without any broken observation. The semivariagram models of biomass of different periods were linear with C/(C0 + C) approaching to 1. Using remote sensing inversion method to estimate forest biomass could provide reliable data source for geostatistics with an estimation precision higher than 75%. Meanwhile, heterogeneity and self-spatial correlation analysis of forest biomass according to geostatistics is a useful supplement to spatial relations of forest biomass by simply using GIS tool. Therefore, combination of remote sensing and geostatistics is confirmed to perform better in spatial-temporal variation analysis of forest biomass.
Abstract:
We studied the enzyme activity in each soil layer (A1, B, and C) and its relationship with soil nutrient availability and active organic carbon to provide scientific proofs for soil fertility evaluation in the process of progressive succession (formation stage, development stage, stability stage, and climax community) in broadleaf and Korean pine mixed forest in the Xiaoxing’anling Mountains by using comparative analysis. The results showed that, the activities of soil enzymes of urease, invertase, catalase and polyphenol oxidase in A1 layer were all significantly higher than in B and C layers in the process of progressive succession. However, the activities of urease, invertase, catalase and polyphenol oxidase in A1 layer were higher to varying degrees in the formation stage than in the development stage. The variation in polyphenol oxidase activity presented a decreasing trend as succession stage progressed. There existed correlations between soil nutrients with activity of soil enzymes urease, invertase, and catalase and polyphenol oxidase. There were highly significant correlations between soil urease, invertase, and rapid K, available P, organic matter, and total N, respectively, but significant correlations between activity of catalase, polyphenol oxidase, and total N, rapid K, available P, and organic matter, respectively. In addition, there was a significant correlation between the activity of urease, catalase, polyphenol oxidase with labile organic carbon and microbial biomass carbon, respectively, but no significant correlation with dissolved organic carbon. The correlations of invertase activity with three types of organic carbon all reached significant level. Soil enzyme activity and nutrient characteristics can be used as comprehensive indexes, which indicate soil fertility levels of different succession in the Xiaoxing’anling region.
We studied the enzyme activity in each soil layer (A1, B, and C) and its relationship with soil nutrient availability and active organic carbon to provide scientific proofs for soil fertility evaluation in the process of progressive succession (formation stage, development stage, stability stage, and climax community) in broadleaf and Korean pine mixed forest in the Xiaoxing’anling Mountains by using comparative analysis. The results showed that, the activities of soil enzymes of urease, invertase, catalase and polyphenol oxidase in A1 layer were all significantly higher than in B and C layers in the process of progressive succession. However, the activities of urease, invertase, catalase and polyphenol oxidase in A1 layer were higher to varying degrees in the formation stage than in the development stage. The variation in polyphenol oxidase activity presented a decreasing trend as succession stage progressed. There existed correlations between soil nutrients with activity of soil enzymes urease, invertase, and catalase and polyphenol oxidase. There were highly significant correlations between soil urease, invertase, and rapid K, available P, organic matter, and total N, respectively, but significant correlations between activity of catalase, polyphenol oxidase, and total N, rapid K, available P, and organic matter, respectively. In addition, there was a significant correlation between the activity of urease, catalase, polyphenol oxidase with labile organic carbon and microbial biomass carbon, respectively, but no significant correlation with dissolved organic carbon. The correlations of invertase activity with three types of organic carbon all reached significant level. Soil enzyme activity and nutrient characteristics can be used as comprehensive indexes, which indicate soil fertility levels of different succession in the Xiaoxing’anling region.
Abstract:
The objective of this study was to reveal the changes of organic carbon (SOC) and black carbon (BC) in soil aggregates after severe burning. With unburned natural Larix gmelinii forest as contrast, we selected severely burned area of natural L. gmelinii forest in Great Xing’an Mountains as research object. The effect of severe burning on organic carbon and black carbon in soil aggregates was studied. The results showed that: 1) After severe burning, the contents of organic carbon and black carbon of surface soil significantly increased. Compared with contrast sample plot, soil organic carbon content in 0-5 cm soil layer increased by 41.56%, and black carbon content significantly increased by 123.69% (P0.05).2) Severe burning significantly increased the percentages of aggregates smaller than 0.25 mm and larger than 5 mm (P0.05), but the percentages of 0.25-5 mm all decreased in 0-5 cm soil layer.3) Compared with contrast sample plot, severe burning significantly increased the organic carbon content of aggregates smaller than 0.053 mm and larger than 5 mm by 127.27% and 177.6% (P0.05), respectively. Organic carbon content of 0.25-2 mm aggregates in three soil layers was lower than contrast sample plot tovarying degrees.The content of soil organic carbon in aggregates increased with the increase of particle size in the two kinds of forest, and showed a trend of decreasing with the increase of soil depth. 4) The characteristics of distribution of black carbon in aggregates were similar to organic carbon. After severe burning, black carbon of aggregates 5 mm,2-5 mm,0.053-0.25 mm and 0.053 mm increased by 4.92,4.19,1.06 and 0.44 g/kg in 0-5 cm soil layer, which was significantly different with contrast sample plot (P0.05). 5) The BC/SOC ratio ranged from 0.05 to 0.41 in two kinds of forest, and severe burning significantly increased BC/SOC ratio (P0.05). A significant correlation was found between organic carbon and black carbon contents in aggregates of each size class.
The objective of this study was to reveal the changes of organic carbon (SOC) and black carbon (BC) in soil aggregates after severe burning. With unburned natural Larix gmelinii forest as contrast, we selected severely burned area of natural L. gmelinii forest in Great Xing’an Mountains as research object. The effect of severe burning on organic carbon and black carbon in soil aggregates was studied. The results showed that: 1) After severe burning, the contents of organic carbon and black carbon of surface soil significantly increased. Compared with contrast sample plot, soil organic carbon content in 0-5 cm soil layer increased by 41.56%, and black carbon content significantly increased by 123.69% (P0.05).2) Severe burning significantly increased the percentages of aggregates smaller than 0.25 mm and larger than 5 mm (P0.05), but the percentages of 0.25-5 mm all decreased in 0-5 cm soil layer.3) Compared with contrast sample plot, severe burning significantly increased the organic carbon content of aggregates smaller than 0.053 mm and larger than 5 mm by 127.27% and 177.6% (P0.05), respectively. Organic carbon content of 0.25-2 mm aggregates in three soil layers was lower than contrast sample plot tovarying degrees.The content of soil organic carbon in aggregates increased with the increase of particle size in the two kinds of forest, and showed a trend of decreasing with the increase of soil depth. 4) The characteristics of distribution of black carbon in aggregates were similar to organic carbon. After severe burning, black carbon of aggregates 5 mm,2-5 mm,0.053-0.25 mm and 0.053 mm increased by 4.92,4.19,1.06 and 0.44 g/kg in 0-5 cm soil layer, which was significantly different with contrast sample plot (P0.05). 5) The BC/SOC ratio ranged from 0.05 to 0.41 in two kinds of forest, and severe burning significantly increased BC/SOC ratio (P0.05). A significant correlation was found between organic carbon and black carbon contents in aggregates of each size class.
Abstract:
The aim of this study was to explore the evidence that Pinus densata is the advanced generation hybrid descendant of Pinus tabuliformis and Pinus yunnanensis from the prospective of photosynthetic physiology. The photosynthetic performance indicators such as photosynthetic rate, stomatal conductance and transpiration rate of parental species (P. tabuliformis and P. yunnanensis), hybrid descendant and the contral (natural P. densata) were measured with Li-6400 photosynthetic apparatus. Moreover, light saturation point and light compensation point of them were estimated. Findings show that: 1) the utilization scope of light intensity of P. densata and hybrid of P. tabuliformis×P. yunnanensis is more extensive than that of P. tabuliformis and P. yunnanensis. 2) Compared with the maximum net photosynthetic rate of parental species, hybrid of P. tabuliformis×P. yunnanensis shows hybrid vigor. 3) Compared with parental species, the stomatal conductance of P. densata and hybrid of P. tabuliformis×P. yunnanensis is lower and declines slowly. 4) The transpiration rate of hybrid of P. tabuliformis×P. yunnanensis is obviously influenced by parental species, which is similar to the performance of Pinus densata. 5) The growth indicators between different combinations of hybridization of P. tabuliformis×P. yunnanensis vary to certain extent, while the average level of growth of the hybrids is close to that of P. densata and P. Yunnanensis. Above results from the perspectives of photosynthetic physiology and vegetative adaptability provide advantageous basis to support the fact that P. densata is the generation of P. tabuliformis×P. yunnanensis and evolves into unique species in particular habitat at high elevations.
The aim of this study was to explore the evidence that Pinus densata is the advanced generation hybrid descendant of Pinus tabuliformis and Pinus yunnanensis from the prospective of photosynthetic physiology. The photosynthetic performance indicators such as photosynthetic rate, stomatal conductance and transpiration rate of parental species (P. tabuliformis and P. yunnanensis), hybrid descendant and the contral (natural P. densata) were measured with Li-6400 photosynthetic apparatus. Moreover, light saturation point and light compensation point of them were estimated. Findings show that: 1) the utilization scope of light intensity of P. densata and hybrid of P. tabuliformis×P. yunnanensis is more extensive than that of P. tabuliformis and P. yunnanensis. 2) Compared with the maximum net photosynthetic rate of parental species, hybrid of P. tabuliformis×P. yunnanensis shows hybrid vigor. 3) Compared with parental species, the stomatal conductance of P. densata and hybrid of P. tabuliformis×P. yunnanensis is lower and declines slowly. 4) The transpiration rate of hybrid of P. tabuliformis×P. yunnanensis is obviously influenced by parental species, which is similar to the performance of Pinus densata. 5) The growth indicators between different combinations of hybridization of P. tabuliformis×P. yunnanensis vary to certain extent, while the average level of growth of the hybrids is close to that of P. densata and P. Yunnanensis. Above results from the perspectives of photosynthetic physiology and vegetative adaptability provide advantageous basis to support the fact that P. densata is the generation of P. tabuliformis×P. yunnanensis and evolves into unique species in particular habitat at high elevations.
Abstract:
Populus simonii×Populus nigra WRKY70 (PsnWRKY70) is a salt stress responsive transcription factor. In order to further identify the proteins that interact with PsnWRKY70 in salt stress response pathway, we used P. simonii×P. nigra leaves treated by 140 mmol/L NaCl solution as materials to construct a homogeneous pGADT7-DEST yeast two-hybrid cDNA library by DSN. PsnWRKY70 gene was subcloned to pGBKT7 vector to construct BD-WRKY recombinant plasmid, and then the BD-WRKY plasmid was used as a bait to screen the yeast two-hybrid cDNA library of P. simonii×P. nigra. After twice screening tests and a rotary experiment, five proteins that interact with PsnWRKY70 were detected. We analyzed the conserved domains of the five proteins and found that there were two hypothetical proteins (HP1 and HP2, HP1 contains a ClpP domain), one cyclase associated protein (CAP1), one RNA recognition motif-containing family protein (RRM) and one Ulp1 protease family protein (Ulp1) among them. The cis-elements that exist in 2 000 bp upstream of the orthologous Populus trichocarpa genes of CAP1, HP1, RRM, HP2 and Ulp1 were also analyzed, and the results suggest that the promoter regions of all the five orthologous P. trichocarpa genes contained plenty of W-box which can specifically bind to WRKY transcription factors. GST-pull down technology was utilized to validate the direct interaction between the complete CAP1/HP1/RRM/HP2/Ulp1 proteins and PsnWRKY70. An equal amount of His-X (X: CAP1/HP1/RRM/HP2/Ulp1) fusion proteins was dropped into normal glutathione agarose resin and GST or GST-WRKY protein-bound glutathione agarose resin respectively, then the interactive proteins were separated by SDS-PAGE. The final Western blot analysis indicated that HP1, RRM and Ulp1 can directly interact with PsnWRKY70 in vitro, while CAP1 or HP2 cannot.
Populus simonii×Populus nigra WRKY70 (PsnWRKY70) is a salt stress responsive transcription factor. In order to further identify the proteins that interact with PsnWRKY70 in salt stress response pathway, we used P. simonii×P. nigra leaves treated by 140 mmol/L NaCl solution as materials to construct a homogeneous pGADT7-DEST yeast two-hybrid cDNA library by DSN. PsnWRKY70 gene was subcloned to pGBKT7 vector to construct BD-WRKY recombinant plasmid, and then the BD-WRKY plasmid was used as a bait to screen the yeast two-hybrid cDNA library of P. simonii×P. nigra. After twice screening tests and a rotary experiment, five proteins that interact with PsnWRKY70 were detected. We analyzed the conserved domains of the five proteins and found that there were two hypothetical proteins (HP1 and HP2, HP1 contains a ClpP domain), one cyclase associated protein (CAP1), one RNA recognition motif-containing family protein (RRM) and one Ulp1 protease family protein (Ulp1) among them. The cis-elements that exist in 2 000 bp upstream of the orthologous Populus trichocarpa genes of CAP1, HP1, RRM, HP2 and Ulp1 were also analyzed, and the results suggest that the promoter regions of all the five orthologous P. trichocarpa genes contained plenty of W-box which can specifically bind to WRKY transcription factors. GST-pull down technology was utilized to validate the direct interaction between the complete CAP1/HP1/RRM/HP2/Ulp1 proteins and PsnWRKY70. An equal amount of His-X (X: CAP1/HP1/RRM/HP2/Ulp1) fusion proteins was dropped into normal glutathione agarose resin and GST or GST-WRKY protein-bound glutathione agarose resin respectively, then the interactive proteins were separated by SDS-PAGE. The final Western blot analysis indicated that HP1, RRM and Ulp1 can directly interact with PsnWRKY70 in vitro, while CAP1 or HP2 cannot.
2016, 38(2): 52-60.
doi:10.13332/j.1000-1522.20150343
Abstract:
Taking 10-year-old hybrid larch test plantation in Linkou County of Heilongjiang Province as the research object, we surveyed and analyzed the growth traits of larch. The variation analysis showed that there were great variations in growth traits. In term of the height, the mean of four families (Larix kaempferi 5 × L. gmelini 12, L. kaempferi 3 × L. gmelini 2, L. kaempferi 12 × L. gmelini 9, L. kaempferi 3 × L. gmelini 9) was 26.09% higher than that of total families, 104% higher than CK, 37.88% higher than Baidaoshan provenance, 16.23% higher than Xiaobeihu provenances (L. olgensis), and 42.02% higher than Wuyiling provenance (L. gmelini). In term of the DBH, the mean of four families (L. kaempferi 5 × L. gmelini 12, L. kaempferi 3 × L. gmelini 2, L. kaempferi 12 × L. gmelini 9, L. gmelini 6 × L. olgensis 6) was 24.94% higher than that of total families, and 20.39% higher than CK. The analysis of variance showed that differences between families were significant. Analysis of ratio of biomass in each part showed that the L. kaempferi 5 × L. gmelini 9 and L. kaempferi 11 × L. gmelini 2 had more trunk biomass, but foliage biomass was lower than other families. Combining the results of multiple comparison and ecological adaptation index analysis, we considered L. kaempferi 5 × L. gmelini 9 and L. kaempferi 11 × L. gmelini 2 as the superior families. In term of height, L. kaempferi 5 × L. gmelini 9 was 24.91% higher than L. kaempferi 5 × L. gmelini 12, 12.23% higher than the mean of total families, and 2.87% higher than CK. In term of DBH, L. kaempferi 5 × L. gmelini 9 was 40.68% higher than L. kaempferi 5 × L. gmelini 12, 21.51% higher than the mean of total families, and 8.50% higher than CK. The analysis of growth rhythm showed that, compared with other families, superior families had a longer growing period, and had a higher growth rate than other families during the rapid growing period of larch.
Taking 10-year-old hybrid larch test plantation in Linkou County of Heilongjiang Province as the research object, we surveyed and analyzed the growth traits of larch. The variation analysis showed that there were great variations in growth traits. In term of the height, the mean of four families (Larix kaempferi 5 × L. gmelini 12, L. kaempferi 3 × L. gmelini 2, L. kaempferi 12 × L. gmelini 9, L. kaempferi 3 × L. gmelini 9) was 26.09% higher than that of total families, 104% higher than CK, 37.88% higher than Baidaoshan provenance, 16.23% higher than Xiaobeihu provenances (L. olgensis), and 42.02% higher than Wuyiling provenance (L. gmelini). In term of the DBH, the mean of four families (L. kaempferi 5 × L. gmelini 12, L. kaempferi 3 × L. gmelini 2, L. kaempferi 12 × L. gmelini 9, L. gmelini 6 × L. olgensis 6) was 24.94% higher than that of total families, and 20.39% higher than CK. The analysis of variance showed that differences between families were significant. Analysis of ratio of biomass in each part showed that the L. kaempferi 5 × L. gmelini 9 and L. kaempferi 11 × L. gmelini 2 had more trunk biomass, but foliage biomass was lower than other families. Combining the results of multiple comparison and ecological adaptation index analysis, we considered L. kaempferi 5 × L. gmelini 9 and L. kaempferi 11 × L. gmelini 2 as the superior families. In term of height, L. kaempferi 5 × L. gmelini 9 was 24.91% higher than L. kaempferi 5 × L. gmelini 12, 12.23% higher than the mean of total families, and 2.87% higher than CK. In term of DBH, L. kaempferi 5 × L. gmelini 9 was 40.68% higher than L. kaempferi 5 × L. gmelini 12, 21.51% higher than the mean of total families, and 8.50% higher than CK. The analysis of growth rhythm showed that, compared with other families, superior families had a longer growing period, and had a higher growth rate than other families during the rapid growing period of larch.
Abstract:
In order to investigate the changes of detoxification metabolic activity in gypsy moth (Lymantria dispar) under the heavy metal pollution stress, we measured the detoxifying metabolism in gypsy moth body feeding on one-year potted seedlings of Populus simonii×P. nigra after treating the soil with three concentrations of copper (Cu, 400, 700, 1 000 mg/kg) and cadmium (Cd, 1.0, 3.0, 6.0 mg/kg). The results showed that Cu and Cd had a significant impact on the detoxification metabolic enzyme in the third and fourth instar larvae. The activities of SOD, ACP and AKP enzymes in vivo in the third instar larvae at medium and high concentrations of Cu and Cd were lower than the control group (P0.05),but at the low concentrations of Cu and Cd, the difference was not obvious (P0.05). The change of activities of POD and GSTs was just the opposite. The activities of POD and GSTs enzymes in the third instar larvae at medium and high concentrations of Cu and Cd increased significantly (P0.05), but not obvious (P0.05) at the low concentrations of Cu and Cd. The activities of SOD, POD, ACP, AKP and GSTs enzymes in the fourth instar larvae at medium and high concentrations of Cu and Cd decreased significantly (P0.05),but not obvious at the low concentrations of Cu and Cd treatment (P0.05). These results showed that the high levels of Cu and Cd stress could significantly interfere with the metabolic detoxification of gypsy moth larvae, and with the third instar larvae developing into the fourth instar, the heavy metal stress finally showed a significant inhibition to the development of larvae, while low levels of Cu and Cd stress had not significant interference with metabolic detoxification of the larvae.
In order to investigate the changes of detoxification metabolic activity in gypsy moth (Lymantria dispar) under the heavy metal pollution stress, we measured the detoxifying metabolism in gypsy moth body feeding on one-year potted seedlings of Populus simonii×P. nigra after treating the soil with three concentrations of copper (Cu, 400, 700, 1 000 mg/kg) and cadmium (Cd, 1.0, 3.0, 6.0 mg/kg). The results showed that Cu and Cd had a significant impact on the detoxification metabolic enzyme in the third and fourth instar larvae. The activities of SOD, ACP and AKP enzymes in vivo in the third instar larvae at medium and high concentrations of Cu and Cd were lower than the control group (P0.05),but at the low concentrations of Cu and Cd, the difference was not obvious (P0.05). The change of activities of POD and GSTs was just the opposite. The activities of POD and GSTs enzymes in the third instar larvae at medium and high concentrations of Cu and Cd increased significantly (P0.05), but not obvious (P0.05) at the low concentrations of Cu and Cd. The activities of SOD, POD, ACP, AKP and GSTs enzymes in the fourth instar larvae at medium and high concentrations of Cu and Cd decreased significantly (P0.05),but not obvious at the low concentrations of Cu and Cd treatment (P0.05). These results showed that the high levels of Cu and Cd stress could significantly interfere with the metabolic detoxification of gypsy moth larvae, and with the third instar larvae developing into the fourth instar, the heavy metal stress finally showed a significant inhibition to the development of larvae, while low levels of Cu and Cd stress had not significant interference with metabolic detoxification of the larvae.
2016, 38(2): 68-73.
doi:10.13332/j.1000-1522.20150140
Abstract:
Slope position is an important factor describing relief in the hillslopes. The automatic extraction of slope position has great significance in the natural habitat analysis and geo-ecological process modelling. Based on digital terrain analysis, we propose a slope position classification method which considers both slope profile and relative position index. And then the algorithm of the method was designed and programmed. According to forest resources survey rule, the slope position extraction test was carried out in the western mountainous areas of Beijing based on DEM data at the 1?50 000 scale. The test has achieved the expected result. The result showed that the method can realize the localization of relative position index calculation and slope profile segmentation,and make the classification more objective and reasonable.
Slope position is an important factor describing relief in the hillslopes. The automatic extraction of slope position has great significance in the natural habitat analysis and geo-ecological process modelling. Based on digital terrain analysis, we propose a slope position classification method which considers both slope profile and relative position index. And then the algorithm of the method was designed and programmed. According to forest resources survey rule, the slope position extraction test was carried out in the western mountainous areas of Beijing based on DEM data at the 1?50 000 scale. The test has achieved the expected result. The result showed that the method can realize the localization of relative position index calculation and slope profile segmentation,and make the classification more objective and reasonable.
Abstract:
The forest ecosystem as a major part of global ecosystems, attracts wide concerns from the inter-disciplinary community of ecology and economics in estimation of its services value. Based on the Forest Ecosystem Function Evaluation Criterion (LY/T 1721?008), the field data of the Baishuijiang national forest ecosystem and land use data acquired by GIS and RS technologies, we assessed the forest ecosystem services value of the Baishuijiang Nature Reserve in Gansu, western China. The total value of forest ecosystem of the reserve is RMB 17.89 billion yuan per year, with the order of service value of each item as biodiversity (43.08%) carbon fixation and oxygen (19.35%) soil conservation (16.17%) water conservation (13.11%) forest products (5.16%) air purification (1.55%) nutrient accumulation (0.96%) forest recreation (0.62%). In terms of the utilization type of service value, the order is value of indirect utilization (51.14 %) value of non-utilization (43.08%) values of direct utilization (5.78%). Estimation of forest ecosystem services value could provide in-depth understanding of the importance of forest ecosystem service value for policy makers. A comparison of other studies reveals could not only check the accuracy of the estimation, but also could find the law between the forest ecosystem service functions. Results of our paper could help the local environment policy makers to develop appropriate forest ecological compensation and other environmental policies, and at the same time such evaluation is also conducive to promoting the government to establish a sustainable environment and economic comprehensive green GDP system that covers the ecosystem. Future research on forest ecosystem services value should be focused primarily on its service function mechanisms, dynamic assessment, spatial distribution and their applications in policy-making.
The forest ecosystem as a major part of global ecosystems, attracts wide concerns from the inter-disciplinary community of ecology and economics in estimation of its services value. Based on the Forest Ecosystem Function Evaluation Criterion (LY/T 1721?008), the field data of the Baishuijiang national forest ecosystem and land use data acquired by GIS and RS technologies, we assessed the forest ecosystem services value of the Baishuijiang Nature Reserve in Gansu, western China. The total value of forest ecosystem of the reserve is RMB 17.89 billion yuan per year, with the order of service value of each item as biodiversity (43.08%) carbon fixation and oxygen (19.35%) soil conservation (16.17%) water conservation (13.11%) forest products (5.16%) air purification (1.55%) nutrient accumulation (0.96%) forest recreation (0.62%). In terms of the utilization type of service value, the order is value of indirect utilization (51.14 %) value of non-utilization (43.08%) values of direct utilization (5.78%). Estimation of forest ecosystem services value could provide in-depth understanding of the importance of forest ecosystem service value for policy makers. A comparison of other studies reveals could not only check the accuracy of the estimation, but also could find the law between the forest ecosystem service functions. Results of our paper could help the local environment policy makers to develop appropriate forest ecological compensation and other environmental policies, and at the same time such evaluation is also conducive to promoting the government to establish a sustainable environment and economic comprehensive green GDP system that covers the ecosystem. Future research on forest ecosystem services value should be focused primarily on its service function mechanisms, dynamic assessment, spatial distribution and their applications in policy-making.
2016, 38(2): 83-89.
doi:10.13332/j.1000-1522.20150317
Abstract:
Snow melting is a main source of river flow and contributes to diminishing drought in spring time in cold regions of northern China. The fact that forest can delay snowmelt runoff has been well known; however, tempo-spatial heterogeneity of snow melting resulted from topography and vegetation still remains unclear. In addition, quantitative estimation of the effect of vegetation and topography on snow ablation would improve the accuracy of watershed hydrology model. In this study, the method of MTCLIM(Mountain microclimate simulation model)was used to calculate or simulate snow evaporation and influence of topography on radiation, the degree day approach modified by topography and vegetation was used to calculate or simulate snow melting rate. The results showed that simulation can reflect the integrated influence of topography and vegetation on snowmelt just as the correlation coefficient of simulation and observation was 0.90. Furthermore, the effect of vegetation on snow melting was greater than that of topography, specifically, regardless of topography, the average snow ablation rate of the entire watershed was 1.26 mm/d which was only 64.6% of that of open plain (1.95 mm/d). However, topography accordingly resulted in a mean snow ablation rate of 1.91 mm/d, almost equal to that of open plain. It should also be noted that simulation accuracy related to specific site still need be enhanced. Snow evaporation cannot be simulated by Priestly-Taylor method based on topography and vegetation, and other factors such as wind need to be taken into account.
Snow melting is a main source of river flow and contributes to diminishing drought in spring time in cold regions of northern China. The fact that forest can delay snowmelt runoff has been well known; however, tempo-spatial heterogeneity of snow melting resulted from topography and vegetation still remains unclear. In addition, quantitative estimation of the effect of vegetation and topography on snow ablation would improve the accuracy of watershed hydrology model. In this study, the method of MTCLIM(Mountain microclimate simulation model)was used to calculate or simulate snow evaporation and influence of topography on radiation, the degree day approach modified by topography and vegetation was used to calculate or simulate snow melting rate. The results showed that simulation can reflect the integrated influence of topography and vegetation on snowmelt just as the correlation coefficient of simulation and observation was 0.90. Furthermore, the effect of vegetation on snow melting was greater than that of topography, specifically, regardless of topography, the average snow ablation rate of the entire watershed was 1.26 mm/d which was only 64.6% of that of open plain (1.95 mm/d). However, topography accordingly resulted in a mean snow ablation rate of 1.91 mm/d, almost equal to that of open plain. It should also be noted that simulation accuracy related to specific site still need be enhanced. Snow evaporation cannot be simulated by Priestly-Taylor method based on topography and vegetation, and other factors such as wind need to be taken into account.
Abstract:
Water is the main factor restricting plant growth in arid and semi-arid regions. Although the amount is very small, soil condensation water, as a sustained and steady water source, is very important to the ecological balance in arid and semi-arid regions. To clarify the formation of soil condensation water on different underlying surfaces, we employed micro-lysimeters and weighing method to study the formation process of soil condensation water and factors affecting it in three plots (sand plot, Artemisia ordosica plot and Salix psammophilia plot) in the Mu Us Desert in northern China from July to August, 2014. Meteorological factors and soil temperature were supervised at the same time. The results were as follows: 1) formation of soil condensation water began immediately after sunset, and ended about one hour after sunrise. Nocturnal regularity of formation of soil condensation water was similar in the three plots. The ending time of condensation water in the A. ordosica and S. psammophilia plots was later than in the sand plot, from which microorganisms in the shrubbery benefitted. 2) During the 17-days observation, the total amounts of condensation water in the sand, A. ordosica and S. psammophilia plots were 3.332, 2.382 and 1.817 mm, respectively. Daily average amounts of condensation water in the A. ordosica and S. psammophilia plots were less than in the sand plot (P0.05), presumably due to the change of underlying surface properties and microclimate caused by shrub cover. 3) Condensation water amount was significantly and positively correlated with relative humidity (P0.01), significantly and negatively correlated with air temperature (P0.01). And, a negative correlation was found between condensation water amount and wind speed (P0.05). Our study can provide scientific supports for evaluation of potential water resources and management of ecosystem in the Mu Us Desert of northern China.
Water is the main factor restricting plant growth in arid and semi-arid regions. Although the amount is very small, soil condensation water, as a sustained and steady water source, is very important to the ecological balance in arid and semi-arid regions. To clarify the formation of soil condensation water on different underlying surfaces, we employed micro-lysimeters and weighing method to study the formation process of soil condensation water and factors affecting it in three plots (sand plot, Artemisia ordosica plot and Salix psammophilia plot) in the Mu Us Desert in northern China from July to August, 2014. Meteorological factors and soil temperature were supervised at the same time. The results were as follows: 1) formation of soil condensation water began immediately after sunset, and ended about one hour after sunrise. Nocturnal regularity of formation of soil condensation water was similar in the three plots. The ending time of condensation water in the A. ordosica and S. psammophilia plots was later than in the sand plot, from which microorganisms in the shrubbery benefitted. 2) During the 17-days observation, the total amounts of condensation water in the sand, A. ordosica and S. psammophilia plots were 3.332, 2.382 and 1.817 mm, respectively. Daily average amounts of condensation water in the A. ordosica and S. psammophilia plots were less than in the sand plot (P0.05), presumably due to the change of underlying surface properties and microclimate caused by shrub cover. 3) Condensation water amount was significantly and positively correlated with relative humidity (P0.01), significantly and negatively correlated with air temperature (P0.01). And, a negative correlation was found between condensation water amount and wind speed (P0.05). Our study can provide scientific supports for evaluation of potential water resources and management of ecosystem in the Mu Us Desert of northern China.
2016, 38(2): 96-104.
doi:10.13332/j.1000-1522.20150199
Abstract:
In order to investigate the applicability of LA hybrids as the breeding parents and select parents with a better fertility in LA×Asiatic lilies, 62 crossings were conducted with 26 LA cultivars and 10 Asiatic cultivars used as parents. Genomic in situ hybridization (GISH) technique was applied for hybrid identification and analysis of chromosomal composition in some hybrid progenies. Main results were obtained as follows: 1) LA triploid hybrids are usually male-sterile, but they can be crossed with diploid or tetraploid Asiatic hybrids as a female parent. 2) Compared with diploid Asiatic hybrids (AA), tetraploid Asiatic hybrids (AAAA) have a better fertility when crossed with LA hybrids. 3) Seven cross combinations with a better fertility were selected: ‘Nashville’בNello?‘Freya’בValdiSole?‘Desiderio’בDetroit?‘Samur’בNello?‘Batistero’בRegata?‘Roussea-u’בVal di Sole and ‘Ercolano’בBenlica? The results of 62 crossings revealed that 3 LA hybrids as female parents (‘Freya?‘Nashville and ‘Orange Tycoon? and 6 Asiatic hybrids as male parents (‘Val di Sole?‘Nello?‘Regata?‘Detroit?‘Benlica and ‘Black out? had high seed-setting rates. 4) The chromosomes recombination between aneuploid eggs that allotriploid hybrids produced and the genomes has high potential in introgression breeding. This study further develops the breeding potential of triploid LA hybrids, and lays the foundation for breeding of commercial lily varieties.
In order to investigate the applicability of LA hybrids as the breeding parents and select parents with a better fertility in LA×Asiatic lilies, 62 crossings were conducted with 26 LA cultivars and 10 Asiatic cultivars used as parents. Genomic in situ hybridization (GISH) technique was applied for hybrid identification and analysis of chromosomal composition in some hybrid progenies. Main results were obtained as follows: 1) LA triploid hybrids are usually male-sterile, but they can be crossed with diploid or tetraploid Asiatic hybrids as a female parent. 2) Compared with diploid Asiatic hybrids (AA), tetraploid Asiatic hybrids (AAAA) have a better fertility when crossed with LA hybrids. 3) Seven cross combinations with a better fertility were selected: ‘Nashville’בNello?‘Freya’בValdiSole?‘Desiderio’בDetroit?‘Samur’בNello?‘Batistero’בRegata?‘Roussea-u’בVal di Sole and ‘Ercolano’בBenlica? The results of 62 crossings revealed that 3 LA hybrids as female parents (‘Freya?‘Nashville and ‘Orange Tycoon? and 6 Asiatic hybrids as male parents (‘Val di Sole?‘Nello?‘Regata?‘Detroit?‘Benlica and ‘Black out? had high seed-setting rates. 4) The chromosomes recombination between aneuploid eggs that allotriploid hybrids produced and the genomes has high potential in introgression breeding. This study further develops the breeding potential of triploid LA hybrids, and lays the foundation for breeding of commercial lily varieties.
2016, 38(2): 105-112.
doi:10.13332/j.1000-1522.20150334
Abstract:
The ecological and environmental safety in the capital city is an issue always highly concerned by the government of China. In recent years, Beijing has greatly increased investment in forestry, and also attracted a wealthy of social funds to uplift the overall level of forestry and the forest ecosystem services. In order to improve the forestry input-output efficiency and to achieve the effective allocation of forestry resources and economies of scale, we selected six forestry input-output indexes, i.e., forestry investment in fixed assets, number of employees at the end of the year in forestry sectors, planting area, proportion of forestry industrial structure, output value of forestry industry and the rate of woody plant cover, and used DEA model which considers the return and scale (BC2-DEA model) to calculate the forestry input-output efficiency in Beijing from 1993 to 2013. The results show that the comprehensive efficiency of forestry input and output in Beijing is relatively high from 1993 to 2013. The average value of comprehensive efficiency is 0.966 in 21 years. As for the change of comprehensive efficiency of forestry input and output, the condition of forestry input-output in Beijing is good since 1993, and its efficiency is generally stable with small fluctuations. In the 21 years, 14 are in a state of DEA efficiency, and 7 in the state of DEA inefficiency. We also analyzed the main factors affecting the forestry input-output efficiency in Beijing, and point out that the change of the forestry investment in fixed assets is presently the main factor while the proportion of forestry industrial structure has little impact. In addition, factors like forestry investment management and production management also have an impact on the production efficiency. We propose that forestry investment in fixed assets in Beijing should keep stability in the future development and the industrial structure for forestry should be adjusted. Furthermore, the level of forestry investment and production management should be raised gradually and constantly in Beijing. Our study may bring important meanings to promote the coordinated development of forestry ecological economy, and improve the forestry input-output efficiency and forestry sustainable development in Beijing.
The ecological and environmental safety in the capital city is an issue always highly concerned by the government of China. In recent years, Beijing has greatly increased investment in forestry, and also attracted a wealthy of social funds to uplift the overall level of forestry and the forest ecosystem services. In order to improve the forestry input-output efficiency and to achieve the effective allocation of forestry resources and economies of scale, we selected six forestry input-output indexes, i.e., forestry investment in fixed assets, number of employees at the end of the year in forestry sectors, planting area, proportion of forestry industrial structure, output value of forestry industry and the rate of woody plant cover, and used DEA model which considers the return and scale (BC2-DEA model) to calculate the forestry input-output efficiency in Beijing from 1993 to 2013. The results show that the comprehensive efficiency of forestry input and output in Beijing is relatively high from 1993 to 2013. The average value of comprehensive efficiency is 0.966 in 21 years. As for the change of comprehensive efficiency of forestry input and output, the condition of forestry input-output in Beijing is good since 1993, and its efficiency is generally stable with small fluctuations. In the 21 years, 14 are in a state of DEA efficiency, and 7 in the state of DEA inefficiency. We also analyzed the main factors affecting the forestry input-output efficiency in Beijing, and point out that the change of the forestry investment in fixed assets is presently the main factor while the proportion of forestry industrial structure has little impact. In addition, factors like forestry investment management and production management also have an impact on the production efficiency. We propose that forestry investment in fixed assets in Beijing should keep stability in the future development and the industrial structure for forestry should be adjusted. Furthermore, the level of forestry investment and production management should be raised gradually and constantly in Beijing. Our study may bring important meanings to promote the coordinated development of forestry ecological economy, and improve the forestry input-output efficiency and forestry sustainable development in Beijing.
2016, 38(2): 113-119.
doi:10.13332/j.1000-1522.20150242
Abstract:
In order to improve the surface properties of wood treated by traditional wax coating technology, the Bruma rosewood sample was treated by modified beewax, which was obtained by modifying nano ZnO with different mass ratios (0.5%, 1.0% and 2.0%). The morphology of the samples and the dispersion of nano ZnO were characterized by scanning electron microscopy (SEM ) and energy disperse spectroscopy (EDAX). The wood surface properties with different nano ZnO contents were investigated through ultraviolet aging resistance, hydrophobicity and antibacterial properties analysis. The results showed that the color stability, hydrophobicity and antibacterial properties were significantly improved after treated with the modified wax with nano ZnO. When the nano ZnO content was 1%, the wood surface properties were optimal. After 96 h ultraviolet aging, the total color difference (ΔE*) of the modified sample was reduced by 42% compared with the unmodified one. The contact angle of the modified sample kept always above 102°. The modified sample has remarkable antibacterial properties, and antibacterial rate reaches 65%. Wood color is stable after treated by nano ZnO modified wax, which has great significance for expanding the range of application of the wax polished wood.
In order to improve the surface properties of wood treated by traditional wax coating technology, the Bruma rosewood sample was treated by modified beewax, which was obtained by modifying nano ZnO with different mass ratios (0.5%, 1.0% and 2.0%). The morphology of the samples and the dispersion of nano ZnO were characterized by scanning electron microscopy (SEM ) and energy disperse spectroscopy (EDAX). The wood surface properties with different nano ZnO contents were investigated through ultraviolet aging resistance, hydrophobicity and antibacterial properties analysis. The results showed that the color stability, hydrophobicity and antibacterial properties were significantly improved after treated with the modified wax with nano ZnO. When the nano ZnO content was 1%, the wood surface properties were optimal. After 96 h ultraviolet aging, the total color difference (ΔE*) of the modified sample was reduced by 42% compared with the unmodified one. The contact angle of the modified sample kept always above 102°. The modified sample has remarkable antibacterial properties, and antibacterial rate reaches 65%. Wood color is stable after treated by nano ZnO modified wax, which has great significance for expanding the range of application of the wax polished wood.
Abstract:
By treating eucalyptus veneer with different amounts of silane coupling agent, we investigated the effect of the treatments on the physical and mechanical performance of as-obtained eucalyptus veneer/polyvinyl chloride (PVC) film composites by hot-cold pressing crafts. Interfacial compatibility of the composites was analyzed using a scanning electronic microscope (SEM). The best treating effect was observed in the composites coupled with 1% silane agent, which resulted in an increase in bonding strength and water resistance. The treatment with 3% silane coupling agent caused the increase in MOE and MOR. After the treatment with silane coupling agent, the interfacial compatibility of the veneer composites was improved.
By treating eucalyptus veneer with different amounts of silane coupling agent, we investigated the effect of the treatments on the physical and mechanical performance of as-obtained eucalyptus veneer/polyvinyl chloride (PVC) film composites by hot-cold pressing crafts. Interfacial compatibility of the composites was analyzed using a scanning electronic microscope (SEM). The best treating effect was observed in the composites coupled with 1% silane agent, which resulted in an increase in bonding strength and water resistance. The treatment with 3% silane coupling agent caused the increase in MOE and MOR. After the treatment with silane coupling agent, the interfacial compatibility of the veneer composites was improved.
2016, 38(2): 124-130.
doi:10.13332/j.1000-1522.20150225
Abstract:
The objectives of this study were to clarify the vibration characteristics of the frame and operation handle of the stump cutting machine, and to establish a reasonable simulation model. Using the professional modal testing system with post-processing software and CAE software (Ansys Workbench), we carried out model test and finite element analysis of the frame and operation handle, and compared their results. The results of model test and finite element analysis can well match each other. For both methods, the error of natural frequency in the first six stages can be controlled within 10%, and the mode of vibration for each stage is basically the same, suggesting that the results of the model test and the finite element analysis can well reflect the actual characteristics of structural vibration. The finite element mode built for the frame and operation handle has a high credibility that it can be used trustingly in statics and dynamics analyses. The link part between the front of the frame and the cutter head shaft, as well as the holding part in the handle, are prone to large amplitude of vibration. Measures like adding vibration isolation material, changing rigid connection to elastic one, and increasing the fatigue strength of vulnerable parts, can be taken to isolate and decrease vibration.
The objectives of this study were to clarify the vibration characteristics of the frame and operation handle of the stump cutting machine, and to establish a reasonable simulation model. Using the professional modal testing system with post-processing software and CAE software (Ansys Workbench), we carried out model test and finite element analysis of the frame and operation handle, and compared their results. The results of model test and finite element analysis can well match each other. For both methods, the error of natural frequency in the first six stages can be controlled within 10%, and the mode of vibration for each stage is basically the same, suggesting that the results of the model test and the finite element analysis can well reflect the actual characteristics of structural vibration. The finite element mode built for the frame and operation handle has a high credibility that it can be used trustingly in statics and dynamics analyses. The link part between the front of the frame and the cutter head shaft, as well as the holding part in the handle, are prone to large amplitude of vibration. Measures like adding vibration isolation material, changing rigid connection to elastic one, and increasing the fatigue strength of vulnerable parts, can be taken to isolate and decrease vibration.
