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RSS2011 Vol. 33, No. 5
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2011, 33(5): 1-7.
Abstract:
The study describes the application of compatible nonlinear equation systems in developing stem taper and volume models and methods of parameter estimation. Three compatible stem taper and volume systems with different inflection points were developed for dahurian larch (Larix gmelinii Rupr.) plantations located in Dailing Forest Bureau, Heilongjiang Province of northeastern China based on a Max and Burkhart segmented taper model. Taper and volume systems share the same parameters. To concurrently minimize error in endogenous variables, seemingly unrelated regression (SUR) procedure of the PROC MODEL in SAS software was used to obtain parameter estimates of equation systems. Coefficient determination, absolute bias, relative absolute bias, root mean square error and relative root mean square error were employed to evaluate the precision of different model systems. The results showed that Max and Burkhart segmented taper and volume model systems with two inflection points provided best precision of model fitting. The lower and upper stem inflection points of dahurian larch were found to be 0.09H and 0.77H at tree height for diameter outside bark, and 0.08H and 0.75H for diameter inside bark. Model validation further confirms that this model system provides the best precision of diameter and volume prediction.
The study describes the application of compatible nonlinear equation systems in developing stem taper and volume models and methods of parameter estimation. Three compatible stem taper and volume systems with different inflection points were developed for dahurian larch (Larix gmelinii Rupr.) plantations located in Dailing Forest Bureau, Heilongjiang Province of northeastern China based on a Max and Burkhart segmented taper model. Taper and volume systems share the same parameters. To concurrently minimize error in endogenous variables, seemingly unrelated regression (SUR) procedure of the PROC MODEL in SAS software was used to obtain parameter estimates of equation systems. Coefficient determination, absolute bias, relative absolute bias, root mean square error and relative root mean square error were employed to evaluate the precision of different model systems. The results showed that Max and Burkhart segmented taper and volume model systems with two inflection points provided best precision of model fitting. The lower and upper stem inflection points of dahurian larch were found to be 0.09H and 0.77H at tree height for diameter outside bark, and 0.08H and 0.75H for diameter inside bark. Model validation further confirms that this model system provides the best precision of diameter and volume prediction.
Abstract:
In order to display more directly the dynamic growth process of individual Mongolian Scots pines in the plantation conditions, we employed a systematic analysis method and a mathematically modeling technique to simulate the morphological characteristics of individual Mongolian Scots pines. By referencing previous research of crown structure models, we established the morphological simulation model of individual Mongolian Scots pines through quantitative analyses of its morphological field data. Then, the growth visualization system was established with the OpenGL on the developing platform of VC++6.0. The system is composed of a morphology model suite, a crown model suite, a growth model suite, a visualization suite, a scene control suite, a database and a users interface. The operation shows that the system realizes the organic integration between the growth mechanism and visual expression of morphological characteristics of individual Mongolian Scots pines, and also well displays the concept of organic integration among crown structure model, growth model and visualization model. Meanwhile, the system can vividly simulate the morphological characteristics and growth process of individual Mongolian Scots pines. Obviously, our work lays a foundation for plantation visualization management, and also offers a good reference for the visualization of other species.
In order to display more directly the dynamic growth process of individual Mongolian Scots pines in the plantation conditions, we employed a systematic analysis method and a mathematically modeling technique to simulate the morphological characteristics of individual Mongolian Scots pines. By referencing previous research of crown structure models, we established the morphological simulation model of individual Mongolian Scots pines through quantitative analyses of its morphological field data. Then, the growth visualization system was established with the OpenGL on the developing platform of VC++6.0. The system is composed of a morphology model suite, a crown model suite, a growth model suite, a visualization suite, a scene control suite, a database and a users interface. The operation shows that the system realizes the organic integration between the growth mechanism and visual expression of morphological characteristics of individual Mongolian Scots pines, and also well displays the concept of organic integration among crown structure model, growth model and visualization model. Meanwhile, the system can vividly simulate the morphological characteristics and growth process of individual Mongolian Scots pines. Obviously, our work lays a foundation for plantation visualization management, and also offers a good reference for the visualization of other species.
2011, 33(5): 8-12.
Abstract:
Forests are usually distributed on rugged mountains, therefore the elimination of topographic effects becomes one of the essential issues to improve monitoring accuracy of forest cover by remote sensing. Here we introduced a novel topography-adjusted vegetation index (TAVI) which is capable of removing topographic effects in rugged terrain based only on infrared and red wavebands data from optical remote sensing images, without support of digital elevation model (DEM) data. The Landsat TM images acquired in 1998 and 2008 respectively were utilized in case study to validate the TAVI performance and monitor the changes of forest cover with TAVI. From the regression analysis between TAVI and the solar incidence cosine and contrast analysis between TAVI and normalized difference vegetation index (NDVI) in the study area, it was discovered that TAVI can resist the topographic effects remarkably and was much better than NDVI in that the slope of linear regression equation of TAVI and the solar incidence cosine was only between ±0.04, and also their correlation coefficient was just between ±0.08. The forest cover images in rugged areas computed from TAVI displayed a planar spatial distribution instead of texture pattern resulting from topography. The dynamic monitoring results turn out that forests in the research area grow in a generally sustainable way during 1998--2008.
Forests are usually distributed on rugged mountains, therefore the elimination of topographic effects becomes one of the essential issues to improve monitoring accuracy of forest cover by remote sensing. Here we introduced a novel topography-adjusted vegetation index (TAVI) which is capable of removing topographic effects in rugged terrain based only on infrared and red wavebands data from optical remote sensing images, without support of digital elevation model (DEM) data. The Landsat TM images acquired in 1998 and 2008 respectively were utilized in case study to validate the TAVI performance and monitor the changes of forest cover with TAVI. From the regression analysis between TAVI and the solar incidence cosine and contrast analysis between TAVI and normalized difference vegetation index (NDVI) in the study area, it was discovered that TAVI can resist the topographic effects remarkably and was much better than NDVI in that the slope of linear regression equation of TAVI and the solar incidence cosine was only between ±0.04, and also their correlation coefficient was just between ±0.08. The forest cover images in rugged areas computed from TAVI displayed a planar spatial distribution instead of texture pattern resulting from topography. The dynamic monitoring results turn out that forests in the research area grow in a generally sustainable way during 1998--2008.
Abstract:
By using a spatially explicit landscape model (LANDIS), we simulated the long-term (within 300 years) dynamics of forest fire regime under four scenarios of harvesting modes, i.e., no cutting, clear cutting, gradual cutting and selective cutting, in the Huzhong Forest Region in Da Xingan Ling Mountains.Results show that forest harvesting could decrease fine fuel loads, but no significant difference occurs among various harvesting modes. Forest harvesting could increase coarse fuel loads, with the largest increase under clear cutting scenario. In addition, forest harvesting could increase the area and frequency of forest fire as well as the fire occurrence probability. Fire occurrence probability under selective cutting scenario was the lowest. Moreover, forest harvesting could increase the fire risk class, which was the lowest under selective cutting scenario. We suggest that selective cutting mode should be taken under same cutting volume in order to decrease the influence of forest harvesting and fire disturbance on forest ecosystems and hence, to guarantee the healthy and sustainable development of forest ecosystems in this region.
By using a spatially explicit landscape model (LANDIS), we simulated the long-term (within 300 years) dynamics of forest fire regime under four scenarios of harvesting modes, i.e., no cutting, clear cutting, gradual cutting and selective cutting, in the Huzhong Forest Region in Da Xingan Ling Mountains.Results show that forest harvesting could decrease fine fuel loads, but no significant difference occurs among various harvesting modes. Forest harvesting could increase coarse fuel loads, with the largest increase under clear cutting scenario. In addition, forest harvesting could increase the area and frequency of forest fire as well as the fire occurrence probability. Fire occurrence probability under selective cutting scenario was the lowest. Moreover, forest harvesting could increase the fire risk class, which was the lowest under selective cutting scenario. We suggest that selective cutting mode should be taken under same cutting volume in order to decrease the influence of forest harvesting and fire disturbance on forest ecosystems and hence, to guarantee the healthy and sustainable development of forest ecosystems in this region.
Abstract:
Based on the use of variance ration (VR), 2×2 contingency table,χ2 test and interspecies association coefficient calculation, we examined interspecific association of dominant species both in polar-birch secondary forest and in spruce-fir forest. The results showed that mean variance of the 12 principal arbor species in poplar-birch secondary forests was 0.932, closes to 1, and had no significant correlation; but in spruce-fir mixed forest, it showed positive correlation, which indicated that the stage was relatively stable and adapted to the environmental conditions. The positive correlation of the whole community was strengthening along with the progression of succession. The end-result of competition would lead to the pioneer tree, Betula platyhylla and Populu. davidiana, which were declining species, be replaced by the zonal climax species spruce-fir forest in the future. The overall correlations among multi-species reflect the general trend among various species in community. The interspecific association further explains that the community we studied is in the transitional stage, ie from the polar-birch secondary forest to spruce-fir mixed forest.
Based on the use of variance ration (VR), 2×2 contingency table,χ2 test and interspecies association coefficient calculation, we examined interspecific association of dominant species both in polar-birch secondary forest and in spruce-fir forest. The results showed that mean variance of the 12 principal arbor species in poplar-birch secondary forests was 0.932, closes to 1, and had no significant correlation; but in spruce-fir mixed forest, it showed positive correlation, which indicated that the stage was relatively stable and adapted to the environmental conditions. The positive correlation of the whole community was strengthening along with the progression of succession. The end-result of competition would lead to the pioneer tree, Betula platyhylla and Populu. davidiana, which were declining species, be replaced by the zonal climax species spruce-fir forest in the future. The overall correlations among multi-species reflect the general trend among various species in community. The interspecific association further explains that the community we studied is in the transitional stage, ie from the polar-birch secondary forest to spruce-fir mixed forest.
Abstract:
Clematis acerifolia is a critically endangered species endemic to an extremely narrow distribution range in Beijing Municipality. This species is often found on the vertical cliffs in gorges of Fangshan and Mentougou districts. Although most of the taxonomic treatments placed it into Sect. Cheiropsis, its systematic position has never been tested by the molecular evidence. To access the systematic position of C. acerifolia, sequences of the ITS, the plastid atpB-rbcL spacer, psbA-trnQ spacer and rpoB-trnC spacer regions from the whole genus were analyzed using parsimony and Bayesian inference methods. The results showed that: 1) relatively low resolution and support values were obtained in the separate analyses but were enhanced in the combined data analyses; 2) Clematis together with Naravelia formed a clade and these two genera should be merged; 3) traditionally taxonomic treatment of C. acerifolia was not supported and this species may not be a member of Sect. Cheiropsis; 4) the position of C. acerifolia was detected to be isolated in the genus and it may represent a relic species of Holarctic Clematis.
Clematis acerifolia is a critically endangered species endemic to an extremely narrow distribution range in Beijing Municipality. This species is often found on the vertical cliffs in gorges of Fangshan and Mentougou districts. Although most of the taxonomic treatments placed it into Sect. Cheiropsis, its systematic position has never been tested by the molecular evidence. To access the systematic position of C. acerifolia, sequences of the ITS, the plastid atpB-rbcL spacer, psbA-trnQ spacer and rpoB-trnC spacer regions from the whole genus were analyzed using parsimony and Bayesian inference methods. The results showed that: 1) relatively low resolution and support values were obtained in the separate analyses but were enhanced in the combined data analyses; 2) Clematis together with Naravelia formed a clade and these two genera should be merged; 3) traditionally taxonomic treatment of C. acerifolia was not supported and this species may not be a member of Sect. Cheiropsis; 4) the position of C. acerifolia was detected to be isolated in the genus and it may represent a relic species of Holarctic Clematis.
2011, 33(5): 34-41.
Abstract:
The diversity of plant species and sexual system in a Populus lasiocarpa Oliv. community in the Dalaoling Nature Reserve of Hubei Province were assessed by richness index, diversity index and evenness index. In total, 182 species representing 143 genera in 73 families are recorded in P. lasiocarpa community. The genera with only one or two species occupy the dominant position in community. The species richness in P. lasiocarpa community is affected by the elevation, slope and the forest microenvironment. It reaches the maximum value at the quadrat 3. The more common families and less common species among the four quadrats are related to the degrees of difference among their microenvironments. The P. lasiocarpa community is in the process of succession. The age structure of P. lasiocarpa belongs to an increasing type in the quadrat 1, but a declining type for the other three quadrats. The sexual system of plants is diverse in P. lasiocarpa community. Hermaphroditism has the highest proportion and monoecious and dioecious plants also play the important role in the community. In the tree layer, the most important type is dioecy, which is consistent with the sexual system of the constructive species. The hermaphroditism is the most important type in the shrub and herb layers and the proportion of hermaphroditism increases with the increasing number of species in the herb layer. In addition, the importance values of the constructive species, P. lasiocarpa, is the maximum in the tree layer, especially in the quadrat 3. The changes of species diversity index are consistent with sexual system diversity index in the four quadrats. The diversity index of the tree layer change little, but it increased gradually with the increasing elevation in the shrub layer and reached the maximum at the quadrat 3 in the herb layer, which is affected by the number of species in different layers. The evenness index is the maximum in the lowest elevation in all three layers, indicating that the most even distribution of plant species and sexual system.
The diversity of plant species and sexual system in a Populus lasiocarpa Oliv. community in the Dalaoling Nature Reserve of Hubei Province were assessed by richness index, diversity index and evenness index. In total, 182 species representing 143 genera in 73 families are recorded in P. lasiocarpa community. The genera with only one or two species occupy the dominant position in community. The species richness in P. lasiocarpa community is affected by the elevation, slope and the forest microenvironment. It reaches the maximum value at the quadrat 3. The more common families and less common species among the four quadrats are related to the degrees of difference among their microenvironments. The P. lasiocarpa community is in the process of succession. The age structure of P. lasiocarpa belongs to an increasing type in the quadrat 1, but a declining type for the other three quadrats. The sexual system of plants is diverse in P. lasiocarpa community. Hermaphroditism has the highest proportion and monoecious and dioecious plants also play the important role in the community. In the tree layer, the most important type is dioecy, which is consistent with the sexual system of the constructive species. The hermaphroditism is the most important type in the shrub and herb layers and the proportion of hermaphroditism increases with the increasing number of species in the herb layer. In addition, the importance values of the constructive species, P. lasiocarpa, is the maximum in the tree layer, especially in the quadrat 3. The changes of species diversity index are consistent with sexual system diversity index in the four quadrats. The diversity index of the tree layer change little, but it increased gradually with the increasing elevation in the shrub layer and reached the maximum at the quadrat 3 in the herb layer, which is affected by the number of species in different layers. The evenness index is the maximum in the lowest elevation in all three layers, indicating that the most even distribution of plant species and sexual system.
2011, 33(5): 56-60.
Abstract:
In order to provide a theoretical foundation for nitrogen fertilizer management of Quercus variabilis seedlings, using exponential nitrogen fertilization regimes, the effects of nitrogen treatments on light-response curves of Q. variabilis seedlings were studied under sand-cultured condition. The seedlings were planted in pots, supplied with four nitrogen application levels (0, 120.6, 216.4 and 329.2 mg/(seedling?year)). The results show that various nitrogen application levels had different effects on the light-response curves of Q. variabilis leaves, depending on the growth phases. At the initiation phase, all the simulation parameters of light-response curves showed no significant differences among treatments. At the fast-growth phase, the lack of nitrogen weakened the photosynthetic capability of seedlings in treatment CK (0 mg/(seedling?year)) sharply, which reduced the light saturation point (LSP), maximum net photosynthetic rate (Pmax) and the apparent quantum efficiency (α); meanwhile, the light compensation point (LCP) expressed a trend of increase. When the nitrogen level was raised from 120.6 to 216.4 mg/(seedling?year), no significant variation about Pmax was found between the two treatments; however, the LCP of the seedlings in 216.4 mg/(seedling?year) treatment was lower and the LSP was higher. Yet, excessive nitrogen supply (329.2 mg/(seedling?year)) played a negative role on the photosynthetic ability of Q. variabilis seedlings. At the later phase, relatively higher photosynthetic efficiency was maintained in the seedlings in 216.4 mg/(seedling?year) treatment, comparing with the common decline in other three treatments.
In order to provide a theoretical foundation for nitrogen fertilizer management of Quercus variabilis seedlings, using exponential nitrogen fertilization regimes, the effects of nitrogen treatments on light-response curves of Q. variabilis seedlings were studied under sand-cultured condition. The seedlings were planted in pots, supplied with four nitrogen application levels (0, 120.6, 216.4 and 329.2 mg/(seedling?year)). The results show that various nitrogen application levels had different effects on the light-response curves of Q. variabilis leaves, depending on the growth phases. At the initiation phase, all the simulation parameters of light-response curves showed no significant differences among treatments. At the fast-growth phase, the lack of nitrogen weakened the photosynthetic capability of seedlings in treatment CK (0 mg/(seedling?year)) sharply, which reduced the light saturation point (LSP), maximum net photosynthetic rate (Pmax) and the apparent quantum efficiency (α); meanwhile, the light compensation point (LCP) expressed a trend of increase. When the nitrogen level was raised from 120.6 to 216.4 mg/(seedling?year), no significant variation about Pmax was found between the two treatments; however, the LCP of the seedlings in 216.4 mg/(seedling?year) treatment was lower and the LSP was higher. Yet, excessive nitrogen supply (329.2 mg/(seedling?year)) played a negative role on the photosynthetic ability of Q. variabilis seedlings. At the later phase, relatively higher photosynthetic efficiency was maintained in the seedlings in 216.4 mg/(seedling?year) treatment, comparing with the common decline in other three treatments.
2011, 33(5): 42-48.
Abstract:
Anatomic characteristics of clonal growth of root suckers of Populus euphratica was studied by means of conventional paraffin method. The results show that primary xylems of transverse lateral roots are triarch or tetrarch, with developed phelloderm in periderm, and formed by six to eight layers of parenchymatous cells. The proportion of secondary phloem, located in the secondary vascular tissue of cross-sections of transverse lateral roots, is significantly less than secondary xylem. The early generated secondary xylems are characterized by the majority of nonwoody wood fiber cell in cell wall, and vascular ray well develops. The clonal growth of root suckers of P. euphratica is due to the development and growth of adventitious buds on transverse lateral roots. Adventitious buds originate from cork cambium of transverse lateral roots, and cork cambium cells form primordia of adventitious buds by cell division. The cell division, proliferation and differentiation of adventitious primordium formed visible primordia on the surface of transverse lateral roots, and these primordia directly develop as root suckers. Primordia present temporal characteristics of synchronous and asynchronous generation, and spatial characteristics of simple-point and multi-point gathering generation. The base of adventitious primordia could generate new sub-primordia during its growth process. This is the key reason that clonal growth of root suckers caused root suckers growing in different sizes and the densely fasciculate shape. It also indicated that P. euphratica had strong ability of clonal growth of root suckers.
Anatomic characteristics of clonal growth of root suckers of Populus euphratica was studied by means of conventional paraffin method. The results show that primary xylems of transverse lateral roots are triarch or tetrarch, with developed phelloderm in periderm, and formed by six to eight layers of parenchymatous cells. The proportion of secondary phloem, located in the secondary vascular tissue of cross-sections of transverse lateral roots, is significantly less than secondary xylem. The early generated secondary xylems are characterized by the majority of nonwoody wood fiber cell in cell wall, and vascular ray well develops. The clonal growth of root suckers of P. euphratica is due to the development and growth of adventitious buds on transverse lateral roots. Adventitious buds originate from cork cambium of transverse lateral roots, and cork cambium cells form primordia of adventitious buds by cell division. The cell division, proliferation and differentiation of adventitious primordium formed visible primordia on the surface of transverse lateral roots, and these primordia directly develop as root suckers. Primordia present temporal characteristics of synchronous and asynchronous generation, and spatial characteristics of simple-point and multi-point gathering generation. The base of adventitious primordia could generate new sub-primordia during its growth process. This is the key reason that clonal growth of root suckers caused root suckers growing in different sizes and the densely fasciculate shape. It also indicated that P. euphratica had strong ability of clonal growth of root suckers.
2011, 33(5): 69-74.
Abstract:
Lignin was extracted from the Acanthopanax senticosus remainders, coming from pharmaceutical production process, with 1,4-butanediol as an extracting reagent. The supercritical antisolvent (SAS) process was studied to prepare nanoscale lignin and test its antioxidant capacity. The optimal condition by a four-level orthogonal design is as follows: precipitation temperature 35? precipitation pressure 30 MPa, temperature difference +10 and concentration of lignin solution 0.5 mg/mL. Nanoscale organic lignin with mean particle size of (0.144±0.03) μm was obtained by verification experiments. The EC50 of the nanoscale and non-nanoscale organic lignin on DPPH was (0.563±0.02) mg/mL and (0.884±0.02) mg/mL, respectively. The results indicated that the DPPH scavenging capacity of nanoscale organic lignin is more improved than that of non-nanoscale organic lignin.
Lignin was extracted from the Acanthopanax senticosus remainders, coming from pharmaceutical production process, with 1,4-butanediol as an extracting reagent. The supercritical antisolvent (SAS) process was studied to prepare nanoscale lignin and test its antioxidant capacity. The optimal condition by a four-level orthogonal design is as follows: precipitation temperature 35? precipitation pressure 30 MPa, temperature difference +10 and concentration of lignin solution 0.5 mg/mL. Nanoscale organic lignin with mean particle size of (0.144±0.03) μm was obtained by verification experiments. The EC50 of the nanoscale and non-nanoscale organic lignin on DPPH was (0.563±0.02) mg/mL and (0.884±0.02) mg/mL, respectively. The results indicated that the DPPH scavenging capacity of nanoscale organic lignin is more improved than that of non-nanoscale organic lignin.
Abstract:
A solution cultivation experiment with Pinus koraiensis seedlings was conducted to study the effect of different NH+4/NO-3 ratio on nitrogen absorption，nitrogen assimilation enzyme and growth. The results showed that more nitrogen was absorbed by the seedlings in high NH+4/NO-3 ratio solution, whose total biomass was more than the others. Nitrate reductase (NR) activity was higher in the roots than the leaves, NO-3 promoted NR activity, which responsed to increased NO-3 availability of the solution. Glutamine synthetase (GS) activity and glutamate dehydrogenase (GDH) activity was improved by the induction of exogenous NH+4. GS activity was higher in the leaves than the roots, and which was higher in the seedlings of high NH+4/NO-3 ratio solution. GDH activity of the roots and the leaves was high, and which was higher in the seedlings of high NH+4/NO-3 ratio solution.
A solution cultivation experiment with Pinus koraiensis seedlings was conducted to study the effect of different NH+4/NO-3 ratio on nitrogen absorption，nitrogen assimilation enzyme and growth. The results showed that more nitrogen was absorbed by the seedlings in high NH+4/NO-3 ratio solution, whose total biomass was more than the others. Nitrate reductase (NR) activity was higher in the roots than the leaves, NO-3 promoted NR activity, which responsed to increased NO-3 availability of the solution. Glutamine synthetase (GS) activity and glutamate dehydrogenase (GDH) activity was improved by the induction of exogenous NH+4. GS activity was higher in the leaves than the roots, and which was higher in the seedlings of high NH+4/NO-3 ratio solution. GDH activity of the roots and the leaves was high, and which was higher in the seedlings of high NH+4/NO-3 ratio solution.
Abstract:
In order to select suitable tree species for carbon sink and determine forest management cycle, we used a new analytical method to study carbon storage and its dynamics in major afforestation species in the north of China. Results show that 1) the mature age of Pinus tabulaeformis, Robinia pseudoacacia and Populus euramericana were 67, 40 and 30 years, respectively. 2) Wood density of P. tabulaeformis and R. pseudoacacia presented a slowly-increasing trend in the initial phase and reached the maximum value at age 30. After age 30, wood density of P. tabulaeformis decreased gradually until reaching a stable value, while those of R. pseudoacacia declined continuously. For P. euramericana, wood density increased quickly before age 4, increased slowly from age 4 to 18 and declined from age 18 to 28. 3) The carbon storage of P. tabulaeformis showed a relatively large variation, with the maximum value of 60.52% at age 20 and the minimum value of 46.14% at age 40. In contrast, the carbon storage of R. pseudoacacia varied greatly before age 25 and then became stable, with the maximum value of 56.96% at age 5 and the minimum of 42.58% at age 25. The carbon storage of P. euramericana changed little; it declined slowly from the maximum value of 48.64% to the minimum of 46.64%. 4) The average carbon storage of P. tabulaeformis, R. pseudoacacia and P. euramericana peaked at age 70 (2.5267 kg), 40 (3.7939 kg) and 30 (2.7810 kg), respectively.
In order to select suitable tree species for carbon sink and determine forest management cycle, we used a new analytical method to study carbon storage and its dynamics in major afforestation species in the north of China. Results show that 1) the mature age of Pinus tabulaeformis, Robinia pseudoacacia and Populus euramericana were 67, 40 and 30 years, respectively. 2) Wood density of P. tabulaeformis and R. pseudoacacia presented a slowly-increasing trend in the initial phase and reached the maximum value at age 30. After age 30, wood density of P. tabulaeformis decreased gradually until reaching a stable value, while those of R. pseudoacacia declined continuously. For P. euramericana, wood density increased quickly before age 4, increased slowly from age 4 to 18 and declined from age 18 to 28. 3) The carbon storage of P. tabulaeformis showed a relatively large variation, with the maximum value of 60.52% at age 20 and the minimum value of 46.14% at age 40. In contrast, the carbon storage of R. pseudoacacia varied greatly before age 25 and then became stable, with the maximum value of 56.96% at age 5 and the minimum of 42.58% at age 25. The carbon storage of P. euramericana changed little; it declined slowly from the maximum value of 48.64% to the minimum of 46.64%. 4) The average carbon storage of P. tabulaeformis, R. pseudoacacia and P. euramericana peaked at age 70 (2.5267 kg), 40 (3.7939 kg) and 30 (2.7810 kg), respectively.
2011, 33(5): 75-80.
Abstract:
In order to reveal the ecological role of ants in southeastern Tibet, distribution patterns of ant species from Mount Sejila were investigated for the first time by the sample-plot and search-collecting methods. In total, 31 species belonging to 3 subfamilies and 14 genera of Formicidae are recognized. Among them, 2 genera and 3 species belong to Ponerinae, 7 genera and 17 species belong to Myrmicinae and 5 genera and 11 species belong to Formicinae. In the Mount Sejila area, most of the ant species (about 2/3) are poorly adapted to alpine conditions and found below an elevation of 3 000 m. Relatively few species (about 1/3) can physiologically adapt to higher elevations and found above 3 000 m in elevation. The species richness of ants increases with decreasing elevation. This phenomenon is primarily due to thermal factors (air temperature). The types of vegetation applied by ant species is restricted by air temperature and plant richness. Distribution patterns of ant species are also affected by slope direction and position, which can constrain the local heat accumulation. The direction of the slopes preferred by ants differs from species to species. On Mount Sejila, distribution patterns of ant species in the same genus are very distinct. Myrmica smythiesii Forel and M. bactriana Ruzsky are the most widely distributed species, occupying the widest range of habitats.
In order to reveal the ecological role of ants in southeastern Tibet, distribution patterns of ant species from Mount Sejila were investigated for the first time by the sample-plot and search-collecting methods. In total, 31 species belonging to 3 subfamilies and 14 genera of Formicidae are recognized. Among them, 2 genera and 3 species belong to Ponerinae, 7 genera and 17 species belong to Myrmicinae and 5 genera and 11 species belong to Formicinae. In the Mount Sejila area, most of the ant species (about 2/3) are poorly adapted to alpine conditions and found below an elevation of 3 000 m. Relatively few species (about 1/3) can physiologically adapt to higher elevations and found above 3 000 m in elevation. The species richness of ants increases with decreasing elevation. This phenomenon is primarily due to thermal factors (air temperature). The types of vegetation applied by ant species is restricted by air temperature and plant richness. Distribution patterns of ant species are also affected by slope direction and position, which can constrain the local heat accumulation. The direction of the slopes preferred by ants differs from species to species. On Mount Sejila, distribution patterns of ant species in the same genus are very distinct. Myrmica smythiesii Forel and M. bactriana Ruzsky are the most widely distributed species, occupying the widest range of habitats.
2011, 33(5): 81-85.
Abstract:
The acoustic signals produced by insects are species-specific, and therefore can be employed for detection and identification purposes. This experiment aims to find a new way to automatically identify insects by their acoustic characteristics. Stridulation signals of four bark beetles, Dendroctonus valens, Tomicus yunnanensis, T. brevipilosus and D. armandi, were recorded under stress condition. Then after noise reduction, the signals were cut into one-echeme segments by audio software Adobe Adition2.0. With MATLAB7.1, borders of all of the segments were detected and twelve Mel-frequency cepstral coefficients were extracted as feature parameters which were then put into Back-Propagation Network as training and test samples. The numbers of training samples were set to 20, 40, 60, 80 and 100, and the number of test samples of the four beetle species were 54, 95, 54 and 50 separately. The results indicated that the identification success increased with the rise of the number of training samples. As the number of training samples increased to 100, the identification success reached the highest level, 98.14%, averaging 93.29%. In order to verify how the number of beetle species affects to recognition rates, the four species were subjected to pairwise comparison and the results showed that the recognition rates were higher than that when four species were tested together.
The acoustic signals produced by insects are species-specific, and therefore can be employed for detection and identification purposes. This experiment aims to find a new way to automatically identify insects by their acoustic characteristics. Stridulation signals of four bark beetles, Dendroctonus valens, Tomicus yunnanensis, T. brevipilosus and D. armandi, were recorded under stress condition. Then after noise reduction, the signals were cut into one-echeme segments by audio software Adobe Adition2.0. With MATLAB7.1, borders of all of the segments were detected and twelve Mel-frequency cepstral coefficients were extracted as feature parameters which were then put into Back-Propagation Network as training and test samples. The numbers of training samples were set to 20, 40, 60, 80 and 100, and the number of test samples of the four beetle species were 54, 95, 54 and 50 separately. The results indicated that the identification success increased with the rise of the number of training samples. As the number of training samples increased to 100, the identification success reached the highest level, 98.14%, averaging 93.29%. In order to verify how the number of beetle species affects to recognition rates, the four species were subjected to pairwise comparison and the results showed that the recognition rates were higher than that when four species were tested together.
2011, 33(5): 86-90.
Abstract:
In order to discuss the exogenous genes expression and effect of Bt-BADH-GA20ox-rolB multigenes on transgenic plants, four transgenic tobacco lines and a control strain were taken as materials and the experiments included determination of endogenous hormones, salt tolerance test, Bt toxic protein measurement and growth observation. The results indicated that the rooting ability of transgenic plants was enhanced. Endogenous hormones（IAA, GA3）derived from roots, stems and leaves were significantly different from controls. At a low concentration of NaCl, there is no difference between transgenic plant and control, while at 300 mmol/L of NaCl the growth of control was restrained with and the transgenic plant was normal. The Bt toxic protein was detected at a high level in both stems and leaves of the transgenic plants. The development of prodenia was obviously inhibited by feeding the leaves of transgenic plants. The transgenic plants grew vigorously after being transplanted. The average height and basal stem of transgenic plants were 1.61 and 1.37 times higher than those of control respectively.
In order to discuss the exogenous genes expression and effect of Bt-BADH-GA20ox-rolB multigenes on transgenic plants, four transgenic tobacco lines and a control strain were taken as materials and the experiments included determination of endogenous hormones, salt tolerance test, Bt toxic protein measurement and growth observation. The results indicated that the rooting ability of transgenic plants was enhanced. Endogenous hormones（IAA, GA3）derived from roots, stems and leaves were significantly different from controls. At a low concentration of NaCl, there is no difference between transgenic plant and control, while at 300 mmol/L of NaCl the growth of control was restrained with and the transgenic plant was normal. The Bt toxic protein was detected at a high level in both stems and leaves of the transgenic plants. The development of prodenia was obviously inhibited by feeding the leaves of transgenic plants. The transgenic plants grew vigorously after being transplanted. The average height and basal stem of transgenic plants were 1.61 and 1.37 times higher than those of control respectively.
2011, 33(5): 97-102.
Abstract:
A HsfA2 gene isolated from Arabidopsis thaliana ecotype Columbia was transferred into ground-cover Chrysanthemum ‘Beilinhuang by the Agrobacterium-mediated method. After antibiotics screening and molecular detection, eight positive transgenic lines were obtained. RT-PCR detection results showed that the exogenous AtHsfA2 gene was expressed in seven transgenic lines. The results of heat stress treatment also showed that the ability of transgenic plants to heat stress was significantly higher than that of non-transgenic plants. This research obtained Chrysanthemum lines with higher resistance ability to heat stress through transgenic method and may provide scientific references for transgenic breeding of ornamental plants.
A HsfA2 gene isolated from Arabidopsis thaliana ecotype Columbia was transferred into ground-cover Chrysanthemum ‘Beilinhuang by the Agrobacterium-mediated method. After antibiotics screening and molecular detection, eight positive transgenic lines were obtained. RT-PCR detection results showed that the exogenous AtHsfA2 gene was expressed in seven transgenic lines. The results of heat stress treatment also showed that the ability of transgenic plants to heat stress was significantly higher than that of non-transgenic plants. This research obtained Chrysanthemum lines with higher resistance ability to heat stress through transgenic method and may provide scientific references for transgenic breeding of ornamental plants.
Abstract:
Based on agar plate tests, 18 isolates from 23 white rot fungi were selected to a subsequent wood block decay test. According to the ratio of Klasson lignin losses to holocellulose losses, three isolates, Perenniporia ochroleuca D9597, Funalia trogii C6978 and Trametes orientalis C6320, showed selective delignification on Populus nigra. Based on primary component analysis, three different types of degradation were found during the fermentation of P. nigra by 18 white rot fungi: type A represents selective delignification; types B and C can selectively decompose holocelluloses, but type C has a stronger capacity than type B. Investigation was carried out on the UV absorbance spectra of ethanol extracts of wood particles treated by P. ochroleuca D9597, F. trogii C6978 and T. orientalis C6320 for 20 days, and lignin in the treated wood was found to be decomposed markedly.
Based on agar plate tests, 18 isolates from 23 white rot fungi were selected to a subsequent wood block decay test. According to the ratio of Klasson lignin losses to holocellulose losses, three isolates, Perenniporia ochroleuca D9597, Funalia trogii C6978 and Trametes orientalis C6320, showed selective delignification on Populus nigra. Based on primary component analysis, three different types of degradation were found during the fermentation of P. nigra by 18 white rot fungi: type A represents selective delignification; types B and C can selectively decompose holocelluloses, but type C has a stronger capacity than type B. Investigation was carried out on the UV absorbance spectra of ethanol extracts of wood particles treated by P. ochroleuca D9597, F. trogii C6978 and T. orientalis C6320 for 20 days, and lignin in the treated wood was found to be decomposed markedly.
2011, 33(5): 103-108.
Abstract:
In this study, we analyzed 84 SSR primer pairs from closely related species and designed 23 EST-SSR primer pairs from NCBI for developing more mei flower(Prunus mume Sieb. et Zucc.)new SSR makers. Twelve mei flower cultivars were used to do polymorphic test on these primers. The results show that 69 SSR primer pairs can amplify bands with the efficient amplification ratio of 82.1%. A total of 85 alleles were detected by 14 primer pairs with an average of six effective alleles per primer. The effective number of alleles was between 2.072 and 5.539, with the average of 4. The polymorphic information content (PIC) value was between 0.483 and 0.786, with the average of 0.695. The average Shannon Index was 1.528, with the genetic similarity coefficient among 12 materials ranging from 0.13 to 0.60 and the average of 0.26. Based on the UPGMA analysis, P. mume ‘Yudie Longyou and P. mume ‘Xiao Yudie contained similar inheriting basement, about 0.60, and the similarity value between P. mume ‘Meiren and P. mume ‘Huangjin was smallest, about 0.13. The designed 22 EST-SSR primer pairs can amplify bands, with the effective amplificaition rate of 95.6%. Eleven primer pairs demonstrated the polymorphic characteristics, accounting for 47.8% of all the EST-SSR.
In this study, we analyzed 84 SSR primer pairs from closely related species and designed 23 EST-SSR primer pairs from NCBI for developing more mei flower(Prunus mume Sieb. et Zucc.)new SSR makers. Twelve mei flower cultivars were used to do polymorphic test on these primers. The results show that 69 SSR primer pairs can amplify bands with the efficient amplification ratio of 82.1%. A total of 85 alleles were detected by 14 primer pairs with an average of six effective alleles per primer. The effective number of alleles was between 2.072 and 5.539, with the average of 4. The polymorphic information content (PIC) value was between 0.483 and 0.786, with the average of 0.695. The average Shannon Index was 1.528, with the genetic similarity coefficient among 12 materials ranging from 0.13 to 0.60 and the average of 0.26. Based on the UPGMA analysis, P. mume ‘Yudie Longyou and P. mume ‘Xiao Yudie contained similar inheriting basement, about 0.60, and the similarity value between P. mume ‘Meiren and P. mume ‘Huangjin was smallest, about 0.13. The designed 22 EST-SSR primer pairs can amplify bands, with the effective amplificaition rate of 95.6%. Eleven primer pairs demonstrated the polymorphic characteristics, accounting for 47.8% of all the EST-SSR.
2011, 33(5): 109-114.
Abstract:
In order to reduce the dependence of soilless culture of flowers on peat and increase the recycling rate of green waste, we made a research to assess the feasibility of green waste composting replacing the peat as growing media. By using peat and green waste as raw materials, we utilized six kinds of growing media，including peat(Y), carbonized green waste (TY), composting (DZ), peat+carbonized green waste(Y+TY), peat+composting(Y+DZ), peat+carbonized green waste+composting(Y+TY+DZ) to cultivate Calathca rotundifola cv. Fasciata. Through measuring and analyzing ten growth indexes, ie total fresh weight, fresh root weight, fresh leaf weight, total dry weight, dry root weight, dry leaf weight, total crown, branching number, plant height and root length, we could get the results of positive effects of six kinds of growing media on the cultivation of C. rotundifola cv. Fasciata and the rank order was Y+DZY+TYDZYY+TY+DZTY. It can be seen that green waste composting undertaken a certain treatment can replace all or part of the original imported peat to cultivate C. rotundifola cv. Fasciata, and three of the six treatments were better than the original peat. The growth of C. rotundifola cv. Fasciata was promoted after using three kinds of growing media. Thus, the green waste could be treated as an excellent growing media to the soilless culture of C. rotundifola cv. Fasciata.
In order to reduce the dependence of soilless culture of flowers on peat and increase the recycling rate of green waste, we made a research to assess the feasibility of green waste composting replacing the peat as growing media. By using peat and green waste as raw materials, we utilized six kinds of growing media，including peat(Y), carbonized green waste (TY), composting (DZ), peat+carbonized green waste(Y+TY), peat+composting(Y+DZ), peat+carbonized green waste+composting(Y+TY+DZ) to cultivate Calathca rotundifola cv. Fasciata. Through measuring and analyzing ten growth indexes, ie total fresh weight, fresh root weight, fresh leaf weight, total dry weight, dry root weight, dry leaf weight, total crown, branching number, plant height and root length, we could get the results of positive effects of six kinds of growing media on the cultivation of C. rotundifola cv. Fasciata and the rank order was Y+DZY+TYDZYY+TY+DZTY. It can be seen that green waste composting undertaken a certain treatment can replace all or part of the original imported peat to cultivate C. rotundifola cv. Fasciata, and three of the six treatments were better than the original peat. The growth of C. rotundifola cv. Fasciata was promoted after using three kinds of growing media. Thus, the green waste could be treated as an excellent growing media to the soilless culture of C. rotundifola cv. Fasciata.
2011, 33(5): 122-125.
Abstract:
To evaluate the weakest location and detect damage at the earliest possible stage to avoid the future catastrophic failure, in this study, the modal testing was performed on wood beams to generate the first two mode shapes. A novel statistical algorithm was proposed to extract the damage indicator by computing the local modal flexibility before and after damage in timbers. The different damage severities, damage locations and damage counts were simulated by removing mass from intact beams to verify the algorithm. The results show that the proposed statistical algorithm is effective and suitable to the designed damage scenarios. It is reliable to detect and locate the local damages under different severities, locations and counts. The peak values of the damage indicators computed from the first two mode shapes are sensitive to different damage severities and locations and they are also reliable to detect the multiple damages.
To evaluate the weakest location and detect damage at the earliest possible stage to avoid the future catastrophic failure, in this study, the modal testing was performed on wood beams to generate the first two mode shapes. A novel statistical algorithm was proposed to extract the damage indicator by computing the local modal flexibility before and after damage in timbers. The different damage severities, damage locations and damage counts were simulated by removing mass from intact beams to verify the algorithm. The results show that the proposed statistical algorithm is effective and suitable to the designed damage scenarios. It is reliable to detect and locate the local damages under different severities, locations and counts. The peak values of the damage indicators computed from the first two mode shapes are sensitive to different damage severities and locations and they are also reliable to detect the multiple damages.
2011, 33(5): 115-121.
Abstract:
To investigate the response of wood density to climate change, wood density of Picea crassifolia trees at lower tree line in the middle Qilian Mountains, northwestern China was measured using Silviscan-3. Chronologies of annual, earlywood, latewood, maximum and minimum density were established by dendrochronological methods. Relationships of chronologies to monthly mean, maximum, minimum temperatures and monthly precipitation were analyzed. The results indicated that wood density of P.crassifolia trees positively correlated with temperatures and negatively correlated with precipitation. Annual and earlywood density significantly correlated with monthly mean temperatures in June to September, with monthly maximum temperatures in June, July and September, and with monthly minimum temperatures in October in previous year and in July and September in current year. Minimum density significantly correlated with temperature in June to August, with monthly maximum temperatures in June and July, and with monthly minimum temperatures in July. Annul density significantly correlated with precipitation in March. Earlywood and minimum density significantly correlated with precipitation in June. Latewood and maximum density did not show significant relationships with temperature and precipitation, latewood density was less sensitive to climate than earlywood density. Those results indicate that temperature has directly influence and precipitation has indirectly impact on wood density, temperature in summer is main climate factor influencing wood density of P.crassifolia in Qilian Mountains, northwestern China.
To investigate the response of wood density to climate change, wood density of Picea crassifolia trees at lower tree line in the middle Qilian Mountains, northwestern China was measured using Silviscan-3. Chronologies of annual, earlywood, latewood, maximum and minimum density were established by dendrochronological methods. Relationships of chronologies to monthly mean, maximum, minimum temperatures and monthly precipitation were analyzed. The results indicated that wood density of P.crassifolia trees positively correlated with temperatures and negatively correlated with precipitation. Annual and earlywood density significantly correlated with monthly mean temperatures in June to September, with monthly maximum temperatures in June, July and September, and with monthly minimum temperatures in October in previous year and in July and September in current year. Minimum density significantly correlated with temperature in June to August, with monthly maximum temperatures in June and July, and with monthly minimum temperatures in July. Annul density significantly correlated with precipitation in March. Earlywood and minimum density significantly correlated with precipitation in June. Latewood and maximum density did not show significant relationships with temperature and precipitation, latewood density was less sensitive to climate than earlywood density. Those results indicate that temperature has directly influence and precipitation has indirectly impact on wood density, temperature in summer is main climate factor influencing wood density of P.crassifolia in Qilian Mountains, northwestern China.
2011, 33(5): 126-129.
Abstract:
During maintenance of ancient wood architectures, it is critical to non-destructively and effectively determine the residual mechanical properties of key wood structural members, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials used in this study were larch (Larix principis-rupprechtii) timber samples taken from the drum-tower of Zhengjue Temple of Yuanmingyuan (Old Summer Palace) in Beijing. The timber samples were cut into standard specimens first, and then stress wave measurements, micro-drilling tests and density tests were conducted. Product of resitograph and stress wave speed squared is defined as modulus of stress-resistograph in this study. We conducted static bending and compression parallel to grain tests on the standard specimens to determine the modulus of elasticity, bending strength and compression strength. Our analysis indicated that the modulus of stress-resistograph had good linear regression relationships with modulus of elasticity (MOE), modulus of rupture (MOR) as well as compression strength, and the coefficients of determination were 0.505 6, 0.260 9 and 0.477 3 respectively. In order to better evaluate the main residual mechanical properties with parameter of the modulus of stress-resistograph, 95% confidence regression equations are suggested to be used in real situation.
During maintenance of ancient wood architectures, it is critical to non-destructively and effectively determine the residual mechanical properties of key wood structural members, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials used in this study were larch (Larix principis-rupprechtii) timber samples taken from the drum-tower of Zhengjue Temple of Yuanmingyuan (Old Summer Palace) in Beijing. The timber samples were cut into standard specimens first, and then stress wave measurements, micro-drilling tests and density tests were conducted. Product of resitograph and stress wave speed squared is defined as modulus of stress-resistograph in this study. We conducted static bending and compression parallel to grain tests on the standard specimens to determine the modulus of elasticity, bending strength and compression strength. Our analysis indicated that the modulus of stress-resistograph had good linear regression relationships with modulus of elasticity (MOE), modulus of rupture (MOR) as well as compression strength, and the coefficients of determination were 0.505 6, 0.260 9 and 0.477 3 respectively. In order to better evaluate the main residual mechanical properties with parameter of the modulus of stress-resistograph, 95% confidence regression equations are suggested to be used in real situation.
2011, 33(5): 130-135.
Abstract:
In the southern forest region of China, forest products transportation has been authorized, and the document confirmation, transport quantity, time and track need to be consistent with timber scaling checklist. The traditional supervisory measures have some negative influence on forestry production. Transportation Supervisory System was established in the project. The actual timetable of the transport, including starting point, track and finishing point was received by GPS receivers, and a wireless Internet of Things (IOT) was formed by connecting with servers and official mobile phones by GPRS. After the transport track information was received by server and compared with timber scaling checklist, the electronic supervision could be achieved, and the nearest law enforcement vehicle would be sent to track and inspect the transport abnormity. The field test of forestry showed that the average delay of this system was 2.7 s, packet loss rate 1.2%, which met the requirements of track supervision. The application of this system would save law enforcement human resource, reduce law enforcement cost and enhance scientific management.
In the southern forest region of China, forest products transportation has been authorized, and the document confirmation, transport quantity, time and track need to be consistent with timber scaling checklist. The traditional supervisory measures have some negative influence on forestry production. Transportation Supervisory System was established in the project. The actual timetable of the transport, including starting point, track and finishing point was received by GPS receivers, and a wireless Internet of Things (IOT) was formed by connecting with servers and official mobile phones by GPRS. After the transport track information was received by server and compared with timber scaling checklist, the electronic supervision could be achieved, and the nearest law enforcement vehicle would be sent to track and inspect the transport abnormity. The field test of forestry showed that the average delay of this system was 2.7 s, packet loss rate 1.2%, which met the requirements of track supervision. The application of this system would save law enforcement human resource, reduce law enforcement cost and enhance scientific management.
2011, 33(5): 136-143.
Abstract:
The biological characteristic，community composition and structure，ecosystem characteristic，genetic diversity，forest cultivation，disease and pest control and ecotourism assessment of rare and endangered plant Castanopsis kawakamii，were reviewed in this study.With high species diversity and complex community structure，C.kawakamii natural forest in Sanming city of Fujian province was a transitional type between central and southern subtropical evergreen broad-leaved forests.The overmature population，species competition and human disturbance all could affect the dynamic periodic fluctuations of C.kawakamii populations.Therefore，C.kawakamii forest was already in a decline stage，with few individuals in middle age,difficult germination of seeds in field and poor growth of C.kawakamii seedlings.Due to the natural succession trend of C.kawakamii populations by Castanopsis carlesii，Schima superba and Pinus massoniana in C.kawakamii forest edge，it should further strengthen the protection of C.kawakamii seedlings and young trees to promote its population regeneration and maintain the stability of the population age structure.In addition，the carbon pool storage，nutrient pool storage，soil respiration rate，litter fall storage and soil total microorganism biomass of C.kawakamii natural forest were higher than those of the forest plantation.C.kawakamii natural forest had good self-fertility ability，which could effectively maintain the soil fertility.Moreover，the protection of C.kawakamii natural forest resource should be strengthened and promoted to realize its sustainable management.Finally，the advance research direction of C.kawakamii biological conservation was presented.
The biological characteristic，community composition and structure，ecosystem characteristic，genetic diversity，forest cultivation，disease and pest control and ecotourism assessment of rare and endangered plant Castanopsis kawakamii，were reviewed in this study.With high species diversity and complex community structure，C.kawakamii natural forest in Sanming city of Fujian province was a transitional type between central and southern subtropical evergreen broad-leaved forests.The overmature population，species competition and human disturbance all could affect the dynamic periodic fluctuations of C.kawakamii populations.Therefore，C.kawakamii forest was already in a decline stage，with few individuals in middle age,difficult germination of seeds in field and poor growth of C.kawakamii seedlings.Due to the natural succession trend of C.kawakamii populations by Castanopsis carlesii，Schima superba and Pinus massoniana in C.kawakamii forest edge，it should further strengthen the protection of C.kawakamii seedlings and young trees to promote its population regeneration and maintain the stability of the population age structure.In addition，the carbon pool storage，nutrient pool storage，soil respiration rate，litter fall storage and soil total microorganism biomass of C.kawakamii natural forest were higher than those of the forest plantation.C.kawakamii natural forest had good self-fertility ability，which could effectively maintain the soil fertility.Moreover，the protection of C.kawakamii natural forest resource should be strengthened and promoted to realize its sustainable management.Finally，the advance research direction of C.kawakamii biological conservation was presented.
2011, 33(5): 144-150.
Abstract:
According to the data source used, the major methods globally used to estimate forest above-ground biomass were introduced in this paper. The methods can be categorized into forest inventory data based method and remote sensing based method. Based on previous studies conducted in China and abroad, we summarized the characteristics and the deficiencies of these two kinds of methods and then preliminarily explored the synergetic method in estimating forest aboveground biomass using multi-source data. In accordance with the deficiencies of estimation methods, some discussions about the scale, parameterization and validation of the models were given and some work concerning the estimation of forest aboveground biomass in the future was stressed.
According to the data source used, the major methods globally used to estimate forest above-ground biomass were introduced in this paper. The methods can be categorized into forest inventory data based method and remote sensing based method. Based on previous studies conducted in China and abroad, we summarized the characteristics and the deficiencies of these two kinds of methods and then preliminarily explored the synergetic method in estimating forest aboveground biomass using multi-source data. In accordance with the deficiencies of estimation methods, some discussions about the scale, parameterization and validation of the models were given and some work concerning the estimation of forest aboveground biomass in the future was stressed.
Abstract:
The wild populations of yew trees in northeastern China are rarely attacked by insects and diseases. To better understand its defense mechanism behind such phenomenon, potential antifeeding activity of two key secondary metabolic compounds of yew, cephalomannine and taxol, were tested against Lymantria dispar L. larvae in both “selective and “non-selective birch leaf disc bioassays. Our results showed that both cephalomannine and taxol exhibited significant antifeeding effect on L. dispar larvae. The antifeedancy of cephalomannine seemed to increase with its concentration in a dose-responsive fashion in both the “selective and “non-selective tests, reaching 67.46% and 72.37%, respectively, at 2 mg/mL. In contrast, taxol showed a very strong antifeeding effect even at the lowest concentration tested, reaching 87.18% of antifeedancy in “no-selective test at 0.25 mg/mL. In the “selective bioassay, the antifeeding activity of taxol seemed to decrease with the feeding time at 1 mg/mL or lower, but increased with the time at higher concentrations (1 mg/mL),reaching 74.95% after 48 h. In general, taxol showed stronger antifeeding activity against L. dispar larvae than did the cephalomannine. The significant antifeeding activity of the two metabolic compounds of yew, especially taxol, might partially explain why the yew trees are not or rarely attacked by insects.
The wild populations of yew trees in northeastern China are rarely attacked by insects and diseases. To better understand its defense mechanism behind such phenomenon, potential antifeeding activity of two key secondary metabolic compounds of yew, cephalomannine and taxol, were tested against Lymantria dispar L. larvae in both “selective and “non-selective birch leaf disc bioassays. Our results showed that both cephalomannine and taxol exhibited significant antifeeding effect on L. dispar larvae. The antifeedancy of cephalomannine seemed to increase with its concentration in a dose-responsive fashion in both the “selective and “non-selective tests, reaching 67.46% and 72.37%, respectively, at 2 mg/mL. In contrast, taxol showed a very strong antifeeding effect even at the lowest concentration tested, reaching 87.18% of antifeedancy in “no-selective test at 0.25 mg/mL. In the “selective bioassay, the antifeeding activity of taxol seemed to decrease with the feeding time at 1 mg/mL or lower, but increased with the time at higher concentrations (1 mg/mL),reaching 74.95% after 48 h. In general, taxol showed stronger antifeeding activity against L. dispar larvae than did the cephalomannine. The significant antifeeding activity of the two metabolic compounds of yew, especially taxol, might partially explain why the yew trees are not or rarely attacked by insects.
