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RSS2021 Vol. 43, No. 3
Display Method:
Abstract:
Abstract:
ObjectiveStand-level volume, biomass and carbon stock models or tables are necessary quantitative tools for implementing forest management inventory. Developing stand volume, biomass and carbon stock models for ten major forest types in forest region of northeastern China is not only an exploration of methodology, but also provides reference results for practice.
MethodBased on the field measurement data of 2 000 sample plots distributed in 10 forest types in northeastern China, i.e. spruce & fir (
Piceaspp. &
Abiesspp.), larch (
Larixspp.), Mongolian scotch pine (
Pinus
sylvestrisvar.
mongolica), Korean pine (
Pinus koraiensis), oak (
Quercusspp.), birch (
Betulaspp.), poplar (
Populusspp.), elm (
Ulmusspp.), linden (
Tiliaspp.), and other three precious broadleaved species (
Fraxinus mandshurica,
Juglans mandshurica&
Phellodendron amurense), the stand-level volume, biomass and carbon stock models were developed through independent nonlinear regression (INR), simultaneous error-in-variable equations (SEIVE), and SEIVE with dummy variable modeling approach.
ResultThe coefficients of determination (
R
2) of the population-averaged stand-level volume, biomass and carbon stock models based on all sample plots were 0.945, 0.805 and 0.839, respectively; and those of tthe models with type-specific parameters were 0.959, 0.949 and 0.951, respectively. The
R
2values of stand-level volume, biomass and carbon stock models for 10 forest types were all more than 0.86, the mean prediction errors (MPE) were all less than 3%, and the mean percent standard errors (MPSE) were almost less than 10%. For the volume stock models, the
R
2values were between 0.876?.980, MPE were between 0.90%?.95%, and MPSE were between 5.14%?1.89%; for the biomass stock models, the
R
2values were between 0.864?.988, MPE were between 0.66%?.07%, and MPSE were between 3.61%?1.60%; and for carbon stock models, the
R
2values were between 0.866?.988, MPE were between 0.67%?.96%, and MPSE were between 3.65%?1.57%.
ConclusionThe volume stock per hectare of different forest types mainly depends upon basal area and mean tree height of forest stands, and the biomass stock mainly relates to volume stock and mean tree height. The SEIVE with dummy variable modeling approach is a feasible method for developing stand-level stock models. The developed volume, biomass and carbon stock models for 10 major forest types in northeastern China in this study meet the need of precision requirements to the regulation on forest management inventory, indicating that the models can be applied in practice.
2021, 43(3): 9-17.
doi:10.12171/j.1000-1522.20200075
Abstract:
ObjectiveQuantile regression and quantile groups were used in this article to model and predict height to crown base, which provided new ideas and methods for the construction of height to crown base models.
MethodThe data were collected from the measured data of natural forests of
Larix gmeliniiin 4 forest farms of Xinlin in Daxing anling of northeastern China. Nonlinear regression was used to build the basic and generalized models of the height to crown base and then extended to quantile regression. Four types of sampling designs (the largest DBH tree sampling, the smallest DBH tree sampling, the mean DBH tree sampling and random sampling) and three quantile group (
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0.1, 0.5, 0.9), five quantile group (
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0.1, 0.3, 0.5, 0.7, 0.9), nine quantile group (
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0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9) were used to predict height to crown base. The prediction effects of different quantile groups were compared as well as the impact of different sampling designs. Two-fold evaluation was used to compare the prediction effects of nonlinear regression, optimal quantile regression and optimal quantile group. Model evaluation criteria included mean absolute error (MAE), root mean square error (RMSE), mean percentage of error (MPE) and adjustment determination coefficient (
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).
Result(1)Whether it is nonlinear regression or quantile regression, the fitting MAE of generalized models can be reduced by 6% to 12%, RMSE can be reduced by 6% to 10% compared with basic models. And the validation effects of generalized models were also better than basic models. There was a negative correlation between height to crown base and DBH, and a positive correlation between height to crown base and
H
DOMand BA. (2) Median regression had the best fitting ability among all quantiles, and the effects of median regression were similar to that of nonlinear regression. Quantile regression can describe the distribution of height to crown base. (3) All three quantile groups can predict height to crown base and the effect was not much different. The three quantile group was sufficient to predict height to crown base. The results of two-fold evaluation for median regression were similar to that of nonlinear regression, while three quantile group’s prediction ability was the best. Compared with nonlinear regression and median regression, the MAE and MPE of three quantile group decreased about 20% and 4% respectively,
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increased about 16%. (4) The optimal sampling designs for basic and generalized quantile groups were five mean DBH trees and seven largest trees, respectively.
ConclusionThe height to crown base models based on three quantile group (
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0.1, 0.5, 0.9) in this study can improve the prediction accuracy. The optimal sampling design of the basic and generalized quantile groups is 5 mean DBH tree sampling and 7 largest DBH tree sampling, respectively. Considering the accuracy of prediction and the cost of investigation, it is recommended to select 5 medium trees from the sample plot to predict the height to crown base when quantile groups are applied in practice.
Abstract:
ObjectiveOn the basis of pipe model and the theory of water transportation pattern through tree rings, we investigated the canopy productivity structure of
Larix olgensisand leaf biomass models for four larch subspecies to provide a theoretical and technological background for evaluating canopy productivity and studying the pattern of water transportation through tree rings.
MethodWe analyzed the canopy productivity structure and fitted leaf biomass models with the data collected from canopy analysis, biomass sampling and dye tracer experiment in tree trunks, as well as comparing the selected predictors and the estimation accuracy of the models for varied larch subspecies at different ages.
Result(1) The sectional area of current-year ring of 11-year-old
Larix olgensisat breast height accounted for 19.64% of the total sectional area capable of conducting water but provided the water transportation for 29.8% of the total canopy leaf area, indicating that the water transportation rate of current-year ring was faster than others. (2) Based on pipe model and the theory of water transportation pattern through tree rings, both leaf area and leaf biomass were affected to a certain degree by the water transportation capacity and branch mechanical support capacity, which were represented by two types of predictor variables relating to branch mass and water transportation capacity, respectively. (3) The biomass models with two types of predictor variabels for the four
Larixsubspecies had high estimation accuracy. (4) In order to facilitate the application, models with two predictors were fitted, and predicted values given by these reduced models were highly correlated to leaf biomass observations for the four
Larixsubspeices. (5) We fitted an ANCOVA model of leaf biomass on sectional area of branch at base, with the four
Larixsubspeices incorporated. Statistical tests for testing homogeneous intercept and slope showed that the slope and intercept for
Larix gmeliniiwere significantly different from those for other three subspecies, and so was
Larix principisfrom
Larix leptolepis.In comparison, the difference between
Larix principisand
Larix olgensiswas not significant. The results reflectd the differences in the canopy shape of the four larch subspecies.
ConclusionThe pipe model and theory of water trasportation pattern have a wide application prospect in studying tree productivity structure and productivity evaluation. According to this, explanatory variables for leaf biomass can be divided into two categories, related to branch mass and water trasportation capability, respectively. The fitted standard model and reduced models of leaf biomass could produce accurate estimates for the four
Larixsubspecies.
2021, 43(3): 27-35.
doi:10.12171/j.1000-1522.20200377
Abstract:
ObjectiveChalcone synthase (CHS) is one of the rate-limiting enzymes of phenylpropanoid pathway which plays superior roles in the production of secondary metabolites. In this study, by cloning and bioinformatics analysis of
CHSgene and analyzing the relationship between
CHSgene expression and flavonoid synthesis of
Koelreuteria paniculata, we hope to provide reference for further study of flavonoid biosynthesis pathway related genes, evolution of
CHSgene family and coloration mechanism of
Koelreuteria paniculata‘Jinye?
Method
CHSgenes were isolated and characterized by RT-PCR from
Koelreuteria paniculata. And the expression patterns of
CHSgene in different tissues of
Koelreuteria paniculataand in the leaves of
Koelreuteria paniculataand
Koelreuteria paniculata‘Jinye‘italic/> in May, July and September were analyzed by qRT-PCR; the differential flavonoid metabolism between
Koelreuteria
paniculataand
Koelreuteria paniculata‘Jinye‘i>was screeidues ether.
ResultTwo full-length DNA of CHS genes were cloned named
KpCHS1 and
KpCHS2 . The
KpCHS1 gene sequence was found to be 2 492 bp and comprised an open reading frame of 1 173 bp, encoding for 390 amino acid residues, the
KpCHS2 gene sequence was found to be 1 321 bp and comprised an open reading frame of 1 182 bp, encoding for 393 amino acid residues ether. Alignment of the predicted amino acid sequence of KpCHS2 had been shown to have high sequence similarity with KpCHS1, with four CHS specific conserved motifs and one chalcone synthase active site. Furthermore,
KpCHS1 and
KpCHS2 were generally expressed in roots, stems, leaves and seeds of
Koelreuteria paniculata. Among them, the expression of
KpCHS2 was the highest in seeds, while that of
KpCHS1 was higher in leaves. In roots and stems, the expression levels of the two genes were similar and lower. The expression pattern analysis showed that in
Koelreuteria
paniculataand
Koelreuteria paniculata‗/b>
Jinye‘italic/>, the expression ofKpCHS1 decreased with the increase of months, while the expression ofKpCHS2 did not show obvious regularity. In the July plant samples, the expression ofKpCHS1 gene inKoelreuteria paniculata‘Jinye‘italic/> was higher than that inKoelreuteriapaniculata. Besides, we analyzed the metabonomics ofKoelreuteria paniculataandKoelreuteria paniculata‘Jinye leaves in July, and screened out the different flavonoids. It was found that kaempferol-7-o-glucoside, 7-hydroxycoumarin, quercetin-3β-D-glucoside, and kaempferol, naringin, which were important intermediate products in flavonoid biosynthesis, were significantly increased inKoelreuteriapaniculata‘Jinye‘i>leaves.
ConclusionKpCHS1 and KpCHS2 belong to the chalcone synthase family of
Koelreuteria paniculataand are highly homologous, but they are distributed in far branches of the phylogenetic tree. It is speculated that the two proteins may have great differences in the catalytic function of amino acid activity.
KpCHS1 and
KpCHS2 are expressed in roots, stems, leaves and seeds, and higher in leaves and seeds of
Koelreuteria paniculata. Our results indicate that the expression of
KpCHS1 gene is highly related to the synthesis of flavonoids in
Koelreuteria paniculata.
2021, 43(3): 36-43.
doi:10.12171/j.1000-1522.20200235
Abstract:
ObjectiveLong non-coding RNA (lncRNA) is a class of transcripts, which are larger than 200 nt in length and have extremely low protein-coding ability or without protein-coding ability. LncRNA is one of the key regulators of plant stress response. In this study, we studied the salt-tolerant physiological indexes under the salt stress of transiently overexpressing lncRNA of
Tamarix hispida, and analyzed whether it had the ability to improve the salt tolerance and enrich the molecular mechanism of woody plant lncRNA in response to stress. It laid a foundation for the molecular regulation mechanism of lncRNA
MethodIn this study, a differential expression lncRNA-224223.1 was selected and named
ThSAIR6 from transcriptomes of
T. hispidaunder salt stress. The quantitative real-time PCR (qRT-PCR) was used to analyze the expression pattern of
ThSAIR6 in leaf tissues of wild type
T. hispidaunder salt stress. It could initially identify whether it responded to salt stress or not. Overexpression vectors (pROKII-ThSAIR6) were constructed in order to further study the stress tolerance. Overexpression (OE) and control
T. hispidaplants were obtained by agrobacterium-mediated high-efficient transient transformation system. Physiologic indexes related to salt tolerance of OE and control
T. hispidaplants under salt stress were measured in order to judge whether it could improve the salt tolerance of
T. hispidaplants.
ResultThe results of qRT-PCR showed that the expression quantity of
ThSAIR6 in wild type plants significantly increased after salt stress for 24 h (
P< 0.05), indicating that it could response to salt stress. The results showed that overexpression of
ThSAIR6 in
T. hispidaplants significantly decreased the contents of H
2O
2and
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(
P< 0.05), enhanced the POD and SOD activities (
P< 0.05), and lowered the amount of dead cells, the electrolyte leakage and water loss rate of
T. hispidatissues at the same time.
ConclusionIn conclusion, lncRNA
ThSAIR6 of
T. hispidacan response to salt stress. Overexpression of
ThSAIR6 in plants significantly decreases the contents of H
2O
2and
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, enhances the POD and SOD activities, improves ROS scavenging, and reduces cell damage of plant tissues under salt stress, thus effectively improves its salt tolerance.
2021, 43(3): 44-54.
doi:10.12171/j.1000-1522.20200293
Abstract:
ObjectiveDue to the water scarcity and the improvement in urban greening, the tension has grown from the struggles for water between industries, urban life, and urban afforestation in Beijing. Thus, it is the top priority to explore the response mechanism of urban greening tree species to arid habitats and to screen the low-water consumption and high-water utilization landscaping tree species for high-quality urban forest landscape.
MethodTypical greening tree species including
Ginkgo biloba,
Koelreuteria paniculata,
Sophora japonica,
Platycladus orientalis,
Pinus tabuliformis, and
Pinus bungeanain Beijing were selected and subjected to three groups of soil water stresses such as slight drought (SLD, 50%?0% field capacity (FC)), moderate drought (MD, 30%?0% FC) and extreme drought (ED, lower than 30% FC). The interspecific differences in the instantaneous water use efficiency (WUE
i) and mean water use efficiency (WUE
L) of these tree species under water stresses and their relationship to eco-physiological factors were investigated based on the stable isotope technology and the observations on tree physiological traits.
ResultThe photosynthetic capacities and WUE
iin
G. biloba,
K. paniculata,
S. japonicaand
P. orientalisdecreased significantly compared with control (CK, 90%?00% FC) when potted soil volumetric water content (SWC) was less than 70% (
P< 0.05), whereas there was no significant difference in WUE
iof
P. tabuliformisand
P. bungeanasubjected to continuous drought (
P> 0.05). The WUE
Ls of evergreen tree species were significantly higher than those of deciduous tree species under MD and ED (
P< 0.05). The WUE
Ls of three deciduous tree species differed in response to extreme drought (
P< 0.05), and the sequence of WUE
Ls in three deciduous tree species was
S. japonica>
K. paniculata>
G. biloba. The WUE
Ls of
G. bilobaand
K. paniculatain SLD, and
P. orientalisand
P. tabuliformisin MD reached their respective peaks and then decreased along with the increases in soil water stress; while those of
S. japonicaand
P. bungeanaincreased with potted soil drying, and were 44.19% and 30.35% higher than control, respectively at severe drought condition (
P< 0.05). Comparing the correlations between photosynthetic parameters, WUE
iand WUE
Lof different tree species, it was found that the stomatal conductance (
g
s) of
G. biloba,
K. paniculataand
S. japonicasignificantly affected its photosynthesis and transpiration processes (
P< 0.01) and hence exerted a strong influence on WUE
i, while those in evergreen tree species such as
P. orientalis,
P. tabuliformis, and
P. bungeanawere insensitive to the variation in soil moisture and had little impact on WUE
i(
P> 0.05). The WUE
Lof evergreen tree species was higher than that of deciduous ones under moderate and extreme water stress.
ConclusionTherefore, considering the limited water resources of Beijing, evergreen tree species have stronger abilities to conserve water content and optimize photosynthetic performance to improve their water use efficiency, to adapt to arid habitats than those of deciduous trees in Beijing.
Abstract:
ObjectiveIn order to study the effects of understory vegetation and litter on soil CO
2flux in cold temperate natural forests in China, we analyzed and explored the characteristics of CO
2flux emission under different treatments, to provide reference for the management of forest ecosystem and the study of soil greenhouse gases in Daxing’an Mountains region and theoretical reference.
MethodIn the period from May to September in 2019, the method of static box-gas chromatography was used to study soil CO
2flux emission characteristics in four main forest types (
Betula platyphyllaforest,
Populus davidianaforest,
Pinus sylvestrisvar.
mongolicaforest and
Larix gmeliniiforest) in the north of Daxing’an Mountains.
ResultThe soil CO
2flux of the four forest types under different treatments all showed a single-peak curve changing trend, and the peak appeared in July or August. The removal of litter increased the soil respiration of broadleaved forests and decreased the soil respiration of coniferous forests. However, the changes did not reach a significant level (
P> 0.05). Compared with the natural state, the removal of understory vegetation significantly (
P< 0.05) increased the average CO
2flux of
Betula platyphyllaforest,
Populus davidianaforest and
Larix gmeliniiforest by 27.57%, 15.84% and 24.13%, respectively, but decreased it in
Pinus sylvestrisvar.
mongolicaforest by 0.68% (
P> 0.05). With the simultaneous removal of understory vegetation and litter, the average CO
2fluxes of
Betula platyphyllaforest,
Populus davidianaforest and
Larix gmeliniiforest increased by 20.05%?5.34%, but the
Pinus sylvestrisvar
. mongolicaforest decreased by 12.36%. The average flux of broadleaved forest was significantly larger than that of coniferous forest (
P< 0.05) when the understory vegetation and litter were both removed.
ConclusionThe existence or non-existence of litter and understory vegetation would have different effects on soil CO
2flux. Also, the impact on different forest types also varies. Scientific and reasonable understory management strategy plays a key role in regulating carbon dioxide emissions and the protection of ecological environment.
Abstract:
ObjectiveThe combustion of underground fire is a slow, flameless, long duration smoldering, which does great harm to forest. Daxing’anling region is a frequent area of forest underground fire in northeastern China. This paper aims to study the effects of different heating times and humus particle sizes on the vertical combustion of underground fires, aiming to provide a reference for the prevention, monitoring and suppression of underground fires in the area.
MethodTaking the typical forest type in the Daxing’an Mountains, i.e.
Larix gmeliniiforest as the research object, according to the indoor control simulation of scorching experiment data, SPSS was used to perform two-factor analysis of variance, and the Origin software was used to draw. The effects of three heating times and five humus particle sizes on the spreading speed and the highest temperature at different depths during the vertical combustion of underground fire were studied.
ResultDuring the vertical burning process of the forest underground fire, the temperature of the highest burning at a depth of 3 cm was only affected by the heating time and the difference was significant (
P< 0.05), but the effects of humus particle size on the difference were not significant (
P> 0.05). The highest temperature of combustion at a depth of 6 cm was affected by the heating time (
P< 0.05) and the particle size of humus (
P< 0.05). When the depth was greater than 6 cm, the maximum combustion temperature was only affected by the humus particle size and the difference was significant (
P< 0.05). The spread rate during the vertical combustion of forest underground fires was only affected by the humus particle size. There were significant differences between the spreading speeds (
P< 0.05).
ConclusionThe highest temperature of underground forest fires burning at 3 cm and 6 cm depth rises with the increase of heating time, and the burning temperature is the highest when heated for 2 h. When the vertical combustion depth is 9?1 cm, the humus particle size is 40 mesh, the burning temperature is the highest. Among the effects of humus particle size on the spread speed of forest underground fires, the spread speed of humus particle size 20 mesh is the fastest; when the humus particle size is 60 mesh, it is the criticality in the process of underground fire combustion. The highest combustion temperature and spread speed are lower.
2021, 43(3): 73-84.
doi:10.12171/j.1000-1522.20200065
Abstract:
ObjectiveLitter layer is an important component of forest ecosystem, and it is of unique and key significance to study the spatial distribution characteristics of nutrients for maintaining forest ecological environment and sustainable management.
MethodTo investigate the spatial heterogeneity of litter nutrients at different decomposition stages, we established four 1 ha permanent sample plots in temperate spruce-fir mixed forests. Litter collection and stand survey were conducted using an equidistant grid point sampling method. Litter samples in semi-decomposed (F) horizon and completely decomposed (H) horizon were determined to analyze the spatial variations of litter nutrient concentrations using statistical analysis and kriging interpolation.
Result(1) In the F horizon, concentrations of litter organic carbon (OC), total nitrogen (TN) and total phosphorus (TP) were 421.68, 18.86 and 1.26 g/kg, respectively, and they were 350.78, 17.80 and 2.68 g/kg in the H horizon. Litter OC and TN decreased but TP increased with the increase of decomposition degree. The coefficients of variation of litter OC, TN and TP in the F and H horizons varied in the four sample plots with a range of 10.94%?5.63%. The spatial variation degrees of litter OC and TP in the F horizon were smaller than those in the H horizon. (2) Litter OC, TN and TP concentrations showed higher spatial autocorrelation, primarily resulting from the structure factors at the forest community scale. Litter nutrient concentrations in the four sample plots showed a strip and patch gradient distribution. Litter OC in the F horizon had similar spatial distribution pattern to the H horizon. However, the high-value centres of TN and TP in the F horizon were generally lower in the H horizon. The fractal dimension of litter OC and TP concentrations in the F horizon was higher than that in the H horizon. This indicated that the F horizon exhibited a more complex spatial pattern, whereas litter TN had a better structure and stronger spatial dependence in the F horizon than that in the H horizon. (3) Litter OC and TN in the H horizon had a significant negative correlation (
P< 0.05) with the standing crop of litter but the TP concentration with an opposite relationship. Litter OC and TN in the H horizon were significantly affected by water holding capacity. In addition, litter OC, TN, TP and their stoichiometric ratios were significantly correlated. Litter TN and TP in the F horizon were significantly affected by biodiversity indices and species number, while those in the H horizon were mainly affected by the proportion of conifer species and stems. However, litter TN and TP were more strongly related with stand characteristics in comparison with OC.
ConclusionThe spatial distribution characteristics of nutrients in litter layer over temperate natural spruce-fir mixed forest are affected by litter properties (e.g
.the degree of decomposition and water holding capacity.) and stand structure (e.g
.tree species and stand density.).
Abstract:
ObjectiveIn order to provide the basis for the optimal allocation of vegetation patterns for soil and water conservation in the Loess Plateau and other water resource deficient areas, the effects of different vegetation patterns and fragmentation on runoff and sediment yield were studied.
MethodTo explore the impacts of different vegetation patterns on runoff, sediment, and infiltration in this research, we measured the characteristics of runoff, sediment, and soil infiltration of five vegetation patterns (block-shaped mosaic pattern plots SP1, SP2, horizontal strip pattern plot BP, slope band pattern plot LP, and bare land pattern plot CK, respectively) by field simulated rainfall tests.
Result(1) In general, vegetation had relatively good capacity in sediment reduction and water storage. The sediment reduction efficiency reached 47.44%?1.67%, and the water storage efficiency reached 25.67%?2.94%. Therefore, the sediment reduction capacity of vegetation was stronger than the water storage capacity. (2) The vegetation patterns had statistically significant effects on the runoff and sediment yield on the slope (
P< 0.05). The order of the highest to lowest storage and sediment reduction effects of vegetation patterns were block-shaped mosaic pattern, horizontal strip pattern, followed by the slope band pattern. Thus, the block-shaped mosaic pattern had the best soil and water conservation effect. (3) The process for the runoff occurrence of different vegetation patterns showed a trend of “a rapid-rise phase followed by a relative stable phase? The vegetation patterns helped to delay the occurrence of the runoff peaks. (4) The fragmentation index of vegetation patches was inversely proportional to the erosion and sediment production. The higher the degree of fragmentation of vegetation patches was, the lower the sediment yield and the better the efficiency of water storage and sediment reduction were. (5) The infiltration coefficient of different vegetation patterns was in the following order: the block-shaped mosaic pattern > horizontal strip pattern > slope band pattern > bare land pattern. Further, the Horton model exhibited a good fitting behavior on soil infiltration of different vegetation patterns.
ConclusionThrough the above research, it is found that vegetation and bare land mosaic pattern are significantly better than that of bare land and long strip slope pattern in water storage and sediment reduction. Therefore, in the loess area with limited water resources, vegetation can be planted in the way of alternate distribution of vegetation and bare land to maximize the benefits of water storage and sediment reduction.
Abstract:
ObjectiveThe study on the coupling and coordination relationship between ecological environment and industrial development can help planners obtain the coordinated development trend of Beijing-Tianjin-Hebei region, northern China from an ecological perspective, and provide scientific basis for planning and management.
MethodBased on the MSPA and InVEST models, this study firstly explored the changes of ecological infrastructure, habitat quality and economic development in the Beijing-Tianjin-Hebei region from 2000 to 2017, and then applied the coupling coordination model to comprehensively analyze the coupling coordination of the above three in the region. Finally, the coupling coordination degree of different regions in Beijing-Tianjin-Hebei region in the next five years was predicted by the gray prediction model.
Result(1) The overall ecological infrastructure in the Beijing-Tianjin-Hebei region was in the low level, and the landscape connectivity was poor. The spatial variation of the habitat quality was significant, with an average habitat quality of 0.450, which was not high. (2) The development of agriculture, forestry, animal husbandry and fishery in the northwestern ecological conservation area was stable, while the secondary industry in Tianjin-Hebei region was in a dominant position. As for the transportation, warehousing and postal industries in the eastern coastal development area and the financial industry in Beijing-Tianjin region, they were well developed. (3) The coupling coordination degree in Beijing-Tianjin-Hebei region was ranked from a mild disorder state to a primary coordination state, the regional variations of the coupling coordination levels were significant. Among them, the southern functional expansion area had the highest coupling coordination degree, while it was lowest in the northwestern ecological conservation area. (4) In the next 5 years, the coupling coordination degree in the Beijing-Tianjin-Hebei region will be improved, but the central core functional area will remain on the verge of imbalance, Beijing and the eastern coastal development area will remain in a barely coordinated state, which are key areas need to be optimized in the future. The coupling coordination degree in Tianjin will change from barely coordination to primary coordination, and the northwestern ecological conservation area will change from being on the verge of imbalance to primary coordination, which are the potential areas for coordinated development. The coupling coordination degree of the southern functional expansion area will be transformed into middle-level coordination, which is the fastest development area.
ConclusionThis study evaluated the coupling and coordination of the ecological infrastructure-habitat quality-industrial development in Beijing-Tianjin-Hebei region, and predicted the critical areas with the potential for synergistic development. All of the conclusion can provide a basis for the future coordinated development of Beijing-Tianjin-Hebei region and offer an important reference for ecological construction and industrial development evaluation within other urban agglomerations.
Abstract:
ObjectiveThe quantitative evaluation of the value of green space ecosystem services in urban areas is an important work basis for land space planning. The prediction of its evolution based on the value measurement is more helpful for the planners to understand and measure the existing ecological stock, future development trend and potential problems within the urban area, so as to plan and respond in advance.
MethodIn order to clarify the impact of evolution of land space utilization on the service value of regional ecosystem in Chengde City, Hebei Province of northern China, this paper combines RS and GIS technology to analyze the evolution characteristics of land use/land cover change (LUCC) space utilization in Chengde City. At the same time, the value equivalent factor per unit area was used to calculate the value of ecosystem services in Chengde City. On this basis, MARKOV model was used in this paper to predict the evolution trend of land use in Chengde City in 2026 and the changes of ecological space stock and ecosystem service value.
ResultThe overall ecosystem service value of Chengde City showed an obvious downward trend. From 1995 to 2015 (totally 5 periods, i.e. 1995, 2000, 2005, 2010, 2015), the total values of ecosystem services in Chengde City were 103.851 billion CNY, 103.593 billion CNY, 103.609 billion CNY, 100.971 billion CNY and 99.936 billion CNY, respectively. At the same time, the evolution simulation results showed that the overall service value of Chengde City will still be in a downward trend in 2026, with a value decline of about 997 million CNY.
ConclusionThe spatial dimension of ecosystem service value in Chengde City presents an obvious patch distribution. The core service value is concentrated in the northwestern and southern forest land area, and the time dimension has a significant function reduction. The core reduction area is concentrated in the edge areas of the built-up areas in cities and counties. This study summarized the evolution of ecological service value and spatial change rule of Chengde City from spatial distribution, time evolution and development prediction, so as to provide basis for the development planning and control strategy of the subsequent land space of Chengde City.
2021, 43(3): 117-130.
doi:10.12171/j.1000-1522.20190472
Abstract:
ObjectiveBased on the study of granite and dolomite mountain in Beijing, this study explored the differences of plant communities under different bedrock conditions, and provided scientific basis for vegetation restoration of granite and dolomite mountain in Beijing.
MethodThree granite and dolomite mountains were selected in the experiment. Through the sample survey, the plant community characteristics of two different kinds of bedrock were analyzed from the aspects of species composition, biodiversity, altitude gradient characteristics, similarity coefficient, etc.
ResultThe results showed that: (1) there were 188 kinds of vegetation in granite mountain, belonging to 148 genera of 61 families; 95 kinds of vegetation in dolomite mountain, belonging to 80 genera of 38 families; all of them were dominated by Compistae, Fabaceae and Gramineae, which were the important resources of plant restoration and planting in two kinds of bedrock mountain. (2) By measuring different life styles, the dominant species of tree layer, shrub layer and herb layer between two kinds of bedrock mountain vegetation in Beijing can be used as important materials for mountain restoration. (3) Compared with the characteristics of plant community in granite mountain, it was found that there was no consistency between them; compared with the characteristics of plant community in dolomite mountain, it was found that there was a high consistency.
ConclusionThe plant community species of different granite and dolomite mountain are consistent in dominant families and genera, which are important plant resources for ecological restoration of granite and dolomite mountain. By comparing the similarity between different mountains, we can not generalize the phytoremediation of granite mountain. We should pay attention to distinguish different site conditions. For the dolomite mountain, we can use similar methods and plant species to repair.
2021, 43(3): 131-137.
doi:10.12171/j.1000-1522.20210010
Abstract:
ObjectiveWood preservative treatment is an effective way to prolong the lifespan of wood, reduce deforestation and further improve the ecological environment. In this study, in order to provide a basis for the development of eco-friendly wood preservatives and enrich the wood preservative system, the decay performance of a series of methoxyacrylate fungicides, iodopropynyl butyl carbamate (IPBC) and 4, 5-dichloro-N-octyl-4-isothiazolin-3-one (DCOIT) has been systematically screened.
MethodIn order to discover novel agents with high-activity to control wood rot fungus, the inhibition zone method was used to test the antifungal activity of 5 candidate agents (azoxystrobin, kresoxim-methyl, pyraclostrobin, IPBC and DCOIT) against wood rot fungus. Then the high-activity agents were prepared into water-based formulations, and the method for lab sand block test was used to evaluate interior decay resistance of treated materials at different levels of drug retention.
ResultThe inhibition zone results indicated that azoxystrobin, pyraclostrobin, DCOIT and IPBC showed good inhibitory effects on brown rot fungi and white rot fungi. Especially, pyraclostrobin and IPBC exhibited high antibacterial effects, which were higher than the control agent propiconazole. For the preservative treated radiata pine material under the chemical retention of about 0.21?.46 kg/m
3, the mass loss rates of treatment material by azoxystrobin and pyraclostrobin for white rot fungi and brown rot fungi were 3.1%?.9% and 3.5%?.8%, respectively. Moreover, the mass loss rate of IPBC treatment radiata pine material was 0.9%?.6% under the chemical retention of about 0.2 kg/m
3. The lab sand block test of the preservative treated
Populus tomentosaresults showed that the decay resistance of all the treated samples at different chemical retention levels was much better than that of the untreated samples. However, their mass loss rate was still large. It is not recommended to use this kind of fungicides for the preservative treatment of
Populus tomentosa.
ConclusionIn this study, the antifungal activity of pyraclostrobin and azoxystrobin formulations is equivalent to the control agent propiconazole, and antifungal effect of IPBC is better than propiconazole. So they could be further developed and utilized as a novel wood preservative.
2021, 43(3): 138-144.
doi:10.12171/j.1000-1522.20210024
Abstract:
ObjectiveThe objective of this study is to investigate the effects of brown-rot decay on color, microstructure, and chemical components of wood at the early stage of decay test, as well as provide a theoretical basis for the further explanation of wood degradation mechanism.
MethodThe sapwood of southern pine was decayed by
Gloeophyllum trabeumfor different durations. The microstructure of decayed wood was characterized by field emission scanning electron microscopy (FE-SEM), in order to elucidate the access pathways of brown-rot fungi into wood. Meanwhile, colorimetry, Fourier transform infrared spectroscopy and X-ray diffraction were used to characterize the mass loss, color change, chemical component, functional group change, and crystallinity change of wood after different decay stages.
ResultThe lightness of wood decreased and the total color difference increased during the decay test, with a trend toward rufous surface color. Mycelium entered into the wood through cell structures such as ray parenchyma cells, pits and tracheids, and basically completed the initial colonization after 20 d. The mass loss of wood at the early stage of brown-rot decay was mainly caused by the degradation of hemicellulose, while the degradation of cellulose was less pronounced. At the same time, the distance between crystal planes of cellulose decreased to the minimum value (3.962 Å) while the relative crystallinity increased significantly (47.02%), which prohibited the degradation of cellulose. Therefore, the mass loss rate of wood slowed down after that.
ConclusionAt the early stage of brown-rot decay on southern pine wood, hyphae entered into wood by pits, ray parenchyma cells and tracheids. Hemicellulose in cell wall was preferentially degraded and the lattice distance of crystalline cellulose reduced while the relative crystallinity increased. This research could provide a theoretical basis for the further exploration of brown-rot degradation mechanism of wood, as well as wood preservation.
2021, 43(3): 145-154.
doi:10.12171/j.1000-1522.20200104
Abstract:
ObjectiveThe determination of dimensions of mortise and tenon joint is the premise of editing NC(numerical control) codes of mortise and tenon joint. It is also the foundation of realizing CNC (computer numerical control) machining of mortise and tenon joint. But the existing method of determining the dimensions of mortise and tenon joint by modifying the geometric models repeatedly is low efficiency and high difficulty, which has seriously affected the development of digital machining of mortise and tenon joint. Therefore, it is necessary to design an intelligent method of determining dimension of mortise and tenon joint.
MethodThis paper takes a modified lattice shoulder tenon as example. In the first, the mathematical models of lattices shoulder tenon were established and the dimension parameters of latticed shoulder tenon were extracted by parametric design ideas. Secondly, the correlation functions between dimension parameters of lattice tenon were established based on assembly constraints, which included two perspectives: position relation and match relation. Then, the correlation functions between dimension parameters and process constraints were established, and value ranges and preset values of part dimensions were settled based on process constraints, which included three aspects: NC machining technology, market research and process knowledge. Finally, taking the end dimensions of parts as the input parameters, integrating with associated functions, value ranges, and preset values, the relevant parameter function table was established.
ResultBy establishing the mathematical model of mortise and tenon joint, the dimension parameters of mortise and tenon joint were extracted. According to the assembly and process constraints of mortise and tenon joint, the correlation functions between dimension parameters were established successfully, and the value ranges and the default values were obtained. By founding the correlation function table of dimension parameters, the system can automatically output other dimension parameters by just inputting the cross-section dimensions of the mortise and tenon parts.
ConclusionThe intelligent method of determining dimension of mortise and tenon joint was established on the combination of assembly and process constraints, that was also the scientific arrangement and reuse of process knowledge. This method can not only help to realize the intelligent determination of dimension, but also provide basic condition for intelligent manufacturing of mortise and tenon joints, even solid wood furniture processing.
