The correlations between tree community’s structure and elevation include tree community traits  , tree community structure  , tree community growth  , tropical tree community growth  , tree community  , tree community’s leaf structure  , and community canopy structure  in the environmental (size-dependent changes  , latitudinal  , climate warming  , elevation  , climate variations  , ecological environment   ) dynamics along elevation in the forestry ecosystems. However, there is the correlation between crown volume of (Sophora japonica) tree communities and elevation along elevation gradient in Ye County.
Unfortunately, the concept of different tree community’s structure is used as a framework for investigating the linkages between (Sophora japonica) communities and elevation habitats in Ye County  . Moreover, more and more experiments or models have assessed the relationship between plant communities and elevation along elevation or environment or disturbance gradient  -  . For instance, Liao, et al. (2011; 2014) found that importance values of woody species’s structure were significantly correlated with elevation along elevation gradient on the northern and southern slope of the Fu-Niu Mountain   . Liao, et al. (2011) proposed that plant species biomass were significantly correlated with elevation gradient in the typical wetland area of Yi-Luo River watershed  . Liao, et al. (2014) suggested that biodiversity were significantly negatively correlated with disturbance gradient  . Meanwhile, Sophora japonica is an important international pharmaceutical material in Ye County in 2018.
2. The Physical Geographic Conditions
Ye County was an important county in Pingdingshan Region. The urbanization of ecosystem is results of the historical natural and anthropogenic activities in Ye County. It is regional urbanization mostly in the height of more than 600 m (Figures 1-4; Table 1 and Table 2). Three fields of biodiversity of investigations were conducted in 2018, investigating the dynamics of biodiversity in Ye County (Figures 1-4; Table 1 and Table 2).
Therefore, the objective of this research was to define the correlation between crown volume of (Sophora japonica) tree communities and elevation gradient at spiral-temporal-environmental scales in the forest ecosystem of Ye County in 2018.
Figure 1. A digital cadastre map of location of Henan Province in China.
Figure 2. The geographical location of Pingdingshan Region in Henan Province and the Geographical Location of Ye County in Henan Province. Note: Pingdingshan Region Ye County.
Figure 3. Quadrate settings.
Figure 4. Dynamics of different landscape areas and landscape perimeters and landscape patch numbers in Ye County in 2018. Note: Urbanization of Land Use Farmlands of Land Use Rural Settlements of Land Use Reservoirs Rivers and Wetland Plantation of Land Use Natural Forest of Land Use Grassland of Coverage Ratio during 20% - 50% Grassland of Coverage Ratio > 50%.
Table 1. The natural-physical geographic conditions and vegetation in Ye County.
†Above sea level.
Table 2. Investigation index along the elevation and disturbance gradient variable.
3. Study Methods
A field investigation was conducted in 2018, to study the dynamics of crown volume of (Sophora japonica) tree communities and elevation along elevation in Ye County. The (Sophora japonica) tree community’s ecosystem of Ye County is the dominated by natural ecosystem with tree communities from 50 m to 650 m. Possessing steep environmental gradients along elevation gradient, this area is idea for studying (Sophora japonica) tree communities and species (Figures 1-4; Table 1 and Table 2).
Applying plant community ecology techniques, GIS of techniques, a number of landscape maps, SPSS statistic analysis, we investigated all plant species (dominant and companion communities) on the southern, southeastern, western, eastern, northern, southwestern, northeastern, and northwestern at spiral-temporal-environmental scales along elevation gradient in Ye County in 2018 (Figures 1-4; Table 1 and Table 2).
There are 8 study plots establishing in per 10 m elevation by different azimuth and direction (East, West, South, Southeast, Southwest, North, Northeast, and Northwest) in 2018. A total of 60 plots were set in three times investigating. Each study plot (Figures 1-4), consisted of one 20 × 20 m tree layer quadrate, five (the center and four corners of the study plot) 2 × 2 m shrub layer quadrates and 1 × 1 m herb layer quadrates. Thus, there were 180 tree layer, 900 shrub layer, and 900 herbaceous layer quadrates (Figures 1-3; Table 2 and Table 3). Moreover, different plant species identified during this investigation were assigned into three communities according to plant life form: 1) tree communities; 2) shrub communities; 3) herb communities     .
Firstly, these show that there is crown volume of 18 (Sophora japonica) tree communities along differential elevation between 50 and 200 m in Ye County.
Secondly, this study shows that crown volume of 18 (Sophora japonica) tree communities increased along elevation gradients. Meanwhile, the study analyzed the relationship between crown volume of 18 (Sophora japonica) communities and elevation in Ye County. Regression equation is “y = 27.341x − 104.43, (R2 = 0.7506)”.
Thirdly, there is a significantly positive correlation between crown volume of 18 (Sophora japonica) tree communities and elevation (P < 0.01) in this paper.
In resent years, more and more researches explained the correlation between tree community’s crown volume and elevation  -  . These researches include dynamics of community’s crown volume traits  , tree community’s crown volume structure  , tree community’s crown volume growth    , tree leaf structure of community’s crown volume  , community canopy crown volume and structure  -  along elevation gradient.
Thus, the results indicate that elevation was the dominant environment driver of crown volume of 18 (Sophora japonica) tree communities increased along elevation gradient. This study supported the experiments or models that elevation gradient is an important environmental factor affecting dynamics of tree communities distribution  , tree community variation  , composition and biomass of tree community  , dynamics of tree communities (structure and composition and diversity of tree community)    along elevation gradient at spatial-temporal-environmental scales in the future.
Figure 5. Dynamics of crown volume of 18tree communities along elevation gradient.
Table 3. Correlating to crown volume of tree communities and elevation gradient.
Note: *, P < 0.05; **, P < 0.01.
In this paper, the study explained that there was a significantly positive correlation between crown volume of 18 (Sophora japonica) tree communities and elevation gradient (P < 0.01). This study explained that elevation was the key environmental factor driver of crown volume of 18 (Sophora japonica) tree communities of international pharmaceutical materials increased along elevation gradient from 50 m to 200 m in Ye County in 2018. Therefore, understanding dynamic connecting crown volume of 18 (Sophora japonica) tree communities and elevation can be not just applied to preserve of (Sophora japonica) tree communities, but also applied to sustainable of biodiversity and processes crown volume of (Sophora japonica) tree communities along elevation at spatial-temporal-environmental scales in Ye County in the future.
This work was supported by A Grade of Key Disciplines of Environmental Science Foundation of Pingdingshan University, B Grade of Key Disciplines of Materials Science of Pingdingshan University, Science and Technology Department of Henan Province Foundation of China (KJT-17202310242), The Contracts of the Agreement on the Census of Forest Germplasm Resources in Pingdingshan City (PXY-HX-2017008, KY-2017103101), Science and Technology Department of Henan Province Foundation of China (KJT-092102110165).
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