| Quercus aliena var acuteserata is the largest and most widespread constructive species in Xiaolong Mountain forest region.The study and analysis of the population's age,structure and the dynamic characteristics of population variation are of great significance to the maintaining of forest ecological balance and biological diversity,and contribute to the scientific management and research of the forest ecosystem in Xiaolong Mountain,and meanwhile provide references for the operation and management of the temperate secondary forests in China.This study was on the basis of sample-plot-survey and uses the age class structure,dynamic quantitative indicators,static life table,survival of the population and time series forest of population quantity.The age structure and dynamic changes of Quercus aliena var acuteserata population were analyzed in detail.The main results were as follows:(1)Age structure of the Quercus aliena var.acuteserata populationThis article applied the method of the space to analyze the survey data,and draw drew the Quercus aliena var acuteserata age structure,and counted of Quercus aliena var acuteserata population of the total number of 2210,in which the young tree(age)were 1368 strains,accounting for 61.9% of the total;There were 814 middle age trees,accounting for 36.8% of the total.There were 28 strains of near ripe trees,accounting for only 1.2% of the total.It was concluded that the young forest reserve of the gate of Quercus aliena var acuteserata species in Shanmen forest area of Xiaolong Mountain was riched in young forest reserved enough resource update,a higher percentage of mid-maturation forest,but the mature forest was very few.This explained that Quercus aliena var acuteserata population mainly was in the stage of young trees and middle trees age stage,The forest was basically closed,and basic population development potential was tremendous,which belonged to the stable population.(2)Static life table of Quercus aliena var acuteserata populationAfter the smoothing technique and standardized treatment,the survival number of the whole species was the trend of decline.By analyzing of the individual life expectancy in the Quercus aliena var acuteserata population the results showed: growth(age class 1-2 of age level)-falling levels(age 2 to 6 age)-growth levels(age 6 to 7 age)-falling levels(age 7 to 8 age)-slow growth levels(age 8 to 9 age)-falling levels(age 9 to 13 age).On the whole,the life expectancy of the Quercus aliena var acuteserata in this area showed a trend of first increase and then decline,which presented a wave state.(3)Analysis of the survival curve of Quercus aliena var acuteserata populationIt was concluded that individual number of the population of Quercus aliena var acuteserata in this region was decreasing with the increase of age.In the age of 1-2,the Quercus aliena var acuteserata was in decline,and it was stable at the age of 2-8.starting from above the 9th grade,the dynamic changes of the Quercus aliena var acuteserata obviously declined.Based on the analysis of the mortality curve of the Quercus aliena var acuteserata population in this area,the result of the mortality was fluctuated.The trend of loss rate curve and mortality curve was basically consistent,which reflected the general rule of population.Overall,both mortality and loss rates were shown as follows: the pattern of "drop-rise-drop-rise-drop-drop".(4)The population dynamics of Quercus aliena var acuteserata.Through quantitative dynamic analysis,without considering the external environment disturbance,The dynamic index VPi=0.628>0,and the dynamic index of population age structure in the random disturbance was VPi '=0.0483>0.It showed that population had presented growth,tending to stability.The speed of growth was reduced,which was not completely random disturbance to the plant population structure dynamic VPi' '= 0.977,closed to 1,It showed that the gate of Xiaolong Mountain forest area of Quercus aliena var acuteserata growth of population structure decreased,had been tending to stability,and was sensitive to outside interference.In a word,the population of Quercus aliena var acuteserata in the hilly region of Xiaolong Mountain area tending to be stable.(5)The survival analysis of Quercus aliena var acuteserataThrough analysis of Quercus aliena var acuteserata population four functions,it was concluded that with the increase of age class,the survival curve showed monotone decreasing trend,and the cumulative mortality curve was monotone increasing trend,the survival rate and cumulative mortality rate were both higher than the latter,and the two corresponded to each other,indicating that the mortality of the young trees of the species was larger,which was consistent with the analysis results of the static life table.The contrast between the death density and the danger rate curve of Quercus aliena var acuteserata population was quite obvious,and the death density curve basically presents a stable trend.The risk curve change was bigger,which presented a wave of floating state.By comparing the risk curve,mortality curve and loss rate curve.The three were basically similar,which was consistent with the analysis results of the previous static life and the survival curve.(6)Time series prediction of the number of Quercus aliena var acuteserataAccording to the time series prediction mode,the number of individuals in each age group after the age of 3,6,9 and 12 was predicted and analyzed,and the results showed that the number of individuals at age 4 was reduced by 1.6 percent only after 3 years of age,while the number of individuals at the 11 th age group remained unchanged,and the number of individuals at the remaining age group and the number of individuals aged 6,9 and 12 showed an increase.The larger the number of individuals in this age group,the larger the increase of the number of individuals in this age group,reflecting the abundance and abundance of individual reserve of Xiao long mountain forest region.It could be fully explained that in the future longer succession time,the species of Quercus aliena var acuteserata could still be the dominant population of the deciduous broadleaf mixed forest in the region,which was of great significance for maintaining the ecological balance and forest management in the region. |
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