Studies On The Quantitative Characteristics Of Old-growth Population In Pinus Massoniana Lamb. Plantation

Pinus massoniana Lamb.is a unique native species in the subtropical area of our country, with strong adaptability and rapid growth,it is the most widely afforestation tree in China.And it is a tropical conifer in southeast subtropics of china.It is easy to natural regenerate and afforestation,it play a guiding role in the restoration of forest ecosystems.In this paper,the old-growth forest of Pinus massoniana Lamb.as the main object.It has played a tremendous role in the ecological,scientific research,landscape and culture.At present,the researches on old-growth "fung shui" woodland was less.The study on old-growth forest of Pinus massoniana Lamb. is the base for biodiversity protection and its sustaintable manangement,which has important significance in theory and practice.Old-growth forest of Pinus massoniana Lamb.wasanalyzed and discussed by quantitative statistic method in the work,including diameter structure,fractal characteristics of tree crown,spatial distribution pattern,density dependent effect of population and intraspecific competition.So it could provide theory for Pinus massoniana Lamb.forest plantation and study in the future.(1)DBH was choosen as the index of individual size structure.The results indicated.that diameter and quantity distribution curve of 70 years old,10 years old,4 years old Pinus massoniana Lamb.population was a approximate normal distribution curve,which was taking stand arithmetic mean diameter to be a peak point,medium size of quantity accounted for the most,the tree quantity reduced gradually to its two ends,this curve approximated to a eudipleural mountain curve.Each diameter class of old-growth Pinus massoniana Lamb.population was continuous distribution,medium age forest appeared vacant diameter class,young forest showed continuous distribution.Diameter distribution was texted by different models.The results showed that different models suitabled for the different ages.But weibull distribution was the best.(2)Studying spatial distribution of plant population with different crown breath can give the information for the mechanism of population distribution.Fractal geometry of crown is considered to be a very useful tool for dealing with the distribution of crown.The fractal dimension of Pinus massoniana Lamb.were calculated on three indices:crown breath,base area, volwne.Modified simplex method was used to calculate parameters.The results indicated that the fiactal dimensions were decreased with the ages decreased,the fiactal dimensions of Taxes chinensis varmairei were 3.4071,0.6227,0.1052 respectively,the most largerest fiactal dimension was taken by crown breath.So crown breath was suitable for old-growth Pinus massoniana Lamb.population.(3)The spatial distribution pattern of Pinus massoniana Lamb.population was studied using aggregate indices.The results indicated that Old-growth forest of Pinus massoniana Lamb. and 15-year Pinus massoniana Lamb.presented an uniform distribution,but the other Pinus massoniana Lamb.Population presented an aggregating distribution.(4)In this paper,Hong-Logistic model was proposed to approach the growth law of basal area of Pinus massoniana Lamb.population The method of modified model simplex was applied to optimizethe parameters of model,and the fitting results showed that the growth of tree basal area was well described by logistic model,and the range of diameter class is within 26-30cm with which the growth rate of basal area of the population comes to the highest.The maximum growth phases of edificators in various age are different.The growth of tree basal area was increased with the growth of age,but the change trend of intrinsic rate of increase was opposite to the growth of basal area.The young forest of Pinus massoniana Lamb.population grew rapidly,needed short time return equilibrium state,but Old-growth forest of Pinus massoniana Lamb.Population needed long time return equilibrium state.(5)The model of the relationship between population density and diameter growth,Reineke model and Wu-density effect model were used to density of Pinus massoniana Lamb.population. The results showed that the effects of population density on average diameter,breast-height basal area were significant.The reineke model could simulate the population density effect law of Pinus massoniana Lamb.Well.The model of the relationship between population density and age showed that with the increase of age,the the population density decreased.Used two methods,population density variation trends were similar.(6)This research was to investigate the individual competition characteristics of old-growth forest of Pinus massoniana Lamb.population using 13 variables including RD(Relative breast height diameter),RH(Relative tree height),RCB(Relativecrown breadth),RCL(Relative crown long),RCA(Relative crown area),CV(Tree crown volume),TCEL(Tree crown extendlimit),TCR(Tree crown ratio),TCOR(Tree crown orbicular ratio),TCPR(Tree crown projection ratio),GSI(Growth spaceindex),GSCI(Growth space competition index),CI (Competition index).The research showed that the crown competition index was the best selection to reflect old-growth forest of Pinus rnassoniana Lamb.population.Compared fitting results of different competition index and growth of section area of breast height.Compare different competition index with chest high basal area growth of the results of fitting,relative DBH had the highest correlation coefficients.(7)The old-growth forest of Pinus rnassoniana Lamb,played a tremendous role in the ecological,scientific research,landscape and culture.Human factors and natural factors were a key factor for its renewal,and ecological protective measures suggested in the work should be to carry on actively the work of propagation of old-growth forest of Pinus massoniana Lamb, strengthen the construction of old-growth forest of Pinus massoniana Lamb nature reserve, execute strictly the protection of old-growth forest of Pinus massoniana Lamb and vegetation in its habitat,restore the damaged vegetation,reinforce the monitoring,research and propaganda of old-growth forest of Pinus massoniana Lamb,etc.