Studies On The Population Ecology Of Dominant Population In Secondary Pinus Massoniana And Acacia Confusa Forests In Coastal Area

Population ecological characteristics of Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area in Gushan of Fuzhou, Houshan of Fujian Agriculture and Forestry University were analyzed and discussed by quantitative statistic method in this paper. The results provided the theory for the rational management and sustainable utilization on Coast Protection Forest. The results indicated as follows:(1) By applying the method of "spatial sequence instead of temporal change". The results indicated that size structures of P. massoniana population in Gushan community showed mid-senescent form, A. confusa population in Gushan community various stages of development showed a pyramid shape, P. massoniana and A. confusa population in Houshan were both stages of development showed a pyramid shape. Through comparing with two places size structures, the level of the Houshan P. massoniana population only had seven sizes and Gushan had 10, as the Houshan was a growing population, which was foreseeable P. massoniana population of Houshan trail to a higher level of development, P. massoniana population would continue to dominate in Houshan community.(2) The spatial distribution pattern and dynamics of dominant population in Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area were presented using aggregate indices, Iwao's equation and Taylor's model in this paper, then the causes of evolved pattern was analyzed. The results indicated that the distribution patterns of P. massoniana and A.confusa were all clumped in two community. However, different tree age class distribution patterns vary, P. massoniana and A. confusa had a common trend, which was the saplings and mid-size trees of P. massoniana and A. confusa showed an aggregative trend, but random in big tree stage.(3) Time-specific life table of dominant population in Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area was established based on diameter class, which revealed P. massoniana in earliness in the overall population was gentle change. Gushan P. massoniana death peaks appeared inâ…¤,â…§,â…¨stage, Houshan P. massoniana death peaks appeared inâ…£,â…¥stage. A. confusa population of the two places in theâ…¢,â…¤stage showed death peaks. The survival curve of P. massoniana and A. confusa both belonged to the typical type of Deevey types betweenâ…¡andâ…¢. Gushan,Houshan P. massoniana populations had a peak volatility inâ…¤,â…¥stage, which stocks that P. massoniana from the tree to grow in the process of instability, A. confusa in two places both had a peak volatility inâ…¢stage. The results of spectral analysis showed that the characteristic of quantitative fluctuation of P. massoniana and A. confusa were both multi-harmonic superposition. The cycle fluctuation was maybe correlative with the effect of the competition and competition-related species.(4) In this paper, Liu-Improvement Logistic model was proposed to approach the growth of tree basal area of P. massoniana, A. confusa population. The method of modified model simplex was applied to optimize the parameters of model, and the fitting results showed that Liu-Improvement Logistic model was suitable to the actual growth trend of P. massoniana and A. confusa. population, and the highest growth rates of P. massoniana in two places were both between the third and the forth age class, namely the phase when breast diameter was 16-20cm, the highest growth rates of A. confusa in two places were both between the second and the third age class, namely the phase when breast diameter was 12-16cm.(5) The niche characteristics of the main tree populations in Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area have been analyzed by quantitative mehod. The niche breadth, niche proportional similarity and niche overlap of main tree populations in Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area were measured by taking sample plot as one-dimension resource states, and important value as the resource state descriptor of niche. The results indicated that P. massoniana and A. confusa both had higher niche breadth value, which were absolute dominant species in the Community; and all the dominant populations showed some adaptation to the community enviroment. The results would offer scientific theories for reserving, community structure and dynamic prediction of Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area.(6) In this paper, the percentage of important value of P. massoniana and A. confusa were regarded as the measure of the competitive coefficience, and the dominant degree of normal stands were regarded as their environment capacity, then the competition on these two species were discussed with the Lotka-Volterra equation. The results showed that the sum dominance of P. massoniana and A. confusa. in Gushan and Houshan respectively 185523cm³Â·hm^-2 and 196112cm²Â·hm^-2 when reaching their balance, which was larger than any AT,. Here two species can jointly dominate this community, which indicated the community composition of P. massoniana and A. confusa could use of environmental resources more fully,this was a good theoretical guide for Secondary Pinus massoniana and Acacia confusa Forests in Coastal Area configuration and formation.(7) Based on the study of natural thinning process in plant populations being described by predecessors, Use density effect model N = exp( a ln² S + b ln S + c), considered Growth changes in site conditions deduced the model N = exp(a₁H^b1 ln² S+ a₂H^b2lnS + a₃H^b3), considered the relationship of A. confusa between P. massoniana deducesd the model N = exp(a₁H^b1ln²S+ a₂H^b2lnS+a₃H^b3) + exp(a₄ln² S'+a₅ lnS'+a₆). The results indicated that P. massoniana population density change mechanism not only impact by self-thinning effect, but also restricting by he-thinning of A. confusa. Through the comparison it was found that he-thinning of A. confusa in Gushan was more intense than Houshan.