Studies On The Quantitative Characteristics Of Dominent Population In Casuarina Coastal Communities

Casuarina forest is the best in China's southeast coastal shelterbelt fixing tree species, and is a good green trees all around. At present the studies focus on Casuarina in biomass, productivity, caloric values of each component, the caloric values and community structure of energy distribution and so on, the community structure and population ecology of small studies. Through field investigation, analysis of state-owned forest farms, Changle City, Cape Casuarina niche, distribution pattern, population structure and dynamics characteristics, the purpose is to understand the natural variation of Casuarina equisetifolia, Casuarina shelterbelt so as to provide scientific basis for rational management .To 400m2 for the sampling level, the use of variance ratio test, the percentage of co-occur, association coefficient, point correlation coefficient and chi-square testing of the main tree populations of association. The results showed that:It Was based on survey data to analyze the structural characteristics of Casuarina species dynamics, use "Space instead of Time," "horizontal derive vertical" approach in the preparation of Casuarina species in the specific life table, population survival curve was drawn,mortality rate curve and function analysis with four variable of population dynamics, and finally to spectral analysis. The results showed that: Casuarina survival curve should belong to Deevey-Ⅲtype, the early mortality rate of Casuarina species, the curve slope of the larger environment, the choice of intensity of a great screen, but only then with age, environmental screening of the selection intensity weakened, the lower the mortality rate of Casuarina, sapling stage of the transition phase to the relative balance of nutrition, survival curves tended to be stable, there are two peaks of Casuarina species mortality, respectively, in the first age classⅠ～Ⅱ, the firstⅧ～ⅨAge-class stage. Population viability analysis showed that the monotonic decline of Casuarina species survival function, cumulative mortality function is a monotonous rising, infant mortality rate shows a very high Casuarina species, grow into, the population becomes stable. Pinus species survival curve should belong to Deevey-Ⅱtype, indicating that pine mortality in all age the same population, the firstⅥ～Ⅶpopulation age class pine mortality peak value. Spectral analysis showed that: Casuarina species, Pinus species time series sufficient to show the length of the basic cycle, and the stand has reached a mature stage and can show significant fluctuations inherent cycle length.According to the plot of the actual situation and needs, site of tree height divided by 10 (0, +∞] to study the population structure and the high failure rate between stages. The results show that: Casuarina species in all high-level quantitative statistics, to all plots in the number of 1 to a maximum height level, reached 9578, accounting for survey 40.70% of total strain tree, decreases with each subsequent high-level trends, pine population structure of 6 high proportion of high-level the largest, reaching 38.96%. Casuarina sectionⅡ～Ⅲa high degree of instability of the highest level reached 69.7450%, pine forest to young forest stages in the population aged between failure rate level is basically negative, indicating that young pine forest compared the number of individuals of other ages to be a lot less.Based on actual survey data, using C, I, I &, PAI, Ca degree index and the Cluster Iwao equation Casuarina coastal population distribution pattern has been systematically studied, and compared the changes in the situation of sampling scales. The results showed that: the spatial distribution of Casuarina showed aggregated distribution, and Casuarina in 1600m2 sampling unit, the strongest aggregation, which may be due to various factors affect the population distribution of a certain scale, easy to form in the coupling, if beneficial population growth, population size of individual easily gathered in this growth. Meanwhile, the article also under Iwao's M and the regression equation to calculate the density of Casuarina and allow different theoretical sampling error of area under. This study investigated the population density was 3～8 Casuarina plants/50m2, according to theoretical calculation of sample size should be taken at least 138 plots, the actual sample of this research plots the course of a few samples up to 256, therefore, this study The number of samples required is far greater than theoretical sampling area, measured in this study shows for the aggregated distribution of Casuarina is to be believed, the number of samples to achieve the accuracy requirements.Based on actual survey data, to the important value of species as a resource position on the performance characteristics, quantitative analysis of the main tree species Casuarina communities niche breadth, niche similarity, and niche overlap. The results showed that: Casuarina maximum niche breadth, in the community in an absolutely dominant position, largely because of its wide adaptability, and pine and Acacia auriculiformis smaller niche breadth; community in three major populations similarity between the proportion of value is not too high, although a certain degree of niche overlap, but overall remains low, and competition among species within communities are not very keen. As a result, further research can be used as Casuarina Coastal community structure, dynamics and interspecific relations.Scaling per tree diameter at breast height obtained by the tree to calculate the importance of higher numerical value, and accordingly to calculate the Casuarina and Pinus, Acacia auriculiformis relationship between the species, the results show that: Casuarina and Pinus showed strong negative association, Casuarina and Acacia auriculiformis, Pinus and Acacia auriculiformis between the existence of a weak positive association, on the whole, three kinds of coupling between the weak trend, indicating instability of the community, still in successional stages.Application of the improved model description of population growth, the specific analytic have four parameters, K, C, a,θ, the solution in the parameter when a predetermined initial value,θ= 1, this translated into population growth. Space units for the diameter of the temporal relationship between Casuarina species corresponding to the base area of values, a modified simplex method to establish population-based area of Casuarina Logistic growth model and the model parameters were optimized, and finally got Casuarina species .The intrinsic growth rate of 0.5884.Through the measured data, the density effect on the Casuarina species and natural thinning law, this paper select the average diameter, average tree basal area (g) and total stand basal area (G) as indicators of body size, to represent the tree line the relationship between tree and tree size. The results showed that: Casuarina tree population density and the relationship between the size of population density on the stand of Casuarina that the average diameter at breast height, average tree basal area, total stand basal area were there significant role. Among the various models fitted to model (41) was the best, and a significant regression effect. Therefore, management of Casuarina forest, you must attach proper importance to the stand density control and management, at the same time, this is for the plantation management to provide a reasonable basis.