| Mangroves play an irreplaceable role in biological diversity and disaster prevention function which grow between land and sea as a kind of special plant community. While the mangrove area sharply declined by 60% during the 40 years since the last century 60s. The existing 25,000 hectares of mangroves have almost been destroyed, whose structure are damaged and the function are deteriorated. The status and protection of mangrove in China are not optimistic. The spatial structure of stand refers to the distribution pattern of trees and the arrangement of their properties in space. Spatial structure determines the competition potential and their spatial niche between the trees, and spatial structure also largely determines stands'stability, the possibility of the development and the size of operating space; So how to use the forest spatial structure scientifically and rationally has always been the problem which the forest managers to study.This article researched the spatial structure of mangrove stand with different tidal zones in Gaoqiao mangrove protection areas in Lianjiang city Guangdong province, based on the theory of nature-approximation forest management and spatial structure. The study was divided into two parts:the first part is the analysis of the spatial structure factors. We choose the plots to carry out the sample survey in the study areas in different tidal zones and determine the values of mingling, neighborhood comparison, and neighborhood pattern, as well as the spatial structure parameters of different tidal zones. Also the study comparatively analyse their existing differences, from which we obtained the law of the spatial structure of mangrove stand with different tidal zones. The second part is the analysis of the heterogeneity of spatial structure. The study analyses the spatial structure heterogeneity of mangrove stand with different tidal zones by the application of homogeneity index, based on the theory of nature-approximation forest management.The results indicated that:(1)The mean mingling of high zone was 0.333,the mean mingling of low zone was only 0.305. The mean mingling of middle zone was the highest with the value 0.350. The probability of three tidal zones distribution declined as the degree of mingling increased. The proportion of middle-grade was the highest in middle zone of mangrove, while the proportions of zero-grade and middle-grade was relatively large in high zone and low zone. (2) The value of neighborhood comparison were 0.510,0.522,0.503for high zone,middle zone and low zone. The differentiation degrees of breast diameter in some mangrove dominant tree species in different tidal zones was almost the same, which was higher in middle zone than high zone and low zone. The inferiority in mangrove in high zone and low zone had the highest ratio, while the superiority in mangrove in middle zone was relatively high. (3) The average value of Neighborhood comparison for mangrove in three tidal zones were 0.536,0.528,0.587 respectively. Neighborhood comparison of mangrove in every tidal zone basically showed statistically normal distribution, which was inclined to right deflexion. The value of Neighborhood comparison was between 0.528 and 0.587. Mangrove in every tidal zone had an aggregation distribution pattern, mangrove in middle zone was nearest to Equally distributed. (4) The average value of homogeneity index for three tidal zones were 38.044,49.534,47.231 respectively. The spatial structure heterogeneity of middle zone was higher than high zone and low zone. (5) By analyzing Space Structure factors and Homogeneity index, we could reach the same conclusion:The state of Space Structure in middle zone was superior to high zone and low zone.Breaking through the routine of studying the spatial structure of mangrove from the local, the research used the system thought to analyze the whole mangrove community which was divided into three types respectively with different tidal zones. At the same time, the study analysed and verified the heterogeneity of the spatial structure of mangrove stand by homogeneity index. For the first time, we obtained the law of the spatial structure of mangrove stand with different tidal zones and the spatial structure heterogeneity index of mangrove stand with different tidal zones and also made suggestions to the spatial structure adjustment of mangrove stand with different tidal zones, which is realistically significant to supervise the restoration and conservation of mangrove resources. But the index parameter of some detail spatial structure factor is still the problems to be further studied in the process of the structural adjustment.
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