Abstract:

In order to characterize the age structure and spatial variation of the Pinus thunbergiicoastal protection forest, 42 plots (10 m×10 m) were investigated in Yantai region. All the trees in the plots were identified, measured and tagged by a sampling method. By substituting for time sere with the spatial sere the structure of Pinus thunbergii measured to detect the age structure. According to different distances to the coastline, the spatial variation of P. thunbergii populations was analyzed. The P. thunbergii population had reverseJ shaped DBH class which suggested that the population was in stably developmental phase with sufficient recruitment. A significant correlation between the growth status of P. thunbergiiand its population density was found. There were negative exponential relations between the population density with DBH individual biomass, respectively. The tree height was significantly and negatively correlated to population density. The density effects of P. thunbergii populations were determined by the regeneration difference among different stands. From 50 to 500 m distance to coastline, the population density of P. thunbergii increased and its mean diameter, tree crown declined with the distance to the coastline. The spatial distribution of P. thunbergiipopulation would be mainly attributed to the environmental heterogeneity caused by sea\|land interactions.

Key words: Pinus thunbergii, protection forest, population structure, distance to coastline