This study was performed to investigate effects of air pollution on the Pinus thunbergii forests in Onsan industrial districts, and environmental factors, contents of soluble sulfur in needles, and composition of sorest vegetation were examined. The results obtained in this study were summarized as follows ; 1. The pH of soils, organic matter and total N were low near the source of air pollutants, and sulfur contents in the soils was high in general. Especially there was significant correlation between the sulfur contents in the soil and pH at 1% level. 2. The contents of soluble sulfur in needles ranged from 0.13% to 0.25% and were generally high, and plot 2 and 3 were the highest of all. 3. In the number of species, 7 species appeared in plot 3 and 20 species in plot 7, and they were low near the source of air pollutants. Total number of individuls, species diversity and evenness increased with in creasing distance from the source of air pollutants. 4. There were significant correlations between the contents of soluble sulfur in needles and the number of species and species diversity at 5%, 1% level, respectively. 5. Importance value of each species was low near the source of air pollutants but Quercus species showed high values in all plots. 6. On these studied plots, Pinus thunbergii, Quercus serrata and smilax china were tolerant, and Rhododendron mucronulatum, Rhododendron yedoense var. poukhanense, Platycarya strobilacea and Lespedeza maritima were sensitive to air pollution.
Introduction: Diffusion is process by which an innovation is communicated through certain channel overtime among the members of a social system(Rogers 1983). Bass(1969) suggested the Bass model describing diffusion process. The Bass model assumes potential adopters of innovation are influenced by mass-media and word-of-mouth from communication with previous adopters. Various expansions of the Bass model have been conducted. Some of them proposed a third factor affecting diffusion. Others proposed multinational diffusion model and it stressed interactive effect on diffusion among several countries. We add a spatial factor in the Bass model as a third communication factor. Because of situation where we can not control the interaction between markets, we need to consider that diffusion within certain market can be influenced by diffusion in contiguous market. The process that certain type of retail extends is a result that particular market can be described by the retail life cycle. Diffusion of retail has pattern following three phases of spatial diffusion: adoption of innovation happens in near the diffusion center first, spreads to the vicinity of the diffusing center and then adoption of innovation is completed in peripheral areas in saturation stage. So we expect spatial effect to be important to describe diffusion of domestic discount store. We define a spatial diffusion model using multinational diffusion model and apply it to the diffusion of discount store. Modeling: In this paper, we define a spatial diffusion model and apply it to the diffusion of discount store. To define a spatial diffusion model, we expand learning model(Kumar and Krishnan 2002) and separate diffusion process in diffusion center(market A) from diffusion process in the vicinity of the diffusing center(market B). The proposed spatial diffusion model is shown in equation (1a) and (1b). Equation (1a) is the diffusion process in diffusion center and equation (1b) is one in the vicinity of the diffusing center.