The effect of stand density to soil infiltration rate was assessed in this study. The study site was in the Ehime University Forests, Ehime Prefecture, Shikoku Island, Japan. Soil samples were taken and brought to the laboratory for further laboratory works to determine soil infiltration rate. Eleven treatments were identified according to the forest type/species: natural forests Japanese cedar and cypress plantations with relative yield index (Ry) ranging from 0.37 to 0.95. Three sampling sites were established for each treatment with 3 replicates. Samples were taken from both topsoil and subsoil. Data analysis was conducted using the Statistical Package for the Social Sciences using the General Linear Model Analysis of Variance (One-way Anova) to test whether infiltration rate was statistically different in the eleven treatments. Tukey Honestly Significant Difference was used to compare means in case of significance (p<0.05). Results showed that in topsoil the highest infiltration rate among the forest plantation was found in Japanese cedar and cypress having relative yield between 0.50 and 0.60 and comparable to that of natural forests Those areas without forest operations and having high relative yield (Ry : 0.70 and above) showed the lowest values. There was almost no significant difference for subsoil except slight high infiltration rate for natural forest and Japanese cedar with Ry of 0.50 to 0.60. These results indicate the need of forest operations and the importance of stand density control, a guarantee for a better soil physical property, in particular soil infiltration rate.

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A study was conducted from 1997 to 2004, on the conifer forest of Ehime University to clarify the acid deposition from acid rain. The pH of the most rain was less than 4.59. In conifer forests, the pH of throughfall and stemflow were lower and the EC was greater than that of rainfall. The pH of rainfalls decreased as EC increased, especially at the stemflow of P. densiflora S.et.Z. and P. thunbergii Parl. The pH of stem flow of P. densiflora S.et.Z. and P. thunbergii Parl. were related with the pH of rainfalls at the opening. However the pH of stemflow of Cryptomeria japonica D. Don kept even values irrespective of that of rainfall. Ionic concentration of stemflow was greater than that of rainfall. The concentrations of sulfate and nitrate of throughfall and stem flow were higher than those of the rainfall because of dry deposition and concentration on the canopy and trunk. Obvious acidification of rainfall, throughfall or stemflow could not be observed in this study site.

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Bise village is a planned, traditional village, which was established in the light of Feng Shui during the Ryukyu Kingdom Period. The village landscape features reticular veins of village roads with houses encircled by Fukugi trees. We chose to survey in Bise village in order to clarify the present structure of the habitat - embracing Fukugi trees in the Feng Shui village. The village consists of squares of different size embraced by Fukugi trees. In general, there were one to four parts inside the squares whose borders were delineated by Fukugi tree lines. Four types of residence units, Types 1 to 4 were categorized to refer to the residence unit s of 1 to 4 parts. Types 1, 2 and 3 were the most common cases, and Type 4 was the rarest cases. DBHs of all Fukugi trees surveyed ranged from 1 cm to 66.5 cm. The trees were estimated to range from 2 or 3 to 266 years old. The height of Fukugi trees which were taller than 1 m was very diverse. We also found a lot of seedlings and quite a few stumps in the Fukugi tree lines Thus, it might be assumed that the diversity of the sizes of Fukugi trees resulted from thinning of some mature trees and from some seedlings being kept during the hundreds of years since the village was established. From the size of the Fukugi trees, we could assume that the village was first settled in the center and then was extended to the coastal area with the increase of the population

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Straw checkerboard is a sand dune fixation technique. This study was conducted on the experiments for restoring coastal vegetation by using straw checkerboard to control wind erosion. Straw checkerboard prevented wind erosion, and trapped shifting sand to an elevation of half itself. It also provided N-N03^- into soil, because the straw was resolved in soil. Then it was supposed that seedlings of Carex Kobomugi Ohwi grew up well by using the N-N03^-. Moreover coastal vegetation invaded bare land in speed of 1-2 m in one year, when we controlled wind erosion by using straw checkerboard. As a result, it was considered that straw checkerboard was effective for restoring coastal vegetation on wind erosion area.

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