Rubbish treatment is a serious problem that many cities are confronted with today. As a way of treatment, large-scale reclamation has been carried out in recent years. Most of newly reclaimed lands are used for parks because of the soft ground and being located close to downtown areas. However, the buried rubbish soon actively generates CH₄ gas in reclaimed land. Furthermore, as CH₄ gas is resolved into CO₂ and H₂O by the aerobic bacteria in the surface soil layer, a deficiency of oxygen in the soil causes the trees to die or grow feeble. We practiced the following experimental research for the purpose of improving soil conditions for trees in rubbish buried site, in Tsurumi-Ryokuchi Park in Osaka City
1. The effect of “gassed soil” on the roots of the trees
Sapium sebiferum were sowed on five plots in which “gassed soil” was replaced by amended sandy soil with peat moss content of 10% to a depth of 15cm (Fig. 1). The “gassed soil” on all the plots was as hard as sandstone. Eight months later, even on plots with the greatest generation of gas, there were very few dead seedlings though the growth was poor. This was because oxygen permeated easily into the surface soil layer (Fig. 2). However, the root extension to deeper “gassed soil” were checked irrespective of the shoot growth (Photo 1). Apparently, it is impossible to expect better growth so we must replace “gassed soil” with normal soil before planting, whether gas generation is continuing or not.
2. Effect of ventilation and the growth of tree
The planted plots of different ventilation types shown in Fig. 1 were prepared to observe the growth of trees and the root system. Several plots were allotted to each type, and located irregularly because the generation of gas fluctated according to the location. However, for G-type we selected locations in which gas generating was active. Two or three years old saplings were planted in May 1977. They were Sapium sebiferum, Cry ptomeria japonica, Quercus glauca and Zelkova serrata. The first two species and the remainder weredug up in December 1977 and 1978 respectively.
Figs 5 and 6 show the close relation between the growth of trees and the soil air conditions at a depth of 30cm, with Quercus and Zelkova. It is recognized that each speciesbegins withering at 13% and 10% O₂ concentration respectively, and both die at less than 5%. However, both show relatively good growth at more than 17.5%. In regard to the effect of ventilation, G-type attained the most excellent results (Photo. 3). However, there was a large variation in results between the other types (Photo. 4). Although there was no change in amended soil of G-type, the other types resulted in very bad growth, and the brown sandy soil changed into bluish gray, very compact and reduced soil at the depths of 8 to 15cm. Judging from the soil survey, this is considered to be because of the structure of undergroud like that of Fig. 4.
Accordingly, when planting under the “gassed soil” conditions, we must replace the soil with better soil to the depth which will make sufficient root extension possible. Moreover, in soil in which gas generating is continuing, normal growth can not be attained without preventing gas permeation from the surrounding soil.

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Lately, particulate pollutants that are exhausted by motor vehicles have become an issue. The author made some experiments on trapping the particulates by foliage for explaining the atmospheric purification as a function of buffer planting belts on roadsides. The site of the experiments were near the eastern portal of Nihonzaka tunnel of Tomei-expressway, and ring road Route 7 and 8 in Tokyo. The results of this paper are summarized as follows:
The quantity of particulates trapped by foliage was related to property of the leaves. Small leaves with complicated structure such as serrations, veins and downs were better for increasing of the quantity.
As a result of long term experiments at Tomei-expressway, the quantity was related to the exposed term, and their regression equation was a linear one with a high correlation coefficient in spite of passable rainfall and wind during the term.
And the quantity was related linearly to a concentration of particulate pollutants in the air near the foliage. For that reason, it is necessary for increasing the quantity that the planting site is as near as possible to the source of the pollutants and the polluted air is positively induced into the foliage.
Based upon the results, the quantity of particulates trapped by the buffer planting belt that does not have dense foliage was estimated by computer. At normal atmospheric condition and for a normal arterial road with four lanes, the value obtained was approximately 20kg/year in case of the planting belt of 20m×500m (1ha).

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This study is concerning to the restoration of “The Heijo-kyo, Sa-kyo, 3-jo, 2-bo, 6-no-tsubo, Palace Garden Site” which was the ancient garden excavated in 1979 by Nara National Cultural Properties Research Institute, and is concerning to the reappearance of the scenery viewed from the Garden.
The whole of this study consists of seven sections.
The first section provides the outline of the result of the excavation study in this site.
And the restoration of the locations and the heights of the shelters, the restoration of the eye levels and eye points in the structures, and the restoration of the viewed objects, are provided in the Section-2, 3, 4.
The reappearance of the scenery viewed from the restored structures are mentioned in the Section-5.
Section-6 refers the conclusion of this study, that the structures were divided into two types; using for only garden party and viewing the eastern scenery and the garden.
The final Section; the repletion of this study, refers the difference between the scenery viewed from this Garden and the so called “Shakkei”. “Shakkei”; the technique of the visual connection between the garden and the outside scenery, is generally said to appear in the beginning of modern ages when the garden design and construction was completed. As the age is different, the economic developments and social situations of them are different from each other. There is also the difference of human being's consciousness to the “Nature” between these ages. So the mere scenery viewed from this Palace Garden is not regarded in the same light with “Shakkei”.

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We have known that the Pryeria sinica MOORE are the important defoliator to the Euonymus japonica THUNB. as majior garden plants in Japan.
The appearance of the adult of P. sinica is one time in a year and it falls on the season from the last ten day of October to the middle of November. The egg mass are laid around the tip of stem. The overwintering of this species take place in the stage of egg and the hatching is observed at the beginning part of March of the next year after the laps of a resting state.
In this paper there are presented the results of experiments performed to cold required for completing the diapause in the eggs of P. sinica in Tokyo. The results obtained are summarized as follows:
The optimal constant temperature for the completion of diapause development lies between 2.5 and 15°C, and the upper threshold temperature are about 20°C, respectively.
In fields, the eggs deposited in the beginning of November complete the diapause development by the beginning of January of the next year. Therefore, the eggs of P. sinica hibernate in a state of growth arrested by low temperature during the winter.
The diapause-terminated eggs hatched normaly at any temperature ranging from 7.5 to 22.5°C.

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