Imperial University of Tokyo (present the University of Tokyo), which was the first educational organization for studying and learning these fields. After the laboratory was established, two foreign teachers were invited and taught SABO until 1909. In 1909, Dr. Moroto went to Vienna, Austria, to study SABO under F. WANG. He not only studied in Vienna but also visited many places where SABO projects were executed, for example, in France, Germany, Switzerland, Italy, Czech, Poland, Croatia and Montenegro. Through these studies, he gained much knowledge and technology concerning SABO. Just after coming back to Japan, Dr. Moroto became a professor at the Laboratory of SABO, the Imperial University of Tokyo. He produced some technical books and introduced new technology from Europe in many places in Japan. As a professor, he brought up the next generation and promoted research on erosion control technology and forest hydrology. In this paper the footprint Dr. Moroto left are described in the incipient period of modern SABO on the basis of a large literature and field investigation. This paper will contribute to future exchanges between Japan and European countries in the field of SABO based on these historical relationships.

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Stoutemyer s (1937) method of obtaining rooted cuttings from mature trees, of which ordinary shoots do not root, was applied with success as a methodd of propagation of kini tree. Results were as follows:
Tukekuwae:... Genkoo o okutta ato de, tugi no bunken ga aru koto o sitta. Sore nt yoreba, Denmaruku dewa. kono hoohoo o R. S. -cutting to nazukete Populus nado ni hiroku motiite iru to iu. (Biological Abstracts 1949 Vol. 23, Entrice 8765, 8766. ni yoru.) Larsen, C. M. (1943): Stiklinger afurteagtige Skud paa Rßdder of Baevreasp og
Graapoppel. (Cuttings of softwood shoots from suckers of aspen.) Dansk Skovforenings Tidsskr. 28 : 96-113. 6 fig. 1
......... (1946): Experiments with softwood cuttings of forest trees. Forstl. ForsPgsvaesen Danmark 17 (2): 289-443. 24 fig. 1946.

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シイーカシータブ林に関する群系名については, 様々な用語が報告され, 和名, 英名共に統一されていな い. 用語の統一に向けて用語の歴史や使用の実態について文献の調査を行った. その結果外国語名として subtropische Wald, Laurilignosa, temperate rain forest, lucidophyllous forest など, 和名としては 常緑広葉樹林, 亜熱帯降雨林, 照葉樹林, ロウレル樹林などが使用されていた. 近年の用語の使用状況, 表 現力, 煩雑さなどより判断すると, 国内全体のシイーカシータブ林の群系名として, 英名はlucidophyllous forest, 和名は照葉樹林が適切と考えられた.

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The author encountered the Japanese word sharyohyo (sediment staff gauge) in the context of Japanese sediment and erosion control engineering (known as sabo in Japanese) and, through field research and the study of reference materials, was able to confirm more than ten uses of the word in an old stone pillar and old reports. As a result, the author was able to determine that a syaryohyo was a kind of benchmark used for measuring riverbed and hillside elevation. This paper describes an investigation of sediment transport processes in drainage basins conducted with reference to sharyohyo and relevant old reports from the early days of sediment and erosion control engineering, and the filling in of data missing from records from the Meiji Era to the early years of the Showa Era. In addition, the importance of continuity in conducting observations and data collection in the field of erosion control is described.

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In Japan, there are many native races of forest trees, which are customarily propagated by cuttings. They are acting the same rôle as these of the agricultural crops, but are not considered as clones. They are clone complexes, i. e. the populations consist of resembling clones.
Some one says that these races formed themselves at first as clones. Then, thoughtless treatments of most foresters spoilt them and brought them into much complicated constitution as they are showing at present.
This opinion, however, is very hardly acceptable, because cuttings are customarily collected in a very few number from a single tree, and forest plantation, on the other hand, requires usually large amount of planting materials. It seems to be necessary for growing up a clone, overcoming the above mentioned difficulties, that the genetic conception of clones has already been firmly established.
The following explanation seems, therefore, to be more reasonable that these races have naturally become evident in the course of successive vegetative propagation, and they substantially include many resembling clones.
In a population originated from seeds, each tree has a genotype different from any other tree, and genetic character can take any possible combination each other. When people start to propagate the trees by cuttings refusing the sexual means, they cannot collect cuttings from all the trees included in the population. The number of genotypes becomes, therefore, much decreased, and no more genotypes can be introduced into the population. As the vegetative generation progresses, the included genotypes become smaller and smaller in their number, number of individuals of the same genotype becomes larger and larger, till at last, foresters can easily recognize that some morphological characters are closely relating to some sylvicultural characteristics. Now it is possible to select desirable trees by means of their morphological characters. After several repeated selection, the races are established as those provided with the desirable properties and certain morphological characters.
Two or more clones very closely resembling can not easily be separated in the course of the race formation. It is evident that in the sexual population there are many closely resembling genotypes. It is reasonable to suppose that some of these have been brought into the vegetative population together, when the correlation has become evident between certain morphological and sylvicultural characters. Then, these resembling clones will be all equally selected and included in the same race.
These two phenomena can be clearly demonstrated on the paper using the model population (Figs. 1 & 2).
It is possible, among our native races of Cryptomeria and Thujopsis, there may be some real clones. In some districts, the races have originated from the small number of seedlings or cuttings, which was introduced from the other districts. In these cases, it is highly possible that the races are real clones. We have, however, no means to ascertain it, so we must treat them also as possible clone complexes.
The circumstances are quite different from the above in the case of horticultural trees. In these, it is much easier that the races have been established as the clones from the beginning.
From the stand point of the racial improvement, we must immediately start to separate the most desirable genotypes out of these native races to establish real clones.

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Forest vegetation was severely disturbed by the 1977 eruption of Mt. Usu in Hokkaido. However, most of the intermediately disturbed sites were immediately reforested by decurrentgrowth species(e. g., Acer mono)which survived through the eruption and then grew rapidly. The decurrent-growth species also established their seedlings there to some extent. These responses could be regarded as competitive ones because intermediately disturbed sites are characterized by severe competition. In general, the shade intolerant excurrent-growth species(e. g., Populus maximowiczii)did not invade these sites even though they were severely damaged at the time of the eruption. Unexpectedly, they responded to a few intermediately disturbed sites which they had occupied before the eruption and therefore were damaged severely. Consequently, they reoccupied these sites immediately. They also invaded a few strongly disturbed sites caused by severe volcanic impacts. However, the growth activity was extremely low in these sites ; therefore, the reforestation scarcely progressed. Because such an unharried response could correspond rather to stress tolerant behavior, it was suggested that early successional excurrent-growth species exhibited not noly early succession but also stress tolerant behavior collectively. Their wide-spread distribution was concluded to be due to two such aspects of behavior.

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Two kinds of indices, the warmth index (WI) and the coldness index (CI) were proposed by Lira (1945, 1948) to correlate the geographical distribution of vegetation zones with the thermal condition. This Lira's concept is considered to be useful for the reconstruction of past vegetation during the last 20, 000 years. The distribution maps of WI and CI are made on the basis of the mean monthly temperature for the period from 1921 A. D, to 1950 at 860 weather stations distributed over Japan (Figs. 1 and 2). In this paper, five distribution maps are presented as the representative temperature conditions during the past 20, 000 years. These maps show the thermal limitation of the vegetation zones for five periods when the mean annual tempetature are -7°C, -5°C, -3°C, -1°C and +2°C at different from the present temperature, respectively.
The distribution map of WI and CI at the time when the mean annual temperature is 7°C lower than the present (Fig. 3) roughly represents the thermal limitation of the forest types at the maximum glacial period (about 20, 000_??_18, 000 years B. P.). Based on this map, Hokkaido should be covered with the tundra and subalpine conifer forests. The subalpine conifer forest also covers the Tohoku and Chubu districts. While, most of southwest Japan should be covered with the cool-temperate deciduous forest. Evergreen oak-laurel forests are only found in the lowland in southern Kyushu, Tanegashima and Yakushima islands.
The second map for the case of 5°C lower than the present (Fig. 4) approximately shows the thermal limitation at the late glacial period (about 13, 000_??_10, 000 years B. P.). This map indicates that subalpine conifer forests spread in Hokkaido. While mountainous regions in the Tohoku and Chubu districts are still under the subalpine conifer forest, the forest in the lowlands should be changed into the cool-temperate deciduous one. Evergreen oak-laurel forests invade into the southern coastal area of the Kii Peninsula. It is notable that warm-temperate deciduous forests should appear in western Kyushu, Setouchi and Osaka Bay areas.
The third map for the case of 3°C lower than the present (Fig. 5) is roughly correlated with the condition at the early Holocene period. The thermal limitation of the cool-temperate deciduous forest appears in the Ishikari Plain, Hokkaido. The the main part of Tohoku and Chubu districts are covered with cool-temperate deciduous forests. Warm-temperate deciduous forests extend a wide area in northern Kanto Plain, marginal part of Nobi Plain, and coastal lowlands along the western part of the Japan Sea. The northern limit of the evergreen oak-laurel forest should attain to the southern Kanto Plain in the Pacific Ocean side, while it is located at Matsue City in Shimane Prefecture in the Japan Sea side.
The fourth map for the case of 2°C higher than the present (Fig. 6) approximately shows the thermal limitation at the Hypsithermal time (about 7, 000_??_6, 500 years B. P.). Forests in Hokkaido should be changed into the cool-temperate deciduous one. Inland basins of the Tohoku and Chubu district are covered by the warm-temperate deciduous forest. Evergreen oak-laurel forests spread over the central and southern part of Japan. The northern limit of this forest is located at Kuji City, Iwate Prefecture in the Pacific Ocean side and at the Lake of Jusan, Aomori Prefecture in the Japan Sea side.
The fifth map for the case of 1°C lower than the present (Fig. 7) roughly represents the condition at the latest Jomon and early Yayoi periods (about 3, 000_??_2, 000 years B. P.) . This map is similar to the present potential natural vegetation maps which were made by Honda (1912), Horikawa (1968), Yoshioka (1973) and, Miyawaki et at. (1975), although there are some differences between two types of the maps.

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