The author as a chief of Latin American Research Mission of the University of Tsukuba carried out a field survey on natural environment in the Brazilian Northeast funded by the Ministry of Education, Science and Culture of Japan from December 1980 through February 1981.
Attention to the problems of desertification by the world opinion and the scientific community in many countries has increasingly been paid in the last decade. The drought of the Sahel, which extended from 1968 to 1973, focused public attention to the problems of desertification. In response, the United Nations' Conference on Desertification (UNCOD) was held in Nairobi Kenya, from August 29 to September 9 in 1977.
According to the United Nations' definition (Biswas and Biswas, 1980), “desertification is the diminition or destruction of biological potential of land and can lead ultimately to desertlike conditions; grazing lands cease to produce pasture, dryland agriculture fails, and irrigated fields are abandoned owing to salinization, waterlogging or some other form of soil deterioration”.
The purpose of this report is to present some findings of desertification and its causes by human impacts taking place in both states of sert_??_o of Paraiba and Rio Grande do Norte.
The Nordeste (the Brazilian Northeast) covers an area of 1, 600, 000km², most of which. is semi-arid and has suffered several severe drought for a long time. The Nordeste can be divided into three physiographic divisions such as zona da mata (humid litoral zone), agreste (semi-arid transition zone) and sert_??_o characterized by the caatinga vegetation (semi-arid interior) (Fig. 1).
The caatinga trees have been used for firewoods for chacoal-making, pottery and iron manufactures, and fence posts in domestic affairs. The wood piled in the field in Photos. 4 and 7 are preparing for uses of firewoods and others, and we can see these phenomena in many places in sert_??_o. The deforestation of caatinga trees is one of the most important causes of desertification in sert_??_o.
The deforested caatinga trees have been transported by means of human and horse backs bicycles and big trucks (Photos. 8 and 9).
Recently, SUDENE (Superintendency for the Development of Northeast) has planned “Pros jet Sertanejos” a kind of pilot farm to improve the farmers' standard of living brought about by infrastructural improvements such as construction of irrigation canals, reservoirs, wells, and livestock sheds by borrowing the funds from banks. Although the purposes of the “Projet Sertanejos” have been carried out in many places, the demands of firewoods have been increased and accordingly the deforestation of the caatinga trees has been also increased to meet their demands. These facts seem to bring a significant ecological imbalance.
It is very important to recognize the fact that the desertification in Nordeste is very severe and is now expanding in the area.
The solution of the problem of combating desertification which is truly a global issue has now become one of the most urgent target in the field of area studies and environmental con-servation.

View full abstract

The purposes of this study are, first, to elucidate the meso-scale spatial pattern of agricultural land productivity in Kanto region in 1975 using the 1km² mesh data, and second, to analyze the spatial structure of agriculture in terms of both distance and direction from the center of Tokyo.
Agricultural land productivity was estimated by the number of farm household within each class of agricultural sales and the size of cultivated land.
The scores of agricultural land productivity in the region (16, 088 unit cells) were classi-fied into four groups, and were mapped (Fig. 1). There are 3, 871 meshes (24, 06%) with a low score, and these are mainly villages in mountainous regions and suburban areas and its outer zones around large cities situated some 40km of the center of Tokyo (correspond-ing to paddy field areas along the major railway lines). The meshes with a medium score are 9, 571 in number (59.18%), and are generally distributed in wider range of the eastern part of Kanto region than the western one. It is scarcely possible to find medium score areas in Keihin district. There are 1, 882 (11.70%) meshes with a high score and 814 (5.06%) meshes with a very high score. Generally speaking, these meshes are more numerous in the western part of Kanto region where upland field occupies the large part of cultivated area than in the eastern one where paddy field exists predominantly. The observed concentric pattern of these areas around Keihin district would also suggest that the distribution of agricul-tural land productivity tends to be determined by the distance from the metropolitan mar-ket, in addition to physical conditions.
To examine this pattern typologically and more objectively, the cross-section of agricul-tural land productivity with linear distance from the civic center of Tokyo (location of metropolitan market) to the mesh concerned, was shown in each direction. First, civic cen-ter was set to Nihonbashi in Tokyo, and the belt stretching from Nihonbashi to outer direc-tion with the width of 10km was drawn. Second, the distance from Nihonbashi to the key mesh and the scores of agricultural land productivity were assigned to the horizontal and vertical axes on the profile respectively, and each mesh included in the belt concerned was plotted on the graph. This procedure was done by turning round the belt by an angle of five degrees for 51 directions excluding 21 ones in the southeastern sector (Fig. 2).
Consequently, excluding the northeastern sector in Kanto region and some directions which were undiscriminant of the fluctuant pattern of agricultural land productivity because of the presence of Tokyo Bay, it was confirmed that agricultural land productivity fluctuat-ed with distance from the civic center. Hence, 51 directions were classified into 6 types based on the configuration and number of the heaps which was drawn by the curve connecting maximum agricultural land productivity on each distance (Fig. 3).
1. Distance-decay type (A)
2. Fluctuating type I (B₁)
3. Fluctuating type II (B₂)
4. Fluctuating type III (B₃)
5. Constant/Distance-decay type (C)
6. Gradual increase type (D)
Figures 4 through 9 show a typical example in each type and Figure 10 shows the spatial distribution for all of these types. It is clear that the same types tend to adjoin spatially. Accordingly, in the light of the spatial adjacency of the same types, directions are classified into five sectors. In this way, Kanto region can be considered to be composed of them as follows:
1. Eastern sector in the Kanto plain (0°_??_50°)
2. Northeastern sector in Kanto region (50°_??_90°)
3. Northwestern sector in Kanto region (90°_??_140°)
4. Western sector in Kanto region (140°_??_155°)

View full abstract

In the preceeding studies which determined the location of the Arctic frontal zones on a hemispheric scale, the definition of the Arctic fronts was vague and the locations of the frontal zones varied by authors. The purpose of this paper is to define the Arctic front, to identify it on daily surface synoptic weather charts, to clarify its frequency distribution and to determine the wintertime location of the Arctic frontal zones. The basic weather charts used for this study were “Täglicher Wetterbericht” published by Deutcher Wetter-dienst for winter months (December to February) from 1958 to 1962.
First, to clarify the relations between the surface positions of fronts and the thermal and wind fields of upper isobaric levels, isotherms at 850, 700 and 500mb levels (Fig. 2), isotachs at 300 and 500mb levels (Fig. 3) and a vertical north-south cross section (Fig. 4) were analys-ed in the European sector. The 500mb level analyses were extended to the whole area of the weather charts, Northern Hemisphere except the Pacific and South Asia regions (Fig. 5). As a result, the Arctic fronts could be defined as fronts which were accompanied with the Arctic front jet streams running intermittently in the circumpolar region. The temperature of this jet streams at the 500 mb level was -28 to -44°C, the mean was -34.6°C and the standard deviation was 2, 7°C in the case of January, 1960 (Fig. 6). These results meant that the Arctic front jet streams were discernible from the Polar front jet streams according to its flow pattern and temperature.
Then, all the Arctic fronts appearing on every daily surface synoptic weather charts were classified into the Arctic fronts and the Polar fronts based on the flow pattern and tempera-ture of the jet streams at 500mb level. The total numberr of the Arctic fronts in each five degree square mesh was counted by months. Five year mean monthly frequency distribution (Fig. 7) and locations of the axes of the maximum frequency of the Arctic fronts in each year were shown (Fig. 8). As a result, the Arctic fronts were shown to have the highest frequency extending from Barents Sea to the central inland part of Siberia. This zone was named “Atlantic-Eurasian Arctic frontal zone”. Apart from this frontal zone, a secondary axis extended from central Siberia westward to Baltic Sea. The second highest frequency appeared in the northwestern part of North America, along the mountain range of Alaska and the northern periphery of the Rockies. In the northeastern part of North America, the Arctic fronts tended to concentrate except in February, though its frequency was relatively low (below 20%).
Based on Figs. 7 and 8, winter months' locations of the Arctic frontal zones were deter-mined (Fig. 9). Fig. 9 showed that two principal Arctic frontal zones were recognised in winter, and these were located approximately along the great-circle.

View full abstract

Die wissenschaftliche Erforschung der Waldgrenze begann in Europa im 19. Jahrhundert. Die obere Waldgrenze wurde zuerst als untere Grenze der alpinen Stufe erkannt, and als Grenzhöhe gemessen. Dann wurde versucht, die Lufttemperatur oder Wärmernenge auf die Höhe der Waldgrenze zu beziehen. Infolgedessen wurde klar, daß die Lufttemperatur in der Vegetationszeit eine große Rolle für die Bestimmung der Waldgrenze spielt. Aber es wurde auch untersucht, daß andere Geofaktoren (z. B. Niederschlag, Wind, Schneehöhe, Lawmen, Geländef orm, Boden, Gestein and Eingriff e des Menschen) lokal die Waldgrenze senken and die Baumarten verändern, welche die waldgrenze bilden. Nach deco Zweiten Weltkrieg wurden in Österreich und der Schweiz Versuchsanstalten errichtet, um physiologische and öko=logishe Forschungen, auf diesem Gebiet zu betreiben. Neuerdings erforschen meist deutsche Geographen die Waldgrenze in den Gebirgen der Welt unter geoökologischem Gesichtspunkt. Sie stellen klar, daß die Waldgrenze als eine Landschaft durch die Korrelation der Geofaktoren an jedem Standort . bestimmt wird.
Der Autor faßt in dem Aufsatz solche bisherigen Forschungsergebnisse über die Beziehungen zwischen der Waldgrenze und einzelnen Geofaktoren in europäischen Gebirgen zusammen. Deshalb ist der Aufsatz nützlich, wenn man die Eigenart der Waldgrenzelandschaft in japanischen Gebirgen erklären will.

View full abstract