The upper part of Mt. Daisetsu has one of the most typical periglacial regions in Japan. But long term meteorological observation had not been carried out there. So the present writers carried out the year round meteorological observation at Mt. Daisetsu Hakuun hut (2, 000m above sea level) in 1985. The annual mean air temperature there was -3.8°C, and close to the value in Fairbanks, Alaska, located in discontinuous permafrost zone. Mt. Daisetsu has much more precipitation than many low latitude periglacial regions. The summit area of Mt Daisetsu also has the windward bare ground, where snow can hardly accumulate due to strong winter wind. We concider that there exists permafrost in such bare ground. Air temperature condition suggests that lower limit of permafrost in Mt. Daisetsu lies lower than 2, 000m. The existence of palsas at 1, 720m in Mt. Daisetu supports this. Summit regions of Mt. Daisetsu is under periglacial environment and many active periglacial phenomena occur there. The forest limit in Mt. Daisetsu is not dependent on WI (Warmth Index) 15.

View full abstract

Nishi-tsugaru Coast is located in the lnner Arc of the Northeast Japan Arc. More than six levels of the Pleistocene marine terraces have developed on the coast. This paper describes height distribution of Holocene marine terraces including emerged benches and discusses Holocene tectonic movements on the Nishi-tsugaru Coast. The results are summarized as follows.
1) Four levels of Holocene shorelines are observed on the Nishi-tsugaru Coast and are named LI, LII, BI, and BII in descending order. LI and LII are marine terraces and BI and BII are emerged benches. The lowest paleoshoreline BII has emerged during the earthquakes that occured around lwadate, southern part of this coast in 1704 and off the Cape of Ohdose, northern part of it in 1793.
2) The formative age of the highest terrace LI is ca 6, 000yr B. P. by ¹⁴C dating. It's height ranges 5-8m a. s. l.. Maximun uplift rate reaching to 1.3mm/yr indicates that Nishi-tsugaru Coast is one of the most active region in the Honshu Island.
3) The most rapidly uplifted Holocene terraces are distributed in the areas where Pleistocene marine terraces have been uplifted exceedingly. These areas coincide with the places where the coast traverses Mts. Masugata in the north and Mts. Shiragami in the south. The height distribution pattern of each Holocene paleoshoreline is very similar to that of the lowest bench emerged at the earthquakes in 18th century. Development of Holocene marine terraces in the Nishi-tsugaru Coast is attributed to intermittent upheaval of Mts. Masugata and Mts. Shiragami accompanied by earthquakes through Pleistocene.

View full abstract

We study the limno-biological properties of the lake Taromalin, which is situated at 22°52′12″N and 120°51′E, extending from east to west, on the ridge of the Formosan backbonemoutains of 2180m above sea level. The lake is accompanied by two small and very shallow satellite lakes at its north side at about 300m distance,
1. The geographical outline of the lake are as follows: length of the shore line; 2.0km, surface area; 12.68ha, maximum depth; 34m, mean depth; 17.3m, volume; 2.2×10⁶m³, shore development; 1.38. They imply that Taromalin may be the deepest lake in the natural lake in Taiwan.
2. Natural forest has covered all around the lake shore, which consists of coniforous Tsuga chinensis formosana, broad-leaved Trocodendraceae, Fagaceae, Ericaceae and many kinds of Pteridophytes. Vascular plants found are classified 120 species of 58 Familia in all.
3. We find 62 different species of birds, which belong to 23 Familia including Turdidae and Tamaliidae. Presence of a kind of mandarindack, Aix gareliculata, is especially noteworthy.
4. Neither large aquatic plants nor fishes are found, but a great number of Eudiaptomus formosus are found at the northwestern side of the lake.
5. A jumping layer of water is found in the depth of about 10 to 15m from the lake surface, where temperature, pH value, amount of dissolved oxygen and COD value all change drastically lower. While the value of COD and Fe ions in bottom water are risen, and they are estimated about 5mg/l and 9mg/l respectively.
6. The lake is oligotrophic, but both dissolved materials and, in particular, nutrients such as nitrogen and phosphorous compounds are meager.

View full abstract

[in Japanese]

View full abstract

One of the methods to respond to the reduction of agricultural land in urbanizing area is to get substitute agricultural land in suburban area and begin commuter cultivation. The purpose of this paper is to analyze the commuter cultivation in Itabashi ward, Tokyo.
It was a drastic change for agriculture in Itabashi ward where Takashimadaira housing development was carried out in 1960s. Much agricultural land was lost at that time. Some farmers aimed to continue agriculture through getting subustitute agricultural land in the suburb of Itabashi ward and began commuter cultivation. But agricultural operation has been gradually declined. In suburban area, agricultural lands tend to be managed extensively and causes obstruction for efficient agricultural operation.
Up to now, researches in urbanization of suburban agricultural area focused on the change from agricultural land use to non agricultural land use. It should be also researched that the demand for substitute agricultural land in urbanizing area and the problems caused by transfer of ownership around the areas.

View full abstract