The glaciological studies were carried out on the ground ice in the USA CREEL Permafrost Tunnel, Fairbanks, Alaska, as a part of the JAPANESE ARCTIC HYDROSPHERE EXPEDITION 1968. After classification of ground ice as Ice wedge, Pond ice, Clear ice, Vein ice, the results of ice layers were described in relation to the stratigraphy of the section inside the tunnel. It was found from the fabric analysis of ice on the basis of observation by polarized light that the stereogram of the crystallographic orientation of grain of Ice wedge showed simillar characteristics to those of glacier ice.

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The perennial snow patches, which exist in the mountain ranges in the central and northern parts of Japan, can be considered as follows, (a) one of the processes of metamorphism of snow to ice, (b) a transient state from seasonal snow cover to cirque glacier, (c) a system of water balance, (d) one of the indicators of climate and climatic trends, and (e) one of the objects for climatic control. Therefore, the studies on perennial snow patches will be related to various research fields in earth sciences, namely, physics of snow and ice, glaciology, climatology, paleoclimatology, meteorology, hydrology and geomorphology.

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The experiments on the relation between the rate of sublimation from snow surface and intensity of irradiated radiation or wind velocity to the snow surface are carrid out in the low temperature room that a uniform air temperature and a uniform humidity is keeped up respectively -15°C and 5457%, and by using snow that snow density and the diameter of a granule of snow is respectively 0. 390.41 (g/cm³) and below 0.42mm.
In the text, the experimental apparatus of the low temperature room is shown in Fig. 1, and the snow vessel of sublimation is shown in Fig. 2.
As the radiation source, the Yoko Electric Light were used, and the radiation and the solar radiation are distributed by the same energy quantity from short to long-wave radiation.
Results of experiments :
(1) The rate of subrimation increase quickly with the intensity of irradiated radiation. In Fig. 4 of text, it is shown by solid curve based on the open circle*, and it is given by
E= (4e^-3.828R +20R+2.7U-2.5) ×10^-7… (1)
when U>0.5 (m/s), where E (g/cm²sec), U (m/s) and R (cal/cm²min) are respectively the rate of subrimation, the wind velocity and the intensity of irradiated radiation.
(2) The rate of sublimation with radiation E_R are found to be not concerned with wind velocity (Let it be assumed that the rate of sublimation is the sum of the both of the rate of sublimation with wind velocity E_W and radiation E_R). In Fig. 6 of the text, it is shown by the open curcle*, and it is given by
E_R= (e^-3.828R + 5R-1) ·4 × 10^-7 … (2)
(3) The ratio of LE_R to R (1-r), η are shown by percentage in Fig. 7 of the test, whore L and r are respectively the latent heat of sublimation and albedo of snow surface. η is calculated by assuming r=0.7 for the value of albedo.
* The soled circle and the open square in Fig. 4 and 6 are the values masured by radiation of colour photo-light and heater of nicrom wire respectively.

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The present investigation was done from the point of view of the establishment of forest on the avalanche-hazard slope. The results of the investigation is summarised as follows :
1. Damages of trees by snow-gliding are comparatively little on the low-pitched slope near a round ridge : there are found few examples of break-of-trunk and uprooting.
2. The trunk-bending near the ground is conspicuous, and the diameter at the bending is very thicker.
3. Each tree species, especially Dake-birch (Betula eramnii) , at the site is larger in both height and diameter growths than on the avalanche-hazard slopes.
4. Prevailing wind in growing season is seemed to influence on treegrowth.
Moreover, from many observations we suppose the reforestation as follows :
1. The reforestation on the starting part of avalanche is prosperous, because of the possibility of tree-growing and of the removing of Sasa vegetation in sylvicultural engineerings.
2. Tree species, used to halt the start of avalanche, must be indigenous to the region and tolerable against snow damages : Itayamaple (Acer mono) , Dake-birch, Japanese beech (Fagus crenata) , and Japanese linden (Tilia japonica) may be good for this purpose.

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