On the Terraced Plantation (1)

Abstract

In the districts of heavy snowfalls, the extensive movement of accumulated snow is causing a great deal of damage to planted trees. In order to protect these trees from the damage, the mountainside slopes are cut to form terraces.
The terraced plantation has been practised for many years in some parts of Niigata Prefecture, but there are many problems remaining unsolved.
To solve these problems, the experiment was carried out at Yunotani Village and Koshiji Town in Niigata Prefecture. The terrace cut was made according to the formula as follows :
Koshiji T. H= 8L… (L =150 cm) H= 9L… (L =100 cm and 150 cm) H=10L … (L =100 cm and 150 cm)
Yunotani V. H= 4L… (L =80 cm, 120 cm and 160 cm) H= 6L … (L=80 cm, 120 cm and 160 cm) H= 8L… (L =80 cm, 120 cm and 160 cm)
H : height of the terraces
L : width of the terraces
Investigating the movement of the accumulated snow in the winter of 1966 to 1969, we obtained the following result : The accumulated snow on every terrace was stable where the width of the terrace was over 150 cm, but unstable when it was under 150 cm, revealing the close relation between the movement of the accumulated snow and the width of terraces.