A CONSIDERATION OF TEMPORAL CHANGE IN GRASSLAND DISTRIBUTION ON THE TOHOKU DISTRICT, JAPAN

摘要

We analyzed the temporal change of the grassland area and the relationship between topographic features and grassland distribution. The study area is the Tohoku region, in the northeast of Japan. We use the results of the vegetation survey conducted by Ministry of the Environment of Japan to extract grassland area. The total area of the grassland in the Tohoku district has been increased in 1980 to 1990. We classify the grassland based on the slope angle. Less than 8 degree slope angle area is defined as the flat area, 8 to 15 degree area is the moderate slope area, and more than 15 degree area is the steep slope area. The proportion of the grassland in each class is calculated each year. The grassland ratios increase in the steep slope area. On the other hand, they decrease in the flat area.