Effect of Volcanic Activity on Succession of Woody Vegetation and Growth Environment, and Water Infiltration Rate on Sakurajima Volcano, Japan

Abstract

  We clarify the effect of volcanic activity on the succession of woody vegetation and growth environment, and water infiltration rate on the northern flank of Sakurajima Volcano, Japan. We made survey quadrants at slope distances 2.1 km, 2.3 km, 2.8 km, 3.3 km and 3.6 km from the Minami-dake crater of the volcano and conducted field investigations. The number of trees and tree species, breast height cross-sectional area, Fisher-Williams index of diversity, forest soil thickness, and water infiltration rate all increased with distance from Minami-dake. However, thickness of the volcanic ash layer deposited since the 1914 Taisho eruption and pH of the forest soil surface layer decreased with distance. Because of long-term volcanic activity, woody vegetation in the survey quadrants was poorer than the climax forest. Moreover, the rate of succession of that vegetation, water infiltration rate, and forest soil development were much slower than those of the climax forest.