広域・長期的な河道内植生動態把握に向けた航空写真の更なる活用方法に関する研究～天竜川下流域を対象として～

Abstract

In this study, various applications of aerial photograph analysis were proposed to detect the large scale and long term dynamics of riparian vegetation. By comparing the aerial photographs taken at neighboring shooting date, expansion and destruction rates of vegetation, age of vegetation and critical discharge dividing expansion and destruction of vegetation can be estimated in addition to the surface cover types and vegetation cover rate. The results of the analysis show that the vegetation expansion and destruction rates are considerably large in the study site whereas the vegetation cover rate has gradually increased during last 40 years. The vegetation expansion was expected to occur during the period that the annual maximum discharge had been less than 4000~6500 m3/s.