| Riparian woody vegetation have increased and grown thickly in gravel-bed rivers in Japan since the 1990s. In many of these rivers， management such as cutting and uprooting has been conducted， but it is likely to be insufficient to control the riparian woody vegetation. The purpose of this study was to examine which species have been expanding since 1990 and how effectively those species have been managed. We used the vegetation map of 117 rivers and investigated 13 river fields. Our findings indicate that willow， Robinia pseudoacacia L.， and bamboo are the dominant riparian species and have been increasing in recent years. We found that uprooting was an effective means to prevent the expansion of woody vegetation if branches and rhizomes were removed at once， although only cutting was ineffective. We conclude that riparian vegetation management have to be conducted depending on the particular characteristics of each species. |
