A record of number of trees along the Tamagawa-Josui canal, western Tokyo, felled by the typhoon

Abstract

Typhoon No. 24 in 2018 hit Tokyo at midnight of September 30th for several hours, which resulted in many trees along the Tamagawa-josui canal being felled.　We recorded the number of such trees （> 20 cm in diameter） along the 30 km canal, and found 111 （3.7 tree/km）.　Felled trees occurred more in the eastern part than the western one.　As many as 78.4% of the trees fell down to NW, N and NW directions, suggesting the wind blew from south to north.　One third of the felled trees were relatively large cherry trees.　The Koganei block in the central part of the Tamagawa-josui canal is famous for cherry trees from Edo Era where trees other than cherry are logged.　In this block, wind damage was 7.1 times greater and more cherry trees were felled than in other blocks.　Canopy opening caused by fallen stems and thinning by branch breakage has resulted in more light reaching the ground layer, which will likely cause vegetational changes.