Relationship between the tree vigor of dogwood (Cornus florida) street trees and street configuration in Tokyo

Street trees, which play a certain role in alleviating problems in urban areas, are experiencing the poor growth due to the stress in the urban environment. Therefore, it is necessary to grasp the environmental factors that affect the growth of street trees. In this study, we analyzed the relationship between the degree of decline and street configuration among 2,615 dogwoods planted along the streets in Tokyo. As a result of our analysis, in the area where the buildings were tall, the tree vigor tends to be poor and in the area where the planting type was planting zone rather than planting pot, the tree vigor was tend to be good, in whole Tokyo area. Outside Tokyo 23 wards, there was a tendency for good tree vigor in the area where the road width was wide and the street trees were facing south. In Tokyo 23 wards where tree vigor has deteriorated since 2006, the buildings were tall and the roads width was also narrow. The results of this study show the possibility the effects of sunshine on the dogwood tree vigor are large in the wide areas. In particular, the height of the buildings and road width were regarded as significant factors where the tree vigor was actually degraded.