常願寺川河川敷に見られる河畔林の森林構造を明らかにした.河口近くの森林群落はカワヤナギ,河口から8 kmの森林群落はニセアカシア,河口から13 kmの森林群落はカワヤナギとアキグミが優占種であった.
Forest structures of three stands established on the flood plain in Jouganjigawa-river were investigated by the quadrat method in 2015 and 2016. A survey of stem girth at breast height, tree height, size of canopy, location of tree and identification of species for all trees of 2m or more in height in each quadrat was carried out. (1) In Jouganjigawa1 stand located on 0.8Km from estuary, total basal area (BA) was 11.53 m2/ha. The most dominant species was Salix miyabeana subsp. gymnolepis, because its BA was 6.57 m2/ha and its occupied 57% in all. Fisher's values of the coefficient of diversity (α) and tree density were 1.4 and 1981 trees/ha. (2) In Jouganjigawa2 stand located on 8.0 km from estuary, total basal area (BA) was 5.15m2/ha. The most dominant species was Robinia pseudoacacia, because its BA was 4.63m2/ha and its occupied 90% in all. Fisher's values of the coefficient of diversity (α) and tree density were 0.7 and 278 trees/ha. (3) In Jouganjigawa3 stand located on 13 km from estuary, total basal area (BA) was 1.64 m2/ha. The most dominant species were Elaeagnus umbellata var. umbellate and Salix miyabeana subsp. gymnolepis, because both species showed same BA (0.82m2/ha) and these two species occupied 100% in all. Fisher's values of the coefficient of diversity (α) and tree density were 0.6 and 375 trees/ha.