Fig. 9

The relationships between the formation of earlywood vessels and leaf phenology in Q. serrata (a) and R. pseudoacacia (b). Each symbol indicates a stage during the differentiation of the first earlywood vessels as follows: triangles division of cambial cells, circles expansion of vessel elements, hexagons deposition of secondary walls in earlywood vessels, and squares formation of perforations (disappearance of end walls of vessel elements). Open symbols indicate that the respective stage of differentiation of the first earlywood vessels was observed. Filled symbols indicate that the respective stage of differentiation of the first earlywood vessels was not observed. Partial perforation of vessels was observed at the top of a stem of Q. serrata on 16th April and near the ground in a stem of R. pseudoacacia on 20th April