Seiji YANAI’s scientific contributions

... Under the R. pseudoacacia canopy, however, we found R. pseudoacacia subtrees and shrubs, but no willows, probably because the light level under the Robinia canopy was inadequate to foster the growth of pioneer Salix species (Fig. 6). Although willow seeds germinate effectively and become established in wet conditions (Yanai & Kikuzawa 1991), the differences in site height above water level were small for all of the herb, shrub, and tree communities (Fig. 5). The 95% confidence intervals of the H and Hr; Ss and Sr; and Ts, Tm and Tr comparisons overlapped (Table 7). ...

Reference:

Riparian forest invasion by Robinia pseudoacacia and its effects on riverside vegetation