Climate warming may cause earlier spring snowmelt in high and middle latitudes, potentially affecting plant phenology and growth, but experimental results have been inconsistent. We examined whether vessel type explains varying responses to early snowmelt across tree species. Saplings of three diffuse-porous and three ring-porous species were grown under manipulated and control snowmelt conditions. Species-level effects were not significant, but pooled data revealed a significant interaction between vessel type and treatment, indicating that responses differed between vessel types. Diffuse-porous species showed a slight increase under early snowmelt, whereas ring-porous species showed a slight decrease; however, pairwise comparisons within vessel types did not detect significant differences. In contrast, early snowmelt reduced leaf δ 13 C (a water stress indicator) in diffuse-porous but not ring-porous species suggesting reduced water stress in diffuse-porous species. Sugar concentrations also diverged: diffuse-porous species showed a significant decrease under early snowmelt, whereas ring-porous species remained unchanged, implying contrasting frost-protection strategies. The vessel-specific responses could influence forest dynamics under climate change. Larger studies are needed to confirm these findings and clarify how functional traits such as vessel architecture shape species adaptations to changing snowmelt patterns.
Ueda et al. (Thu,) studied this question.