The researchers studied how calcium chloride affects the photosynthetic process in Prunus sargentii trees commonly found on Korean streets. They watered the trees with different concentrations of calcium chloride before the leaves grew. They found that higher calcium chloride concentrations led to lower chlorophyll levels and reduced photosynthetic rates. The trees also showed decreased ability to convert light into energy and had slower growth. This suggests that calcium chloride can limit the trees' ability to photosynthesize and grow properly.