Print PageClimate change is affecting the phenology of species worldwide. As temperature increases, flowering is beginning to happen earlier in the year. The responsiveness to climate has been observed to vary in a predictable way among species and taxa, with early blooming species being more responsive to changes in temperature than late blooming species. To further understand this phenomenon, we examined a 64 year record of cherry (Prunus x yedoensis ‘Yoshino’ and Prunus serrulata 'Kwanzan' ) bloom dates from Washington D.C.’s Tidal Basin.
Results/Conclusions
The two cultivars response to temperature varied as predicted. On average, the bloom date of Yoshino cherries (an early blooming cultivar) increased 3.4 days for every 1ºC increase in mean February-March temperature, whereas the bloom date of Kwanzan cherries (a late blooming cultivar) increased 3.0 days for every 1ºC increase in mean February-March temperature. Mean February-March temperature explained 56% (based on r2 values) of variation in Yoshino bloom date and 34% of the variation in Kwanzan flowering date. If temperature continues to increase, the peak flowering dates of the two cultivars will begin to diverge. This divergence could have consequences for the cherries, pollinators, and the national cherry blossom festival. We have parameterized a thermal unit model that can predict cherry bloom dates with high accuracy. This model could give further insight into the change in bloom date that is occurring in a changing climate.
