Predicting the Timing of Cherry Blossoms In Washington D.C. and Mid-Atlantic States In Response to Climate Change

We applied a process-based phenology model of temperate deciduous trees to predict peak bloom date of flowering cherry trees (Prunus x yedoensis ‘Yoshino’) in the Tidal Basin, Washington D.C. and the surrounding Mid-Atlantic States in response to the regional climate change projections. We first optimized model parameters with the past blooming data at the Tidal Basin from 1947 to 1970 using daily maximum and minimum temperatures collected from a nearby weather station at the Reagan National Airport. The optimized model was tested against more recent peak bloom data of the same location from 1971 to 2000. The model performance against the recent independent data was satisfactory (r² = 0.70, RMSE=6.4 days). We then estimated the future peak bloom dates for the Tidal Basin and the surrounding states including Maryland, Virginia, and West Virginia by applying this optimized model to four climatological normal years (1971-2000, 2010-2039, 2040-2069, 2070-2099). We analyzed the temporal and spatial variability of the peak bloom dates at four selected locations: Tidal Basin, DC; Baltimore, MD; Richmond, VA, and Kearneysville, WV. Our results indicate that peak bloom dates in the near future (2010-2039) would be accelerated or delayed depending on the location under the A1B emission scenario. Conversely, we found that peak bloom dates are likely to be accelerated by an average of five days during the period of 2040-2069 and by 10 days in the period of 2070-2099 compared with the current bloom dates (1970-2000). Our results suggest that in most areas of the region peak blooms are likely to take place before April with an exception of the Appalachian Mountain range by the end of the century. In addition, the model predictions suggest that there is a strong likelihood that the chilling requirements for dormancy release in the flowering cherry trees in the Tidal Basin and southern coastal areas may not be met by the end of the century; this may result in unpredictable blooming habits of the flowering cherries in the region.