April 3, 2023
Campus Cherry Blossoms
Last updated 6:15 PM, Sunday, April 2nd, 2023
By Henry Kessler
Hello Huskies and Happy Sunday!!!
March recently turned over into April and in case you haven’t noticed, spring is springing! Besides the passing of the Spring Equinox, daily average temperatures are noticeably on the rise, the day length is increasing, and most notably our beautiful Sakura trees are blooming throughout campus. If you haven’t been able to check them out yet, make sure to head over to the Quad soon, as our cherry trees are currently in peak bloom, meaning 70-80% of buds have sprouted into their defining pink or white blossoms. You can also check out the live cams set up in the Quad or see some pictures posted by visitors with the #uwcherryblossom hashtag on twitter or instagram.
The cherry trees in the UW Quad photographed April 2, 2023. Henry Kessler/University of Washington.
Around this time every year, the quad lights up with thousands of visitors who come to check out the iconic cherry trees at the University of Washington during the U District Cherry Blossom Festival. Elsewhere, Cherry Blossom Festivals are a large tourist attraction such as in Washington D.C or throughout Japan, where Sakura Trees are native. Plantings of cherry trees began in the US in Washington D.C in 1912, after Japan presented over 3,000 trees as a gift of friendship to the People of the United States. Seattle’s Cherry Blossom Festival was initiated in 1976 by the generous gift of 1,000 cherry trees from Takeo Miki, Japan’s former prime minister. This gift was in commemoration of America’s bicentennial friendship between the people of Washington state and Japan. Cherry blossoms carry great spiritual significance in Japanese culture and their blooming has been celebrated with rituals called Hanami since the 9th century!
Based on this large, global interest in seeing the beautiful transformation of Cherry trees, there is a demand for an accurate forecast of the timing of blossoms. However, exact timing can be difficult to determine as different cherry tree species blossom at different times depending on certain environmental conditions. Additionally, warming associated with climate change is known to alter ecosystem processes such as plant phenology, or the timing of organism development. Determining the sensitivity to these environmental conditions is important for tracking how peak bloom dates change as a result of climate change. There is ongoing research by students and faculty at the UW into predicting the peak bloom of cherry blossoms.
The six stages of cherry blossom development. From: https://vcbf.ca/2020/03/09/six-stages-of-cherry-blossom-development-from-buds-to-flowers-infographics/
So what are these environmental conditions and how do they impact plant phenology? Studies have revealed that blossom development is mostly a temperature-sensitive process, where warmer temperatures encourage earlier bloom dates while cooler temperatures cause a delay in peak bloom. During the past decades, significant shifts in general tree phenology in temperate regions have been observed, as growing season length is increasing and peak bloom is advancing due to the rises in the average global temperature. Additionally, Yoshino cherry blossoms – the main species of Sakura at UW – are highly correlated with transition-season temperatures, from February through early March, as the accumulation of temperature during this time has a strong influence on the flowering process. Climate change is impacting seasonality, including warmer temperatures during the winter and spring, creating the conditions for earlier blooms. One concern with this is the tree’s susceptibility to cold snaps, as early periods of warmth falsely indicate that spring is arriving and initiate flower bloom. Then, if temperatures dip back to their seasonal-norm, this temperature shock damages the health of the tree. Expected changes to the climate may become so extreme that the locations which currently support the Sakura population may be unable to in the future. On top of climate, cherry blossoms are also sensitive to weather patterns, where patterns that bring high winds and precipitation can shorten the period that the tree holds its flowers.
The cherry trees in the UW Quad photographed April 2, 2023. Henry Kessler/University of Washington.
The heritage of Hanami festivals stems from a distant culture that is highly important locally. Remembering that the Sakura were originally a gift of friendship from Japan to the US, protecting these trees is symbolic of protecting this relationship. Additionally, festivals that celebrate the blossom create opportunities for businesses in the University District. Future monitoring of the phenology of the Sakura trees on the UW campus is important to maintain the traditions associated with our beloved trees.
I hope you all have a great week 2, Huskies!!
Reach forecaster Henry Kessler at theuwdawgcast@uw.edu, on Twitter @TheUWDawgcast, or on Instagram @uwdawgcast.
