Hundreds of Japanese cherry trees have welcomed visitors to the Tidal Basin in Washington, D.C.'s National Mall since 1912. Every spring, these trees blossom into a spectacular show of pink and white, attracting thousands of annual tourists. Yet, in 2024, these icons face novel threats from sea level rise, land subsidence, and crumbling seawalls. Currently, water overflows portions of the Tidal Basin's seawalls twice a day during normal tidal conditions.
On any given walk along the Tidal Basin, a high tide can overtake pedestrian pathways and inundate cherry tree root systems. Here, water has risen four feet over the past century, one foot from sea level rise, and three feet from its sinking foundation.
Flooding represents a challenge for trees because waterlogged soils have less oxygen which stresses tree roots. Cherry trees generally have moderate tolerance to flooding - they are neither the most sensitive or the most tolerant of trees. However, some of the Japanese cherry trees in the Tidal Basin are now inundated almost daily, and this will likely kill them with time. Flooding is also a big issue for people visiting the trees. The trees don't like to get their feet wet too often and neither do we.
-Keryn Gedan, Ph.D., Associate Professor of Biology at The George Washington University
"Stumpy," an iconic cherry tree on the south bank of the Tidal Basin, will be one of 158 cherry trees cut down as the National Park Service starts rebuilding crumbling sea walls in mid-2024, projected for completion in 2027.
Along the Potomac River, 18 cherry trees in West Potomac Park face a similar fate as their 140 neighbors in the Tidal Basin. The 113 million dollar project, which requires 300 total trees to be removed for site preparation, will rehabilitate 6,800 feet of seawall and extend its life expectancy by 100 years.
When the project is complete, the Park Service will plant 455 new trees, including 274 cherry trees. Those removed, like Stumpy, will be transformed into mulch to provide nutrients and protection to the roots of their replacements.