WASHINGTON — They work year round for just a few fleeting moments' worth of flowers. 

The National Parks Service arborists say keeping the Mall's 3,800 cherry trees healthy isn't easy. 

“Our big challenges are managing the soil conditions around the trees," said lead arborist Jason Gilles.

Every year the blooming trees attracts hundreds of thousands of people to the Tidal Basin. 

But all that foot traffic compacts the trees' root systems, which makes it more difficult for the trees to absorb the nutrients they need, said Gilles. 

Flooding is another big concern, according to Gilles.

“Anybody who visits the Tidal Basin is going to notice a lot of tree stumps,” said Gilles.  “Tidal inundation is happening at a greater frequency than it did in the past, and it’s saturating the root zones of the trees.”

Some of the arborists have been caring for the trees for 32 years.

“It’s a responsibility you take seriously. It’s obviously a high visibility asset to the nation and you want to be the one that when it’s on your watch, you’re doing it well,” Gilles said. 

The average cherry tree lives to be about 25-years-old, but thanks to the care they’re given, many of the trees on the Mall are twice that age. Among the oldest trees are some of the original trees that were brought over from Japan in 1912-- and are now over a century old.

“To see trees that are getting past the 50 to 60-year mark is a pretty incredible thing,” said Gilles. “And given the issues we have with the soil, the foot traffic etcetera, it’s an even more incredible thing.”

The arborists say knowing that makes it all the more gratifying when the trees reach peak bloom again.  

“When you manage the cherries on the National Mall, the crew is entwined in what I would say is the national American epic,” said Gilles. “So every year when this occurs-- given the history of it-- there’s that feeling of being part of something greater than yourself, of collective achievement. And you can see that pride on the crew’s face.”