LAKE BALBOA >> Each spring for nearly a quarter-century, thousands have converged upon Lake Balboa to lollygag under one of the nation’s biggest bursts of cherry blossoms.

But after four years of drought, the pink-and-white cloud hovering over what were once 900 cherry trees in the center of the San Fernando Valley is in danger of being gone for good, a victim of too-warm winters, too little rain and too little drainage in the Sepulveda Basin, city officials say.

Half the trees around Lake Balboa have died within the past five years, according to a September city parks survey. Much of the other half appears to be on life-support.

“It’s sad,” said Laura Bauernfeind, head of the Forestry Division for the Department of Recreation and Parks, who grew up in Van Nuys, attended nearby Birmingham High School and recalls when Lake Balboa was but a cornfield. “When these individual trees were planted, the trees were doing well. Now they’re struggling, to say the least.”

Taking root

The grove of prunus serrulata took root in 1992 at the dawn of the 27-acre Lake Balboa, now the heart of sprawling Anthony C. Beilenson Park.

As the U.S. Army Corps of Engineers filled the $20 million lake with reclaimed water from the Donald C. Tillman Water Reclamation Plant next door, an anonymous donor from Japan figured out how to make it beautiful.

In Japan, blooming cherry blossoms are a sign of spring and central to quiet picnics and jubilant flower festivals. In the United States, the most recognized collection grows in Washington, D.C., where 3,500 trees light up the National Mall, courtesy of a gift from Japan.

And in the Valley — where 800 Pink Cloud cherry trees were first planted at Lake Balboa 23 years ago, with 100 more added a few years later and 150 replanted around 2009, officials say — the blooming cherries became a rite of spring.

“Five years ago, it was like a cherry forest,” said Kenny, who declined to give his last name, who had driven from his home near LAX one day this summer to read a book atop what was once known as Cherry Hill, on a small peninsula jutting into the lake. “People used to come from all over to take pictures. It was very beautiful.

“Now it’s kind of pathetic. … The grove is gone.”

Dying trees

Former Los Angeles County Supervisor Zev Yaroslavsky, in a blog post three years ago, outed the Valley’s cherry benefactor as the Canare Corp., a Japan-based cable manufacturer.

“They had an office in the San Fernando Valley and wanted to give back to the city,” James Ward, once in charge of maintenance of Los Angeles parks, told him. “They even sent some of us back to learn how the Japanese maintain the trees.”

But of the more than 1,000 Pink Cloud cherry trees Canare helped plant at Lake Balboa, according to the parks survey, 486 survive.

Over half of those trees were found to be in “poor or critical condition,” Bauernfeind said. And the reasons for their demise are many.

The Pink Clouds were chosen because of their ability to withstand L.A.’s warmer weather, but the hotter drought years haven’t provided enough chilly nights below 45 degrees that such trees need, she said.

While the ornamental cherry trees were once planted with special tubes in the poorly draining soil, the infrequent rain hasn’t been able to leach away harmful salts and minerals in recycled water.

And as the trees sit on city property, they must conform to the city’s watering restrictions.

“Coupled with the fact that we’ve had hotter-than-normal winters, the least number of proper chilling hours and below-normal rains and restrictions on irrigation, we’ve had the perfect storm against cherries,” Bauernfeind said. “It’s not proven the ideal site for these trees.

“Pink Cloud cherries in Japan can live for decades. What we’ve found is that Los Angeles is not the ideal microclimate. Right now, there are no plans afoot for cherry tree replanting. … As the trees die, they’ll be removed.”

Study underway

The weather has also taken its toll on 350,000 trees within the city’s more than 450 parks, where between 4 percent and 6 percent have died or are at risk of dying because of drought, she said.

The parks department has now teamed with City Plants, formerly Million Trees Los Angeles, and the U.S. Forest Service to study tree varieties more suitable for a changing climate. This spring, they plan to plant two trees each of a dozen species of trees at eight unnamed coastal and inland parks to study their long-term suitability.

Residents are disappointed at the cherry tree loss. On a recent day, most of the mature cherry trees around the 1.3 mile perimeter of Lake Balboa were dead, their leafless boughs only sustaining an occasional heron. The leaves of younger trees were brown and wilted.

“I noticed the trees, almost dead,” said Iancu Zica, 78, of Reseda, a native of Romania who walks around the lake once a day, looking at the silver lifeless forms. “Perhaps it’s the soil. I don’t know what’s happened here. Three years ago, these trees looked good. Now, not so good.”

David Honda, a Japanese-American who once served on a city committee to found the Japanese Garden in the Sepulveda Basin, blamed the city for not conserving its precious gift.

“Shame on them,” said Honda, of Northridge. “The Japanese-American community in Los Angeles will be outraged once they learn the way the city has handled trees that will never be replaced.”