A four-year-old boy was killed in front of his father after a eucalyptus branch fell on him in a California park — with his family now filing a wrongful death lawsuit alleging the trees have been doomed for decades.

Ronan Kerr was struck on the head by a “large” piece of a eucalyptus tree while playing in Villa La Jolla Park in San Diego in June, according to a GoFundMe organized for his family.

Ronan Kerr was killed after a eucalyptus branch fell on him in front of his father in a San Diego park in June. GoFundMe

He was beside his father, Cathal, and his 7-year-old brother, Charles, when the 34-foot branch plummeted 60 feet down from the tree, according to a wrongful death lawsuit obtained by the San Diego Union-Tribune.

Cathal Kerr tried to swoop in to grab both the boys, but was unable to catch Ronan in time. The branch then struck little Ronan and his father, according to the lawsuit filed on Tuesday in San Diego Superior Court.

The 4-year-old died after seven days in the hospital, the lawsuit said, according to the outlet.

His father, Cathal, also suffered several harrowing injuries, including a traumatic brain injury, facial lacerations, and broken bones, the document said.

The lawsuit, filed against the city of San Diego and two city contractors reportedly in charge of tree upkeep, claimed that the fateful branch that struck Ronan was clearly unhealthy and decayed.

The 4-year-old died after seven days in the hospital, the lawsuit said. GoFundMe

His father, Cathal, also suffered several harrowing facial injuries, including a traumatic brain injury, facial lacerations, and broken bones. GoFundMe

“The tree’s branches and limbs were large, elongated, heavy, angled, and improperly maintained to the point that it was obvious to a trained eye that the tree would catastrophically fail,” the lawsuit said, according to the outlet.

The suit alleged that branches from eucalyptus trees or other trees have dangerously fallen at least 30 times since 1983, including in Villa La Jolla park, the outlet reported.

In 1983, a 4-year-old was killed by a fallen branch at the entrance to the San Diego Zoo. In 2013, a pregnant woman and a man were also injured by a fallen tree at the UC San Diego campus, according to the lawsuit.

“Eucalyptus trees in San Diego parks … were posing significant dangers to the public,” the lawsuit alleged.

“The city’s inspection and maintenance protocols were grossly inadequate to identify hazardous trees before they failed.”

The lawsuit seeks to have all eucalyptus trees deemed a danger to the public in parks and school yards be either removed or managed, the outlet reported.

The Kerr family described Ronan in his obituary as a “lover” and a “tender soul.” GoFundMe

It also requested that trees be inspected on time and that tree inspections and risk assessments be posted publicly by the city.

The Kerr family described Ronan in his obituary as a “lover” and a “tender soul,”

“Ronan was a bright light in the lives of all who knew him – full of heart, humor, and boundless curiosity,” his obituary read.

“He adored his big brother and always wanted whatever he had – not just his toys, but his attention, his love, and his approval. His family was his world, and nothing made him prouder than being helpful,” his family wrote.

Attorneys for the Kerr family and the city of San Diego did not immediately respond to a request for comment from The Post.