According to Ventura fire Battalion Chief Douglas Miser, the man was trimming a palm tree at Golf N' Stuff Thursday morning when a branch broke off and he fell.
The coroner's office told the Ventura County Star that the man, identified as 62-year-old Nicholas Rojas of Fillmore, died of blunt force trauma at an area hospital four hours after his fall.
According to the hours posted on the facility's website, the park was closed when Rojas fell.
State job safety officials are investigating the death.
The Associated Press contributed to this report.