The mother of a bride was crushed and killed when a tree fell on her during the family's wedding photos.

Margerita Mojarro, 61, died in Penn Park, California, hours after walking daughter Patty down the aisle.

The four-year-old niece of the bride also suffered critical head trauma when the 100-foot eucalyptus tree uprooted and crashed on them.

Several people were trapped underneath the tree in Saturday's tragedy.

The park has been closed indefinitely while the investigation continues.

Whittier Mayor Joe Vinatieri told the LA Times on Sunday: "The mother lost her life. A 4-year-old is injured. How do you explain it? You can't.

"The tragedy of the situation is on the hearts and minds of many people. We need to pray for the family because of the injuries and losing someone on a day that's supposed to be a great celebration."

The cause of the tree falling has not been confirmed, but LA's Deputy Fire Chief said that "a large amount of rain" followed "drought conditions", which could have weakened its roots.