There was no one injured when the tree came down sometime overnight at Walnut Creek's Lancaster Park near Lilac Drive and Lancaster Road, said city spokeswoman Gayle Vassar.
City officials have not yet determined what caused the tree to fall. The house it landed on was being examined by city inspectors this morning.
Vassar said Lancaster Park is owned and maintained by the city, and had been inspected within at least five years by the city's arborist.
She added that the approximately 20,000 trees on city-owned property are inspected on a 5-year rotation to ensure they are healthy.
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