 They are believed to have been grown from cuttings taken from the Spanish Colonial c. 1800 planted olive orchard trees at the Mission San Fernando Rey de España across the Valley.When the site was designated a Historic-Cultural Monument in 1967, there were 76 olive trees along several blocks of western of Lassen Street.According to the Chatsworth Daughters of the American Revolution chapter, there are 49 trees surviving/remaining in the 2010s.