The Scout tree lot opened in 1969 and has operated continuously since then.
The Black Lives Matter flag will be flown with the U.S. and California flags at the corner of Vista and Highland Avenues in the heart of Piedmont.
"Despite repeated warnings from city staff, users of this facility have continued to play group sports in violation of COVID-19 health orders" made by the Alameda County Public Health Department, the city said in an advisory. "We regret having to take this action, but the actions of field users have necessitated it."
Other cancellations include the annual party in the park, and neighborhood block parties, with the city saying it will not issue street closure permits.
The closure at the park, also known as Piedmont Sports Field, went into effect on Thursday and will continue until further notice.
Unyque Alley, 40 of Oakland, was arrested Thursday for stealing the contents of a customer's package.
The lot -- which will have over 1,500 Noble and Douglas fir and Silvertip trees, as well as garlands and wreaths - is open 9 a.m. to 7 p.m. Saturdays and Sundays, and 4 to 7:30 p.m. weekdays through Dec. 22.