There were several Earth Day celebrations and events Thursday. One of the biggest and most successful was the official City of Sacramento Earth Day Celebration. The event was held at Cesar Chavez Park and in the plaza of City Hall. An estimated 3,500 people of all ages attend this years' event. It was supported by Mayor Kevin Johnson and the City Council. The City of Sacramento Neighborhood Services Department organized the event.   I spoke with Neighborhood Services Department Director Vincene Jones. Jones and her staff started back in January giving early notice to Sacramento area schools, informing them of the event and its value as a field trip. Local media was enlisted to help get t