Earth Day cleanup By Submitted Content - April 25, 2024 Courtesy of the Friends of Princeton Open Space A record number of volunteers gathered at the Billy Johnson Mountain Lakes Preserve in Princeton to join with Friends of Princeton Open Space (FOPOS) for two special Earth Day cleanup and planting sessions, a community potluck lunch and a native plant giveaway on April 20. FacebookTwitterEmailPrint Courtesy of the Friends of Princeton Open Space A record number of volunteers gathered at the Billy Johnson Mountain Lakes Preserve in Princeton to join with Friends of Princeton Open Space (FOPOS) for two special Earth Day cleanup and planting sessions, a community potluck lunch and a native plant giveaway on April 20.