A grave-sweeper marking the Chung Yeung Festival by burning offerings could become the first to be prosecuted for allegedly causing a hillfire. If convicted, the man could face a $25,000 fine and one year in jail under the Forests and Countryside Ordinance. The man is alleged to have left embers behind, which then began to blaze in Plover Cove Country Park, Tai Po on Monday. He was stopped by Agriculture and Fisheries Department staff in the park. From Saturday to Monday more than 100 department staff and 40 Civil Aid Services officers patrolled hillfire black spots across the territory. To prevent fires, they provided visitors to graves with metal containers to burn offerings and distributed fire-prevention leaflets. A department spokesman said about 6,000 trees were burned in 172 hillfires reported between Saturday and Monday. 'A baby tree costs about $20,' the spokesman said. The bulk of the trees were in Tai Lam Country Park, Tuen Mun.