涉三大乡镇、面积超千亩，北京城市副中心这项大工程开建

Core Insights - The Tongzhou District has officially launched the 2025 key afforestation project, marking the transition from preparation to implementation, covering 1007.6 acres of green space [1] - The project aims to enhance the ecological construction of the urban sub-center by creating near-natural forests with distinctive colorful leaves [1] - The initiative is expected to increase the forest coverage rate by approximately 0.3 percentage points, improving the ecological corridor system [1] Project Details - The afforestation project will focus on three towns: Zhangjiawan, Kuoxian, and Yongledian, each with tailored ecological landscape plans [1] - The project will be executed with a detailed operational plan, including special inspections based on the unique needs of the three towns [1] - Third-party quality assessments will be conducted to ensure the construction standards for the three featured landscapes are met [1] Environmental Achievements - Since the 14th Five-Year Plan, Tongzhou District has significantly expanded its green ecological space, achieving a historical PM2.5 annual average concentration that meets national secondary standards [2] - All eight monitored water quality assessment points have reached Class III or above [2] - The district has successfully created the first national forest city in a plain area in the city, with a park green space service radius coverage rate of 95.33% [2]