联合国粮农组织-森林-水管理指南（英）-2021-184页_6mb

Summary of A Guide to Forest-Water Management

Core Content

This guide, published by the Food and Agriculture Organization of the United Nations (FAO), the International Union of Forest Research Organizations (IUFRO), and the U.S. Department of Agriculture (USDA), focuses on the integration of forest and water management. It aims to improve global understanding of the relationship between forests and water, and to provide a framework for monitoring, managing, and valuing forest-water interactions.

Main Points

Forest-Water Relationships

• Forests and trees are integral to the global water cycle, regulating water quantity, quality, and timing.
• Forested watersheds supply 75% of the world's accessible freshwater and provide water to over half the global population.
• Changes in tree cover significantly affect hydrology, increasing risks of erosion, water stress, and forest fires.

Importance of Water Security

• Water security is a major global challenge, especially with climate change exacerbating water stress.
• A water-centred approach to forest management can offer nature-based solutions for enhancing global water resilience.

Monitoring and Reporting

• Standardized global methods for monitoring forest-water relationships are lacking due to the contextual nature of these systems and resource limitations.
• The guide introduces a new approach for monitoring riparian forests using available data and software, emphasizing the importance of integrating remote sensing, field methodologies, and citizen science.
• The Forest and Landscape Water Ecosystem Services (FL-WES) tool is highlighted as a key resource for monitoring and assessing these interactions.

Managing Forests for Water

• Sustainable forest management for other goods and services (e.g., timber) is compatible with water-quality objectives, though trade-offs may be necessary.
• Forest managers can influence evapotranspiration and the division of rainwater into runoff and infiltration, which directly affects water availability.
• Resilient forest management practices can reduce the risk of catastrophic decline in ecosystem services, including those related to water.
• Specific practices such as variable-density thinning (VDT) and road infrastructure management are examined for their impact on water resources.

Valuing Water from Forests

• The global value of water services provided by forests has declined by nearly USD 10 trillion per year between 1997 and 2011.
• Payments for Watershed Services (PWS) are proposed as a mechanism for benefit-sharing and cooperation, especially in the absence of strong governance frameworks.
• PWS schemes include water fees (utility-led) and multiple-benefit partnerships, with examples from various countries.
• Communication strategies are emphasized as essential for increasing the effectiveness of forest-water initiatives, gaining political and public support, and building trust with communities and stakeholders.

Key Ecosystems for Forest-Water Management

• The guide identifies four key ecosystems:
  • Mangroves: Provide essential ecosystem services, including climate change mitigation and coastal protection. About 30-35% of mangroves have been lost since the 1980s, and their conservation is critical.
  • Peatland forests: Play a vital role in water regulation and carbon storage. Peatland drainage increases fire risk, and restoration is essential for maintaining water services and reducing degradation.
  • Tropical Montane Cloud Forests (TMCFs): High in water yield due to their location in high-rainfall areas and cloud-water capture. They are rare and face significant threats from deforestation and land use change.
  • Dryland forests: Support millions of people and influence the water cycle despite limited water availability. Management strategies such as canopy opening and pruning can help increase soil and groundwater recharge.

Key Information

• Global Context: Only 12% of the world's forests are managed primarily for water. This underscores the need for greater attention to water in forest management.
• Tools and Technologies: The guide highlights the use of remote sensing tools (e.g., SEPAL), decision-support systems (e.g., FL-WES), and citizen science initiatives (e.g., the Blue Targeting Tool).
• Policy and Governance: PWS schemes are promoted as part of broader local participatory governance, not as a substitute for ineffective government or community management.
• Economic Value: The economic value of water services is discussed, including the impact of land use changes on treatment costs and the net present value of agricultural yield losses due to flooding.
• Communication and Branding: A nine-step communication strategy is proposed to enhance community engagement, policy commitment, and investment in forest-water projects.

Conclusion

A Guide to Forest-Water Management is a comprehensive resource that outlines the importance of integrating forest and water management. It provides tools, methodologies, and insights to support the sustainable management of forests for water security, emphasizing the role of ecosystems, policy, and community engagement in achieving this goal. The guide is intended to stimulate strategic discussions and offer practical guidance at multiple scales.