A novel method for increasing water-yields, pine forests of the Northern Gulf of Mexico, USA 

Abstract. With a burgeoning world population that is expected to reach 10 billion by 2050, 30 % more than today, there is an urgent need to harness available water resources to support regions across the world. This study introduces a new method to identify, prioritize, and select areas for pine basal area reduction to maximize water yields in pine forests along the Northern Gulf of Mexico, USA. The method, demonstrated in the Apalachicola Region of Northwest Florida, an area covered by dense vegetation and pine plantation forests, has experienced freshwater loss due to increased upstream water demand, climate change, and past forest management practices. Potential initial water-yield gains were: 1) 469 m³ d⁻¹ if all pine basal areas were reduced from current to a maximum of 18 m² ha⁻¹, and 53,400 m³ d⁻¹ if pine basal areas were reduced from current to a maximum of 7 m² ha⁻¹ for the Apalachicola Region. The method identifies watersheds mainly along the Apalachicola and other rivers and near the Gulf coast that have the greatest potential to increase water yields. Increasing forest water yields translates to increased freshwater availability and improved forest and soil health, water quality, and ecosystem function, services, and resilience, as well as socioeconomic outcomes for communities and people who rely on ecotourism and fisheries for their livelihoods. This method will empower forest managers to focus scarce resources in targeted areas to maximize water-resource benefits per resource investment. Although demonstrated in the Apalachicola Region, the method is easily transferable throughout other pine forests of the Northern Gulf Coast Region. This scientifically sound method is repeatable, scalable, and easily upgraded and adapted as newer, higher resolution datasets become available and relationships between forest metrics, evapotranspiration, and water yields are improved.