Managing forest plantation landscapes for water conservation

Abstract

Forest ecosystems play an important role in water conservation yet forest plantations are considered detrimental because of their high water use. The current worldwide trends of reduction in natural forest and expansion of forest plantations increases the need for forest managers to contribute to water conservation, implementing management plans that integrate economic (productivity and growth), social (equity of access to water and land-use conflicts) and environmental (climate change and biodiversity impacts) factors. In this paper, we show examples of forest management alternatives at macro- and meso-scales that could contribute to improve water conservation in forest plantation landscapes. At the macroscale, we assess water use in different forest plantation areas in Brazil by analyzing the theoretical thresholds for the management of evapotranspiration. Then, using data from an experimental catchment, we modeled water yield reduction by a forest plantation over multiple years and assessed how different meso-scale forest plantation management alternatives affected water flow regulation. Results show that at a macroscale it is important to consider the natural climatic constraints of water availability. Evidence shows that forest plantations in the tropics use water according to its availability, and the appropriate choice of species/varieties and associated forest management options are crucial for water conservation. At the meso-scale we found that the proportion of native forest plays an important role in the reduction and regulation of water use, and therefore a system of mosaic management may be able to stabilize water flow across plantation landscapes.