Water use by common trees provides foundational data for forest and water management
Why measure tree water use? Understanding water use at the species level will be one of the main targets in the management of rural and urban forests in the future. Scientific work on this topic can serve as a guide for how public and private landowners decide which trees might best maximize the benefits, and minimize costs, related to timber production and water resource management.
Studies have shown a lack of consistency in how soil moisture affects the amount of water that a tree will use. Thus, the Forest Service partnered with North Carolina (NC) State University and the NC Forest Service to further refine what we understand about soil moisture and water use in common trees in the Piedmont of NC. Water use was measured in five species at different locations in a watershed for two years. The researchers found that when more water is available, some tree species use much more of it. For example, loblolly pines growing near a stream used 65 percent more water than loblolly pines growing near the top of a hill. In contrast, white oaks near a stream only had 12 percent higher water use than white oaks on the hill. This work improves upon a broader understanding of the relationship between species-specific water use and soil moisture, and how to scale tree-level water use to the watershed-scale. Making links between soil moisture and tree water use at the watershed-scale is rarely done but is critical to providing guidance to water resource managers on watershed management and on how much water will be available for downstream water supply.
