Forests Supply Water to Puerto Rico

Puerto Rico’s forests are still recovering from Hurricane Maria. Local scientists estimate that one out of five trees in the El Yunque National Forest were lost during or after the storm. Widespread forest restoration and monitoring efforts are underway. But that work isn’t focused on just the trees in those forests — water supply is an important ecosystem…  More 

Projections of Future Climate and Annual Runoff

Hydrologists have traditionally relied on historic precipitation data to estimate broad-scale runoff. “Rainfall was always number one,” says USDA Forest Service scientist Ge Sun. “But things are changing and getting more complicated.” Sun co-authored a recent modeling study that investigated how other climate factors might influence future changes in runoff. The researchers were intrigued by…  More 

Megafires, Wildland Fires, and Prescribed Burns

Healthy forests are important for clean and abundant water supplies. A recent USDA Forest Service study examined how wildland fires, including megafires, and prescribed burns affect river flow. The study is the first nationwide look at fire impacts on surface freshwater resources. Led by Dennis Hallema, research hydrologist and ORISE fellow, the research team analyzed…  More 

New Forest, New Water Yield

Today, forests abound in the southern Appalachians. However, there was a time in the early 1900s when many forests were harvested or cleared so that the land could be used to grow crops or provide pasture. “The forests that have returned may use water differently,” says U.S. Forest Service research ecologist Katherine Elliott. Elliott and…  More 

Estimating Ecosystem Water Use

For more than a decade, U.S. Forest Service and Chinese scientists have collaborated to understand how human activities affect carbon and water cycles in managed ecosystems. Working through the U.S.-China Carbon Consortium, scientists share data from a network of eddy covariance flux towers across the two countries. The towers measure the flow of water vapor,…  More 

An Assignment in Africa Connects Forests, Water, and People

Steve McNulty, Ge Sun, and Erika (Cohen) Mack hiked for three hours on a winding trail over steep hills through land thick with trees and vines. They arrived at a pool and looked up at a towering waterfall. If they had stood at the top of the waterfall, they would have seen forested land stretching…  More 

Watersheds of the Future Could Mirror a Variable Climate

With some exceptions, precipitation, water yield from forests, and forest growth and productivity generally increase from west to east across the United States. Shifts in temperature and precipitation associated with climate change may not necessarily alter these general west-to-east trends, but U.S. Forest Service and university researchers do anticipate great variability in how watersheds respond…  More 

Water Yields from Southern Appalachian Watersheds in Decline since the 1970s

Where would we be without the water we get from cool mountain streams? In the densely populated southeastern U.S., forested watersheds are particularly important to drinking water supplies. Recent estimates show that southern forests deliver surface drinking water to some 48.7 million people, with streams from the mountainous Southern Appalachian region alone providing water supplies…  More 

How Drought Affects Forests and Streams

Across the U.S., forested watersheds filter surface water that drains into the rivers that supply drinking water for many of the nation’s cities. Besides providing high quality water for humans needs, forest trees regulate streamflow, mitigate flooding, and help create and maintain the water conditions that support healthy aquatic ecosystems. Drought affects the ability of…  More 

More Productive U.S. National Forests and Grasslands Could Yield Less Water in a Future Climate

A warmer climate may lead to higher growth and productivity on U.S. national forests and grasslands, but university and U.S. Forest Service researchers say this could reduce quantities of fresh water flowing from most of these lands, even with increases in precipitation. Results were published today in Scientific Reports. “The national forests and grasslands managed…  More