News and Events
We don’t often think about what’s underneath our feet, but soils are essential for the food we eat, building materials for our homes, the clean water we drink, storing carbon and mitigating climate change, even the air we breathe.
“Soils are the foundation of everything in terms of growth and productivity,” says USDA Forest Service researcher Jennifer Knoepp. Knoepp explains that “soils have integrated all the conditions that have resulted from the growth of an ecosystem” and thus reflect the past and present vegetation, climate, and biology. This profound interaction between soils and life is why scientists study soils in the context of forests.
An estimated 35 percent of the global terrestrial carbon is stored in soil and biotic carbon pools, such as forests. These pools can store or release carbon. Because forests store immense amounts of carbon, forest management is becoming part of efforts to increase carbon sequestration and mitigate greenhouse gas emissions.
The Southeast hosts an impressive network of forested wetlands. These wetlands improve water quality, reduce flooding, store excess carbon, and provide important habitat for wildlife. They are also particularly vulnerable to changes in climate and land use.
Forests provide the most stable and highest quality water supplies among all land uses. A report by the Southern Research Station of the USDA Forest Service quantifies the role of state and private forest lands (SPF) in providing drinking water supply across the southern United States.
A new study uses a USDA Forest Service modeling tool – the Water Supply Stress Index, or WaSSI, ecosystem services model – to explore the relationship between water use, river flows, and fish populations across the conterminous U.S. Brian Richter from the University of Virginia led the study. SRS researcher Peter Caldwell’s expertise with WaSSI was instrumental in relating water use to depletion of river flows.
What is the most sustainable way to harvest a forest? A team led by USDA Forest Service scientists Katherine Elliott and Chelcy Miniat, along with Forest Service intern Andrea Medenblik, tries to answer this question. Data were analyzed from a long-term study looking at the biomass effects of partial-cutting versus clear-cutting in different watersheds in the southeastern US. Their results were published in the journal New Forests.
With its symbiotic bacteria, black locust (Robinia pseudoacacia) makes its own nitrogen fertilizer – and can share it with other tree species. “In early successional temperate forests, symbiotic nitrogen fixation is often the main source of new nitrogen,” says USDA Forest Service scientist Chelcy Miniat.
Millions of people depend on the forests of the Southern Appalachian Mountains for drinking water. As climate, land use, and land cover changes alter the forest structure in these mountains, they also alter water budgets. “The Southern Appalachian Mountains are a humid montane environment – they are essentially a cooler version of the tropics,” explains USDA Forest Service project leader and research ecologist Chelcy Miniat. “With so much rain coming in, it is important to understand how the forests use the water, especially when the remainder becomes the South’s drinking water supply.”
Forests are made of three-dimensional life forms that constantly interact with each other and with the abiotic factors in their environment. A recent study shows how complex those interactions can be.
“Trees growing within an evergreen shrub layer can be almost 20 feet shorter than trees without a shrub layer,” says USDA Forest Service scientist Katherine Elliott.
Electric blue squares dotted the urban landscape. From the descending plane, USDA Forest Service visitors thought they might be swimming pools. Alas, they were tarps covering the roofs of homes and keeping leaks at bay on rainy days.
These tarps were the first sign of lingering damage from Hurricanes Irma and Maria. Broken roads, twisted streetlights, and downed power lines exhibited the storms’ impacts on the island’s infrastructure.
The planet is warming, and warmth revs the machinery of life. “As it gets warmer, living things burn up more carbon through respiration,” says USDA Forest Service scientist Chris Oishi. “It’s true of trees and soil microbes.”
Soil is bursting with invertebrate life, microbial life, and living plant roots. It’s also where decomposers do their work. All of this activity requires oxygen and releases carbon dioxide.
What will fish communities of the North Carolina Piedmont look like in the future?
“Many factors could affect this,” says U.S. Forest Service research hydrologist Peter Caldwell. “Water withdrawals could be one of the most important.”
Since 1950, heavy rains have become more common in the southern Appalachians. U.S. Forest Service researchers have witnessed such changes at Coweeta Hydrologic Laboratory.
“Coweeta receives as much as 90 inches of rain each year,” says SRS researcher Chelcy Miniat. “The topography is steep, and the bedrock is solid. We can account for most of the rainfall that enters the basin.”
The planet is changing, and the hydrologic cycle will change along with it. Extreme droughts – as well as extremely wet weather – are expected to become more frequent and more intense. “These changes may interact with topography to affect species composition in unexpected ways,” says Chelcy Miniat.
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.
Katherine Elliott discusses preparatory measures being taken at Coweeta in the face of the Rock Mountain Fire.
Research Ecologist Chris Oishi discusses techniques for measuring sap flux, and introduces a new processing program that can help interpret and normalize this data.
The USFS research station in Otto, has been recording watershed data every five minutes since 1934. The information reveals a lot about climate change and drought issues.
Scientists forecast that for many parts of the U.S., climate change will bring higher temperatures and more frequent and severe periods of drought. In parts of the West, forests are already changing as a result of drought, but all U.S. forests may be impacted, in turn affecting other important resources such as clean air and water.
In mountainous areas, cold air flows along the surface of the earth from mountain tops to valleys, and as it moves, it dramatically affects local temperatures. “Many ecosystem processes – including carbon uptake and storage – are affected by temperature,” says U.S. Forest Service research ecologist Chris Oishi.
After disturbances, healthy ecosystems are usually resilient enough to return to a pre-disturbance state. However, some disturbances are extreme enough to permanently shift an ecosystem, a phenomenon known as a regime shift.
On August 15, journalists headed to the SRS Coweeta Hydrologic Laboratory in Otto, North Carolina. On the way, James Fox, director of the National Environmental Modeling and Analysis Center, described relationships between “the green and the blue” – forests and water. The topic was a recurring theme, especially during the tour of Coweeta. Coweeta is the longest continuous environmental study on any landscape in North America and one of the oldest gauged watershed sites in the world.
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 to 10 million, many of them living in major cities such as Atlanta, Georgia.
Much of what we know today about the hydrology of forested watersheds was learned through early research at the U.S. Forest Service Coweeta Hydrologic Laboratory.
During April 13-16, 2016, scientists and staff at the U.S. Forest Service Coweeta Hydrologic Laboratory hosted the Strategies for Ecological Education and Diversity (SEEDS) 11th annual leadership meeting. An award-winning program of the Ecological Society of America (ESA), SEEDS focuses on students at the undergraduate level, with the mission to diversify and advance the ecology profession by stimulating and nurturing the interests of underrepresented students to participate and lead in the field of ecology.
For over 19 million people in the South – roughly the population of Florida – clean water begins in the region’s national forests. That’s according to a report by the U.S. Forest Service Southern Research Station published in late 2014. The report provides information at a level not previously available on the amount of surface drinking water national forest lands provide to communities in the South, and features an appendix of maps that show in detail the water flowing from national forests in the South in relation to surface water intakes for nearby cities and towns.
From the depths of the soil to the top of the atmosphere, nitrogen is everywhere. It is also indispensable to plants and animals. The vast majority of nitrogen atoms contain the same number of uncharged particles. However, a few atoms are ‘stable’ isotopes that have one extra uncharged particle. Although the extra particle adds a miniscule amount of weight – much less than one trillionth of an ounce – living things prefer compounds that contain the lighter nitrogen atom to the heavier isotope.
On November 20, for the second year in a row, 5th grade students from Mountain View Intermediate School in Macon County, North Carolina, visited the U.S. Forest Service Southern Research Station Coweeta Hydrologic Laboratory (Coweeta) in nearby Otto to tour the facilities and learn about some of the exciting research taking place at the outdoor laboratory that’s home to long-term research now focused on the impact of climate change and other disturbances on southern Appalachian forests.
A new research study by U.S. Forest Service scientists finds that changes in rainfall patterns in the southern Appalachians due to climate change could reduce growth in six hardwood tree species common to the region. The findings have implications for forest managers in the Southeast, where climate variability (more extreme events or changes in precipitation distribution) could cause major shifts in forest composition and structure.
Streams in the southeastern U.S. are among the most ecologically rich in the world, but climate change, land cover change, and withdrawals threaten the health of their aquatic ecosystems.
Plant diversity in eastern U.S. forests comes not only from trees, but from the ferns, wildflowers, and other herbaceous plants on the forest floor. Some researchers have found that as much as 90 percent of plant diversity is due to these understory species. “Until recently, not much was known about the role these plants play in ecosystem processes,” says U.S. Forest Service scientist Katherine Elliott.
Since the 1950s, urban areas have increased by more than 400 percent, and are now home to 80 percent of Americans. Water resources in these areas are threatened, and understanding how urbanization affects water quantity and quality is increasingly important.