Down to Earth
Whether you are speaking to a forester or a farmer or an urban gardener, they will tell you that everything comes down to earth. While we often admire the trees and overlook the soil in which they are growing, this product of weathered, eroded rock is a rich and complicated ecosystem. In December, we give you the dirt on dirt with profiles of a scientist, research a product and partnership that are all about soil.
The Ground Beneath Our Feet travelling soil tent combines elementary GLOBE soil curriculum materials, hands-on soil observations, and art to teach students about the importance of forest soils. The Ground Beneath Our Feet is a partnership between the Forest Service, the Global Learning and Observations to Benefit the Environment (GLOBE), the Arts Alliance of Northern New Hampshire, and the White Mountain National Forest.
Mary Beth Adams
Mary Beth Adams was introduced to the world of soils as an undergraduate at Purdue University by a teacher who made it all come alive. “I was fascinated by the life in the soil, and the absolute importance of soil for life on earth – and still am,” said Adams. Today, Adams is a research soil scientist, experimental forest proponent, and recent award winner who conducts research out of the Northern Research Station’s office in Morgantown, WV.
Growing up in southern Indiana, Adams lived at the end of the road with woodlots on two sides of the house. “We played and explored those woods endlessly, in all seasons,” said Adams. “My family also travelled a lot and every summer we visited National Parks and National Forests in the western United States, camping all the way.”
Much of Adams’ research has been conducted on the Fernow Experimental Forest in West Virginia and she has been involved in the Experimental Forest and Ranges (EFR) working group since its inception, serving in a variety of leadership roles. Today there are 81 Experimental Forests and Ranges across the country that are dedicated to long-term research on ecosystem processes, silviculture and forest management options, wildlife habitat characteristics, and forest growth and development. “No other agency or organization has so many research forests and ranges, nor the wealth of information, data and experience in long-term research as we do in the Forest Service – these are national treasures,” said Adams.
Adams is currently working on the Fernow Watershed Acidification Study, on the Fernow Experimental Forest. Graduate students and faculty from many universities, and scientists from all over the world, are using this experiment and its data to understand forest processes and solve environmental problems. “This is a good example of how collaboration and partnerships capitalize on existing infrastructure and research,” said Adams.
The Society of American Foresters (SAF) recently honored Adams with the Barrington Moore Memorial Award. The award recognizes outstanding achievement in biological research leading to the advancement of forestry and recognizes unusual productivity and quality with a significant impact on forestry. In the 63 years that the award has been presented, Adams is the first woman to receive it.
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FIA soil inventory provides fertile ground for research
Grant Domke will tell you that there is more to soil than what meets the eye, and he can be specific about its attributes.
Domke, a research scientist, leads the forest carbon estimation team for the Northern Research Station’s Forest Inventory and Analysis (FIA) program. His appreciation for the significance of FIA’s soil inventory data has grown recently as he seeks to quantify how forests contribute to the global carbon cycle. “We are recognizing that soils represent the earth’s largest terrestrial carbon sink,” he said.
The availability of consistent, systematic data about forest soils is essential to his work and the FIA Program has delivered. Since 2001, soil data has been collected as part of the larger forest inventory of the FIA program, which monitors approximately one sample location (FIA plot) every 6,000 acres in the United States.
Measurement of soil conditions and quality have produced a rich archive of data that is fueling an array of research that increases understanding of earth’s fundamental systems and improves how forests are managed. One 2019 study based on FIA soil data discovered that mycorrhizal fungi (fungi found in or on tree roots) associations across the continental United States are being influenced by climate change, leading to more carbon storage and more rapid release of nitrogen into waterways in eastern forests. Another described how the presence of certain types of soil fungi makes forests more vulnerable to invasive plants, as the fungi increase the nutrients available to both trees and understory plants. Replanting trees aids forest recovery but also increases soil carbon storage over the next century by an additional 2 billion tons of carbon, which is about 1 percent of all U.S. greenhouse gas emissions, according to a 2018 paper based on the FIA soil dat.
All FIA data are publicly available through the FIA DataMart. Soils data are part of FIA’s intensive sampling protocol (approximately 1 plot sampled every 96,000 acres), which also includes forest health and understory plant species.
Efforts to improve the methods and models for estimating soil variables in the FIA database are underway. Incorporating remote sensing into the data collection and estimation process is of particular interest. This additional information will both improve model estimates and facilitate the development of maps that extend soil data estimates beyond the FIA plot network. In addition, the saving potential is enormous in remote areas such as interior Alaska, where helicopters are often required to access plots.
Domke thinks the investment in these new methods is worthwhile. “Soil is the foundation to everything from the water we drink to the food we eat,” he said.
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Below-ground fungi signal changing forest composition and shifts in nutrient cycling
When studying forests, it is important to look down as well as up. Fungi associated with tree roots, called mycorrhiza, are revealing where human influences are shifting forest composition and how nutrient cycling may change as a result.
Mycorrhizal fungi help plants take in water and nutrients; the plants provide carbon for the fungi. More than 90 percent of plants are associated with mycorrhizal fungi and specific trees species associate with specific types of fungi. Tree species associate predominantly with either arbuscular mycorrhizal (AM) fungi, which grow inside root tissue, or ectomycorrhizal (EM) fungi, which live on the outside of a tree’s roots.
Human influences are shifting forest mycorrhizal associations at the continental scale, according to a 2019 study published in the journal Science Advances by lead author Songlin Fei and Insu Jo of Purdue University, Forest Service co-authors Grant Domke of the Northern Research Station and Chris Oswalt of the Southern Research Station, and Richard Phillips of Indiana University.
The collaborators produced the first comprehensive map showing the distribution of tree mycorrhizal associations across the contiguous United States. Analysis indicated that climate is the most important factor driving whether a forest will be populated principally by AM-associated trees, which dominate in warm and dry regions, or EM-associated trees, which dominate in cold and humid regions. Fire frequency and atmospheric deposition of nitrogen also influenced whether AM or EM-associated trees dominated the forest composition.
The team also examined changes in the distribution of mycorrhizal associations over the last 30 years in the eastern United States and the resulting implications for forest productivity and carbon storage. “Mycorrhizal fungi can alter nutritional dynamics of the soil. This has global implications for nutrient cycling,” Domke said.
According to the study results, AM-associated trees have increased their dominance in the eastern United States, which may also increase the carbon and nitrogen available in the soil. Because AM- forests cycle nutrients more quickly, the increase could lead to both additional carbon storage and more nitrogen released into aquatic systems, a potential detriment to water quality.
More information on Shifts in dominant tree mycorrhizal associations in response to anthropogenic impacts >>
Baltimore Green Space
In the city of Baltimore, patches of forest stand as silent reminders of development anticipated and abandoned decades ago. In a partnership with Baltimore Green Space, a nonprofit land trust, researchers with the Northern Research Station’s Baltimore Field Station are exploring a largely unexplored corner of urban soil: undisturbed land.
Baltimore Green Space works with neighbors and scientists to better understand urban forests and the health and environmental benefits they provide. After 6 years of working with neighbors, Baltimore Green Space has begun acquiring never-developed forest patches for the benefit of the neighbors who love them, according to Executive Director Katie Lautar.
The partnership with the Northern Research Station has been crucial to establishing a scientific basis for protection of these forests. Ian Yesilonis, a soil scientist in the Baltimore Field Station, and Matt Baker of the University of Maryland, Baltimore County, worked with Baltimore Green Space to develop a forest health research protocol for the city’s forest patches.
Yesilonis said that until he partnered with Baltimore Green Space, his research had been focused on city-wide projects, such as studies of metals and toxicity and carbon storage across the city’s different land use and covers. “This partnership has given me an opportunity to get familiar with urban forest patches and to begin exploring the condition of soils that, by and large, have not been studied,” he said. “Once you start coming up with research questions, they develop into a lot more questions and interesting ideas.”
“Ian’s work has been crucial to helping us establish the health of soils in urban forests,” Lautar said. “And our work with the USDA Forest Service is helping us to legitimize the value of urban forests and the work that neighborhood leaders do to care for them.”
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