Contact Information
I am interested in climate change, nitrogen deposition, and land use change and how they impact biogeochemical cycles
Education
Ph.D. University of Georgia
Research interests
I am interested in the fate of atmospherically derived carbon (C) and nitrogen (N) in forest ecosystems and the microbial response to elevated inputs of these biologically important elements. Fossil fuel burning, agricultural practices and other land-use changes increase the abundance of CO2 and oxides of N (NOx) in our atmosphere, and soil microorganisms serve as both source and sink for these C and N compounds. Understanding the biogeochemistry of these elements in soil and the role of microorganisms in transforming these elements is vital to estimating the long terms effects of human activities as well as defining the function of microbial communities.
I use stable isotope techniques to trace N and C in forest ecosystems, including elemental fate in the phyllosphere, soil and ground and stream waters.
Current Projects:
(1) Impact of Canopy Nitrogen Deposition on Forest Carbon Storage:
A manipulative Experiment at the Howland AmeriFlux Site
(Active duration: 2001-2010)
Project goals: The Howland Integrated Forest Study (HIFS) is a commercial Spruce-Hemlock forest in central Maine and is the site of several atmospheric and terrestrial studies beginning in the mid-1980's:
http://www.howlandforest.org
Past and current studies are part of national programs dedicated to the studying effects of atmospheric deposition on forest ecosystem function. We are currently testing the theory that depositional N will enhance C storage by releasing a limitation on forest growth. We fertilized the canopy (via helicopter) of a 21 ha area with N approximating 2-3 times natural inputs per year as ammonium nitrate. We then collect environmental samples, needles, wood, rainwater and soils, to determine where this N resides in the short and long term. The project is designed to address terrestrial processes regulating carbon balance in forest ecosystems, and relies upon long term Net Ecosystem C exchange measurements being made at this site as part of the Ameriflux program:
http://public.ornl.gov/ameriflux/Participants/Sites/Map/index.cfm
Relevant publication(s) arising from this work:
Dail DB, Hollinger DY, Davidson EA, Fernandez I, Lee, Sievering HC, Scott NA and Gaige E. (2009) Distribution of Nitrogen-15 tracers applied to the canopy of a mature spruce-hemlock stand, Howland, Maine, USA. Oecologia 160:589-599.
Gaige E, Dail DB, Hollinger DY, Davidson EA, Fernandez IF, Sievering HC, White A and Halteman W. (2007). Changes in canopy processes following whole-forest canopy nitrogen fertilization of a mature spruce-hemlock forest. Ecosystems 10:1133-1147
(2) Economically Viable Forest Harvesting Practices That Increase Carbon Sequestration
(Active duration: 2000-2009)
Project goals: In addition to storing C, many forests are also sources of timber and wood fiber. This is certainly the case in Maine where many thousands of acres of forested lands are actively used to meet our demand for timber and paper products. In most carbon accounting budgets, however, forest harvesting is usually considered to cause a net release of carbon (as CO2) from the terrestrial biosphere to the atmosphere (Dixon et al., 1994; Harmon et al., 1990; Houghton et al., 1999). As the debate about mitigating increased atmospheric CO2 moves from science to a search for solutions, a central question becomes whether commercial use of forests could be managed to contribute to terrestrial sequestration of C, rather than cause net release of C to the atmosphere. This project addresses whether forest management practices can be developed that will meet the multiple goals of providing wood and paper products while also sequestering C from the atmosphere. Can recently adopted management practices be both economically viable and cause increased carbon sequestration? The objective of the project is to determine whether shelterwood cutting regimes now being adopted in the commercial forests of Maine and other areas can achieve these multiple goals.
Relevant publication(s) arising from this work:
Scott NA, Rodrigues CA, Hughes H, Lee JT, Davidson EA, Dail DB, Malerba P and Hollinger DY (2004). Changes in carbon storage and net carbon exchange one year after an initial shelterwood harvest at Howland Forest, ME. Environmental Management 33(Suppl. 1):S9-S22.
(3) Mechanisms of abiotic nitrate immobilization in temperate forest soils
(Active duration: 2003-2005)
Project goals: Recent studies of the environmental fate of nitrogen in deposition suggest that soils are an important sink for this element (Gunderson et al., 1998; Nadelhoffer et al., 1999). Despite decades of work on the fate of nitrogen in forest soils and in agricultural systems, we have a poor understanding of the mechanisms leading to the sequestration of N and how these mechanisms may govern the eventual availability of atmospherically-derived N to plants, which are often N limited. This study, beginning in late 2002, will investigate biotic and abiotic fates of nitrate-N in forest soils in the N.E. United States. Recent work has suggested (see Dail et al., 2001) that rapid, abiotic interaction of nitrate-N and soils can occur and that this interaction might temporarily reduce the availability of N to soil microorganisms and ultimately, to plants.
Relevant publication(s) arising from this work:
Davidson EA, Dail DB and Chorover J (2008). Iron Interference in the quantification of nitrate in soil extracts and its effect on hypothesized abiotic immobilization of nitrate. Biogeochemistry 90(1):65-73. DOI 10.1007/s10533-008-923106
Davidson EA, Chorover J and Dail DB (2003). A mechanism of abiotic immobilization of nitrate in forest ecosystems: the ferrous wheel hypothesis. Global Change Biology 9(2):228-236
Dail DB, Davidson EA and Chorover J (2001). Rapid abiotic transformation of nitrate in an acid forest soil. Biogeochemistry 54(2):131-146.
(4) Reducing uncertainty about the effects of climate variation on forest
ecosystems by measuring, modeling, and analyzing intermediate-turnover
carbon pools
(Active duration: 2007-2009)
Project goals: Existing models do not well predict measured interannual variation in net ecosystem exchange of CO2 (and thus carbon storage or release). With PI: Andrew Richardson (Harvard University), I am assessing the turnover of forest floor layers (Litter layer and O horizon) of a deciduous (Bartlett forest, NH) and coniferous (Howland, ME) forests as a result of differing climate conditions.
Publications
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