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Summer Research Project 2021

• Title: Forest Carbon Sequestration Sub-project 2: Atmospheric deposition effects on forest carbon sequestration
• Group Project Leader: Jonathan Thompson
• Mentors: Meghan Blumstein; Emma Conrad-Rooney; Joshua Plisinski; Mayra Rodriguez Gonzalez; Pamela Templer; Jonathan Thompson
• Collaborators: David Basler; Danelle Laflower
• Project Description:

  This is part of the group project 'Forest Carbon Sequestration: Effects of land use change, atmospheric deposition, and genetic variation,' which has the overarching theme of controls on carbon sequestration in the Northeast.
  
  • What is the potential contribution of land use and management practices toward increasing forest carbon sequestration to achieve greenhouse gas mitigation goals within forests of New England?
  • Do atmospheric inputs of multiple elements, such as nitrogen, phosphorus, and cations (calcium, magnesium, potassium, sodium) affect rates of carbon sequestration in mixed temperate and northern hardwood forests of New England and other forested sites around the U.S.?
  • To what extent is seasonal timing of leaf-out in oaks under genetic control, and how can this knowledge inform genomic rescue programs to help trees to adapt to a warming world?
  
  Sub-project II – Atmospheric deposition effects on forest carbon sequestration (1 student; Mentors: Pam Templer and Emma Conrad-Rooney)
  
  Background: In recent decades, much research has focused on anthropogenic activities that increase inputs of “reactive” nitrogen (N) to forests through increases in emissions and atmospheric deposition of N. There has been great concern among scientists and policy-makers about these N inputs leading to N saturation of terrestrial ecosystems, whereby N inputs exceed biological demand with adverse consequences for soils, plant growth, and interconnected aquatic ecosystems. However, atmospheric N deposition is now declining over large areas of rural North America and there have been remarkable declines in N availability and export from non-aggrading forests that cannot be explained by declines in atmospheric deposition alone. Now, concerns about N saturation and over supply are being replaced with concerns about N oligotrophication causing N limitation of forest productivity and diminished capacity of ecosystems to recover from disturbances and to sequester carbon (C) in the face of rising atmospheric concentrations of carbon dioxide. In contrast to rural areas, urban areas are still experiencing high levels of atmospheric deposition (as both N and phosphorus), yet we lack a clear understanding of how these patterns of deposition affect C cycling in both rural and urban forest ecosystems.
  
  The consequences of these patterns in atmospheric deposition for carbon sequestration in temperate forests in unknown, but are important given that forests across New England vary in how much carbon they sequester. For example, mixed temperate forests in southern New England, such as those at Harvard Forest doubled their rates of carbon sequestration between 1992 and 2015, while net carbon sequestration in northern hardwood forests of New Hampshire approached zero by the 1990s, meaning many northern hardwood forests of New England likely no longer serve as a net carbon sink. Variation in rates of atmospheric deposition and/or tree species across forests of this region could explain some of this variation.
  
  Objective and Approach: In this project, the REU student will utilize data publicly available from the National Atmospheric Deposition Program to quantify changing nitrogen, phosphorus, and cation inputs to northeastern US forests over time and use these data along with measures of forest productivity to determine whether there is a link between patterns and rates of atmospheric deposition of multiple elements and forest C sequestration.
  
  Typical Week:
  - Student will participate in dedicated weekly meetings and bi-weekly journal club
  - Student will join Thompson Lab meetings (MWTh at 930 ET)
  - Student will meet with other sub-project students at least weekly for peer-to-peer networking and mentoring
  - Student will read papers about atmospheric deposition and forest nutrient and carbon cycling.
  - Student will use data from the NADP website to analyze deposition of nutrients such as nitrogen, phosphorus, and cation across the United States, but particularly in New England, and compare urban to rural deposition.
  - Student will compare nutrient availability data to forest productivity data to investigate connections between atmospheric deposition and carbon sequestration.

• Readings:

  Decina SM, PH Templer, and LR Hutyra. 2018. Atmospheric inputs of nitrogen, carbon, and phosphorus across an urban area: unaccounted fluxes and canopy influences. Earth's Future 6:134-148.
  
  Duveneck, M. J. and J. R. Thompson. 2019. Social and biophysical determinants of future forest conditions in New England: Effects of a modern land-use regime. Global Environmental Change 55:115-129. https://doi.org/10.1016/j.gloenvcha.2019.01.009
  
  Finzi, A. C., Giasson, M.-A., Barker Plotkin, A., Aber, J. D., Boose, E. R., Davidson, E. A., Dietze, M. C., Ellison, A. M., Frey, S. D., Goldman, E., Keenan, T. F., Melillo, J. M., Munger, J. W., Nadelhoffer, K. J., Ollinger, S. V., Orwig, D. A., Pederson, N., Richardson, A. D., Savage, K., Tang, J., Thompson, J. R., Williams, C. A., Wofsy, S. C., Zhou, Z., Foster, D. R. 2020. Carbon budget of the Harvard Forest Long-Term Ecological Research site: pattern, process, and response to global change. Ecological Monographs 10.1002/ECM.1423: 95 pp
  
  Groffman PM, CT Driscoll, J Duran, JL Campbell, LM Christenson, TJ Fahey, MC Fisk, C Fuss, GE Likens, G Lovett, L Rustad, PH Templer. 2018. Nitrogen oligotrophication in northern hardwood forests. Biogeochemistry 141:523-539.
  
  Reinmann AB, J Susser, EMC Demaria, PH Templer. 2019. Declines in northern forest tree growth following snowpack decline and soil freezing. Global Change Biology 25:420-430.

• Research Category: Soil Carbon and Nitrogen Dynamics, Regional Studies, Group Projects, Forest-Atmosphere Exchange