Project Funding: 2011 - 2014

NRA: 2009 NASA: Terrestrial Ecology   

Funded by NASA

Abstract:
The structure and function of forests have been dramatically altered by the intensification of disturbance and chronic stressors such as nitrogen deposition. Given the importance of forests in the climate system, understanding their response will improve the ability of models to predict future changes in climate and identify potential feedbacks. In a recent finding, we showed that variation in canopy nitrogen over temperate and boreal forests is strongly and positively correlated with shortwave surface albedo and that both variables are related to whole-canopy photosynthetic capacity. This result raises new questions about whether disturbances that influence the nitrogen cycle have a more complex influence on climate than has previously been considered-through alteration of surface energy exchange as well as carbon assimilation. We propose to investigate these issues by conducting a synthesis of data from previous NASA investigations, augmented with a limited number of new measurements and data from complimentary studies. We plan to test whether the nitrogen-albedo relationship that has been observed over a broad range of forest types also occurs at finer resolutions within local forest landscapes. We will then examine the degree to which canopy albedo and N concentrations are affected by physical disturbances, including stand-replacement events caused by logging and fire, as well as biogeochemical effects of elevated nitrogen deposition. We will also examine whether locally observed disturbance effects are manifested over wider spatial scales using a global albedo product in comparison with mapped estimates of N deposition and forest disturbance. Our analysis builds on a long legacy of ecological imaging spectroscopy and the proposed research bears direct relevance to the HyspIRI Decadal Survey mission. All analyses will be carried out with the additional goal of seeking generalizeable canopy detection methods that can be applied using data from HyspIRI.

Publications:

Ouimette, A. P., Ollinger, S. V., Richardson, A. D., Hollinger, D. Y., Keenan, T. F., Lepine, L. C., Vadeboncoeur, M. A. 2018. Carbon fluxes and interannual drivers in a temperate forest ecosystem assessed through comparison of top-down and bottom-up approaches. Agricultural and Forest Meteorology. 256-257, 420-430. DOI: 10.1016/j.agrformet.2018.03.017

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Spectral Reflectance Features Related to Foliar Nitrogen in Forests and their Implications for Broad-Scale Nitrogen Mapping   --   (Scott V. Ollinger, Lucie C. Lepine, Andrew P. Ouimette, Mary E. Martin)   [abstract]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Investigating the Relationships Between AVIRIS Reflectance, Foliar Nitrogen, and Nitrogen Deposition across the Northeastern US   --   (Mary E. Martin, Scott Ollinger, Lucie Lepine)   [abstract]

2010 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• Examining Trends in Foliar N and Albedo in Response to Disturbance in Canadian Forests   --   (Lucie C. Lepine, Scott V. Ollinger, Mary E. Martin, Steve E. Frolking)   [abstract]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile