Now showing items 1-16 of 16

    • Canopy nitrogen, carbon assimilation, and albedo in temperate and boreal forests: Functional relations and potential climate feedbacks 

      Ollinger, S. V.; Richardson, Andrew; Martin, M. E.; Hollinger, D. Y.; Frolking, S. E.; Reich, P. B.; Plourde, L. C.; Katul, G. G.; Munger, J. William; Oren, R.; Smith, M.-L.; Paw U, K. T.; Bolstad, P. V.; Cook, B. D.; Day, M. C.; Martin, T. A.; Monson, R. K.; Schmid, H. P. (Proceedings of the National Academy of Sciences, 2008)
      The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth's climate system has been considered. Despite this, ...
    • A continuous measure of gross primary production for the conterminous United States derived from MODIS and AmeriFlux data 

      Xiao, Jingfeng; Zhuang, Qianlai; Law, Beverly E.; Chen, Jiquan; Baldocchi, Dennis D.; Cook, David R.; Oren, Ram; Richardson, Andrew; Wharton, Sonia; Ma, Siyan; Martini, Timothy A.; Verma, Shashi B.; Suyker, Andrew E.; Scott, Russell L.; Monson, Russell K.; Litvak, Marcy; Hollinger, David Y.; Sun, Ge; Davis, Kenneth J.; Bolstad, Paul V.; Burns, Sean P.; Curtis, Peter S.; Drake, Bert G.; Falk, Matthias; Fischer, Marc L.; Foster, David Russell; Gu, Lianhong; Hadley, Julian L.; Katul, Gabriel G.; Matamala, Roser; McNulty, Steve; Meyers, Tilden P.; Munger, J. William; Noormets, Asko; Oechel, Walter C.; Paw U, Kyaw Tha; Schmid, Hans Peter; Starr, Gregory; Torn, Margaret S.; Wofsy, Steven Charles (Elsevier BV, 2010)
      The quantification of carbon fluxes between the terrestrial biosphere and the atmosphere is of scientific importance and also relevant to climate-policy making. Eddy covariance flux towers provide continuous measurements ...
    • Distribution and mixing of old and new nonstructural carbon in two temperate trees 

      Richardson, Andrew D; Carbone, Mariah S; Huggett, Brett A; Furze, Morgan E; Czimczik, Claudia I; Walker, Jennifer C; Xu, Xiaomei; Schaberg, Paul G; Murakami, Paula (BlackWell Publishing Ltd, 2015)
      We know surprisingly little about whole-tree nonstructural carbon (NSC; primarily sugars and starch) budgets. Even less well understood is the mixing between recent photosynthetic assimilates (new NSC) and previously stored ...
    • Evaluating remote sensing of deciduous forest phenology at multiple spatial scales using PhenoCam imagery 

      Klosterman, Stephen; Hufkens, Koen; Gray, J. M.; Melaas, E.; Sonnentag, O.; Lavine, I.; Mitchell, L.; Norman, R.; Friedl, M. A.; Richardson, Andrew (Copernicus GmbH, 2014)
      Plant phenology regulates ecosystem services at local and global scales and is a sensitive indicator of global change. Estimates of phenophase transition dates, such as the start of spring or end of autumn, can be derived ...
    • Forest ecosystem changes from annual methane source to sink depending on late summer water balance 

      Shoemaker, Julie K.; Keenan, Trevor; Hollinger, David Y.; Richardson, Andrew (Wiley-Blackwell, 2014)
      Forests dominate the global carbon cycle, but their role in methane (CH4) biogeochemistry remains uncertain. We analyzed whole-ecosystem CH4 fluxes from 2 years, obtained over a lowland evergreen forest in Maine, USA. Gross ...
    • Monitoring vegetation phenology using an infrared-enabled security camera 

      Petach, Anika; Toomey, Michael; Aubrecht, Donald Michael; Richardson, Andrew (Elsevier BV, 2014)
      Sensor-based monitoring of vegetation phenology is being widely used to quantify phenological responses to climate variability and change. Digital repeat photography, in particular, can characterize the seasonality of ...
    • A new seasonal-deciduous spring phenology submodel in the Community Land Model 4.5: impacts on carbon and water cycling under future climate scenarios 

      Chen, Min; Melaas, Eli K.; Gray, Josh M.; Friedl, Mark A.; Richardson, Andrew (Wiley-Blackwell, 2016)
      A spring phenology model that combines photoperiod with accumulated heating and chilling to predict spring leaf-out dates is optimized using PhenoCam observations and coupled into the Community Land Model (CLM) 4.5. In ...
    • Nitrogen cycling, forest canopy reflectance, and emergent properties of ecosystems 

      Ollinger, S. V.; Reich, P. B.; Frolking, S.; Lepine, L. C.; Hollinger, D. Y.; Richardson, Andrew (Proceedings of the National Academy of Sciences, 2013)
    • Predicting Climate Change Impacts on the Amount and Duration of Autumn Colors in a New England Forest 

      Archetti, Marco; Richardson, Andrew; O'Keefe, John F.; Delpierre, Nicolas (Public Library of Science, 2013)
      Climate change affects the phenology of many species. As temperature and precipitation are thought to control autumn color change in temperate deciduous trees, it is possible that climate change might also affect the ...
    • Rate My Data: Quantifying the Value of Ecological Data for Models of Terrestrial Carbon Cycle 

      Keenan, Trevor; Davidson, Eric; Munger, James; Richardson, Andrew (Ecological Society of America, 2013)
      Primarily driven by concern about rising levels of atmospheric CO2, ecologists and earth system scientists are collecting vast amounts of data related to the carbon cycle. These measurements are generally time-consuming ...
    • Season Spotter: Using Citizen Science to Validate and Scale Plant Phenology from Near-Surface Remote Sensing 

      Kosmala, Margaret C; Crall, Alycia; Cheng, Rebecca; Hufkens, Koen; Henderson, Sandra; Richardson, Andrew (MDPI AG, 2016)
      Abstract: The impact of a rapidly changing climate on the biosphere is an urgent area of research for mitigation policy and management. Plant phenology is a sensitive indicator of climate change and regulates the seasonality ...
    • Steeper declines in forest photosynthesis than respiration explain age-driven decreases in forest growth 

      Tang, J.; Luyssaert, S.; Richardson, Andrew; Kutsch, W.; Janssens, I. A. (Proceedings of the National Academy of Sciences, 2014)
      Advancing our understanding of how and why forests dynamically change in their productivity is important to predict the future change. The traditional view of forest dynamics originated by Kira, Shidei, and Odum suggests ...
    • Terrestrial Biosphere Model Performance for Inter-Annual Variability of Land-Atmosphere CO2 Exchange 

      Keenan, Trevor; Baker, Ian; Barr, Alan; Ciais, Philippe; Dietze, Michael; Dragoni, Danillo; Gough, Christopher; Grant, Robert; Hollinger, David; Hufkens, Koen; Poulter, Ben; McCaughey, Harry; Racza, Brett; Ryu, Youngryel; Schaefer, Kevin; Tian, Hanqin; Verbeeeck, Hans; Zhao, Maosheng; Richardson, Andrew (Wiley-Blackwell, 2012)
      Interannual variability in biosphere-atmosphere exchange of CO2 is driven by a diverse range of biotic and abiotic factors. Replicating this variability thus represents the ‘acid test’ for terrestrial biosphere models. ...
    • Terrestrial biosphere models need better representation of vegetation phenology: results from the North American Carbon Program Site Synthesis 

      Richardson, Andrew; Anderson, Ryan S.; Arain, M. Altaf; Barr, Alan G.; Bohrer, Gil; Chen, Guangsheng; Chen, Jing M.; Ciais, Philippe; Davis, Kenneth J.; Desai, Ankur R.; Dietze, Michael C.; Dragoni, Danilo; Garrity, Steven R.; Gough, Christopher M.; Grant, Robert; Hollinger, David Y.; Margolis, Hank A.; McCaughey, Harry; Migliavacca, Mirco; Monson, Russell K.; Munger, J. William; Poulter, Benjamin; Raczka, Brett M.; Ricciuto, Daniel M.; Sahoo, Alok K.; Schaefer, Kevin; Tian, Hanqin; Vargas, Rodrigo; Verbeeck, Hans; Xiao, Jingfeng; Xue, Yongkang (Wiley Blackwell (Blackwell Publishing), 2012)
      Phenology, by controlling the seasonal activity of vegetation on the land surface, plays a fundamental role in regulating photosynthesis and other ecosystem processes, as well as competitive interactions and feedbacks to ...
    • Tracking forest phenology and seasonal physiology using digital repeat photography: a critical assessment 

      Keenan, Trevor; Darby, B.; Felts, Libby Sophie; Sonnentag, O.; Friedl, M. A.; Hufkens, K.; O'Keefe, John Francis; Klosterman, Stephen; Munger, J. William; Toomey, M.; Richardson, Andrew (Ecological Society of America, 2014)
      Digital repeat photography is becoming widely used for near-surface remote sensing of vegetation. Canopy greenness, which has been used extensively for phenological applications, can be readily quantified from camera images. ...
    • Using Model-Data Fusion to Interpret Past Trends, and Quantify Uncertainties in Future Projections, of Terrestrial Ecosystem Carbon Cycling 

      Keenan, Trevor; Davidson, Eric; Moffat, Antje; Munger, William; Richardson, Andrew (Wiley-Blackwell, 2012)
      Uncertainties in model projections of carbon cycling in terrestrial ecosystems stem from inaccurate parameterization of incorporated processes (endogenous uncertainties) and processes or drivers that are not accounted for ...