Staff Profile
Photo for Sean McMahon, Forest Ecologist


My lab is focused on understanding how tree demography--the growth, survival, and recruitment of individual stems--is driven by physiological and environmental processes.  We also study how demographic dynamics drive large-scale patterns of forest structure, function, and diversity.  Much of our work evolves from using extant data from both the Smithsonian's ForestGEO network, FIA, remote sensing data sets, and extensive research of Geoffrey Parker, a colleague and forest ecologist at the Smithsonian Environmental Research Center, where we are based.  We also explore these questions by collecting new data whenever possible.  If a research focus is on forest dynamics, there is no limit to the kinds of projects we want to weave into our team.  

I am the Temperate Program Coordinator for the Smithsonian Institution's CTFS-ForestGEO network.   There are currently 17 temperate plots in the program in North America and Europe, with a number of other partner plots in China.  My responsibilities for the network involve facilitating synthetic science, assisting network partners in research, data-collection, and data vetting, storage and curation.  I also work to expand the network into new biomes, with unique flora, distrubance histories, and new partner institutions to promote fundamental research to build a global understanding of forest dynamics.   



  • Taylor, Tyeen C., McMahon, Sean M., Smith, Marielle N., Boyle, Brad, Violle, Cyrille, van Haren, Joost, Simova, Irena, Meir, Patrick, Ferreira, Leandro V., de Camargo, Plinio B., da Costa, Antonio C. L., Enquist, Brian J. and Saleska, Scott R. (2018). Isoprene emission structures tropical tree biogeography and community assembly responses to climate. New Phytologist, 220 (2) , 435-446.
  • LaManna, Joseph A., Mangan, Scott A., Alonso, Alfonso, Bourg, Norman A., Brockelman, Warren Y., Bunyavejchewin, Sarayudh, Chang, Li-Wan, Chiang, Jyh-Min, Chuyong, George B., Clay, Keith, Condit, Richard S., Cordell, Susan, Davies, Stuart J., Furniss, Tucker J., Giardina, Christian P., Gunatilleke, I. A. U. Nimal, Gunatilleke, C. V. Savitri, He, Fangliang, Howe, Robert W., Hubbell, Stephen P., Hsieh, Chang-Fu, Inman-Narahari, Faith M., Janik, David, Johnson, Daniel J., Kenfack, David, et al. (2017). Plant diversity increases with the strength of negative density dependence at the global scale . Science, 356 (6345) , 1389-1392.
  • Evans, Margaret, Merow, Cory, Record, Sydne, McMahon, Sean M. and Enquist, Brian J. (2016). Towards Process-based Range Modeling of Many Species. Trends in Ecology & Evolution, 31 (11) , 860-871.
  • Griffith, Alden B., Salguero-Gómez, Roberto, Merow, Cory and McMahon, Sean. (2016). Demography beyond the population. Journal of Ecology, 104 (2) , 271-280.
  • Herrmann, Valentine, McMahon, Sean M., Detto, Matteo, Lutz, James A., Davies, Stuart James, Chang-Yang, Chia and Anderson-Teixeira, Kristina J. (2016). Tree Circumference Dynamics in Four Forests Characterized Using Automated Dendrometer Bands . Plos One, 11 (12) , 1-20.
  • Janík, David, Král, Kamil, Adam, Dusan, Hort, Libor, Samonil, Pavel, Unar, Pavel, Vrska, Tomás and McMahon, Sean. (2016). Tree spatial patterns of Fagus sylvatica expansion over 37 years. Forest Ecology and Management, 375 , 134-145.
  • Král, Kamil, Shue, Jessica, Vrška, Tomáš, Gonzalez-Akre, Erika, Parker, Geoffrey G., McShea, William J. and McMahon, Sean M. (2016). Fine-scale patch mosaic of developmental stages in Northeast American secondary temperate forests: the European perspective . European Journal of Forest Research, 135 (5) , 981-996.
  • Needham, Jessica, Merow, Cory, Butt, Nathalie, Malhi, Yadvinder, Marthews, Toby R., Morecroft, Michael and McMahon, Sean M. (2016). Forest community response to invasive pathogens: the case of ash dieback in a British woodland. Journal of Ecology, 104 (2) , 315-330.
  • Anderson-Teixeira, Kristina J., Davies, Stuart James, Bennett, Amy C., Gonzalez-Akre, Erika, Muller-Landau, Helene C., Wright, S. Joseph, Abu Salim, Kamariah, Almeyda Zambrano, Angélica M., Alonso, Alfonso, Baltzer, Jennifer L., Basset, Yves, Bourg, Norman A., Broadbent, Eben N., Brockelman, Warren Y., Bunyavejchewin, Sarayudh, Burslem, David F. R. P., Butt, Nathalie, Cao, Min, Cardenas, Dairon, Chuyong, George B., Clay, Keith, Cordell, Susan, Dattaraja, Handanakere S., Deng, Xiaobao, Detto, Matteo, et al. (2015). CTFS-ForestGEO: a worldwide network monitoring forests in an era of global change . Global Change Biology, 21 (2) , 528-549.
  • Anderson-Teixeira, Kristina J., McGarvey, Jennifer C., Muller-Landau, Helene C., Park, Janice Y., Gonzalez-Akre, Erika, Herrmann, Valentine, Bennett, Amy C., So, Christopher V., Bourg, Norman A., Thompson, Jonathan R., McMahon, Sean M. and McShea, William J. (2015). Size-related scaling of tree form and function in a mixed-age forest. Functional Ecology, 29 (12) , 1587-1602.
  • McMahon, Sean M. and Parker, Geoffrey G. (2015). A general model of intra-annual tree growth using dendrometer bands. Ecology and Evolution, 5 (2) , 243-254.
  • McMahon, Sean M., Bebber, Daniel P., Butt, Nathalie, Crockatt, Martha, Kirby, Keith, Parker, Geoffrey G., Riutta, Terhi and Slade, Eleanor M. (2015). Ground based LiDAR demonstrates the legacy of management history to canopy structure and composition across a fragmented temperate woodland. Forest Ecology and Management, 335 , 255-260.
  • Metcalf, C. Jessica E., Ellner, Stephen P., Childs, Dylan Z., Salguero-Gómez, Roberto, Merow, Cory, McMahon, Sean M., Jongejans, Eelke and Rees, Mark. (2015). Statistical modelling of annual variation for inference on stochastic population dynamics using Integral Projection Models. Methods in Ecology and Evolution, 6 (9) , 1007-1017.
  • Sexton, Joseph O., Noojipady, Praveen, Anand, Anupam, Song, Xiao-Peng, McMahon, Sean M., Huang, Chengquan, Feng, Min, Channan, Saurabh and Townshend, John R. (2015). A model for the propagation of uncertainty from continuous estimates of tree cover to categorical forest cover and change. Remote Sensing of Environment, 156 , 418-425.
  • Visser, Marco D., McMahon, Sean M., Merow, Cory, Dixon, Philip M., Record, Sydne and Jongejans, Eelke. (2015). Speeding Up Ecological and Evolutionary Computations in R; Essentials of High Performance Computing for Biologists . PLoS computational biology, 11 (3) , 1-11.