Joseph J. O'Brien

Research Ecologist
Fire Science Team
Center for Forest Disturbance Science
USDA Forest Service
SRS Staff Directory Profile

SRS Publications List


Ph.D. Biological Sciences 2001 Florida International University, Miami, Florida Dissertation title: “The effects of climate on the growth and physiology of tropical rainforest canopy trees.”
M.S. Biological Sciences 1997 Florida International University, Miami, Florida Thesis title: “The distribution and habitat preferences of rare Galactia species (Fabaceae) and Chamaesyce deltoidea subspecies (Euphorbiaceae) native to Florida pine rocklands with a discussion on the origin of endemism in Florida pine forests.”
Tropical Biology: An Ecological Approach 1994 Organization for Tropical Studies, Durham, North Carolina
B.S. Biology 1986 State University College at Geneseo, New York  

Language Skills

Competent in spoken and written Spanish.

Professional Experience

Adjunct Research Associate 2004–Present Joseph W. Jones Ecological Research Center at Ichauway, Newton, Georgia  
Research Ecologist, GS-0408-12 July 2002–July 2007 USDA Forest Service, Center for Forest Disturbance Science, Athens, Georgia Also Co-Coordinator for Latin American and Caribbean fire ecology and management team for USDA Forest Service International Programs.
Visiting Scientist 2002 University of Utah, Department of Biology, Coley/Kursar Lab Assisted in mentoring graduate students and attended Ehleringer/SIRFER Lab Stable Isotopes in Ecology course.
Ecologist 2001–2002 Miami, Florida Worked with Science Applications International Corporation and the Army Corps of Engineers on a remote sensing project to monitor the effectiveness of Florida Everglades wetlands restoration efforts.
Research Assistant 1997–2001 Florida International University, Miami, Florida Collaborator in the Carbono Project, an ecosystem study of climate driven rain forest carbon dynamics at La Selva Biological Station, Costa Rica. Lived on site in Costa Rica for the duration of the project.
Research Assistant 2000 Florida International University, Miami, Florida Designed and built an automated ecosystem carbon flux measurement system for tundra communities as part of climate change research at Toolik Research Station, Alaska.
Research Assistant 1994–1997 Florida International University, Miami, Florida Studied the impact of Hurricane Andrew on the spatial dynamics of fire behavior and fire effects on plant communities in Everglades National Park and Big Cypress National Preserve pine forests.
Research Biologist 1989–1993 National Audubon Society, Tavernier, Florida Studied terrestrial plant community ecology and ecosystem processes in tropical forests in the Florida Keys.
Project Assistant 1988–1989 Institute for Ecosystems Study, Millbrook, NY Field assistant for a study of gypsy moth population dynamics in New York and New England forests.
Logger, Millworker 1986–1988 Schiano Logging, Swain, NY Worked in all aspects of hardwood timber logging and milling in central NY.


The ecology of frequently burned fire dependent ecosystems

A major focus of the scientist’s research program concerns linking fire behavior and fire effects. The examination of the spatial dynamics of fire behavior has opened up a rich avenue of study leading to the funding of three major research projects and several collaborations. Until recently, the lack of spatially explicit fire measurements at fine scales has severely limited the ability to connect the process of combustion with both fuels and fire effects. In frequently burned ecosystems, understanding the variation of intensity within fires is especially crucial since burns are usually complete. That is, surface fuels are usually completely consumed giving the false impression of uniform fire behavior. Without detailed measurements of a fire, it is difficult to piece together fire effects. Unfortunately, capturing and measuring fire behavior is also extremely difficult. Fire is a transient and dynamic phenomenon that occurs in three dimensions and is linked to other dynamic variables such as wind fields and combustion chemistry. It is also dangerous and hard on equipment. Until very recently, measurements of fire behavior were limited to point samples or indices. Accurate estimates of fire radiative energy, the work that drives fire effects, were non-existent or inferred. The scientist has overcome this limitation by exploiting technological advances such as high resolution thermal imaging systems to explicitly connect how the patterns of burning impact post fire ecological processes such as plant mortality and regeneration. He has also shed light on how the spatial arrangement of fuels drives fire behavior and acts to connect the data collected by several other state of the art technologies such as the LiDAR and radiometry. His data has been used by modelers to refine fire spread prediction systems (FIRETEC, Rabbit Rules). These measurements are also an important component of validating and understanding the cross scale radiant flux measurements taken by the radiometers, UAV's and satellites. The scientist’s work has also linked forest structure to patterns in fuels that drive variation in fire intensity, connecting both disturbance ecology and silviculture to fire ecology.

The ecophysiological impacts of fire

The scientist’s background in plant ecophysiology has led to several investigations of the impact of fire damage on tree carbon dynamics. He has investigated the causal mechanisms driving post fire mortality when fire is reintroduced into long unburned forests and how crown scorch impacts carbon flow in longleaf pines (Pinus palustris). His expertise contributed to the successful granting of funds from the USDA National Research Initiative. Ongoing work on the subject includes a collaborative research effort on fire effects on net ecosystem exchange at the Joseph W. Jones Ecological Research Center at Ichauway.

Global change and disturbance interactions

The scientist is engaged in research related to the direct and indirect impacts of climate change. He has active research on wet tropical forest physiological responses to changes in precipitation a project that grew from his doctoral research and is funded by the National Science Foundation. He is also involved in research on the impact of sea level rise on small island ecosystems and the subsequent cascade of disturbance interactions that result. For example, he identified the initiation of an alternative stable state when slash pine (Pinus elliottii var. densa) stands were destroyed by a storm surge following a hurricane in the Florida Keys. The interaction of a ramp disturbance (sea level rise) and a pulse disturbance (storm surge) caused an instantaneous change of state that will likely persist. This is due to the loss of the pines that act as a foundation species by providing critical fine fuels that maintain frequent fires essential for sustaining fire adapted species. He has initiated a project investigating the interaction of an invasive pest with trees stressed by sea level rise in the tropical pine forests of the Turks and Caicos Islands. The end results appear to be similar to those observed in the Keys. The results of these studies will inform efforts to restore both of these species rich ecosystems. He is currently involved in the interaction of canopy wind disturbance on fire behavior and fire effects in southeastern Piedmont and Coastal Plain pine forests.


  • Mitchell, R. J., Liu, Y., O’Brien, J. J., Elliott, K. J., Starr, G., Miniat, C. F., and J.K. Hiers. 2014. Future climate and fire interactions in the southeastern region of the United States. Forest Ecology and Management.
  • Fleming, G.M., Wunderle, J.M., Ewert, D.N., and J.J. O'Brien. 2014. Estimating plant biomass in early‐successional subtropical vegetation using a visual obstruction technique. Applied Vegetation Science 17:356-366.
  • Garbarino V.R., Campbell, J., O'Brien, J., Proctor, H.C., and B. Dik. 2013. Pthiraptera and Acari collected from 13 species of waterfowl from Alabama and Georgia. Southeastern Naturalist 12: 413–426.
  • Callaham, M.A., Jr., Stanturf, J.A., Hammond, W.J., Rockwood, D.L., Wenk, E.S., and J.J. O’Brien. 2013. Survey to evaluate escape of Eucalyptus spp. from plantations in southeastern USA. International Journal of Forestry Research, vol. 2013, Article ID 946374, 10 pages. DOI: 10.1155/2013/946374 Refereed.
  • Zhang, Y., Hanula, J., O’Brien, J.J., Horn, S., Braman, K., and J. Sun. 2013. Evaluation of the impacts of defoliation and herbivory by lace bugs of on Chinese privet (Ligustrum sinense) survival and physiology. Forest Ecology and Management 64: 299-304. Refereed.
  • Aubrey, D.P., Mortazavi, B., O’Brien, J.J., McGee, J.D., Hendricks, J.J., Kuehn, K.A., and R.J Mitchell. 2012. Influence of repeated canopy scorching on soil CO2 efflux. Forest Ecology and Management 282:142-148. Refereed.
  • Callaham, M.A., Scott, D.A., O’Brien, J.J., and J.A. Stanturf. 2012. Cumulative effects of fuel management on the soils of eastern U.S. In: LaFayette, R., Brooks, M.T., Potyondy, J.P.; Audin, L., Krieger, S.L. and C.C. Trettin, Eds. Cumulative watershed effects of fuel management in the Eastern United States. Gen. Tech. Rep. SRS-161. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 202-228.
  • Loudermilk, E.L., O’Brien, J.J., Mitchell, R.J., Hiers, J.K., Cropper, W.P., Jr., Grunwald, S, Grego, J., and J. Fernandez. 2012. Linking complex forest fuel structure and fire behavior at fine scales. International Journal of Wildland Fire 21: 882-893. Refereed.
  • Mitchell, R.J., Clark, K.L., Hurteau, M.D., Palik, B.J., Rocca, M.E., Wimberly, M.C., Bradford, J.B., Brown, P.M., Charney, J.J., Clinton, B., Fule, P.Z., Goebel, P.C., Kennedy, R.S.H., Liu, Y., MacDonald, L.H., O’Brien, J.J., Renninger, H., Scheller, R., Skowronski, N., Starr, G., and A.H. Taylor. 2012. Fire-Climate Interactions: A Technical Input Report for the National Climate Assessment.
  • Reilly, M.J., Waldrop, T.A., and J.J. O’Brien. 2012. Fuels management in the southern Appalachian Mountains, hot continental division In: LaFayette, R., Brooks, M.T., Potyondy, J.P.; Audin, L., Krieger, S.L., and C.C. Trettin, Eds. Cumulative watershed effects of fuel management in the Eastern United States. Gen. Tech. Rep. SRS-161. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 202-228.
  • Maschinski, J., Ross, M.S., Liu, H., O’Brien, J.J., von Wettberg, E.J., and K.E. Haskins. 2011. Sinking ships: conservation options for endemic taxa threatened by sea level rise. Climatic Change 107:147-167. Refereed.
  • O’Brien, J.J., Hiers, J.K., Mitchell, R.J., Varner, J.M., III, and K. Mordecai. 2010. Ecophysiological effects of smoldering fires on mature Pinus palustris. Fire Ecology 6: 1-12. Refereed.
  • O’Brien, J.J. Mordecai, K., Wolcott, L., Snyder, J., and K. Outcalt. 2010. A field guide to hazardous fuels management in sub-tropical pine flatwoods and tropical pine rocklands. General Technical Report SRS-123.
  • Sharik, T.L., Adair, W., Battaglia, M., Baker, F.A., Comfort, E.J., D'Amato, A., DeLong, C., DeRose, R.J., Ducey, M., Harmon, M.E., Levy, L., Logan, J., O’Brien, J.J., Palik, B., Roberts, S.D., Rogers, P.C., Shinneman, D. J., and T.A. Spies. 2010. Emerging themes in the ecology and management of North American forests. International Journal of Forest Research. Vol. 2010, Article ID 964260, 11 pages. doi:10.1155/2010/964260 Refereed.
  • Gardiner, E., Löf, M., O’Brien, J.J., Stanturf, J., and P. Madsen. 2009. Photosynthetic characteristics of Fagus sylvatica and Quercus robur established for stand conversion from Picea abies. Forest Ecology and Management 258: 868-878. Refereed.
  • Hanula, J.L, Wade, D.D., O’Brien, J.J., and S.C. Loeb. 2009. Ground-dwelling arthropod association with coarse woody debris following long-term dormant season prescribed burning in the longleaf pine flatwoods of North Florida. Florida Entomologist. 92:229-242. Refereed
  • Hiers, J.K., O’Brien, J.J., Mitchell, R.J., Loudermilk, E.L., and J.M. Grego. 2009. The wildland fuel cell concept: an approach to characterize fine-scale variation in fuels and fire in frequently burned longleaf pine forests. International Journal of Wildland Fire 18: 315-325. Refereed.
  • Loudermilk, E.L., Hiers, J.K., O’Brien, J.J., Mitchell, R.M., Singhania, A., Fernandez, J.C. Cropper, W.P., Jr., and K.C. Slatton. 2009. Ground-based LIDAR: A novel approach to quantify fine-scale fuelbed characteristics. International Journal of Wildland Fire 18: 676–685. Refereed.
  • Mitchell, R.J., Hiers, J.K., O’Brien, J.J., and G. Starr. 2009. Ecological forestry in the Southeast: understanding the ecology of fuels. Journal of Forestry 107: 381-387. Refereed.
  • O'Brien, J.J. 2009. Linking Fuel heterogeneity to Fire Behavior. Synthesis Session: 7th North American Forestry Workshop, Compiled and Edited by Terry L. Sharik, Page 8.
  • Ross, M.S., O’Brien, J.J., Zhang, K., Ford, G., and A. Morkill. 2009. Disturbance and the rising tide: the challenge of biodiversity management on low island ecosystems. Frontiers in Ecology and Environment 7: 471-478. Refereed.
  • Varner, J.M., Putz, F.E., O’Brien, J.J., Mitchell, R.J., Hiers, J.K., and D.R. Gordon. 2009. Post-fire tree stress and growth following smoldering duff fires. Forest Ecology and Management 258: 2467-2474. Refereed.
  • O’Brien, J.J., Hiers, J.K., Mitchell, R.J., Callaham, M.A., Jr., and S. Jack. 2008. The interactions among pine overstory structure, seedling life history traits and fire in frequently burned neotropical pine forests. Ambio 37: 542-547. Refereed.
  • O’Brien, J.J., Oberbauer, S.F., Clark, D.B., and D.A. Clark. 2008. Phenology and stem growth seasonality in a Costa Rican wet tropical forest. Biotropica 40(2): 151–159. Refereed.
  • Hiers, J.K, O’Brien, J.J., Will, R., and R.J. Mitchell. 2007. Forest floor depth mediates understory vigor in xeric Pinus palustris ecosystems. Ecological Applications 17: 806-814. Refereed.
  • Wolcott, L, O’Brien, J.J., and K. Mordecai. 2007. A survey of land managers on wildland hazardous fuels issues in Florida: a technical note. Southern Journal of Applied Forestry 31: 148-150. Refereed.
  • Myers, R., O’Brien, J., and S. Morrison. 2006. A general description of fire management in Caribbean pine (Pinus caribaea) savannas of la Mosquitia, Honduras. GFI Technical Bulletin 2006-1a. The Nature Conservancy, Arlington, VA.
  • O’Brien, J.J., Mori, G.P., Stahala, C., Callaham, M.A., Jr., and C. Bergh. 2006. Direct effects of prescribed fire on the environment inside a Cuban Parrot (Amazonas leucocephala) surrogate nesting cavity on Great Abaco, Bahamas. Wilson Journal of Ornithology 118 (4): 508-512. Refereed.
  • Mitchell R.J., Hiers, J.K., O’Brien, J.J., Jack, S.B., and R.T. Engstrom. 2006. Silviculture that sustains: the nexus between silviculture, frequent prescribed fire, and conservation of biodiversity in longleaf pine forests of the southeastern United States. Canadian Journal of Forest Research 36: 2724-2736. Refereed.
  • O’Brien, J.J. 2005. Fire effects on soil nutrients. Encyclopedia of Southern Fire Science. Eds. D. Kennard and C. Fowler. USDA Forest Service. EIDs: 9967. Refereed.
  • Kennard, D.K., Outcalt, K.W., Jones, D. and J. J. O’Brien. 2005. Comparing techniques for estimating flame temperature of prescribed fires. Fire Ecology 1: 75-84. Refereed.
  • O’Brien, J.J. 2005. Fire ecology of Caribbean pine forests. In Weaver, P.L. and K.A. Gonzalez (Eds.) Wildand Fire Management and Restoration: Proceedings of the 12th Caribbean Foresters Conference (pp. 56-63). San Juan: USDA Forest Service International Institute of Tropical Forestry.
  • Myers, R., O ’Brien, J., Mehlman, D., and C. Bergh. 2004. Fire Management Assessment of the Highland Ecosystems of the Dominican Republic. GFI publication no. 2004-2. The Nature Conservancy, Arlington, VA.
  • O’Brien, J.J., Oberbauer, S.F., and D.B. Clark. 2004. Whole tree xylem sap flow responses to multiple environmental variables in a wet tropical forest. Plant Cell and Environment 27: 551-567. Refereed.
  • Schwendenmann, L., Veldkamp, E., Brenes, T., O'Brien, J.J., and J. Mackensen. 2002. Spatial and temporal variation in soil CO2 efflux in an old-growth Neotropical rain forest, La Selva, Costa Rica. Biogeochemistry 64: 111-128. Refereed.
  • O’Brien, J.J., and S. F. Oberbauer. 2001. An inexpensive, portable meter for measuring soil moisture. Soil Science Society of America Journal 65:1081-1083. Refereed.
  • Englund, S.R., O’Brien, J.J., and D.B. Clark. 2000. Evaluation of digital and film hemispherical photography and spherical densitometry for measuring forest light environments. Canadian Journal of Forest Research 30(12). Refereed.
  • Veldkamp, E., and J.J. O’Brien. 2000. Calibration of a FDR sensor for humid tropical soils of volcanic origin. Soil Science Society of America Journal, 64: 1549-1553. Refereed.
  • Koptur, S., O’Brien, J.J., and J.R. Snyder. 1998. The influence of hurricane-induced fuel load heterogeneity on the response of endemic understory plants to fire. Final Report, National Park Service Cooperative Agreement CA-5280-4-9012.
  • O’Brien, J.J. 1998. The distribution and habitat preferences of rare Galactia species (Fabaceae) and Chamaesyce deltoidea subspecies (Euphorbiaceae) native to southern Florida pine rockland. Natural Areas Journal 18: 208-222. Refereed.
  • Ross, M., O’Brien, J.J., and L. Sternberg. 1994. Sea level rise and the decline of pinelands in the lower Florida Keys. Ecological Applications 4: 144-156. Refereed.
  • Ross, M., O’Brien, J.J., and L. Flynn. 1992. Ecological site classification of Florida Keys terrestrial habitats. Biotropica 24: 488-502. Refereed.
  • Ish-Shalom, N.L., Sternberg, N.L., Ross, M., and J. O’Brien. 1992. Water utilization of tropical hardwood hammocks of the Lower Florida Keys. Oecologia 92: 108-112. Refereed.
  • Sternberg, L.d.L.S.L., Ish-Shalom-Gordon, N., Ross, M.S., and J.J. O’Brien. 1991. Water relations of coastal plant communities near the ocean/freshwater boundary. Oecologia 88: 305-310. Refereed.