You are here

Carolyn H. Sieg

Research Plant Ecologist

Research Plant Ecologist

Address: 
2500 South Pine Knoll Drive
Flagstaff, AZ 86001
Phone: 
928-556-2151
Fax: 
928-556-2130
Contact Carolyn H. Sieg

Current Research

Plant community and fuels changes through time following severe wildfires and how spatial patterns in forests and regeneration are altered by such disturbances and subsequent management actions. Currently using physics-based fire behavior models to explore effects of disturbances such as bark beetle outbreaks and management practices on fire spread.

Research Interests

I am interested in exploring interacting natural disturbances such as fires following bark beetles, or fires following fires.  I particularly enjoy working in interdisciplinary research teams, even though it can be challenging!

Past Research

Past research focused on northern Great Plains ecosystems and explored the role of natural processes such as fire in shaping ecosystems, and developing management options for introducing these processes into altered systems without severe impacts such as enhancing populations of exotic plant species. I also have extensive research experience with rare plants such as the federally listed western prairie fringed orchid.

Why This Research is Important

Changing disturbance regimes, introduction of exotic species, and rarity of some native species in Western Forests present challenges for land managers. We need a better understanding of how to manage forests impacted by severe wildfires, whether beetle-infested areas present serious fire threats, and strategies for lessening the impact of exotic invasive species.

Education

  • Texas Tech University, Lubbock, Ph.D., Range and Wildlife Management (Fire Ecology), 1991
  • Colorado State University, Fort Collins, M.S., Rangeland Ecology, 1981
  • Colorado State University, Fort Collins, B.S., Wildlife Biology, 1975
  • Professional Organizations

    • Forest Ecology and Management, Editorial Advisory Board ( 2014 to present )
    • Ecological Society of America, Subject Matter Editor ( 2012 to present )
    • Association for Fire Ecology, Associate Editor ( 2007 to present )
    • Northern Arizona University, Adjunct Faculty ( 2001 to present )
      School of Forestry, Environmental Sciences, and Biology
    • Journal of Range Management/Rangeland Ecology and Management, Associate Editor, Chair Of Associate Editors For 2 Years ( 2001 to 2006 )
    • Colorado State University, Adjunct Faculty ( 1995 to 2006 )
    • North Dakota State University, Adjunct Faculty ( 1996 to 2003 )
    • University of Wyoming, Adjunct Faculty ( 1998 to 2001 )
    • South Dakota State University, Adjunct Faculty ( 1985 to 1988 )

    Awards

    Certificate of Appreciation, 2010
    Customer Appreciation (Rocky Mountain Research Station)
    Fellow Award--Society of Range Management, 2007
    For recognition of exceptional service to the Society and its programs in advancing the science and art of range-related resource management.
    US Forest Service Research and Development, 2005
    For contributions to the development of the USDA Forest Service Interim Update of the RPA Assessment, including the biodiversity components
    Top Hand Award--South Dakota Section of the Society for Range Management, 2001
    For outstanding contribution to the South Dakota section and parent organization.
    Charles E. Bessey Award, 2000
    For outstanding regional scholarship and best natural science article. Awarded by The Center for Great Plains Studies for the paper: Recent biodiversity patterns in the Great Basin: implications for restoration and management.
    Wildlife Professional of the year, 1999
    For year 1999
    US Forest Service Research and Development, 1997
    For outstanding contribution to the Forest Service Research and Development strategic planning effort (U.S.Forest Service Research and Development).
    US Forest Service Chief's Award, 1995
    Unit award for exceptional leadership, committment, and accomplishments in the conservation and recovery of threatened, endangered, and sensitive species

    Featured Publications

    Publications

    Hoffman, C. M.; Ziegler, J.; Linn, R. R.; Canfield, J.; Mell, W.; Sieg, Carolyn H.; Pimont, F., 2019. Reply to Cruz and Alexander: Comments on “Evaluating Crown Fire Rate of Spread Predictions from Physics-Based Models"
    Iniguez, Jose; Fowler, James F.; Moser, W. Keith; Sieg, Carolyn H.; Baggett, Scott; Shin, Patrick, 2019. Tree and opening spatial patterns vary by tree density in two old-growth remnant ponderosa pine forests in Northern Arizona, USA
    Malone, Sparkle L.; Fornwalt, Paula J.; Battaglia, Mike A.; Chambers, Marin E.; Iniguez, Jose; Sieg, Carolyn H., 2018. Mixed-severity fire fosters heterogeneous spatial patterns of conifer regeneration in a dry conifer forest
    Ziegler, Justin P.; Hoffman, Chad M.; Fornwalt, Paula J.; Sieg, Carolyn H.; Battaglia, Mike A.; Chambers, Marin E.; Iniguez, Jose, 2017. Tree regeneration spatial patterns in ponderosa pine forests following stand-replacing fire: Influence of topography and neighbors
    Negron, Jose; McMillin, Joel; Sieg, Carolyn H.; Fowler, James F.; Allen, Kurt K.; Wadleigh, Linda L.; Anhold, John A.; Gibson, Ken E., 2016. Variables associated with the occurrence of Ips beetles, red turpentine beetle and wood borers in live and dead ponderosa pines with post-fire injury
    Hoffman, C. M.; Ziegler, J.; Canfield, J.; Linn, R. R.; Mell, W.; Sieg, Carolyn H.; Pimont, F., 2015. Evaluating crown fire rate of spread predictions from physics-based models
    Kent, Larissa L. Yocom; Shive, Kristen L.; Strom, Barbara A.; Sieg, Carolyn H.; Hunter, Molly E.; Stevens-Rumann, Camille S.; Fule, Peter Z., 2015. Interactions of fuel treatments, wildfire severity, and carbon dynamics in dry conifer forests
    Hoffman, Chad M.; Linn, Rodman; Parsons, Russell A.; Sieg, Carolyn H.; Winterkamp, Judith., 2015. Modeling spatial and temporal dynamics of wind flow and potential fire behavior following a mountain pine beetle outbreak in a lodgepole pine forest
    Nelson, Mark D.; Flather, Curtis H.; Riitters, Kurt H.; Sieg, Carolyn H.; Garner, James D., 2015. National report on sustainable forests—2015: conservation of biological diversity
    Shive, K. L.; Fule, P. Z.; Sieg, Carolyn H.; Strom, B. A.; Hunter, M. E., 2014. Managing burned landscapes: Evaluating future management strategies for resilient forests under a warming climate
    Tarancon, Alicia Azpeleta; Fule, Peter Z.; Shive, Kristen L.; Sieg, Carolyn H.; Meador, Andrew Sanchez; Strom, Barbara, 2014. Simulating post-wildfire forest trajectories under alternative climate and management scenarios
    Fulé, Peter Z.; Swetnam, Thomas W.; Brown, Peter M.; Falk, Donald A.; Peterson, David L.; Allen, Craig D.; Aplet, Gregory H.; Battaglia, Mike A.; Binkley, Dan; Farris, Calvin; Keane II, Robert E.; Margolis, Ellis Q.; Grissino-Mayer, Henri; Miller, Carol L.; Sieg, Carolyn H.; Skinner, Carl; Stephens, Scott L.; Taylor, Alan, 2014. Unsupported and inaccurate inferences of high severity fire in historical dry forests of the Western United States dry forests: response to Williams and Baker
    Fule, Peter Z.; Swetnam, Thomas W.; Brown, Peter M.; Falk, Donald A.; Peterson, David L.; Allen, Craig D.; Aplet, Gregory H.; Battaglia, Mike A.; Binkley, Dan; Farris, Calvin; Keane II, Robert E.; Margolis, Ellis Q.; Grissino-Mayer, Henri; Miller, Carol L.; Sieg, Carolyn H.; Skinner, Carl; Stephens, Scott L.; Taylor, Alan, 2014. Unsupported inferences of high-severity fire in historical dry forests of the western United States: Response to Williams and Baker
    Owen, Suzanne M.; Sieg, Carolyn H.; Johnson, Nancy Collins; Gehring, Catherine A., 2013. Exotic cheatgrass and loss of soil biota decrease the performance of a native grass
    Shive, Kristen L.; Kuenzi, Amanda M.; Sieg, Carolyn H.; Fule, Peter Z., 2013. Pre-fire fuel reduction treatments influence plant communities and exotic species 9 years after a large wildfire
    Stevens-Rumann, Camille; Shive, Kristen; Fule, Peter; Sieg, Carolyn H., 2013. Pre-wildfire fuel reduction treatments result in more resilient forest structure a decade after wildfire
    Fowler, James F.; Sieg, Carolyn H.; Casavant, Brian M.; Hite, Addie E., 2012. A tale of two single mountain alpine endemics: Packera franciscana and Erigeron mancus
    McGlone, Christopher M.; Sieg, Carolyn H.; Kolb, Thomas E.; Nietupsky, Ty, 2012. Established native perennial grasses out-compete an invasive annual grass regardless of soil water and nutrient availability
    Hoffman, Chad M.; Sieg, Carolyn H.; McMillin, Joel D.; Fule, Peter Z., 2012. Fuel loadings 5 years after a bark beetle outbreak in south-western USA ponderosa pine forests
    Hoffman, Chad M.; McMillin, Joel D.; Sieg, Carolyn H.; Fule, Peter Z., 2012. Influence of bark beetle-caused mortality on fuel loadings and crown fire hazard in southwestern ponderosa pine stands
    Peppin, D.; Fule, P.; Beyers, J.; Sieg, Carolyn H.; Hunter, M., 2011. Does seeding after severe forest fires in western USA mitigate negative impacts on soils and plant communities?
    Pearson, Dean E.; Sutherland, Steve; Butler, Jack L.; Smith, Jane; Sieg, Carolyn H., 2011. I. Plants
    Flather, Curtis H.; Knowles, Mike; Sieg, Carolyn H., 2011. Indicator 1.04: Number of native forest-associated species
    Jenkins, Sara E.; Sieg, Carolyn H.; Anderson, Diana E.; Kaufman, Darrell S.; Pearthree, Philip A., 2011. Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA
    Peppin, Donna L.; Fule, Peter Z.; Sieg, Carolyn H.; Beyers, Jan L.; Hunter, Molly E.; Robichaud, Pete R., 2011. Recent trends in post-wildfire seeding in western US forests: costs and seed mixes
    Laughlin, Daniel C.; Leppert, Jessica J.; Moore, Margaret M.; Sieg, Carolyn H., 2010. A multi-trait test of the leaf-height-seed plant strategy scheme with 133 species from a pine forest flora
    Fowler, James F.; Sieg, Carolyn H.; McMillin, Joel; Allen, Kurt K.; Negron, Jose; Wadleigh, Linda L.; Anhold, John A.; Gibson, Ken E., 2010. Development of post-fire crown damage mortality thresholds in ponderosa pine
    Britton, Kerry O.; Buford, Marilyn; Burnett, Kelly; Dix, Mary Ellen; Frankel, Susan J.; Keena, Melody; Kim, Mee-Sook; Klopfenstein, Ned B.; Ostry, Michael E.; Sieg, Carolyn H., 2010. Invasive species overarching priorities to 2029
    Peppin, Donna L.; Fule, Peter Z.; Lynn, Janet C.; Mottek-Lucas, Anne L.; Sieg, Carolyn H., 2010. Market perceptions and opportunities for native plant production on the southern Colorado Plateau
    Peppin, Donna; Fule, Peter Z.; Sieg, Carolyn H.; Beyers, Jan L.; Hunter, Molly E., 2010. Post-wildfire seeding in forests of the western United States: An evidence-based review
    Shifley, S. R.; Flather, Curtis H.; Smith, W. B.; Riitters, K. H.; Sieg, Carolyn H., 2010. Status and progress in large-scale assessment of biological diversity in the United States
    Sieg, Carolyn H.; Densow, Julie S.; Huebner, Cynthia D.; Miller, James H., 2010. The role of the Forest Service in nonnative invasive plant research
    Scudieri, Catherine A.; Sieg, Carolyn H.; Haase, Sally M.; Thode, Andrea E.; Sackett, Stephen S., 2010. Understory vegetation response after 30 years of interval prescribed burning in two ponderosa pine sites in northern Arizona, USA
    Owen, Suzanne M.; Sieg, Carolyn H.; Gehring, Catherine A.; Bowker, Matthew A., 2009. Above- and belowground responses to tree thinning depend on the treatment of tree debris
    Fowler, James F.; Sieg, Carolyn H.; Dickson, Brett G.; Saab, Victoria A., 2008. Exotic plant species diversity: Influence of roads and prescribed fire in Arizona ponderosa pine forests
    Pearson, Henry A.; Clary, Warren P.; Moore, Margaret M.; Sieg, Carolyn H., 2008. Range management research, Fort Valley Experimental Forest
    Pearson, Henry A.; Clary, Warren P.; Moore, Margaret M.; Sieg, Carolyn H., 2008. Range management research, Fort Valley Experimental Forest (P-53)
    Sabo, Kyla E.; Hart, Stephen C.; Sieg, Carolyn H.; Bailey, John Duff, 2008. Tradeoffs in overstory and understory aboveground net primary productivity in southwestern ponderosa pine stands
    Raphael, Martin G.; Molina, Randy; Flather, Curtis H.; Holthausen, Richard S.; Johnson, Richard L.; Marcot, Bruce G.; Olson, Deanna H.; Peine, John D.; Sieg, Carolyn H.; Swanson, Cindy S., 2007. A process for selection and implementation of conservation approaches
    Hoffman, Chad; Mathiasen, Robert; Sieg, Carolyn H., 2007. Dwarf mistletoe effects on fuel loadings in ponderosa pine forests in northern Arizona
    Fowler, James F.; Sieg, Carolyn H.; Wadleigh, Linda; Haase, Sally, 2007. Effectiveness of litter removal in preventing mortality of yellow barked ponderosa pine in northern Arizona
    Rogstad, Alix; DeGomez, Tom; Sieg, Carolyn H., 2007. Invasive plants in Arizona's forests and woodlands
    Flather, Curtis H.; Sieg, Carolyn H., 2007. Species rarity: definition, causes, and classification
    Flather, Curtis H.; Ricketts, Taylor H.; Sieg, Carolyn H.; Knowles, Mike; Fay, John P.; McNees, Jason, 2003. Criterion 1: Conservation of biological diversity - Indicator 6: The number of forest dependent species
    Kirby, Donald R.; Lym, Rodney G.; Sterling, John J.; Sieg, Carolyn H., 2003. Observation: Leafy spurge control in western prairie fringed orchid habitat
    Sieg, Carolyn H.; King, Rudy M.; Van Dyke, Fred, 2003. The concept and use of elasticity in population viability models [Exercise 13]
    Sieg, Carolyn H.; King, Rudy M.; Van Dyke, Fred, 2003. Using stochastic models to incorporate spatial and temporal variability [Exercise 14]
    Hornbeck, J.Hope; Reyher, Deanna J.; Sieg, Carolyn H.; Crook, Reed W., 2002. Conservation assessment for groundcedar and stiff clubmoss in the Black Hills National Forest South Dakota and Wyoming
    Wolken, Paige M.; Sieg, Carolyn H.; Williams, Stephen E., 2001. Quantifying suitable habitat of the threatened western prairie fringed orchid
    Sieg, Carolyn H.; Wolken, Paige M., 1999. Dynamics of a threatened orchid in flooded wetlands
    Bunkers, Matthew J.; Johnson, L. Ronald; Miller, James R.; Sieg, Carolyn H., 1999. Old Black Hills ponderosa pines tell a story
    Sieg, Carolyn H.; Flather, Curtis H.; McCanny, Stephen, 1999. Recent biodiversity patterns in the Great Plains: Implications for restoration and management
    ; Sieg, Carolyn H.; Uresk, Daniel W.; Javersak, Jody, 1998. Native woodlands and birds of South Dakota: past and present
    Kirby, Donald; Hanson, Thomas P.; Sieg, Carolyn H., 1997. Diets of angora goats grazing leafy spurge Euphorbia esula-infested rangelands
    Gartner, F. Robert; Sieg, Carolyn H., 1996. South Dakota rangelands: More than a sea of grass
    Hodorff, Robert A.; Sieg, Carolyn H.; Linder, Raymond L., 1988. Wildlife response to stand structure of deciduous woodlands
    Paulson, Deborah D.; Sieg, Carolyn H., 1985. Long-eared owls nesting in Badlands National Park
    Sieg, Carolyn H.; Uresk, Daniel W.; Hansen, Richard M., 1982. The biological costs of not reclaiming bentonite mine spoils
    Old-growth ponderosa pine forests in Long Valley and Fort Valley Experimental Forests provide a window into historical spatial patterns of trees and non-forested openings.
    Researchers are increasingly recognizing that ponderosa pine forests naturally occur in clumps of trees with isolated single trees in a matrix of non-forested openings. Turns out that this spatial pattern is important in sustaining ecological processes such as fire spread, tree growth and regeneration, and creates biodiversity and wildlife habitat. Yet, most past studies have examined spatial patterns on small plots, which underestimates the sizes of tree groups and openings.
    Mycorrhizal fungi attach to the roots of plants and produce fruiting bodies called sporocarps, or mushrooms.  Pines such as these ponderosa pine seedlings rely on these ectomycorrhizal fungi to provide them extra water and nutrients.  Photo by Suzanne Owe
    Soil fungi are important components of the soil microbial community that influence ecosystem resilience and stability after disturbances such as fire. Ectomycorrhizal (EM) fungi increase water and nutrient uptake for their plant hosts in return for carbon. Saprotrophic fungi play an important role in nutrient cycling and are responsible for decomposing wood, plant litter, and soil organic matter. 
    Old-growth ponderosa pine forests in Long Valley and Fort Valley Experimental Forests provide a window into historical spatial patterns of trees and non-forested openings.
    Researchers are increasingly recognizing that ponderosa pine forests naturally occur in clumps of trees with isolated single trees in a matrix of non-forested openings. It turns out that this spatial pattern is important in sustaining ecological processes such as fire spread, tree growth and regeneration, and creates biodiversity and wildlife habitat. Yet, most past studies have examined spatial patterns on small plots, which underestimates the sizes of tree groups and openings.  
    Figure 1. A post-fire ponderosa pine seedling in a high-severity burn patch of the 2000 Pumpkin Fire, Arizona.
    Over the past three decades, wildfires in southwestern United States ponderosa pine forests have increased in size and severity, leaving large patches of tree mortality. Ponderosa pine evolved under fire regimes dominated by low- to moderate-severity wildfires, and they are poorly adapted to regenerating in large patches of high-severity fire. There is concern about these high-severity burn patches because the lack of seed-producing trees can prevent or significantly delay ponderosa pine regeneration.
    Typical attack by wood borers to fire-injured ponderosa pine showing galleries and bark wood residue.
    Rocky Mountain Research Station scientists are looking at tools aimed to respond to insect infestations after a fire occurs, particularly around large-scale conifer forests. Different types of fire injury and tree characteristics, such as the extent of bark damage, crown injury, and tree size were correlated to infestations by different bark beetles and wood-boring insects. Some of the insects occured jointly and were associated with both live and dead trees.
    Simulated fire behavior during the green, red, and gray stages of a mountain pine beetle outbreak under various levels of tree mortality (20%, 58%, and 100% mortality) and low wind speeds.
    This study explored the impact of beetle-induced mortality and wind speed on fire behavior during the pre-outbreak (“green stage”), immediately post-mortality when dead needles remain on trees (“red stage”), and when needles drop to the ground (“gray stage”) in southwestern ponderosa pine forests.
    Fire fighters are increasingly being exposed to fires burning in mixtures of dead and live trees in bark beetle-impacted forests, yet there is limited understanding of bark beetle effects on fire behavior. Two new physics-based models, The Wildland Fire Decision Support System (WFDSS) and HIGRAD/FIRETEC, are providing insights into how and why bark beetle-caused tree mortality affects fire behavior in ways that operational models cannot. 
    Wildfire has long been an important and complex disturbance agent in forests dominated by ponderosa pine in the western United States. However, many recent fires have burned with increased severity across large, contiguous areas, resulting in vast expanses with no surviving overstory trees. Researchers are looking at regeneration rates inponderosa pine forests after high-severity fires and examining the spatial patterns and environmental conditions in affected areas to help managers anticipate natural recovery and plan for post-fire management activities.
    Plants are a vital component of biodiversity but are facing a high rate of extinction worldwide. This research investigated plant density of a regionally rare threatened species, Packera franciscana, in order to detect current population size trends as well as establish a baseline to detect future climate change effects. Research on population stability and flowering or fruiting rates is critically important to the recovery and long-term management of P. franciscana.
    Mechanical mastication is a fuel treatment that is increasingly prescribed to reduce aerial fuel continuity in forests or to remove encroaching trees in shrublands. Mastication shreds trees and shrubs and distributes the resulting woody debris across the topsoil, moving aerial fuels to the soil surface. This practice can inadvertently create ideal habitat for some exotic plant species that are highly invasive.
    Numerous factors influence the establishment and growth of tree seedlings after high-severity wildfires. Understanding spatial patterns and environmental conditions influencing ponderosa pine and aspen regeneration post-wildfire can help managers monitor natural recovery.
    This project explored fire behavior attributes under three levels of tree mortality in a southwestern U.S. forest dominated by ponderosa pine at three stages: pre-outbreak (“green stage”), immediately post-mortality when dead needles remain on trees (“red stage”), and when needles drop to the ground (“gray stage”).