Scientists & Staff
Experimental Forests & Ranges
I study the effect of land management (forest, agriculture and urban land uses) on the terrestrial and aquatic cycling of nutrients, carbon, heavy metals (notably mercury) and water.
Currently I'm working on numerous studies to assess nutrient, carbon and mercury pools and processes in variety of ecosystems. Nutrient work includes studies related to Forestry Best Management Practices in riparian and wetland systems and work aimed at understanding the influence of strategically placed perennial vegetation in agricultural watersheds. Nutrient work also includes the effect of stream restoration on nutrient cycling. My carbon work includes studies looking at landscape level carbon pools and emissions across number of ecosystems including peatlands, and a variety upland vegetation types. The ecosystem carbon work also extends into characterizing the pools of coarse woody debris in forested riparian areas and streams. My mercury work is focused on two main efforts, one to characterize the mercury cycle under increased sulfate deposition and a second to understand the influence of prescribed fire on mercury cycling.
Why This Research is Important
The transport on nonpoint source pollutants including nutrients such as nitrogen and phosphorus are the number one concern regarding the impacts on aquatic ecosystems. This is demonstrated by the numerous issues surrounding the development of Best Management Practices for forest and agricultural systems and regulations that are being imposed by the Environmental Protection Agency (e.g. Total Maximum Daily Loads).
In the Lake States, mercury is of high concern because of its potential to bioaccumulate in the aquatic food chain. Understanding how management can lessen mercury inputs and/or increase storage in terrestrial systems is critical for human health and the fishing industry.
Investigating the landscape level influences on carbon storage and processing will lead to a better understanding of implications of climate change. One of the great uncertainties in climate modeling is the feedbacks that terrestrial systems have on atmospheric carbon, most notably on the green house gases carbon dioxide and methane. Our work is helping fill this important knowledge gap.
- University of Minnesota, Ph.D. Soil Science, 1996
- University of Minnesota, M.S. Soil Science, 1993
- University of Wisconsin - Stevens Point, B.S. Soil Science, 1990
- Adjunct Professor, Department of Biological Sciences, North Dakota State University
- Associate Faculty, Department of Natural Resource Ecology and Management, Iowa State University
- Adjunct Professor, Department of Forest Resources, University of Minnesota
- Adjunct Professor, Department of Soil, Water and Climate, University of Minnesota
- Graduate Faculty, Department of Forestry, University of Kentucky
- Adjunct Faculty, School of Forest Resources and Environmental Science, Michigan Technological University
- Soil Science Society of America
- Society of Wetland Scientists
- American Water Resources Association
- Society of American Foresters
- Ecology and Biology Subject Area, Editorial Positions
- Society of American Foresters, Forest Science and Technology Board, Editorial Positions (2006 - Present)
- Wetlands, Associate Editor (2006 - Present)
- Ecosystems Restoration and Creation, Annual Conference Editorial Review Committee, Associate Editor (1997 - Present)
Featured Publications & Products
- Kolka, Randall K.; Mitchell, Carl P.J.; Jeremiason, Jeffrey D.; Hines, Neal A.; Grigal, David F.; Engstrom, Daniel R.; Coleman-Wasik, Jill K.; Nater, Edward A.; Swain, Edward B.; Monson, Bruce A.; Fleck, Jacob A.; Johnson, Brian; Almendinger, James E.; Branfireun, Brian A.; Brezonik, Patrick L.; Cotner, James B. 2011. Mercury cycling in peatland watersheds. Chapter 11..
- Witt, Emma L.; Barton, Christopher D.; Stringer, Jeffrey W.; Bowker, Daniel W.; Kolka, Randall K. 2011. Evaluating Best Management Practices for ephemeral channel protection following forest harvest in the Cumberland Plateau - preliminary findings.
- Kolka, R. K. 2012. Effects of fire and fuels management on water quality in eastern North America.
- Kolka, Randall K.; Giardina, Christian P.; McClure, Jason D.; Mayer, Alex; Jurgensen, Martin F. 2010. Partitioning hydrologic contributions to an 'old-growth' riparian area in the Huron Mountains of Michigan, USA.
Publications & Products
- Handler, Stephen; Duveneck, Matthew J.; Iverson, Louis; Peters, Emily; Scheller, Robert M.; Wythers, Kirk R.; Brandt, Leslie; Butler, Patricia; Janowiak, Maria; Shannon, P. Danielle; Swanston, Chris; Barrett, Kelly; Kolka, Randy; McQuiston, Casey; Palik, Brian; Reich, Peter B.; Turner, Clarence; White, Mark; Adams, Cheryl; D'Amato, Anthony; Hagell, Suzanne; Johnson, Patricia; Johnson, Rosemary; Larson, Mike; Matthews, Stephen; Montgomery, Rebecca; Olson, Steve; Peters, Matthew; Prasad, Anantha; Rajala, Jack; Daley, Jad; Davenport, Mae; Emery, Marla R.; Fehringer, David; Hoving, Christopher L.; Johnson, Gary; Johnson, Lucinda; Neitzel, David; Rissman, Adena; Rittenhouse, Chadwick; Ziel, Robert. 2014. Minnesota forest ecosystem vulnerability assessment and synthesis: a report from the Northwoods Climate Change Response Framework project.
- Cole, Jason A.; Johnson, Kristopher D.; Birdsey, Richard A.; Pan, Yude; Wayson, Craig A.; McCullough, Kevin; Hoover, Coeli M.; Hollinger, David Y.; Bradford, John B.; Ryan, Michael G.; Kolka, Randall K.; Wieshampel, Peter; Clark, Kenneth L.; Skowronski, Nicholas S.; Hom, John; Ollinger, Scott V.; McNulty, Steven G.; Gavazzi, Michael J. 2013. Database for landscape-scale carbon monitoring sites.
- Olson, D. M.; Griffis, T. J.; Noormets, A.; Kolka, R.; Chen, J. 2013. Interannual, seasonal, and retrospective analysis of the methane and carbon dioxide budgets of a temperate peatland.
- Fissore, Cinzia; Giardina, Christian P.; Kolka, Randall K. 2013. The effects of substrate supply on the temperature sensitivity of soil carbon decomposition.
- Brooks, Robert T.; Eggert, Susan L.; Nislow, Keith H.; Kolka, Randall K.; Chen, Celia Y.; Ward, Darren M. 2012. Preliminary assessment of mercury accumulation in Massachusetts and Minnesota seasonal forest pools.
- Parsekian, Andrew D.; Slater, Lee; Ntarlagiannis, Dimitrios; Nolan, James; Sebestyen, Stephen D.; Kolka, Randall K.; Hanson, Paul J. 2012. Uncertainty in peat volume and soil carbon estimated using ground-penetrating radar and probing.
- Kolka, Randall K.; Sebestyen, Stephen D.; Bradford, John B. 2011. An evolving research agenda at the Marcell Experimental Forest. Chapter 3..
- Grigal, David F.; Bates, Peter C.; Kolka, Randall K. 2011. Ecosystem carbon storage and flux in upland/peatland watersheds in northern Minnesota. Chapter 9..
- Sebestyen, Stephen D.; Dorrance, Carrie; Olson, Donna M.; Verry, Elon S.; Kolka, Randall K.; Elling, Art E.; Kyllander, Richard. 2011. Long-term monitoring sites and trends at the Marcell Experimental Forest. Chapter 2..
- Merten, Eric; Hemstad, Nathaniel; Eggert, Susan; Johnson, Lucinda; Kolka, Randall; Vondracek, Bruce; Newman, Raymond. 2010. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007.
- Bradford, John B.; Weishampel, Peter; Smith, Marie-Louise; Kolka, Randall; Birdsey, Richard A.; Ollinger, Scott V.; Ryan, Michael G. 2009. Detrital carbon pools in temperate forests: magnitude and potential for landscape-scale assessment.
- Bradford, John; Weishampel, Peter; Smith, Marie-Louise; Kolka, Randall; Birdsey, Richard A.; Ollinger, Scott V.; Ryan, Michael G. 2009. Detrital carbon pools in temperate forests: magnitude and potential for landscape-scale assessment.
- Gabriel, Mark C.; Kolka, Randy; Wickman, Trent; Nater, Ed; Woodruff, Laurel. 2009. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield.
- Wells, Gail; Hayes, Deborah; Krause, Katrina; Bartuska, Ann; LeVan-Green, Susan; Anderson, Jim; Gough, Tivoli; Adams, Mary; Schuler, Thomas; Kolka, Randy; Sebestyen, Steve; Kenefic, Laura; Brissette, John; Stout, Susan; Kanoti, Keith; Swanson, Fred; Greene, Sarah; Herring, Margaret; Ritchie, Martin; Skinner, Carl; Lisle, Tom; Keppeler, Elizabeth; Reid, Leslie; Wohlegemuth, Peter; Kitchen, Stanley; McCaughey, Ward; Guldin, Jim; Bragg, Don; Shelton, Michael; Loftis, David; Greenberg, Cathryn; Murphy, Julia. 2009. Experimental forests and ranges : 100 years of research success stories.
- Witt, Emma L.; Kolka, Randall K.; Nater, Edward A.; Wickman, Trent R. 2009. Forest fire effects on mercury deposition in the boreal forest.
- Fissore, Cinzia; Giardina, Christian P.; Kolka, Randall K.; Trettin, Carl C. 2009. Soil organic carbon quality in forested mineral wetlands at different mean annual temperature..
- Perry, Charles H. (Hobie); Amacher, Michael C.; Cannon, William; Kolka, Randall K.; Woodruff, Laurel. 2009. The distribution of mercury in a forest floor transect across the central United States.
- Fissore, Cinzia; Giardina, Christian P.; Swanston, Christopher W.; King, Gary M.; Kolka, Randall K. 2009. Variable temperature sensitivity of soil organic carbon in North American forests.
- Bradford, John B.; Weishampel, Peter; Smith, Marie-Louise; Kolka, Randall; Hollinger, David Y.; Birdsey, Richard A.; Ollinger, Scott; Ryan, Michael. 2008. Landscape-scale carbon sampling strategy-lessons learned. Chapter 17.
- Kolka, Randall; Weishampel, Peter; Froberg, Mats. 2008. Measurement and importance of dissolved organic carbon. Chapter 13.
- Weishampel, Peter; Kolka, Randall. 2008. Measurement of methane fluxes from terrestrial landscapes using static, non-steady state enclosures. Chapter 12.
- Mitchell, Carl P.J.; Branfireun, Brian A.; Kolka, Randall K. 2008. Spatial characteristics of net methylmercury production hot spots in peatlands.
- Fissore, Cinzia; Giardina, Christian P.; Kolka, Randall K.; Trettin, Carl C.; King, Gary M.; Jurgensen, Martin F.; Barton, Christopher D.; McDowell, S. Douglas. 2008. Temperature and vegetation effects on soil organic carbon quality along a forested mean annual temperature gradient in North America.
- Steber, Aaron; Brooks, Ken; Perry, Charles H.; Kolka, Randy. 2007. Surface compaction estimates and soil sensitivity in Aspen stands of the Great Lakes States.
- Thompson, James A.; Kolka, Randall K. 2005. Soil carbon storage estimation in a forested watershed using quantitative soil-landscape modeling.
- McClure, J. M.; Kolka, R. K.; White, A. 2004. Effect of forest harvesting best management practices on coarse woody debris distribution in stream and riparian zones in three Appalachian watersheds.
- Giese, Laura A. B.; Aust, W. M.; Kolka, Randall K.; Trettin, Carl C. 2003. Biomass and carbon pools of disturbed riparian forests.
- Giese, Laura A.B.; Aust, W.M.; Kolka, Randall K.; Trettin, Carl C. 2003. Biomass and carbon pools of disturbed riparian forests.
- Svec, J. R.; Kolka, R. K.; Stringer, J. W. 2003. Defining perennial, intermittent and ephemeral channels in eastern Kentucky: application to forestry best management practices.
- Verry, E. S.; Kolka, R. K. 2003. Importance of Wetlands to Streamflow Generation.
- Birdsey, R.; Hollinger, D.; Heath, L.; Hoover, C.; Kolka, R.; Smith, M. L.; Ryan, M. 2003. Pilot Studies for Enhanced Forest Land Measurement.
- Kolka, R. K.; Trettin, C. C.; Nelson, E. A.; Barton, C. D.; Fletcher, D. E. 2002. Application of the EPA Wetland Research Program Approach to a floodplain wetland restoration assessment.
- Smidt, Mathew F.; Kolka, Randall K. 2001. Alternative skid trail retirement options for steep terrain logging.
- Kolka, R. K.; Grigal, D. F.; Nater, E. A.; Verry, E. S. 2001. Hydrologic cycling of mercury and organic carbon in a forested upland-bog watershed.
- Kolka, Randy K.; Nelson, E. A.; Trettin, C. C. 2000. Conceptual assessment framework for forested wetland restoration: the Pen Branch experience.
- Dulohery, C. J.; Kolka, Randy K.; McKevlin, M. R. 2000. Effects of a willow overstory on planted seedlings in a bottomland restoration.
- Kolka, Randy K.; Singer, J. H.; Coppock, C. R.; Casey, W. P.; Trettin, C. C. 2000. Influence of restoration and succession on bottomland hardwood hydrology.
- Grigal, D. F.; Kolka, Randy K.; Fleck, J. A.; Nater, E. A. 2000. Mercury budget of an upland-peatland watershed.
- Nelson, Eric A.; Dulohery, Neil C.; Kolka, Randall K.; McKee, William H., Jr. 2000. Operational restoration of the Pen Branch bottomland hardwood and swamp wetlands - the research setting.
- Barton, Christopher; Nelson, Eric A.; Kolka, Randall K.; McLeod, Kenneth W.; Conner, William H.; Lakly, Michelle; Martin, Douglas; Wigginton, John; Trettin, Carl C.; Wisniewski, Joe. 2000. Restoration of a severely impacted riparian wetland system - The Pen Branch Project.
- Giese, Laura A.; Aust, W. Michael; Trettin, Carl C.; Kolka, Randall K. 2000. Spatial and temporal patterns of carbon storage and species richness in three South Carolina coastal plain riparian forests.
- Kolka, Randall K.; Nater, E.A.; Grigal, D.F.; Verry, E.S. 1999. Atmospheric Inputs of Mercury and Organic Carbon into a Forested Upland/Bog Watershed.
- Kolka , Randy K.; Nater, E. A.; Verry, Elon S,. 1999. Atmospheric Inputs of Mercury and Organic Carbon into a Forested Upland/Bog Watershed.
- Kolka, R. K.; Grigal, D. F.; Verry, E. S.; Nater, E. A. 1999. Mercury and Organic Carbon Relationships in Streams Draining Forested Upland/Peatland Watersheds.
- Kolka, Randall K.; Grigal, D.F.; Verry, E.S.; Nater, E.A. 1999. Mercury and Organic Carbon Relationships in Streams Draining Forested Upland/Peatland Watersheds.
- Kolka, Randall K.; Trettin, Carl C.; Nelson, E.A. 1998. Development of an Assessment Framework for Restored Forested Wetlands.
- Kolka, Randall K.; Wolf, Ann T. 1998. Estimating actual evapotranspiration for forested sites: modifications to the Thornthwaite Model.
- Kolka, Randall K.; Nelson, Eric A.; Bonar, Ronald E.; Dulohery, Neil C.; Gartner, David. 1998. The Pen Branch Project: Restoration of a Forested Wetland in South Carolina.
- Kolka, Randall K.; Trettin, Carl C.; Nelson, E.A.; Conner, W.H. 1998. Tree Seedlings Establishment Across a Hydrologic Gradient in a Bottomland Restoration.
- Kolka, Randy K.; Grigal, D.F.; Nater, E.A. 1996. Forest soil mineral weathering rates: use of multiple approaches.
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