Scientists & Staff

IPCC Work in Zimbabwe

Randy Kolka

Research Soil Scientist
1831 Hwy 169 East
Grand Rapids, MN, 55744
Phone: 218-326-7115

Contact Randy Kolka

Resume (882 KB PDF)

Current Research

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

Professional Experience

  • Faculty of Graduate Studies, Faculty of Natural Resources Management, Lakehead University 2012 - Current
  • Faculty of Graduate Studies, Faculty of Natural Resources Management, Lakehead University 2012 - Current
  • Adjunct Professor, Department of Biological Sciences, North Dakota State University 2008 - Current
  • Associate Faculty, Department of Natural Resource Ecology and Management, Iowa State University 2004 - Current
  • Adjunct Faculty, School of Forest Resources and Environmental Science, Michigan Technological University 2004 - Current
  • Adjunct Professor, Department of Forest Resources, University of Minnesota 2002 - Current
  • Graduate Faculty, Department of Forestry, University of Kentucky 2002 - Current
  • Adjunct Professor, Department of Soil, Water and Climate, University of Minnesota 2002 - Current

Professional Organizations

  • Soil Science Society of America
  • Society of Wetland Scientists
  • American Water Resources Association
  • Society of American Foresters (SAF)
  • Ecology and Biology Subject Area
  • Society of American Foresters, Forest Science and Technology Board (2006 - Present)
  • Wetlands (2006 - Present)
  • Ecosystems Restoration and Creation, Annual Conference Editorial Review Committee (1997 - Present)

Featured Publications & Products

Publications & Products

Research Datasets

  • Verry, Elon S.; Elling, Arthur E.; Sebestyen, Stephen D.; Kolka, Randall K.; Kyllander, Richard. 2018. Marcell Experimental Forest daily streamflow data. Fort Collins, CO: Forest Service Research Data Archive.
  • Verry, Elon S.; Elling, Arthur E.; Sebestyen, Stephen D.; Kolka, Randall K.; Kyllander, Richard. 2018. Marcell Experimental Forest peatland and upland water table elevations. Fort Collins, CO: Forest Service Research Data Archive.

National Research Highlights

Need photos

Warming Peatlands Emit Carbon Faster than Previously Known

Year: 2020

Peatlands occupy just 3 %of the planet but store about 30 %of the soil carbon in terrestrial landscapes. A team of scientists is exploring whether climate change could transform peatlands from a carbon sink to a carbon source and, if so, how quickly.

Prairie strip embedded in an agricultural (corn) watershed.  The prairie strips increase nutrient and sediment retention, reduce runoff, and increase biodiversity

Incorporating ecosystem services into Midwest agriculture

Year: 2017

Science-based Trials of Rowcrops Integrated with Prairie Strips (STRIPS) is transforming the way farmers conduct agriculture in the Midwest. STRIPS strategically integrates small strips of native prairie into rowcrop agriculture to achieve a greater number of benefits, including reduced soil erosion and better habitat for birds, pollinators, and other insects.

Instrumentation inside SPRUCE chamber. Oak Ridge National Laboratoy.

Largest Climate Change Experiment on the Planet: SPRUCE

Year: 2016

The Spruce and Peatland Responses Under Climatic and Environmental Change Experiment (SPRUCE) is stretching scientists’ ability to manipulate ecosystems to assess the effects of climate change (elevated temperature and carbon dioxide levels) in a high-carbon peatland in northern Minnesota. Because of the massive amount of carbon northern peatlands store, they will have dramatic feedbacks on global greenhouse gas emissions. Research at SPRUCE aims to understand climate change processes affecting both carbon and organisms, which will improve data used in global circulation models and allow scientists to better predict climate in the future.

Well-managed northern conifer forests were found to store more carbon than those that have been exploitatively harvested. Laura Kenefic, U.S. Department of Agriculture Forest Service.

Sustainable Northern Conifer Forest Management Stores More Carbon than Exploitative Harvesting

Year: 2016

An important part of climate change mitigation is carbon storage in forests and wood products. Yet managers are often uncertain about which management approaches maximize carbon storage. New findings from long-term research in northern conifers in Maine reveal that sustainable forest management results in greater carbon storage than exploitative harvesting.

Figure 1. Contrasts of fire severity (light: a,b; severe (severe: c, d) for the Pagami Creek Fire. Remotely-sensed estimates of fire
severity such as the relative difference normalized burn ratio (RdNBR) are most strongly related to tree impacts. Loss of C, N, and Hg
from the forest floor were most strongly related to soil burn severity indices measured at the point of sampling, where the sampling
ring in b & d are 30 cm in diameter. Brian Sturtevant, U.S. Department of Agriculture Forest Service.

Scaling Up Ecosystem Impacts of the Pagami Creek Fire in Northern Minnesota

Year: 2016

Quantifying fire severity is critical to understanding the ecosystem impacts of wildfire. Forest Service research demonstrates the magnitude of ecosystem impacts from large wildfires, the challenges of relating those impacts to repeatable and scalable fire severity indices, and the application of remote sensing to help scale severity and ecosystem impacts of large wildfires.

Phenocam and Antenna on top of the pierce laboratory at the Hubbard Brook Experimental Forest, NH. USDA Forest Service

“Smart Forests” Digital Environmental Sensors and Telecommunications Take Research to New Levels

Year: 2015

Scientific breakthroughs of the 21st century will be powered by tools that help researchers collect and manipulate massive datasets, visualize that data, and offer new ways of understanding the scientific processes behind that information. Forest Service scientists are taking a lead in developing a national Experimental Forests and Ranges “Smart Forests” Network. This network of wired forests uses digital environmental sensors, wireless communications, and new data visualization programs to create a powerful integrated research and monitoring program for the nation’s air, water, forest and rangeland resources.

Prairie strip embedded in an agricultural (corn) watershed.  Prairie strips increase nutrient and sediment retention, reduce runoff, and increase biodiversity.  Iowa State University

Prairie Strips Lead to Better Environmental Health and Greater Socioeconomic Vitality

Year: 2012

Forest Service scientists help Midwestern farming communities understand how to transform strategic portions of the agricultural landscape into perennial plant communities

Last modified: Monday, May 2, 2022