August 17, 2016

Research and Restoration in an Oak Savanna-Fen Mosaic

MacCready Reserve, Michigan State University, Jackson, Michigan

We toured an ongoing oak savanna restoration experiment comparing unmanaged, burning, and thinning + burning treatments. Four stations on the tour addressed the restoration process and results of the savanna restoration experiment, including:

  • comparison of burn only and thinning + burning treatments
  • vegetation and pollinator interaction
  • prescribed fire operations in oak savanna/woodland restoration
  • restoration of the adjacent fen

A number of resources from the field day are now available below:

  • Managing Oak Systems - Take Home Considerations For Pollinators
  • Summary of Lessons Learned Shared by Field Tour Participants
  • Bibliography of Literature from the Experiment
  • Bibliography of Relevant fire-oak literature from the northeastern U.S.
    • many of these research papers can be accessed for free through the US Forest Service Northern Research Station



  • Lars Brudvig - assistant professor of plant biology at Michigan State University
  • Mitch Lettow - land steward at Southwest Michigan Land Conservancy - studied restoration's impact on pollinator communities on the site.
  • Patrick Duffy -  forest manager, W.K. Kellogg Experimental Forest - current prescribed burn manager
  • Mark Mackay - ecologist at Michigan Department of Natural Resource wildlife division - providing an overview of the state of oak systems in southwest Michigan



Pollinator response to restoration – floral faunal interactions

View or download a PDF version of Mitch Lettow's brief overview of results from pollinator research project at the site.

(Lettow, M. C., Brudvig, L. A., Bahlai, C. A., & Landis, D. A. (2014). Oak savanna management strategies and their differential effects on vegetative structure, understory light, and flowering forbs. Forest Ecology and Management, 329, 89-98.).

Lettow summarized the main considerations for pollinators during oak ecosystem restoration:

  1. Thin and burn management techniques can rapidly increase bee abundance and bee richness through several potential mechanisms
  2. Burn only management techniques provide more limited benefits to pollinator populations (e.g. reduction of canopy cover, increase understory light levels, establish a diversity of flowering plants, bee use)
  3.  Maintaining non-managed or lightly managed refugia habitat can be beneficial for sensitive pollinator species (e.g. swallowtail butterflies)
  4. Burning no more than 1/3 of any one habitat type will help burned areas repopulate with pollinators
  5. Use of variable management techniques for the same habitat can create diversity within a site
  6. Intermediate fire frequency can help limit damage to sensitive pollinator species while achieving other habitat objectives
  7. Suppressing understory invasive plants can be critical to establishing high quality bee habitat, particularly before significant canopy thinning takes place
  8. Creating robust pollinator populations at a site may increase seed set in understory forb species, leading to long-term expansion of understory vegetation

Wrap up discussion- summary notes

View or download a PDF of the wrap up discussion to see all of the comments and new questions.

At the end of the field tour, we asked participants two questions:

1. What is one thing you will take away from this field day?

2. What is one question you had that was not answered, or a new question rasied by the tour?

This is what participants shared for their take away lessons:

It was valuable to learn about the rationale for slow approach to canopy thinning (especially in context of response of nuisance natives to greater thinning)

I might forget the details, but the demonstration site was effective – being able to see the differences in treatments, side by side, across trails is really memorable.

Pollinators – seeing that different insect functional groups responded differently to different treatments suggests importance of heterogeneity (using different treatments across a site to provide habitat for different groups of species with different needs).

Impressed at the rate of the pollinator response to thinning and burning.

Learning about management tools – particularly using propane torch to get rid of buckthorn seedlings (after cutting/treating established buckthorn, kill newly germinated buckthorn seedlings before they develop a root system).

After seeing this, I feel like we are on the right path with the techniques we’ve been using. There’s research behind (supporting) management recommendations.

Field tour bibliography

Thanks to Mark Mackay for compiling a list of peer-reviewed publications on fire and oak management relevant to the demonstration site and southern Michigan.

View or download a PDF of fire and oak literature.