Old-Growth Forests in Slovenia


A foggy view of an old-growth forest dominated by European beech and white fir (the rock is limestone; this forest reserve is on ‘karst’ topography with many large sinkholes).

Faculty member Kerry Woods is spending a month in Slovenia as a Fulbright ‘senior specialist,’ where he is collaborating with colleagues at the Forestry School of the University of Ljubljana to build a network of researchers working with long-term permanent plots to understand ecosystem properties of old-growth forests.  Such forests are interesting, in part, for their rarity.  Europe retains very few old-growth forests, but the small country of Slovenia (one of the most heavily forested countries in Europe) has quite a few tracts, and several host study plots established over 30 years ago.

Such under-used, heritage data-sets can give us insight into the ‘baseline’ properties of forest ecosystems.  Does diversity increase or decrease with forest age?  Old forests can be very large carbon reservoirs on a per-area basis, but are they acting as carbon sources or sinks?  Do such properties and processes converge among old-growth temperate forests in different parts of the  world (for example, the old-growth forests Woods studies in Michigan)?

The project will culminate with a workshop attended by researchers from several European countries.  The workshop will, we hope, lead to future collaborations undertaking integrative meta-analysis of data-sets from temperate forests around the world


; they can help us understand the processes that maintain diversity,

Old-growth Fieldwork


Part of the study area at the Dukes Natural Area in the Hiawatha National Forest

Two 2014 grads — Joe Kendrick and Ellen Hanson — and two current students — Charlotte Uden and Roi Karlinsky — are spending four weeks in Michigan’s Upper Peninsula working with faculty member Kerry Woods in his on-going research on old-growth forests.  They join about 40 other student researchers who have worked on this project since 1989.


It’s good to find a log for lunch; the mosquitoes are worse near the ground. (Roi Karlinsky, Joseph Kendrick, Ellen Hanson, Charlotte Uden)

The project revolves around monitoring of permanent study plots established as early as 1935 — one of the longest-term records for any old-growth forest.  The work has been supported by the National Science Foundation, the Mellon Foundation, the U.S. Forest Service, The Huron Mt. Wildlife Foundation, and Bennington College faculty grants. A series of resulting publications can be downloaded from this site.

The 2014 season features a late season — trees are still leafing out along the Lake Superior shoreline, where ice-floes were still present three weeks ago — and unusually numerous and hungry mosquitoes.  A large supply of deet (N,N-diethyl-meta-toluamide) is proving essential.

This is our lab: carbon budgets in campus forests

The “Forests” class — a field-oriented class introducting concepts of ecology and evolution (taught by faculty member Kerry Woods) — recently remeasured two study plots established in 2004 in campus forests.

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Class members posing with their trees. Left to right: Emily Sanders, Dane Whitman, Nick Atherton, Kevser Kedici, Syvlia Madaras, Kily Dalrymple. Photo by Reily Gordon.

Remeasurements will allow estimation of biomass accumulation and turn-over — in other words, whether these forests are overall carbon sinks or sources. (the stand pictured here is a plantation of native red pine planted in the 1960s by former faculty member Bob Woodworth and his students).

It’s generally thought that New England’s forests are ‘carbon sinks’ because they are relatively young, post-agricultural ecosystems and so still growing — but we do not know how generally or how long that can be expected to be true, so we will keep monitoring the roughly 200 acres of forest on the Bennington College campus.

Faculty Research on ecological effects of changing climates


Old-growth forest at the Dukes Research Natural Area (U.S. Forest Service) in northern Michigan — source of the data-set used in published analyses.

Faculty member Kerry Woods participated in a multi-author study assessing the effects of climate change on forest understory communities in North America and Europe.  Using multi-decade data-sets from 29 research sites analyses show that a general trend of compositional change reflecting increases in warm-adapted species may be moderated where forest canopies have become denser. This work was published online (before print) in the Proceedings of the National Academy of Science  in a paper titled “Microclimate moderates plant responses to macroclimate warming” (doi: 10.1073/pnas.1311190110).  Woods contributed one of five data-sets from North America; his long-term studies in old-growth forests of northern Michigan have supported several other publications.  Another of the North American data-sets is from Peter White of the University of North Carolina — a Bennington alum from 1971.

This research has been reported by the BBC, on Belgian national news (including a video clip of lead author Pieter de Frenne of University of Ghent — in Dutch), and in press releases from Oxford University and several other universities.

Science Workshop 29 March — Long-term studies, ecological baselines, and the way things ought to be:


A high-biomass old-growth stand of eastern hemlock in northern Michigan

After decades of studying ancient forests, we’re less confident of what we know about them than we were thirty-five years ago.  For the last 20+ years I’ve been working with long-term permanent study plots in old-growth forest in Michigan.  I began with the hope that an exceptionally deep data-record would allow me to test hypotheses about mechanisms behind equilibrial dynamics.  Now I’m convinced that our initial assumption — that these ecosystems represented a sort of steady-state, climax ‘baseline’ — was flawed, and the natural landscape is much more dynamic than we imagined.  If that’s the case, what are the implications for concepts of nature conservation and ecological restoration?  What is to be conserved or restored if there’s no detectable natural baseline condition?

I will review about the findings of my old-growth research with a focus on new results, talk about  some new work using new technologies to try to understand whether these forests are carbon sources or sinks, and wind up with some exploration of what this all means for forest conservation priorities under climate change, Pleistocene rewilding, and the cloning of extinct species.

Old-growth forests in Portland

Over thirty Bennington students have worked with faculty member Kerry Woods in his ongoing, long-term research in old-growth forests in Michigan.  The most recent results from that project were presented in August, 2012 at the 97th  national meetings of the Ecological Society of America in Portland, OR. You can find a copy of the poster presentation here.

The photo shows two members of the 2009 field crew at work at the Michigan field-site.