Wooster Geologists

The College of Wooster Tree Ring Lab faculty, staff and students have teamed up to publish results of  an analysis of a network of tree-ring sites in Northeast Ohio to ask the question what is driving the changing climate response of the trees. The tree-ring sites include young (100-year-old) white oaks in Secrest Arboretum, Wooster, two sites of post-settlement age (about 200-years old) from Wooster Memorial Park and The Kinney Field Park both in Wooster and four old growth sites (>300 years old) from some of our favorite sites including The College of Wooster campus, Cornerstone Elementary, Browns Lake Bog, David Kline’s (the author) old growth forest on his farm and Johnson Woods the largest tract to old growth white oak forest in Ohio.

Paleoclimate class (2021) at Johnson Woods Orrville Ohio. One of the key sites in the paper and one of the key sites in the Midwest. Originally cored by Ed Cook (Lamont-Doherty Tree Ring Lab) in 1980, the site has been updated by The College of Wooster Tree Ring Lab and by Justin Maxwell at the Indiana University Tree Ring Lab. Students sampling the remanent white oak stand at Browns Lake Bog a site managed by the Nature Conservancy. 

Coring the second-growth white oaks in Wooster Memorial Park.

Another second growth site is within the Wooster city limits at the Kinney Field Park.

The College of Wooster campus maintains an impressive stand of old growth white oaks on its campus. Here members of the Holden Arboretum Tree Corps sample one the the impressive old trees.Secrest Arboretum (on the Wooster campus of the CFAES) is one of our favorite sites to cores trees. Many of the trees from  all around the world have lived in Ohio for over 100 years. Here one of the coauthors cores a white oak planted about 100 years ago.

A final word on this study. Future warming in the Midwest is projected to see increases in spring precipitation, likely decreases in late summer precipitation, which if coupled with an increase in maximum summer temperatures would increase the moisture stress on these trees. Our examination of these varying climate responses with respect to site characteristics and forest age can help future assessments of tree health and the forest’s ability to sequester carbon, as well as facilitate efforts to reconstruct climate by using a range of tree sites for intervals when sensitivity in old growth sites is lost.

These data from the sites in Northeast Ohio are available in the International Tree-Ring Databank maintained by NOAA and many of these records have been incorporated into the North American Drought Atlas contributed to the larger climate science community by Ed Cook and colleagues.

References:

Acknowledgements: This work was funded by The College of Wooster, NSF Geopaths and NSF – EAR 2039939 grants.

Wooster Earth Scientists traveled to Erie PA to attend the joint Northeast /North-Central Geological Society of America for a weekend of geology talks, posters and fieldtrips.

Above Grace presents her senior Independent study research entitled “A LAKE RECORD OF ENVIRONMENTAL CHANGE IN NORTHEASTERN OHIO SINCE EUROPEAN COLONIZATION” abstract here.

Proto presented ALASKA’S FIRST WESTERN RED CEDAR TREE-RING CHRONOLOGY described here. 

Proto here describes the winter signal that they discovered in the tree-ring record of the red coastal cedar from Southeast Alaska.

Lauren describes her Alaskan tree-ring work on the southern coast of central Alaska.

Lauren’s poster FIVE NEW MOUNTAIN HEMLOCK TREE-RING CHRONOLOGIES FROM SOUTHEAST ALASKA: NEW RECORDS OF CLIMATE – here she just shared the research with alum Nick Fedorchuk who now a professor at Southern Connecticut University.

Evie (foreground) with Anika and Ihaja looking on – explains their work on four deciduous conifers from Secrest Arbooretum. These trees may be key players in future high CO2 environments in a warming world as they were in the past. the title: USING DENDROCLIMATIC ANALYSIS OF EXOTIC DECIDUOUS CONIFERS IN AN ABORETUM TO DOCUMENT TREE GROWTH IN RESPONSE TO CLIMATE CHANGE, NORTHEAST OHIO, USA described in their abstract here. 

Amanda’s IS work is explained in this poster and her lightening talk is shown below. The title CAN VOLCANIC EVENTS FORCE DECADAL COOLING IN THE NORTH PACIFIC? is described in this abstract.

Linking short scale (1-2 year cooling forced by volcanic events) appears to serve to force cooling SSTs in the North Pacific that can persist for a few decades.

Wooster faculty also presented results of research – above Dr. Eva Lyon describes her work on a Pleistocene lake from West Virginia. Her title PALEO-LAKE BUCKEYE: A NEW SEDIMENTARY ARCHIVE OF PALEOENVIRONMENTAL CONDITIONS ACROSS THE PLEISTOCENE-HOLOCENE TRANSITION IN THE CENTRAL APPALACHIAN MOUNTAINS and abstract can be found here. . Wooster students are now working on these lacustrine sediments. G. Wiles also presented: PROGRESS IN USING TREE-RING CHRONOLOGIES TO RECONSTRUCT LAURENTIAN GREAT LAKE LEVELS, which focused on reconstructing Lake Erie levels using tree rings. Tim Fisher (U.Toledo) also presented collaborative work with Wooster on Lake Erie water levels here.

Drs. Lyon and Wiles attended a fiedtrip to Presque Isle during the meeting to examine the coastal erosion. This trip will serve as a planning trip for a potential future fieldtrip of a combined course in Paleoecology and Hydrology in the fall of 2025.

A breakwater offshore dampens the power of the waves and the piles perpendicular to shore slow the longshore drift and sediment loss of the beach.

This van at the visitor’s center is a map of the features viewed on the trip – Presque Isle and, on the Canadian side, Long Point, are spits and tombolos located on glacial moraines that formed about 14,000 years ago during deglaciation of the Laurentide Icesheet.

It was a lively group – of students, professionals and faculty.

Wooster Memorial Park has been a great resource for The College of Wooster Earth Sciences (ESCI), Biology among others. Here the ESCI course in Paleoclimate, under permit from the Friends of Wooster Memorial Park, sampled 20 second growth Eastern Hemlock with the aim of determining the climate response of the species in the Park. A recent publication by the Wooster Tree Ring Lab incorporated results from past sampling in the park that was concerned with the changing climate response of white oak trees. This oak study can be found here Wiles et al., 2025.

Lidar Map of Wooster Memorial Park – the green field in the west of the park is the approximate location of tree-ring sampling.

The class took advantage of a spectacular day for the sampling.

Nick demonstrating the coring technique using an increment borer.

Another perfect core, once trained, the five groups went into sampling mode.

For most of the group, this was their first experience coring and it was clear some were naturals at the technique.

First-ever core reveal photo – a proud dendrochronologist.

Another first.

Coring for the first time.

Coring and at the same time keeping a sharp eye out for wildlife.

A first – ever core safely archived in a reusable plastic straw.

Even the TA was caught working in this photo.

Deep in the hemlock forest – group three assesses another hemlock.

On the cliff’s edge tree workers and tourists confer.

Another core reveal photo.

Here five sizeable hemlocks lie in a row – blown down by the summer storm of 2022.

All the root throw from hundreds of downed trees is significantly changing the sediment budget in the tributaries.

From the storms and trees killed by the emerald ash borer there is plenty of wood for log jams.

A portion of the park was used for raising shade trees back in the day. Here is one of the shade trees that remains.

Reflecting on the completed coring and anxious to get to the lab work.

One of the many, diverse rocks in Rathburn Run. Special thanks to the Friends of Wooster Memorial Park and the City of Wooster for maintaining the park and allowing us to sample there.

The Macedonia Missionary Baptist Church was established in 1849 and is Ohio’s first Black church and the only surviving antebellum Black church in the state of Ohio. The building is now being restored under the direction of Hardlines Design, Columbus Ohio. The Wooster Tree Ring Lab was contacted to help in the dating of the timbers in the church’s structure.

Charles Linthicum, Macedonia Trustee and Charissa Durst standing in front of the church in the summer of 2023 before the renovation began.

A scene also prior to renovation showing the interior of the church. The structure was moved and rebuild likely in the late 1800s so tree-ring dates on the timber may help to distinguish the portions of the structure that were original.

Renovation underway in February of 2025.

Nick Wiesenberg made a trip in February to the site to core the now-exposed beams during the renovation. Here Nick is sampling flood joists made from white Oak.

Nick points out the waney edge of this timber – the waney edge is the outer ring (bark year) and once assigned a calendar age indicates the calendar year the tree was cut.

Straps keep the walls of the church in tact as the restoration proceeds.

A historical marker and sign explain the history and the restoration of the Church. The work is funded, in part, by a Save America’s Treasures Grant from the Historic Preservation Fund administered by The National Park Service along with several other foundations and donors.

The College of Wooster Paleoclimate Class was fortunate to visit, Dr. Lonnie Thompson, director and founder of the Byrd Polar Ice Core Lab during lab. Here Dr. Thompson give the class the rundown of all the “firsts” in tropical and ice core lab history. We are looking forward to viewing the relatively recent movie about Dr. Thompsons’ epic career – Canary. 

Dr. Thompson describes the core collections from the tropics and from higher latitudes and the findings that are relevant to ongoing climate changes of today and into the future. His core sites include high altitude ice caps and glaciers in Peru, Bolivia, Tanzania, New Guinea, Tibet and Alaska. The class will be using his data from Quelcaya in Peru as projects and labs. Published data from the ice core lab is freely available for download and use through the NCEI (National Center for Environmental Information) maintained by NOAA.

Ice coring in remote and logistically challenging field sites depends on the understanding the physics of ice and glaciers as well as the mechanical behavior of metals and other materials. The team has been able to rack up the records of “Firsts” through experience and collaboration.

For example, understanding the rheology of ice in vital. Like the Earth’s crust, glaciers have a brittle zone near the surface and a more ductile zone at depth. The temperature of the ice and its behavior is critical to designing and machining the drills that work to successfully recover these frozen archives.

One of the highlights of the trip is touring the freezer where the ice cores are archived. The temperature is maintained at -30F and the scientist work under these conditions.

Ice core shopping at -31F.

The group is blown away thinking about how an ice cores can reveal information about the variability of the monsoons on a variety of timescales.

Special thanks to Nick Wiesenberg for arranging the trip and for providing snacks. The Paleoclimate class is lucky to have such able logistical support. Dr. Thompson would agree that logistics is more than half the battle in a successful expedition.

Dr. Eva Lyon ((photo above on June Lake, CA) Wooster Earth Sciences Professor and Wooster Alum.) has recently published her work “A high-resolution record of Late Holocene drought in the eastern Sierra Nevada (California, USA) from June Lake carbonate geochemistry” in Quaternary Research. With the backdrop of some of the worst recent droughts being experienced in the last millennium in the American Southwest (Williams et al., 2022), Lyon and her team extends the drought history for the Sierra Nevada (Figure 1) back almost 5000 years using well-dated sediment cores from lakes (Figure 2). They used oxygen and carbon stable-isotopes rations combined with X-ray fluorescence counts of calcium and titanium to identify six intervals of past droughts.

Figure 1. (A) Regional map showing location of study area: ML, Mono Lake; SM, Stonehouse Meadow; PL, Pahranagat Lake. (B) Lakes and streams of the study area, which are found along CA State Route 158 (the June Lake Loop). Water isotope values for locations indicated by white squares (oxygen, deuterium). (C) June Lake bathymetric map. White circles indicate locations of the lake cores.

The lake record (Figure 2) that is dated using radiocarbon, reveals the dry times that include many of the famous drought in the American West including the Current Warm Period, the Medieval Climate Anomaly (about 1000 years ago, also a warm time in the West) and three pulses of drought earlier during the Late Holocene Dry Period (~3500-2000 cal yr BP).  Records like these provide a perspective to the ongoing drought in the American West. Those scientists that model hydroclimate use such well-dated records of past changes in lakes as a way of better anticipating future climate. This work is particularly important as the world moves into the greenhouse climate of the future.

Figure 2. Plot of changes in core geochemistry with time. From left to right: (A) total inorganic carbon (%TIC), sampled every 2–3 cm; (B) ratio of calcium to titanium (Ca/Ti), sampled every 1 mm; (C) oxygen isotope values in per mil (δ¹⁸O_carb), sampled every 2–3 cm where %TIC was high enough to permit measurement; (D) carbon isotope values in per mil (δ¹³C_carb), sampled every 2–3 cm where %TIC was high enough to permit measurement. Here, the six dry intervals described in the text are particularly prominent as increases in oxygen isotope values—these are denoted by horizontal yellow or red bars. The horizontal blue bars indicate the wetter intervals, including the pluvial between the two peaks of the Medieval Climate Anomaly (MCA) megadrought and the Little Ice Age (LIA) (~500–100 cal yr BP, as defined in IPCC, 2021). LHDP, Late Holocene Dry Period.

Reference:
Lyon EC, Erhardt AM, Streib LC, Zimmerman SRH, McGlue MM. A high-resolution record of Late Holocene drought in the eastern Sierra Nevada (California, USA) from June Lake carbonate geochemistry. Quaternary Research. Published online 2025:1-15. doi:10.1017/qua.2024.38.

Williams, A.P., Cook, B.I., Smerdon, J.E., 2022. Rapid intensification of the emerging southwestern North American megadrought in 2020–2021. Nature Climate Change 12, 232–234.

The group posing in front of some generations of draglines at the Zollinger Pit in Rittman. Many thanks to the operators for giving us permission to spend a spectacular afternoon at the site.

Figure 1. Map showing some the the local topographic features. A lake resided in the valley prior to the Laurentide ice advance into the basin. The lake at some point drained down the Killbuck Spillway to the west.

Figure 2. This stylized sedimentary sequence from T.V. Lowell provides a framework for the site. Preglacial lacustrine setting overrun by the ice sheet.

Figure 3. The base of the sequence is a series of varve-like sediments consisting of silt-clay couplets. The group determined that is this high sediment charged environment these were likely not annual but diurnal (daily).

Figure 4. The swallows build their nest into the silt and this sequence overall is coarsening upward. Note the vertical downcutting along the boundaries of joint in this unconsolidated sediment pile.

Figure 5.  An introspective moment reflecting on the environment at the bottom of a proglacial lake just prior to advance of the Laurentide ice sheet into the basin.

Figure 6. The group working our the direction of the paleocurrent based on a series of climbing ripples with clay drapes – could they be daily couplets?

Figure 7. This facies model is a good conceptual cartoon of the setting.

Figure 8. A rare moment when the entire class was working. The upper unit record the glacial tills recording the ice advance and retreat from the site.

Figure 10. As the ice advanced and thickened over the site it smear the sediments into a deformation till, and as the ice thickened and effective normal stress increased the till was lodged onto the sediment pile.

Figure 11. The lodgement till at the top of the sequence, which, in turn, is capped by a melt-out till. The class was able to determine the ice was not absent from the site.

Figure 12. The melt-out till showing fluid escape structures and ball and pillow structures indicating loading and melt out.

Figure 13. Closeups of the ball and pillow structures.

Figure 14. Dropstone were evident and here we see a dropstone made of a stone and a till clast. This indicates icebergs in the lake dumping sediments into the lake.

Figure 15. A portion of the class spent much of the time mining gypsum crystals. The presence of gypsum crystals at the pit indicate a desert environment? We explained the gypsum as a case of saturated groundwater and, of course, kinetics.

Figure 16. Some healthy skepticism about the site and the origin of the sediments.

The Geomorphology (GEOM24) class posing along the Little Killbuck River Valley. Looming in the background is the delta built into Lake Killbuck during immediate post-glacial times about 14,000 years ago. The sediments are so well exposed, in part, due to some recent illegal hydraulic mining  for sand and gravel.

Figure 1. Two versions of the measured section showing the coarsening upward sequence of sediment making the Gilbert-type delta built into the paleolake. This sequence of unconsolidated sediments sits on the Mississippian siltstones and shales.

Figure 2. The shale is evident to the left of the class members. Clays, silts and colluvium marks the flooding of the valley and the beginning of the bottomset beds in the delta.

Figure 3. The foreset beds are composed to silt and sands with frequent clays and deformation reflecting changes in water levels and the high rates of sedimentation and slumping.

Figure 4. A “flow roll” of a mix of foreset sands and lacustrine clays likely deformed through slumping along the delta front. Note the liesegang rings in these likely 14,000 year old sediments.

Figure 5. A somewhat enigmatic fracture clay layer is likely due to a ephemeral increase in lake level, or a change in the delta depocenter. There was some discussion of a ice readvance, however, this is unlikely.

Figure 6. Front lower left to upper right – the photo captures the disconformity at the bottom, the foresets to the upper right and the cut and fill structures of the topsets. The diagram below summarizes the overall structure of the delta.

Thanks for Nick Wiesenberg for helping with logistics in all the Geomorphology fieldtrips this past semester and for digging many holes.