Concluding 2018 summer research in the Tree Ring Lab

July 27th, 2018

Summer 2018 research in the Tree Ring Lab has come to a close. The group of five students worked on a variety of projects, learning about the climate and history of Ohio and Alaska, and the application of different dendrochronological techniques and statistical analyses. They also gained experience effectively conveying their research to others and writing official reports of their findings.

The summer research team on their last day working together (Left to right: Greg Wiles, Nick Wiesenberg, Victoria Race ’19, Juwan Shabazz ’19, Kendra Devereux ’21, Josh Charlton ’19, and Alexis Lanier ’20).

AMRE students with a sampled oak tree at Brown’s Lake Bog in Wooster, Ohio (Alexis Lanier ’20, Juwan Shabazz ’19, and Kendra Devereux ’21).

The AMRE team accomplished a lot during the eight weeks they were here on campus. Their research started with the principles of dendrochronology, when they learned how to count individual tree rings and measure their widths under the microscopes. From here, the team learned how to run this data in different programs like COFECHA and ARSTAN. This process allowed them to date many historical structures across Northeast Ohio such as Gingery Barn and Miller House and Barn. You can find a full list on the TRL’s reports page.

AMRE students with Nick Wiesenberg collecting samples from historical structures at Sonnenberg Village in Kidron, Ohio.

Alexis and Kendra visiting one of the historical structures at Sonnenberg Village.

The AMRE students also learned how to take these chronologies and make hypotheses regarding past climate by uploading the data to Climate Explorer and running various correlations with other datasets.

We were fortunate enough to go out in the field and personally collect most of the data that we worked with this summer. These eventful trips included a lot of tree coring and required lots of bug spray. Some of the AMRE group’s favorites trips included Stebbin’s Gulch and Brown’s Lake Bog.

Stebbin’s Gulch at the Holden Arboretum (Left to right: Josh Charlton ’19, Juwan Shabazz ’19, Alexis Lanier ’20, Kendra Devereux ’21, and Dr. Wiles).

Juwan with the machete, ready to clear a path for the rest of the team at Brown’s Lake Bog.

Lining up to cross the moat at Brown’s Lake Bog after a weekend of strong thunderstorms.

Kendra Devereux ’21 with the sample bag at Barnes Preserve in Wayne County.

Josh Charlton ’19 coring a tree at Stebbin’s Gulch in the Holden Arboretum.

The other two summer researchers working in the Tree Ring Lab this summer, seniors Victoria Race and Josh Charlton, have been working with tree ring data collected from Alaska. Their work focuses on the modeling of Columbia Glacier located in Prince William Sound, Alaska. They are currently working on an abstract to submit to the upcoming GSA conference this fall. Stay tuned for more information regarding their project!

AMRE students with Victoria Race ’19 and Arrow at Brown’s Lake Bog.

Special thanks to the National Science Foundation, the Sherman Fairchild Foundation and the AMRE program for helping to make this research possible. Enjoy the rest of your summer!

Summer Research at Wooster: Rain-on-Snow in Alaska

July 13th, 2018

The following post is courtesy of Anna Cooke (’20), who worked with Dr. Alex Crawford through Wooster’s Sophomore Research Program this summer

In the heat of Ohio’s summer, it’s been a small bit of relief to turn my attention to Alaska; or more specifically, to rain on snow events in Alaska. A rain on snow event is pretty much exactly what it sounds like. It occurs when rain falls on a preexisting snowpack. For this to happen, the temperature must rise above freezing during a precipitation event. If the temperature then falls below freezing following the event, the result is a layer of ice on the surface of, in, or underneath the snowpack.

But why should those of us who live in the continental interior care?

Rain on snow, hereby referred to as ROS, has some interesting and possibly devastating effects. One such effect is on caribou populations. The diet of Alaskan caribou varies, but something that most caribou have in common is the dependence on ground foliage, such as lichens, as a winter food source (Joly et al., 2015). ROS is dangerous for caribou because of the possibility that the resulting ice layers will block this food source. Nutritional stress caused by ROS can lead to declining birth rates and calf weights. At the most extreme, mass die-offs can result from starvation (Mallory and Boyce, 2018). The resulting population decline or emigration of caribou impacts the hunters who rely on the caribou as a food source.

Fig 1: Caribou photo courtesy of Dr. Karen Alley.

Other impacts of ROS include the shutdown of airports and loss of revenue from tourism, and permafrost degradation. If enough rain infiltrates through the snowpack to its base, when it refreezes, the latent heat that is released will maintain a soil temperature of 0 degrees Celsius when it should be much colder. The resulting warming of subsurface temperatures could destabilize permafrost systems, causing slope instability and avalanches (Rennert et al., 2009).

Identifying ROS Events

If we want to mitigate the effects of ROS events, it is important that we understand where, when, and how often they occur. To do this, ROS can be identified and analyzed using climate models, satellite data, and observational data from weather stations. One difficulty in identifying ROS events is that no one agrees on just what a ROS event is. Some people define it as 3 mm of rain falling on 5 mm of snow water equivalent, or SWE, which is the amount of water present if the snowpack were to be melted. Others use different thresholds than 3 and 5 mm. Some use measures such as over 12 continuous hours of precipitation visually classified as drizzle and greater than 0.0 mm.

Despite this variation all identification strategies share one limitation: none keep track of refreezing after the precipitation event. This is an issue because ROS without refreezing does not have the same impacts as ROS followed by freezing, and if we are interested in the events most likely to have strong effects, refreezing is imperative.

I experimented with different identification strategies and thresholds trying to find a method that was restrictive enough that I wasn’t overcounting the number of events, but not so stringent that I was undercounting. The graphs below show the average number of events per year divided by season at five different weather stations in Alaska when counting events as 0.1 inches of precipitation on 0.1 inches of SWE, or 1 inch of snow depth for stations where SWE is not available. The first graph shows the total number of ROS events counted. The second graph shows the number of ROS events followed by refreezing. In all cases, fewer events are counted when refreezing is accounted for, and in several cases no more than half of ROS events are followed by refreezing. Thus, it’s likely that many studies are overestimating the number of impactful ROS events.

Results

Fig 2: Number of rain on snow (ROS) events per year by season for (top) all events and (bottom) events followed by refreezing.

As you can see from the graph above, most ROS events seem to occur in the spring, which is defined as March, April, and May. ROS functions a bit differently depending on the season. In the fall, the temperatures are often warm enough for rain to occur, but there may not be a snowpack for the rain to fall on. In the winter, the limiting factor is not snowpack, but rain, since the precipitation that falls is more likely to be snow. In the spring, the presence of a snowpack and the increase of the temperature to allow for rain are likely. However, a refreezing event is less likely. Moreover, even if there is refreezing afterwards, the number of days that the temperature remains below freezing is likely to be lower than the number of days for a winter event.

As such, events in each season pose different threats to caribou herds. In the fall, healthy caribou which have spent the summer with plentiful food access are more likely to be weakened than killed off. However, major winter events in which the snowpack is frozen over for weeks afterwards are more likely to decimate populations. Events in the spring are also dangerous because, even though the ice is not likely to inhibit foliage access for more than one or two weeks at a time, caribou may already be weakened from harsh winters.

Since there are so many factors to take into account in the study of ROS events, more research is necessary, especially since the frequency with which events occur is likely to increase with global warming. There are ways that we can mitigate the effects of ROS on wildlife and human populations, but only if we can understand its causes and effects. The research done this summer is piece of a larger story, and it was a pleasure to add this piece to the puzzle.

Fig 3: Caribou photo courtesy of Dr. Karen Alley

Works Cited:

  • Joly, Kyle, Samuel K. Wasser, and Rebecca Booth. 2015. Non-Invasive Assessment of the Interrelationships of Diet, Pregnancy Rate, Group Composition, and Physiological and Nutritional Stress of Barren-Ground Caribou in Late Winter. PLoS One, 10 (6): 1-13 (DOI: 10.1371/journal.pone.0127586).
  • Mallory, Conor D. and Mark S. Boyce. 2018. Observed and predicted effects of climate change on Arctic caribou and reindeer. Environmental Reviews, 26 (1): 13-25.
  • Putkonen, J., T.C. Grenfell, K. Rennert, C. Bitz, P. Jacobson, and D. Russell. 2009. Rain on Snow: Little Understood Killer in the North.EOS,90 (26): 221-222.
  • Rennert, Kevin J., Gerard Roe, Jaako Putkonen, and Cecilia M. Bitz, 2009. Soil Thermal and Ecological Impacts of Rain on Snow Events in the Circumpolar Arctic. Journal of Climate,22: 2302- 2314 (DOI: 10.1175/2008JCLI2117.1).

The Northern Pacific Coastal Temperate Rainforest (PCTR)

July 4th, 2017

The high rainfall and high coastal ranges nourish the icefields of southern Alaska along and with the extensive carbon-rich forests and ecosystems of the Northern Pacific Coastal Temperate Rainforest (PCTR).

Chris surveys the North Pacific noting the extensive moisture source and ocean pasture that is just offshore of the terrestrial ecosystems we are studying.

Malisse sits atop a shore pine, another slow growing coastal species that is experiencing potential decline.

Kerensa sites atop an obducted ophiolite – we were 71% sure that there were pillows in the basalt.

Josh cores another Alaska Yellow cedar – we were able to sample three sites in the Juneau area. These cedars are in decline due to warming and loss of snowpack, which makes their fine roots vulnerable to frost. Our objective is to work up the tree-ring record of the sites to contribute to our understanding of the decline.

Alora takes a break from taking notes and GPS coordinates for each tree.

Ice caves fund to explore and act as a conduit to meltwater and warm air accelerating the melt.

Blue the dog – takes a break from pursuing porcupines in the muskeg.

Nick of the Ophiolite.

Kerensa wades through the deep texture of coastal carbon.

Buried forests emerge from the wasting margin of the Mendenhall Glacier.

Nugget Falls – this is a classic hanging valley that has been revealed by the Mendenhall Glacier over the past 80 years.

A granite erratic just offshore.

A marmot sites on a stone in front of the emerging shoreline and new stands of Sitka Spruce.

A recently stripped cedar. The Tlingit strip the trees for a variety of reasons, primarily to procure the inner bark for weaving.

The field group taking a rest on the way back from Cedar Lake. The group is now working intensively on the Yellow Cedar cores to develop the tree ring record.

Thank you Jesse Wiles for your excellent photography and logistical support.

Team Alaska’s Last Day

July 3rd, 2017

To wrap up an incredible journey, Team Alaska scrambled over glacially-scoured rock faces and occasionally bush-whacked through thick shrubbery to Mendenhall Glacier. Small glimpses of the glacier that were periodically revealed through high points or gaps in the forest

Approaching Mendenhall Glacier…can you spot the people for scale?

Subglacial hydrology, captured within an ice cave #NoFilter

Malisse, Chris and Kerensa explore the Ice Caves beneath the Mendenhall Glacier.

Jesse treks out onto the vast, icy terrain

Team Alaska plays follow the leader to get off the glacier safely

Alora coring subfossil snag trees from the Little Ice Age.

Taking in the immensity of the glacier

Day 4 – Keck Gateway – Alaska

June 27th, 2017

Day 3 consisted of Team Alaska exploring Juneau the way a tourist might. The group roamed around the downtown area stopping at quaint book stores, trading posts, and the Alaska State Museum. This allowed the team to relax their aching feet and gain a new perspective of the city and borough of Juneau. After visiting the museum, the team gained a deeper appreciation for Alaska’s native cultures and complex history.

On day 4, Team Alaska conquered Bridget Cove, led by local forest ecologist and conservationist John Krapek. In order to get to the site, the team hiked over a mile of steep terrain covered by a large and spinous plant called Devil’s club. The team was able to collect a plethora of samples including that of yellow-cedar and western hemlock. After collecting the samples, the team took a lunch break and enjoyed a nearby muskeg. Finally, Team Alaska descended the slippery and densely vegetated trail, which was marked only by their previous footsteps. We wish Team Utah the best of luck braving triple digit weather, excited to meet back in Ohio in the coming days!

The group smiles upwards as Jesse snaps a quick picture.

A quick look at one of the group’s field notebooks.

John shows us how the ecologists do it!

Malisse of the pines.

Kerensa cranks out another core.

Alora peers into the canopy.

A wild Dr. Wiles is spotted from a far.

Josh gets his arm workout for the day.

Chris and Jesse take a break and find a tree to climb. No trees were harmed in the making of this picture.

Team Alaska Day Two

June 26th, 2017

Team Alaska hikes through the woods on a cloudy day to Cedar Lake. At this site they retrieved over 50 increment cores from 25 trees, which will be compared with tree-ring data from Cedar Lake collected in previous years. Lunch included an astounding view of the Pacific Ocean, the misty Chilkat Mountain Range, and some seals! The day ended with another home-cooked meal, followed by some well-earned rest.

Malisse is always ready for the camera.

Nick, Wooster’s geology department technician, relaxes on a rocky outcrop for lunch. Nine miles behind him can be seen the expansive Chilkat Mountain Range.

The group finds a rope swing above a creek beside a public-use cabin. Be careful, Chris!

Alora hikes through the temperate rain forest in search of more cedars to core!

Kerensa wades through skunk cabbage to find the rest of the trail.

Team Alaska poses before Cedar Lake; behind them you can see the yellow-cedars waiting to be cored.

Josh cores high on the tree to avoid sampling a rotted section. Good workout!

Jesse, Team Alaska’s exceptional photographer, takes his turn coring some trees.

Nick and Dr. Wiles compare fresh cores while Alora records data.

Team Alaska Day One

June 25th, 2017

Day one involved team Alaska hiking the East Glacier Trail led by Brian Buma, a forest ecologist from the University of Alaska Southeast. Their goal was to sample yellow-cedar trees at high elevation sites and understand how the dynamics of the forest relate to climate change. The trip was off the beaten path after 2 miles and continued for another 6 miles through a steep, muddy, dense understory. The group only stopped to eat lunch, but it was a sublime day with amazing company. Upwards of 50 samples were collected from a boggy environment, known as a “muskeg”. After a very long but exciting day the group headed down the trail for home-cooked fish tacos. Yum!

Brian Buma, forest ecologist, gives the group information regarding adolescent cedar trees.

The group treks through the unknown terrain, they may be lost.

After realizing they were not actually lost Team Alaska catches their breath and admires the views atop the mountain.

Chris measures the DBH, diameter at breast height, to assist Brian Bumas’ study of these economically, culturally, and ecologically important trees.

Alora stands in the foreground to upstage the natural beauty of the mountain, it is possible to look good in a bug net!

Team Alaska poses for a quick photo-op before starting their fieldwork.

Josh, member of Team Alaska, reads his field notes and records data.

Kerensa labels a straw, containing a yellow-cedar tree core for future analysis.

Malisse, renowned multi-tasker, records field notes, holds cedar cores and protects herself from the hordes of insects trying to sample her blood. Thanks to Jesse Wiles for the photographs.

A Strong Start to the 2017 Keck Gateway Project

June 22nd, 2017

Guest Blogger: Addison Thompson (’20 Pitzer College and Team Keck Member)

The 2017 Keck Gateway Team.

Amid our first official day at the College of Wooster, spirits were high as we embarked on the five week Keck Gateway Project.  The Gateway Project encompasses two different scientific enquiries which will span three states; Ohio, Utah, and Alaska.  The goal of the project centered in Utah is to determine the age of geologically young lava flows (now igneous rock) in the Ice Springs Volcanic Field of central Utah in order to add another piece to the unsolved puzzle of the Earth’s geologic history.  The goal of the project centered in Alaska aims to gain a better idea of why Cedar trees in Juneau are in decline.  The information gained from the students working in Alaska will help pinpoint specific environmental factors that are adversely affecting ecosystems, trees in particular.  This portion of the project is one week long.

Evidence of a tree core.

Once the data from the Utah and Alaska field sites are complied, both teams will return to the College of Wooster to complete lab tests in order to answer each respective hypothesis. This portion of the project is roughly three weeks long.  The participants of the project also have the opportunity to attend and present the findings of their research at the GSA’s (Geological Society of America) annual conference in Seattle in mid-October.

The first full day of the project was a beautiful one and we dove into the topic material with gusto.  We began at 9am in the geology department which is located in Scovel Hall and had a discussion about the rules of authorship and the details of what mentoring means with Dr. Pollock and Dr. Wiles.  Following that, details for the field work trips (Utah and Alaska) were coordinated and supplies like rock hammers and chisels were evenly distributed.  At that point it was time to break for a much needed lunch.  The Keck group met back at Scovel Hall around 1:30, just in time for a jaunt around the Oak grove led by Dr. Wiles, during which the group cored three trees to determine their age.

The processing of coring trees involves inserting a hollow drill into the tree, then removing the sample of the tree located in the hollow drill.

An excited Team Alaska member extracts her tree core.

The Alaska team will use this method hundreds of times in order to determine the health of trees in a large area.  With the first day complete, our group looks forward to strengthening our bonds and embarking on our geology research.

On the second day, the Utah group and the Alaska group split to their respective labs to discuss the minutia of the trips.

The Utah group examined basaltic rocks from the Black Rock Desert, the location where they will be conducting their fieldwork.

These rocks had previously been dated via two techniques: one being Varnish Microlamination (VML) which aims to date the rocks by measuring the coating on rock surfaces, the other being Cosmogenic Nuclide Dating which measures the accumulation of radioactive isotopes in the surfaces of the lava flows.

Meanwhile the Alaska group learned more about tree coring, a practice they will become very familiar with during their stay in the last frontier.

This concluded our work for the day, and we broke for lunch.  The rest of the day was spent preparing for our arduous journeys to the field sites the following morning.  We went shopping to stock up on various items for the trips.  The day came to a conclusion with a delicious dinner and some frisbee outside Douglas Hall.

Much to their chagrin, the Alaska group was departing the College of Wooster at 4am on the third day.  The Utah group was given a more lenient departure time, 6am, because their destination was 2,113 miles closer to the College.  There were no issues rising bright and early and both groups headed to Cleveland Hopkins Airport with anticipation of the journey ahead of them and slightly weary eyes.  To make matters more interesting for the Alaska group, their travel plans routed them through Dallas Fort Worth…not quite in their desired direction but they were sports nonetheless. And so the day went, a travel day.  The Utah group touched down in Salt Lake City in the mid afternoon and began the two hour drive to the town of Fillmore, only stopping once for a much needed dinner.  Eventually the group made it to their campground and settled in their cozy cabins.  After a long day of travel and two hours lost, a rest is what the doctor ordered.  As of writing this, the Alaska group is currently still in transit to Juneau.  Tomorrow marks the first official day of field work in the Black Rock Desert for the Utah group and there is an excited fervor hanging in the air.  All the tools and measurement devices are prepped and ready to go.

 

 

 

 

Wooster geologists begin their 2016 Geological Society of America meeting adventure

September 25th, 2016

bell-092516DENVER, COLORADO — Seventeen Wooster students have now arrived in Denver for the annual meeting of the Geological Society of America. Eleven of them are giving presentations of some sort. We are very proud of each. Dr. Meagen Pollock and I may not be able to get to each poster, so we’re going to post what we can when we can. Today was big for Wooster’s Dendrochronology (Tree-Ring) Lab under the direction of Dr. Greg Wiles. All the work today was from various Alaska expeditions.

Early this morning I found Brandon Bell (’18, above) with his poster. Brandon is a double-major in history and geology. His project here on the Bering Expedition is quite fitting.

deck-585-092516Clara Deck (’17) here presents her dendroclimatic project.

deck-at-work-585-092516Clara at work doing the poster thing.

gunderson-092516Jeff Gunderson (’17) is also representing Wooster’s dendrochronology lab with his fine poster.

hilton-585-092516Annette Hilton (’17) is presenting for the dendrochronology lab.

mcgrath-585-092516As is Sarah McGrath (’17).

I’m very impressed with our students and their cheerful, confident and creative presentations. It is a daunting task giving a poster at a national meeting, and they are doing it exceptionally well.

More student presentations later! We’re having a good and productive time in Denver.

 

23 Hours of Sunlight and 22 Hours of Bugs (Part 2)

July 5th, 2016

Guest bloggers: Andrew Wayrynen and Jeff Gunderson

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We take our berry picking very seriously

Oh so you thought you got rid of Team Alaska, didn’t you? Yeah well, just as there are as many cedar sites in Juneau as there are cruise ship tourists, we’re back with part 2. Now where were we?

After our Kayak at McBride Glacier amongst the massive icebergs in the fjord, we— Jesse Wiles, Dr. Wiles, Jeff Gunderson, Andrew Wayrynen, and Nick Weisenberg— decided to take to the ice by foot. As such, the following day we made the short kayak to the outwash plain at the terminus of Riggs Glacier, a massively cold testament to what the coastal Alaskan climate can do. While on the glacier, it was impossible not to feel humbled and awe-struck by its enormity. It was a friendly and welcome reminder as to why the science truly matters.

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A Jeff for scale at Riggs Glacier

Exploring Riggs glacier was a wonderful experience, but the time soon came for another dendroclimatological expedition. Our goal was to search for wood in the recently vacated valley where once Riggs and McBride Glaciers connected. To our pleasure there was hardly any alders, which made the mission less trying, yet there was no shortage of braided streams that provided ample opportunities for a boot full of freezing glacier water. Unfortunately, there was only one log to be found and sampled in the entire valley. As sure as the bugs did bite, we brought it home.

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Dr. Wiles coring the lone log in the valley

The following day, an all-too-familiar gray haze took command of the skies that dripped upon us a rather watery substance called rain. As the bold, rugged mountain-worn scientists slated to bridge that 2000-year gap, we took the day off. We explored our camp cove and admired huge beached icebergs.

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Andrew investigates the dead ice 

 That day at our camp in Muir Inlet would prove to be our last, as Todd, the wise NPS boat captain, arrived in late morning of the following day with Dan Lawson to take us to Tlingit Point. However, we made a historically significant stop along the way. Before navigating Glacier Bay’s icy waters, Todd worked in Yosemite Valley in California, inadvertently following John Muir’s footsteps in his late 19th century search for glaciers. Much to Andrew’s excitement, he guided us to the site of John Muir’s cabin, which was built in 1879 by Muir and friends. Having been so busy as geologists, our crew relished in the opportunity to have a stab at archaeology.

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 John Muir’s cabin in the late 19th century where the terminus of Muir Glacier once was (left) and the same cabin today (right)

Now camped at Tlingit Point, we had our sights on the Mountain Hemlock situated atop the hills above us. The climb up was incredible in practically every sense of the word. While ascending, the chances of peering out to the bay and soaking in the gorgeous vistas were about the same as falling into patch of delicious wild strawberries. Near the top, the alders thinned and the brush only came up to ankle-height, but alas the bugs persisted, hungrier than ever. Once amid the old growth, we cored the mighty hemlocks and safely tucked away the obtained samples.

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Andrew tries his hand at coring for the first time

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Mountain goats became new friends to the Wooster Geology Department

 Things we learned: Giant Hogweed makes your skin more susceptible to UV rays and can cause third degree sunburns (no, those puss bubbles on your hand aren’t spider bites, Jeff). It doesn’t really rain in Alaska- spare your wallet and don’t buy rain gear if you go. Apparently, Alaskan mosquitoes are wildly undernourished. Dendrochronology/Dendroclimatology is amazing. Our favorite rock is becoming a tree.

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The view from the top of Tlingit Point marked the end of an awesome field season

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