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Ecology & Environmental Sciences Graduate Program

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Making Sense of Maple Syrup

Understanding more about the relationship between weather and maple sap flow, and how Maine syrup producers will adapt to climate change is the focus of research being conducted by a University of Maine graduate student.

Jenny Shrum, a Ph.D. candidate in the ecology and environmental sciences graduate program in the UMaine School of Biology and Ecology, is attempting tounravel the biophysical relationships between weather and sap flow. The goal is to better understand what drives flow and how expected trends in climate may affect the processes and harvesters in the future.

Shrum plans to collect on-site weather station data and sap flow rates at three test sites and to interview small- and large-scale producers to determine if those who have been managing sugar maple stands for years will be more or less resilient to climate change, and if large-scale producers will be better equipped to adapt. Her research is supported by the National Science Foundation and EPSCoR through UMaine’s Sustainability Solutions Initiative and its Effects of Climate Change on Organisms research project.

The physiological process for sap flow is not completely understood, Shrum says. It involves a complex interaction between freezing and thawing of the xylem tissue within the tree, and the molecule sucrose which maple trees use to store carbohydrates between seasons.

“When the tree defrosts, the frozen liquid in the tree becomes fluid and that provides a medium for the sugars that are stored in the trunk to get to the branches,” Shrum says, adding that in order to continue flowing, the ground also has to be defrosted so the tree can pull in water during the next freeze cycle and recharge the positive pressure in the trunk to restart sap flow.

Sugar maple trees grow as far north as New Brunswick and as far south as Georgia, yet maple syrup is only produced commercially in the 13 most northern states because of the colder weather, Shrum says.

In Maine and other northern areas, more than one freeze-thaw event happens during the winter. This lets the process repeat and allows the season to last between six and eight weeks as opposed to a few days, which is likely in southern states such as Georgia and Missouri, where maple trees grow but aren’t commercially tapped. Warm weather or microbial build-up in taps usually ends the season, according to Shrum.

In Maine, the season usually starts sometime between the middle of February and the middle of March, and continues for about six weeks, Shrum says.

“This winter has been really weird; we’ve had really warm weather and really cold weather and as far as sap flow, that might be a good thing,” Shrum says. “But not enough is known.”

One change that has been proven is the start time of the sap season.

“Studies are starting to show that the preferred block of time for tapping is starting earlier if you base it on ideal temperatures,” Shrum says, citing a 2010 Cornell University study by Chris Skinner that found that by 2100, the sap season could start a month earlier than it does now.

For big-time operations, Shrum says an earlier season probably won’t be a problem because they can just tap their lines earlier, but she’s not sure how smaller Maine operations will adapt.

“They might not be able to change their season,” she says. “A lot of the smaller operators have multiple jobs; they make money off maple syrup, but also in other fields such as woodcutting or construction. It just so happens maple syrup is a block of time when they’re not doing anything else, so it makes sense. But if that season changes, it might not fit into their schedule as well.”

Shrum will interview a variety of producers — small- and large-scale operators, people who have been tapping trees for 30 or more years and people who started within the past five years — to learn the reasons for tapping and better understand resilience within these groups.

To record weather and sap flow data, Shrum, who holds a bachelor’s degree in biology from Humboldt State University, will deploy weather stations at maple tree stands in Albion, Dixmont and Orono. She’s also using iButtons to record soil temperatures and time-lapse photography of the buckets to record hourly sap flow rates. She can then relate flow rates to variables the weather stations record, such as temperature, precipitation and sunlight.

Although climate change is likely to affect sap flow, Shrum is confident there will always be maple syrup made in Maine.

“None of the climate change scenarios that have come up result in maple trees not growing in Maine. We’re definitely still going to have freezing events in Maine; it’s not going to get so warm that that’s not going to happen,” she says.

Shrum says maple syrup could become a big commodity in Maine if more of a market was created through government incentive plans, and if the state decided to make it a priority — similar to Vermont.

“Everything is good about maple syrup. There’s very little that’s controversial about it, and the biology is fascinating,” Shrum says.

Contact: Elyse Kahl, 207.581.3747

Image Description: maple syrup

EES Graduate Program Holiday Party

On December 10, EES Graduate Faculty and Students convened for the Second Annual Holiday Party. Following a pizza dinner, the group divided up into teams for the First Annual EES Squash Car Races. Teams transformed garden gourds into racing machines using holiday paper, glitter, paper, and yes, mustaches. We hope to see you there next year!

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EES Director Aram Calhoun to Discuss Vernal Pool Conservation

Department of Wildlife Ecology &
Ecology and Environmental Sciences Program present…

Aram J.K. Calhoun

 University of Maine
Professor of Wetland Ecology and
Director of Ecology & Environmental Sciences Program

Vernal Pool Conservation: Merging Science and Policy

Monday, November 25th
Room 204 Nutting Hall
12:00 PM

Please contact Kris Hoffmann (; 978.660.7991) to make arrangements to meet with the speaker.

If you are a person with a disability and need an accommodation to participate in this program, please call Kris Hoffmann at 978.660.7991 to discuss your needs. Receiving requests for    accommodations at least two days before the program provides a reasonable amount of time to meet the request, however all requests will be considered.

The University of Maine does not discriminate on the grounds of race, color, religion, sex, sexual orientation, including transgender status and gender expression, national origin, citizenship status, age, disability, genetic information, or veteran’s status in employment, education, and all other programs and activities.~ The following person has been designated to handle inquiries regarding nondiscrimination policies:~ Director, Office of Equal Opportunity, 101 North Stevens Hall, 207.581.1226.

Image Description: Aram Calhoun

Within Reach: Journey to Find Sustainable Community

EES Presents

Within Reach: Journey to Find Sustainable Community

November 6, 2013

100 Nutting Hall 3:00 – 4:45 p.m.

Discussion with film Producer and co-cyclist Amanda Creighton immediately following the film.

WITHIN REACH explores one couple’s pedal-powered search for a place to call
home. Mandy and Ryan gave up their jobs, cars and traditional houses to “bikepack”
6,500 miles for nearly 2 years around the USA seeking sustainable

To find out more about the film visit:


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AP Reports on Research into Superstorm Sandy’s Effects on Tidal Marshes

The Washington Post, Boston Herald, Wall Street Journal, Newsday and Portland Press Herald were among several news organizations to carry an Associated Press article on research being conducted by the University of Maine, Maine Department of Inland Fisheries and Wildlife, University of Connecticut and University of Delaware on the effects of Superstorm Sandy on plant and bird communities in tidal marshes from Maine to Virginia. The study aims to determine what makes marshes and these communities more vulnerable when it comes to severe weather. Brian Olsen, professor in UMaine’s School of Biology (and EES) and co-principal investigator of the study, was interviewed for the article.

Alex Bajcz Selected for 2013-2014 Correll Fellowship

Alex Bajcz, a Ph.D. student advised by Frank Drummond, has been selected for the prestigious Correll Fellowship for the 2013-2014 academic year. The Correll Fellowship includes a 12 month stipend of $19,500, a tuition waiver of up to 19 credits and full health insurance during the 2013-2014 academic year.

While the Faculty Council was impressed by all of the nominees for the Correll Award, Alex’s academic achievements at UMaine as well as his research goals were exceptional. In his nomination letter in support of Alex, Frank Drummond wrote, “He is the kind of student that as faculty we all love to mentor. Alex’s research is innovative and has both strong basic and applied components. He is interested in plant ecology as it relates to evolutionary tradeoffs that plants must balance in their strategies for investments of resources towards reproduction and vegetative growth. He has spun this question so that it has a strong pollination ecology component, an area that is a major focus of my research…Alex is a very strong student. I am impressed with his talents and I enjoy his intellectual curiosity and enthusiasm. I have no doubt that he will represent the EES Graduate program and UMaine at the highest level.”

Congratulations, Alex!

EES Professor Frank Drummond in the News

EES and SBE Professor Frank Drummond was featured in an article about pollination of Maine’s wild blueberry fields in the Huffington Post.

Mo Correll Delivers 2013 Commencement Speech

EES Ph.D. Candidate and Graduate Student Government President Mo Correll delivered the Commencement Speech at the May 2013 Graduate Hooding Ceremony. The text of her speech is below.

Hello graduates! I am honored to be here with you all today. I speak to you as president for the graduate student government; I am also a PhD candidate in Ecology and Environmental Science, a proud member of the Olsen Lab in Deering Hall, and part of the Climate Change Institute on campus. Over the past few years I have gotten to know many of you, and see several faces in the gradating class here that are very near and dear to me. I see many more that I recognize, but wish I had gotten to know better. I see teachers, physicists, ecologists, and artists; I see professors, businesswomen, politicians, and agriculturalists. I see people who have worked alongside me, struggling to understand classwork, or grant applications, or the directions for filling out forms for the graduate school. And let me say, I am extremely jealous of all of you! For all of your varied backgrounds, today marks a life accomplishment for all of you, and you should be proud. I am continually impressed by the quality and variety of research, education, and creative accomplishments on this campus, and I can confidently say that as graduates you are already leaders, teachers, mentors, and innovators. You will represent yourselves and the University of Maine well as you move forward.

We come from a small community at the University of Maine, set in between the Maine coast and the Appalachian mountains. I hope you’ve all been able to summit Mt. Katahdin, enjoy Acadia National Park, and spend at least one day basking, swimming, or maybe even surfing on a southern Maine beach. I hope you’ve all eaten a Maine lobster, attend a woodsman competition, and incorporated at least some plaid into your wardrobe during your time here.

For all that our state boasts, I think I can speak for many of us here when I say that sometimes this place can a little feel tiny or confined. What’s a graduate student to do in Orono when they need caffeine past 7 PM? And why can’t anything in this town be named after something besides a bear? While we may all sometimes struggle within the confines of a small town in rural Maine, I think we find a clear strength in our size and geography through the incredibly inclusive academic community that we foster. While we may be small, we are mighty! We are the land-grant and flagship University of our state; the research and professionals produced here are competitive at a national and international level. However, what makes University of Maine students truly unique is the path we take in achieving that distinction; we achieve excellence through teamwork and support. Not only are we mighty; we are friendly as well. I have never felt as simultaneously challenged and encouraged as I have during my past three years in UMaine’s academic community. I have seen myself grow and thrive through the classwork and outstanding mentorship provided to me, and from the intense support I experience from my peers. I truly hope you all have found similar opportunities for such development during your time at our school. I say this often and will say it again today; I am so excited to collaborate with all of you when our paths cross in the professional world, because a degree from The University of Maine, to me, will always signify partnership and a high standard of excellence through teamwork that is so important in the competitive world today.

I wish you all luck as you take your next steps into the world. Perhaps that step is accepting your first job in your field! Or perhaps it is the next round of graduate education here, or at another institution. Or, perhaps you aren’t quite sure yet what that next step will be – don’t worry, we’ve all been there, and you’ll figure it out. As you all move forward in your different directions, I will leave you with one of my favorite quotes;

“There is no path to happiness; Happiness is the path.”

I hope you all find success in the paths that you choose, and that you are able to take a little of Maine with you along the way. Good luck, class of 2013! Ill see you out there soon.

EES Faculty Member to Receive 2013 Presidential Research and Creative Achievement Award

Dr. Francis Drummond

Four faculty members in physics, insect ecology, finance and computer science will receive the University of Maine’s top annual awards May 11 as part of Commencement activities on campus. Entomologist Frank Drummond has been a member of the UMaine community for a quarter-century. He is a professor in the School of Biology and Ecology, and University of Maine Cooperative Extension. The breadth of his career is reflected in his research interests that range from pollination ecology to insect pest management, and scientific techniques that span statistical modeling and computer simulation to molecular genetics. His research venues range from Maine’s blueberry and potato fields to Australian sugarcane plantations. Drummond has always worked in cooperative research with other researchers at UMaine and beyond. Today, his productivity and project diversity involves 60 research colleagues. Drummond has been the principal or co-principal investigator on more than $15.7 million in research funding. That funding includes USDA grants investigating the genetics of blueberry production and pollinator conservation to address colony collapse disorder in honeybees. Since joining the UMaine community, Drummond has been leading bee research, focused on their health, conservation and role as crop pollinators. As an applied entomologist, Drummond finds solutions to important agricultural insect problems, especially in Maine. One of his many successful efforts to help farmers manage the blueberry maggot fly, an effort that saved growers money and reduced the environmental impact of insecticide applications. With several UMaine colleagues, Drummond has researched and developed organic methods for blueberry production — the only complete organic insect pest management plan for wild blueberry production in North America. Drummond also created a model to predict the impact of human activity on streams, which became the basis for Maine law and informed national Environmental Protection Agency guidelines.

Abigail Sullivan selected for the 2013 Edith Patch Award

EES Masters Student Abigail Sullivan has been selected for the 2013 Edith Patch Award.  The Edith Patch Award is given each year to graduate and undergraduate women in acknowledgement of distinguished work they have done while at the University of Maine, and in recognition of their promise for future contribution to the fields of science, agriculture, engineering, or environmental education.  The awardees receive a small honorarium, and are invited to deliver a brief presentation about their work at the Annual Earth Day Reception in honor of Dr. Edith Marion Patch.  This year’s reception will be held on Sunday, April 21, 2013 from 3:00 to 5:00 p.m. at the Thomas Lynch University Club, on the second floor of Fogler Library.


Contact Information

Ecology & Environmental Sciences Graduate Program
246 Nutting Hall
Orono, ME 04469-5775
Phone: 207-581-3176 | Fax: 207-581-9225E-mail:
The University of Maine
Orono, Maine 04469
A Member of the University of Maine System