Catherine Henry

June 2023

My Journey to the Forest

Bailey Conservation Fellow Catherine Henry provides a snapshot of her science fellowship with The Nature Conservancy (TNC). 

When I started graduate school, I wanted to learn more about how forests work. How do plants and animals interact? Why do certain types of trees thrive in one area and not another? What plants indicate if a forest is healthy? More importantly, I wanted to learn how we could use what we know about forests to improve forest management—ensuring that future forests have many different species, offer food and shelter for animals and provide the timber products that we use in daily life.

Enter the Essel and Menakka Bailey Conservation Fellowship. This program, funded by Essel and Menakka Bailey, is designed to help develop the conservation leaders of tomorrow. Initiated in 2018, the program provides recent graduates and early career conservation professionals with the opportunity to work in a collaborative environment that combines a deep dive into a specific project with a broad introduction to major conservation issues.

For me, completing this science fellowship with TNC allowed me to continue my quest to learn about forests in order to improve their conservation and management. As my almost two-year fellowship comes to a close, I’m sharing my experience as a science fellow with TNC.

What exactly is a fellowship?

In graduate school, I received a Ph.D., also known as a doctoral degree. A Ph.D. program essentially trains you to become an expert in your area of research and to gain the tools to conduct research, which is all about asking questions and figuring out ways to answer them. While there are many career paths available following a Ph.D—including working as a professor, working in industry or for the government—many recent graduates enter a short-term position to receive further training or specialization to refine their skills, often to become a more competitive applicant for a position as a professor and researcher. These short-term positions are known as a post-doctoral (or post-doc) fellowship.

There are other fellowship opportunities at TNC for folks from all academic and work backgrounds—not all fellowships are for Ph.Ds! All fellowships at TNC are united by providing skills, training and experience for people looking to become involved in conservation. Check out this blog post, written by my colleague and former TNC fellow, to learn about other fellowship projects! 

What projects have I worked on?

While most post-docs are hosted by a professor or lab group at a university, a post-doctoral position with The Nature Conservancy is unique. In my almost two years at TNC, I was able to continue refining my skills as a researcher while also learning about the goals, needs and operations of a conservation nonprofit. I had opportunities to contribute to ongoing TNC projects, like our pilot implementation of the Family Forest Carbon Program in the Northwoods. I also spent time determining how to utilize national information collected by the U.S. Forest Service to further learn about forests.

Outside of my research projects, my time at TNC was enriched by working with and learning from colleagues supporting different aspects of our mission—from writing and human relations to government experts and field staff. I participated in staff enrichment days, conducted science outreach and worked on a team to improve staff wellbeing. My two years with TNC were full of opportunities for learning and growth.

What’s next for me?

One of the benefits of a fellowship at TNC is that, by diversifying my skill set, there are endless possibilities before me. In the fall, you can find me back in a university classroom, teaching students about forest management and sharing with them lessons I’ve learned from my fellowship at TNC. After that, the possibilities are endless, but I’m sure I’ll always find my way back to the woods.

December 2022

How do trees survive the winter?

In the winter months, Michigan is often blanketed in snow. While we all bundle up in layers of warm clothing, trees are relying on their own layers to protect themselves from the chill. 

“I’m freezing!” How often do you say or hear those words during a Michigan winter? While people have the comfort of retreating to a warm home, or animals to a protective nest or den, trees are rooted in place. How do trees survive the long, cold Michigan winter?

To answer that question, we need to first step inside of a tree to understand how trees grow and survive. Many people are familiar with naming the outer components of a tree—for example, bark, leaves, trunk, branches and twigs. But inside each tree are different layers, each with its own purpose.

Let’s move through a tree—from the outside in.

Outer bark: Think of this like a suit of armor. Bark protects the tree. This is the part you can see!

Inner bark: This is a thin layer responsible for moving tree food (called sap) throughout the tree. Hence, the need for a suit of armor!

Cambium: This is how a small tree becomes a big tree. This is the area which is actively growing—adding on new cells each year.

Sapwood (or xylem): This is how trees move water and minerals from the roots to the leaves. Leaves are thirsty!

Inner wood (or heartwood): The storage and structural support of the tree. This part of the tree doesn’t move any water or food.

How do trees not freeze?

In the late summer and early fall, shortening day length—which means less time to absorb energy from the sun—and cooling temperatures are a warning sign to trees of winter to come. Growing more slowly, they build smaller and smaller cambium cells. We call this “late wood” since it’s late in the growing season. This period of limited growth is known as early rest.

Eventually, low temperatures encourage trees to enter true dormancy or winter rest, and they totally stop their cambium growth. By stopping their growth and resting, trees can survive freezing temperatures and harsh winter conditions. Some dormant trees can withstand temperatures as low as -360˚ F! However, not all types of trees enter true dormancy, and some just stay in a version of early rest. Trees that enter true dormancy are considered hardier, or less sensitive, to the cold.

What happens after the winter rest? 

Though it may seem far off now, trees will soon be entering post-dormancy, or after rest, in the spring. During this time, growth begins again. And eventually, in the summer the cambium cells get bigger, forming what we call “early wood.”

When looked at with the human eye (often with the help of a microscope!), latewood (from the late summer/early fall) appears dark, and the earlywood appears light. This is why we can count tree rings for trees growing in parts of the world where cold temperatures in winter cause growth to slow down and stop once a year.

On some winter days, we might want to be like the trees—resting and hibernating. But other times, we may heed the quiet call of the winter woods with a hike, snowshoe or cross-country ski excursion among these hibernating giants. Check out one of our preserves for your next adventure in Michigan’s winter wonderland!

Sources:
Barnes, B.V., Zak, D.R., Denton, S.R., and Spurr, S.H. 1980. Forest Ecology. 4^th edition, New York: John Wiley & Sons, 1998.
Speer, James H. 2010. The Fundamentals of Tree Ring Research. Tuscon: The University of Arizona Press.

Catherine R. Henry, Michael B. Walters, Andrew O. Finley, Gary J. Roloff, Evan J. Farinosi (2021). Complex drivers of sugar maple (Acer saccharum) regeneration reveal challenges to long-term sustainability of managed northern hardwood forests. Forest Ecology and Management, 479 (0378-1127). https://doi.org/10.1016/j.foreco.2020.118541

Catherine Henry and Kate Carter (2021). Communicating Climate Change Content in Small and Mid-Sized Museums: Challenges and Opportunities. Journal of Museum Education, 46(3), 321-333. https://doi.org/10.1080/10598650.2021.1937791