Student Blog Series

Learn from student researchers in the Center for Tree Science as they share their new science communication skills in this student blog series.

Content Detail

Student researchers in the annual Research Experiences for Undergraduates (REU) program use trees as model systems to investigate questions related to evolution, ecology, conservation, and management in natural and built environments.

Individuals gain direct experience in all aspects of a research project, from researching the primary literature to sampling design, collecting and analyzing data, and presenting at a final symposium.

Learn about their projects and experiences first-hand in this Student Blog Series, launched in the summer of 2022.

Luis Alvarez

Summer 2022, Aurora University

 

“While in Nature or in the Lab, Something is Always Watching”

I was told if I waited for good weather to collect data in the field then I would never get it done. Very true, but what I wasn’t told was that “unfavorable weather” meant pouring rain that dropped the temperature low enough to see my breath in the dead of summer and a heat wave a few days later with a high of 98 degrees. Nevertheless, it was amazing.

While collecting roots out in The Morton Arboretum oak collection, the pouring rain made me feel like I was in the rainforest. It gave me a sense of peace and an adrenaline boost simultaneously. Collecting roots in the heat gave me a glance at the “squirrel war” in action.

These overlooked (and often pesky) creatures are just about everywhere you turn your head at the Arboretum. Growing up in this flat state, things like squirrels amaze me especially when I get too close and instead of running, they get defensive. The males were displaying more curiosity by inching closer to me while grasping to their branches as I tore roots out of the soil. It was also comforting to realize that I was not alone out in acres of meadow and towering trees.

From squirrels straight to the lab

The roots I collected are from oak trees that vary in size, and overall health. Oak trees remind many people of their childhood, often because they were planted in what are now older neighborhoods. Maybe you even threw a rope swing over one of their sky-scraping branches as a child just like I did. Oak trees have been declining in the Midwest and we are suspecting the decline is caused by a root rot disease called Phytophthora.

Due to changes in weather patterns, it is thought that there are better conditions in the environment for the Phytophthora disease than there is for our long-lived Oak trees. The lab is where the other half of my time is spent, testing to see if my samples have Phytophthora root rot or not. Yes, my samples… you take ownership of the data you collected because it was hard work (these are the only type of children I plan on ever having; samples).

The laboratory can be intimidating with all of its precise procedures and high-tech equipment. However, in a lab like this, you are also not alone… There are always pathogens growing in a dish somewhere, ginormous fungi sitting on the bench, diseased branches, ticks in tiny vials, or a random blue mud wasp crawling along the ceiling.

I am so glad to be able to say that I am supporting the recovery of the iconic oaks. As my immigrant parents would say, who would’ve thought that someone cares about a tree dying!

Norbaya Durr

Summer 2022, Elmhurst College

 

“Coexistence: Plants, Elements, and Ecosystems”

The first Jurassic Park (1993) movie’s adventure, suspense, comedy, and science transformed my sense of life and existence when I was kid. More than anything, it inspired my curiosity about what was, what is and what could be. In the movie, scientists conducted research, learned about prehistoric animal genomes, spliced genes, and reanimated Jurassic-era dinosaurs. Yet, prehistoric animals weren’t the only organisms brought back to the 20th Century.

Plants like ferns, cypress, ginkgos, and cycads (all of which still exist today and are present at The Morton Arboretum) were either brought back or utilized to recreate Jurrassic-era plant environments.

While just about all of science interests me, if I were a scientist in the first Jurassic Park movie, I might have needed a 100-foot radius of barbed-wire surrounding me in the field, but I’d study the plants…

Whis is what I do now as a budding scientist in the 21st Century (without the barbed wire, presently that is). I study plants and their interactions influenced by non-living (or abiotic) materials like elements, and living (or biotic) factors, like microorganisms, and how their development over evolutionary time (a very long time) contributes to how they function or grow, reproduce, survive and interact in their environments. Even more so, I study how their interactions impact ecosystem health, such as climate regulation and nutrient cycling, including within human societies. 

My summer 2022 research project is looking at differences in herbaceous plant elementomes (elemental makeup) and hyperaccumulation (high levels of metals in plants), their impacts on ecosystem nutrient balance, and if plant families or lineage relationships play an impactful role. The herbaceous ecosystem I study is called Ware Field, and it is an experimental prairie. My mentor is Dr. Meghan Midgley and I work in her Soils Ecology lab.

Plants like all organisms are made up of a mixture of elements that you probably remember learning about from the Periodic Table in school. Just as we humans drink water to stay hydrated, and eat food to gain nutrients to sustain and support our bodies, plants do the same thing.

In plant science, the elementome or specific combination of elements in plants not only allows for plants to be plants, but also contribute to the balance of nutrients and minerals in soil, air and water. 

Plant food is a combination of elements and molecules. Just like human food, plant food could also be low or high in nutrients, or be utilized in any other combination, including impacted by types of essential, and non-essential metals present in the soil, such as arsenic, lead, and chromium. Usually, arsenic, lead, and chromium are fatal to plants, but some plants are able to survive, grow and reproduce despite having high concentrations of toxic metals within their organs. 

Every Plant due to its genetics, evolutionary lineage, and ecological and physiological processes has distinct elemental makeups that coexist within plant organs (roots, leaves, stems), but may be altered and/or impacted by different elemental combinations within a particular environment. To get a better look at the elemental makeup of some of the Ware Field plants so that I can understand their nutrient needs and hyperaccumulation impact on growth and community assembly, and if there are elementome trends across their lineages, I first treated plant tissues with mechanical and chemical processes.

Angelina Harley

Summer 2022, Clemson University

“Pine Roots: A Battleground”

Today is harvest day! This means that within the span of a few hours, I will randomly select 8 Eastern White Pine saplings from each of my five treatment groups and remove their roots, stem, and fresh needles, and prep the samples for testing. After randomly selecting all of my saplings, I use a wagon to move them outside the greenhouse and begin the process of de-potting, washing, and cutting them.

Why am I breaking down these saplings? I will be studying how a tree defends its roots from different pests (such as insects or fungi). To do this, I treated 5 groups of White Pines with different elicitors. Elicitors are compounds that cause a plant to make a defense- it basically tricks the plant into thinking it is being attacked, causing the plant to make more things to protect itself. This research is important because it can lead to more efficient, as well as environmentally safe, insecticides and fungicides!

Immediately after the samples are harvested, they are stored in a cooler before being transported to a freezer.  I take the root samples and pour liquid nitrogen over them to freeze them and make them brittle and easier to grind. Then, I measure out different amounts into tubes and store them, as well as the extra ground-up roots, in the freezer.

These samples will be analyzed by separating different chemical compounds found in the roots based on how they react with the column in a machine. This process is called high-performance liquid chromatography. It is important because it will allow me to see if treating white pines with different elicitors will cause a generalized defense, or if each treatment causes a unique defense.

These roots have been frozen with liquid nitrogen, and are about to be ground up using the mortar and pestle.

Chloe Hendrikse

Summer 2022, Ohio University

Hello! My name is Chloe Hendrikse. I am a National Science Foundation Research Experiences for Undergraduates intern at The Morton Arboretum. This summer, each of the research interns in this program is responsible for their own research project contributing to tree science.  For my project, we are answering the question of whether the accuracy of the computer program STRUCTURE is consistent when identifying hybrids among different numbers of species.

Hybrids are created when two different species come together to create offspring. One common example is a liger which is a mix of a lion and tiger. My research will focus more on being applicable to plant hybrids: specifically oaks.

During the program, I have been most excited about applying my coding experience to research. It has been very challenging, but I am proud of how much I have been able to do and learn, especially figuring out how I best overcome challenges with coding which will be very helpful to apply in future projects.

This opportunity has helped me determine what I might enjoy doing for my career. I have been able to talk to a lot of people about different possibilities after I graduate, from applying to graduate school, to starting a career. I have always been interested in graduate school but had no idea of what I wanted to focus on. Through this internship, I have found an interest in genetics, and I now have an idea of what my next steps are.

If you want to keep up with my project and learn more, feel free to check out the Hoban Lab website and my project’s repository on Github.

Claire Henley

Summer 2022, Michigan State University

“Clones Take Over West Texas”

In the Caprock Escarpment of West Texas, there is a shrub, the Shinnery oak, Quercus havardii. While most oaks that come to mind are tall trees, the shinnery oak is actually a low-growing shrub. An interesting characteristic of this oak is that it grows as clones, with most of it existing underground and what we can see aboveground are actually “shoots” (leaves and stems) from just a single plant. The leaf shape and size is varied within the same clone and between different clones.

This summer I went to a town called Spur, in Texas to actually collect samples – or cuttings – of the shrubs. The goal of this summer is to get a fuller understanding of the differences within a clone and between other clones. To do this I have to take pictures of each leaf and branch clipping and run it through computer software. I have taken pictures of leaves and branches from last year.

The next step in this project is coming up with a plan for the fieldwork. Working with my mentors, Dr. Chuck Cannon and Sam Panock, we brainstormed our game plan for Texas. We need 3 samples from each clone and the clones we will collect from were chosen from Google Earth images. The IMSA, The Illinois Mathematics and Science Academy, and high school students Lily Song and Renya Duffy helped with this process.

Once in the field, we used a drone to fly over each clone to take a picture of it and find the center. The images taken by the drone are used to compare the Google Earth imagery (last updated in 2016 for the area) to what is currently out there. 

In addition to the actual physical collection of the shrub, we established a list of measurements that need to be recorded. In the field, we recorded the dieback, an estimate of how dead the tree is, of the shrubs and counted the stem density from three of these sampling sites. Our fieldwork happened in late June, so to prepare for this beforehand I was able to practice a basic version of the sampling methods on The Morton Arboretum grounds by finding some shrubs.

Now for the part I’ve been waiting for since I was told I was going to be a part of the program: fieldwork in Texas! Sam Panock and I flew down to Lubbock Texas June 21st. The first thing we noticed? The heat: it was 100 °F when we landed!

 

The hour-long drive from Lubbock to Spur was flat and farmland. Not what I was expecting to see at first based on Dr. Cannon’s description. But true to his word we turned a corner and suddenly valleys and canyons with exposed rock and beautiful red dirt. The following morning started at a crisp 5:30 a.m. and the real work began. We started to collect our samples and data and it turned out to be more than we anticipated.

Our original goal was to sample ten clones in one morning; we got to five before the heat became too much. That evening after it cooled off, we went out and sampled two more clones. On Thursday, we were joined by Dr. Antonio Castilla, who is a faculty member at Midwestern State University, studying the genetics of Shinnery oaks. His joining helped out a lot with cutting down time; and for pushing the truck when it got stuck in the sand!

By the end of the fieldwork, we collected three physical samples and recorded data from 23 individual clones, leaving me with 69 samples and data sets to process the rest of the summer.

When not in the field, I pressed the samples collected in a plant press and removed a few leaves from each sample for Dr. Castilla to use for genetic material later in his research. In the coming weeks, I will continue to analyze the data and begin to piece together what all this variation means. Is it a byproduct of historical hybridization with other oaks? Or is it related to the drought response of the individual clone? I was able to gain so much knowledge and understanding of the scientific process from my mentors, Dr. Cannon and Sam Panock, and our additional partner Dr. Castilla.

 

Jorge Jaime-Rivera

Summer 2022, University of Miami

“What Happens Underneath Prairie Plants?”

Prairies are a very important part of the natural world, one of the reasons is that they provide habitat for a wide variety of plants and animals. Unfortunately, most of the prairies in North America have been disturbed or destroyed by urbanization and agriculture. The prairies that are still left undisturbed, to the best extent possible, are called remnant prairies. 

In order to better understand these threatened ecosystems, researchers at The Morton Arboretum in Lisle, IL started an experimental prairie on the west side of the campus. Throughout the years, they have learned a lot about what happens above the ground on a prairie, ranging from what characteristics of a plant are predictors of how well it can survive – such as plant height, or their growth form – to how the biodiversity impacts their surroundings. You can read more about this experiment here.

However, not a lot of data has been collected on the plant’s roots, since they are underground and hard to study. As I am working in a soil ecology lab, if we want to see how plants impact the soil, we need to look at the part of the plant that interacts with the soil the most: roots. This is where my project enters the pictures! We have over 100 species of plants at our experimental prairie and 5 pots of each species were grown in a greenhouse. Emma Leavens and Dr. Meghan Midgley, along with many volunteers, took care of the plants throughout the entire last summer so that I could come in and “destructively harvest” them. 

Destructive harvesting involves taking the plants out of the pots, rinsing the sand off the roots, and separating the roots from the rest of the plant. Once the roots are separate and clean, I put them through a scanner that uses a software called “WinRhizo” to measure traits such as the average diameter of the roots, the total length of the roots, and the volume of the roots.

Now that I am done with all of the scanning, I am going through the data and analyzing it to see what trends and patterns I can find within it, and what trade-offs exist among the different traits that I measured. For example, we expect that there will be a trade-off between the diameter of roots and their length. This means that some plants such as grasses will have longer thinner roots to acquire nutrients and resources themselves, while other plants will have thicker roots to make room for beneficial fungi that help them retrieve nutrients from the soil. If we can better understand the relationships among root traits, we can strategically plant our species in our prairie restoration experiment to ensure that they survive, thrive, and reproduce. Through this better understanding, we can also help remediate our prairie soils to restore the nutrients that have been lost over time, making better habitats for important animals.

 

Ian Lauderback

Summer 2022, University of Tennessee

“The Daily Grind”

Today I spent the entire 100 Fahrenheit degree day outside sanding and grinding down slices of trees. This may sound kinda crazy, and I definitely felt a little crazy at times, but the reason why I’m doing it is actually really cool.

These tree slices, or tree cookies (which is a really great and fun term), are samples of Green Ash trees that have been injected with a type of insecticide to help protect them from Emerald Ash Borer, or EAB for short. Emerald Ash Borers are an invasive beetle species that arrived in the US in the early 2000s and quickly began killing our nation’s Ash trees. Luckily, a treatment was created that in most cases was able to prevent infestations in trees. The treatment, involves several injections of insecticide that would have to be put into the tree and repeated every three years.

Unfortunately, while it prevents the tree from being damaged from the EAB, not everything about the treatment is great. The constant, repeated injections into the trees actually have a large effect on the tree’s insides. This brings me back to why I was outside sanding tree cookies in 100 degree weather – the research that I am doing is examining how the injections affect the tree and whether or not they weaken it. I do this by sanding down the cookies and then taking pictures of them so that I can better analyze the change in size and location of the discolored areas. Hopefully, this will lead to a better understanding of how injections affect trees and will help us preserve Ash trees even longer into the future.

Today I spent a rare full day inside working on my computer. While it was really great to finally get out of the heat, today served a much more important purpose for me, the gathering of data. I spent the day looking at images of my Ash tree cookies, and using the imaging software ImageJ, to measure the surface area of the xylem (the woody parts of the cookies), the discolored areas of the cookie including the false heartwood, and the discolored areas of the cookie not including the false heartwood. The metrics will allow us to see how the discoloration changes both tree to tree, as well as how the discoloration spreads up a tree. 

These images and the data collected from them were only possible to obtain, because of all the previous work I did outside sanding and planing the cookies. After sanding, I added odorless mineral spirits to the cookies before imaging in order to obtain higher-quality pictures.

Marshall McCall

Summer 2022, Emory University

“Rooting Around the Morton Arboretum”

Walking through The Morton Arboretum is an exciting stimulation of the senses. If you love trees as much as I do, then you will probably love observing the variety of tree species the arboretum has to offer with leaves, bark, and shapes of all sorts.

Spending time working in the soil ecology lab with Dr. Meghan Midgley however, has brought my attention to what is happening beneath the surface of what we regularly observe when walking through the forest. It turns out, that there is just as much exciting variation and activity happening below ground as there is above ground, and we’re only beginning to understand the extent of it!     

In order to get the nutrients they need to survive, trees have huge root systems which branch out into the soil searching for things like the elements Nitrogen and Phosphorus. It turns out that these tree roots alone aren’t able to find as many nutrients as the tree needs though. In order to absorb the hard-to-get nutrients, tree roots can actually “pay” tiny organisms in the soil to make the nutrients available by releasing carbon-based compounds that these organisms can eat. Trees may also exude chemicals that are used to release nutrients from soil minerals or even to communicate with other tree roots! The compounds that trees push out through their roots are called “exudates” and that is what I am studying. 

I hope to uncover the differences in root exudation between different tree species. In particular, we hope to understand which root traits, such as size and shape, actually drive trees to release these different amounts of carbon in order to “pay” their partner organisms. Hopefully, with this knowledge, scientists can better predict how much carbon trees are putting into the world’s soils in the face of atmospheric change. To do this, we are taking samples from all sorts of trees: evergreens (keep their leaves all year long), deciduous (drop their leaves in the fall), long roots, short roots, etc. With such a huge number of interconnected variables and traits to measure, it will be important to disentangle the relationships between them.

In order to collect data on root exudates, I spend a lot of hands-on time working with tree roots. One of my favorite things about my experience so far is the ability to spend some days in the beautiful forest digging for tree roots, and other days in the mosquito-free lab analyzing the root samples and observing each species’ unique traits. As most people, I never spent much time looking at tree roots before this research project, but after spending hours unearthing, cleaning, and scanning them, I am beginning to recognize that each tree species has completely different shapes, colors, and textures of roots. I’m even starting to have favorite types of roots (mine is pawpaw).

Kelsey Patrick

Summer 2022, Aurora University

“Getting to the Root of It: Four Seasons at the Morton Arboretum”

Why we study roots

For the health of our planet and all it supports, connecting and learning about the environment is important (and exciting)! Scientists and the public are working harder than ever to strengthen that connection and address issues such as climate change, deforestation, loss of biodiversity, and more.

Plants, as the backbone of ecosystems, are a common focus of this work, but much of the story involving environmental processes remains an underground mystery. Roots perform vital ecosystem functions by regulating water and nutrient cycles. The smallest roots in a plant’s root system (known as “fine” roots), are not only controlling the individual plant’s water uptake, but also how much water that plant puts back into the soil and atmosphere.

Who knew the rain falling on our heads could be coming from a leaky root? A similar story can be told regarding root influence on ecosystem nutrient cycling. Carbon and nitrogen fluctuations in the soil and atmosphere are largely driven by roots. To uncover how roots grow, interact, and influence the world around us, our Root Biology lab at The Morton Arboretum uses the following tools:

Minirhizotron scanners  
Using this tool, we can see how roots grow and die over time. Plastic tubes are placed in permanent locations within our forestry plots, allowing us to scan the same area at four different depths.

Sap flow meters
This tool uses temperature change to measure sap movement up the tree.We can observe when water uptake and flow fluctuates depending on tree species, season, temperature, and precipitation.

Dendrometers
Did you know that the trunk of a tree expands and contrasts everyday? With the help of dendrometers, we can track these daily changes in tree diameter as well as the growth over longer periods of time.

Phenocams
By tracking leaf greenness throughout the season in our forestry plots with cameras, we can see how species differ in leaf emergence timing. The root lab has been matching this leaf data with minirhizotron scans for three years now to compare when leaf growth and root growth occurs.

Respiration measurements
Beginning this past spring, we have started taking respiration measurements in some of our forestry plots. The chamber seen in the picture to the right is placed on a column on top of the soil. This allows us to measure the CO2 emissions of roots, mycorrhizal fungi, and soil microbes.

What will I be doing? Drowning Trees.
Over the next year I will be helping out with data collection and maintenance of all of the above … but wait, there’s more! Trees in many regions, especially urban settings, experience frequent flooding events. During and after heavy rainfall, the soil can become saturated with water (i.e. waterlogged). This leads to low oxygen levels in the soil. Roots need oxygen to “breathe,” just like us. So you can imagine that these conditions present many problems to trees.

Metabolism, growth, water flow, and filtration of toxic compounds are just a few of the main plant functions impacted by waterlogged soils. To study the responses of tree roots to flooding, my primary project will track root growth, death, tissue stress levels, and photosynthesis of four different tree species before and after a 2-week waterlogging period.

Using a root-lab invention coined the “rhizo-pot”, we will be able to view the root systems of two maple species and two magnolia species through clear windows. In addition to tracing the roots, we will also be taking images, photosynthesis measurements, and running tissue analysis to get an idea of what is going on inside of the tree.

How does root response influence tree survival and recovery from flooding events? Do roots have specific strategies to deal with flooding? Uncovering the answers to the above questions is critical for understanding what is going on belowground. In the coming years, flooding events are projected to increase in frequency and magnitude in many regions (Christensen et al. 2007). We can start to address this issue before we are in too deep!

Josephine Schall

Summer 2022, University of Chicago

“What you can do for Trees”

 Trees are important to humanity and the planet, now more than ever. They can cool our cities, reduce air pollution, and improve our physical, mental, and social well-being. You can help protect trees—all you need is your phone. Using free apps, you can record the condition of trees. With the information you gather, tree scientists can determine how to best care for trees in your community.

One of these apps, Healthy Trees, Healthy Cities, was developed by the U.S. Forest Service and The Nature Conservancy with this goal in mind. The app allows users to perform a variety of tasks, such as recording basic tree information like species and size as well as conducting a health check.

Part of my internship at The Morton Arboretum this summer is using this app to determine the health of trees in the Gateway to Tree Science exhibit. This exhibit shows the challenges urban trees face including pests, soil quality, and improper pruning.

Trees in the exhibit are treated differently to determine how the treatments affect tree health; for example, part of the exhibit shows trees planted in different soil types like clay, soil compacted under concrete, and loose soil. I use the Healthy Trees, Healthy Cities app to check each tree’s health.

When I check a tree, I look at how many twigs are missing leaves, how many of the leaves are discolored, how many of the leaves have holes or are torn, how many large branches appear dead, and how much sky can be seen through the tree’s crown.

Each of these variables can indicate how healthy a tree is. I input each separately, and the app calculates an overall “Stress Index” number for the tree. That number is recorded in a spreadsheet that tree health experts can download and view. Using the locations of trees included in the spreadsheet, they can find and check in on trees facing greater stress.

By entering information on a tree, you can help it receive proper care. Trees are everywhere, and tree scientists need help monitoring them all. From your observations, tree scientists can determine how different trees are faring and which need the most attention due to pests and other stressors. You have the power to protect trees!

 

Madelyn Thompson

Summer 2022, Samford University

“The Mysterious Case of Sugar Maple Leaf Shape”

What comes to mind when you think of sugar maples? Maybe you imagine tasty maple syrup. Does the leaf on the Canadian flag come to mind? Perhaps you picture their beautiful fall foliage. All these images of sugar maples show how iconic these trees are.

As a young scientist doing research, I get to spend my summer looking at their leaves. “Why?” you may ask, “Wouldn’t such important trees already be well studied?” 

The answer, surprisingly, is no. There is still a lot that scientists don’t know about sugar maples, especially about their taxonomy. Taxonomy is the study of naming and classifying living things into groups and is the backbone of our understanding of the natural world. It helps us understand the diversity that exists in the world and gives us a way to refer to groups that we see are different from each other. Right now, sugar maple taxonomy is a mess. Scientists don’t know how to classify them. They don’t know if the differences they see in the trees mean that there are many species of sugar maple or just one species with lots of variation. 

Look at these two specimens. Can you tell a difference in the shape of their leaves? 

 Dried twigs with leaves from herbarium specimens of two different types of sugar maples. Herbaria, where botanists store dried plant collections, are important sources of information for scientists, such as records of historical plant distributions and a wealth of genetic information. 

No worries if you can’t. Even trained botanists have a hard time consistently distinguishing them by shape alone. Even though I’ve looked at hundreds of sugar maple leaves so far this summer, I also struggle to identify them. Believe it or not, these branches are classified as two different subspecies of sugar maple. A subspecies is a way to group organisms when differences occur within one species. If they really are subspecies, we should find the ways they look different so we can identify them properly. 

That’s where I come in. My research is to determine if these leaves really are distinct in terms of their shape, and I’m doing that by selecting points on hundreds of leaves and seeing if the computer can detect differences that humans can’t see. 

 Not everything I’ve done this summer has involved looking at leaves digitally and programming the computer to analyze my data. I also got to travel back to my home state, Alabama, to do fieldwork. While I was there, I got to spend my days in the forest collecting leaves from the two different kinds of sugar maples that I’m researching. The collecting involved an 18-foot-tall pole pruner to cut high branches, newspaper to hold the leaves, a field press to temporarily flatten the leaves so they can one day become dried herbarium specimens, and lots and lots of bug spray. High-tech, I know! (Check out Claire’s blog post if you want to hear about other kinds of cool tech in botany fieldwork. P.S. it has to do with drones!) 

Having my office in the woods for a few weeks was fun. I got to do some bird watching, or perhaps I should say bird listening since the foliage was so dense that spotting the birds was difficult. I also got to explore the wildflowers, amphibians, insects, and landforms of the area, including a cave! 

So, after all this work, what does this research really mean? Clearing up the taxonomy and classification of this group is important because it is the foundation that is needed to do further research to understand the world around us. As it stands right now, a scientist will not be able to tackle a project on sugar maples, especially those in the midwest and southern US, because of the confusion about exactly what entity we’re dealing with.

Once the taxonomy is settled, the next steps of research could be ecological, practical, economical, and more: determining why there are variations in sugar maples across the geographic region where these trees occur, learning to accurately identify them in midwestern and southern forests, or even helping the maple syrup industry. But none of this could be done without first defining exactly what we’re looking at. As for you, this opens up a whole world of complexity and mystery in a common tree. Now, when you look at a sugar maple, you know that there’s more than meets the eye. 

Isabella Vergara

Summer 2022, Grinnell College

“Listening to the Breath of the Earth”

Brittle leaves and branches crunch and crackle underfoot as I wander through paths that I can barely make out as they resist the surge of understory growth grappling for the dappled rays of sun. Birds converse in the White Oaks above me, insects buzz by my ears, investigating me and my heavy yellow box, wondering at the thick cloud of citrus and eucalyptus bug spray that I’ve saturated my clothes with. I slap away a few mosquitos hoping to grab a quick snack on my arm. A frustrated redwing blackbird shouts expletives at me from a nearby branch, as I insist that I’ll only be in his territory for just a few more minutes.

As I set my heavy equipment down, I take a moment to breathe in the moist and sweet scent of decaying leaves. If I listen carefully, below the chatter and motion of insects and animals, I can hear the sounds of the trees. The wind tousles the knee-high blades of grass and brushes against waxy oak leaves that move in the wind like open palms, feeling the direction of the breeze. I imagine the sound of the quiet movement of water flowing from deep beneath the dark earth and evaporating from the surfaces of crisp green leaves and from scaly pine needles. As the water is released from the plant leaves and needles, so too, is the oxygen you inhale and the carbon dioxide you exhale.

We can’t hear it, but the forest is breathing. Each plant, each insect, each bird is releasing CO2 into the air. Even the things we can’t see are breathing. Beneath my muddy hiking boots are endless meters of roots and fungi, entangled with vast quantities of soil microbes that all weave themselves together to make the soil a rich and nourishing place to live. To make the soil community as wonderful as it can possibly be, each soil component has their own neighborly responsibility to the soil community.

Tree roots and fungi are tight-knit friends; the tree roots give fungi their carbon, and in exchange, the fungi give them soil nutrients that they wouldn’t normally have access to. These nutrients wouldn’t be easily available to the trees and other organisms without free-living microbes and fungi that release specialized digestive juices to break down leaf and organic matter into bite-sized bits of carbon and nitrogen that everyone in the soil neighborhood can enjoy.

Without these soil communities, nothing would be able to access the nutrients to be able to grow and support aboveground ecosystems. Despite the vital role of these underground networks, little is known about how they function within different ecosystems. My research works to tease apart the strands that make the fabric of the soil community.

Every Wednesday morning, I drive a little golf cart to different plots around the Arboretum. White Oak, Quercus bicolor, Ohio Buckeye, Aesulus glabra, Sugar Maple, Acer saccharum, Norway Spruce, Picea abies. Trees that look familiar to me, but the Latin names feel unfamiliar on my tongue.

From the bed of the golf cart, I haul my yellow IRGA, a device used to measure the rate of soil respiration, or how much the earth is breathing. I look for red plastic tags that peek out over the thick understory growth that mark where I should measure respiration. Each tag is placed next to a white PVC pipe buried deep in the ground. We have four types of PVC pipes, each lined with different sizes of mesh, which separate the respiration of each member of the soil community; roots, fungi, and free-living microbes.

By measuring the respiration rate of different components of the soil community each week, we hope to be able to pull apart the threads of the soil community network to understand how much each component contributes to overall soil respiration. After several months of these weekly measurements, we will determine how soil respiration changes as the trees turn to bright reds, oranges, and yellows, or when they drop their leaves for winter, or when they bud with fresh, tender leaves, or when they are soaked with summer rain.

Since we are measuring respiration at plots dominated by different tree species, we hope to be able to understand how these underground relationships are affected by the tree species that provide the essential carbon nutrients to other soil community members. I am excited to be able to determine how the puzzle pieces of root, fungi, and free-living microbes fit together in the ever-changing landscapes of forests so we can further appreciate their immense service to our ecosystems.