Megan E. Leach, MFC Curriculum Coordinator
There's nothing more satisfying to me than finding an answer to a question. This past fall I was finally able to answer a question that had been bugging me for over a year.
PART 1: THE OBSERVATION
Last fall (2018), as I was walking in the woods, I noticed that many of the yellow leaves on the ground had a single leftover green stripe. "Curious", I thought to myself and went along with my walk, snapping pictures of my dogs as we went. The next walk we took was in a completely different part of town and the same pattern was strewn across the ground. "More curious", was the thought in my head this time, so I grabbed a handful of the green striped leaves to photograph at home. The pattern was striking against my dark table and a fun art project but I kept my observation to myself and gave it no further thought after my photography session.
PART 2: THE QUESTION
Flash forward to this fall (2019). I'm out on one of my regular walks and I notice the yellow leaves with the green stripe AGAIN! The discovery now became an obsession and something I must share with my community (Instagram in this case; pictured right), so I took as many photographs as I possibly could and made a collage. I wanted to convey the sheer number of leaves with this same pattern. I posted the picture and the likes and comments started to trickle in. One of my friends made the comment "Is it because they are clones?? This is so cool.". After some thought, I replied "I don't think so. It's all over the woods and dirt roads." but it was too late I had to investigate this suggestion.
PART 3: THE RESEARCH
I began my research by looking up general information about aspen trees (scientific name: Populus tremuloides, also called quaking aspen or poplar). This took me to websites like Wikipedia, The National Forest Foundation, and the US Forest Service page about aspen. I learned that aspen trees are early colonizers and do very well with sunshine and moist soils. They reproduce by BOTH sexual reproduction and through vegetative growth of shoots from lateral roots on a tree. An aspen clone can be somewhat small or up to 100 acres in size. The largest aspen clone, called the Pando Clone, is located in Utah's Fishlake National Forest and covers an area larger than 100 acres!
My walks are separated by 10 miles, which means the aspen clone in Jackman, Maine beats the largest known clone by hundreds of acres OR maybe there are a bunch of clones all spaced out that still produce the same leaf pattern in the fall...I still don't really have my answer. I decided to go straight to an expert so I used google scholar to look up the most recent research on aspen clones. This led me to a scientist named Dr. Jeff Mitton, a professor at The University of Colorado in Boulder, who I emailed with an explanation of my discovery and question. He promptly emailed me back and explained that it is a possibility that I could be looking at leaves from a clone but it would be an enormous clone. It is also less likely for aspens to grow as clones on the east coast because our soil moisture is high making it a perfect habitat for seed germination. In the spring I could measure bark color, lower branch angles, bark flecking, and look at the catkins to see whether they are all the same gender (aspens grow as either male or female trees, some other plant species grow with both reproductive organs). I was now ready for a 5-6 month wait to take my measurements!
PART 4: THE ANSWER
It turns out that I didn't have to wait 5-6 months to find my answer. I was browsing through Facebook, something that I do fairly regularly, and one of the pages that I follow shared a blog post about "Green Islands". The cover picture showed a fall aspen leaf with green stripes. I became ecstatic and immediately clicked on the post to read it. It turns out that there are extremely tiny organisms called leaf miners. These minuscule animals can fit between the tough outer layers of leaf tissue to feed on the soft inner leaf tissue. You can see the evidence of a leaf miner infestation as little trails of missing color on leaves. Some leaf miners live their lives with bacteria that prevent chlorophyll from breaking down. In the fall, this is great because the leaf miners can continue to eat the green, chlorophyll filled, leaf tissue while the chlorophyll in the rest of the leaf breaks down to reveal the beautiful colors of the compounds so characteristic to this time of year. PHEW. The leaf miners are a larval stage of a moth, so they will eventually pupate and emerge as an adult moth. I had to see these little creatures myself and with the evidence all around me I grabbed a few leaves and sure enough, at the corner of every green strip was a brown area where the larva lived. When I cracked the area open I could see a clear larva wriggling around. CASE CLOSED...now I can just imagine the number of leaf miners that surround me every fall, living with their symbiotic bacteria and munching away on chlorophyll that hasn't yet decayed. Oh, the questions that I have to answer now...
PART 5: INQUIRY IN THE CLASSROOM
My experience this fall was a best-case scenario example of student-centered or inquiry-based learning. As you read through my experience you can get a sense of all of the standards or content that students could learn as they go through the discovery process. NGSS life science standards from elementary through high school fit beautifully into this experience and it was right in my "backyard". If you live in Maine and have aspen trees near your school I highly recommend looking for this organism in the fall. It's a perfect blend of outdoor education, classroom discovery and brings students through the scientific method.
Unfortunately, many classrooms aren't structured to foster this type of learning experience. As teachers we have standards that we must meet and we have deadlines. This means we must move through the material and we can't necessarily wait for students to go through this learning process to teach the content. You have a few options to still incorporate student-centered learning in your classroom. You could have students complete a semester or year-long project, have students work through inquiry labs at the beginning of each unit that you teach, or embed inquiry-based labs or projects in each unit. Do what fits your classroom and your schedule. Here are a few lessons from my experience that can help your student be successful.
A. Social Observations/Communication
You may have noticed that by myself I wouldn't have moved so smoothly or quickly through the discovery process. I questioned what was going on and thought it was amazing but I was stuck. Everyone gets stuck. I have an undergraduate degree in botany and a master's degree in ecology and I still get stuck. Have you ever watch a game show where the contestant is asked to name five things in a certain category? You, the viewer, can name these in no time but for some reason, the contestant puts out one answer and then freezes. The pressure and excitement are so great that nothing comes out of their brain and they lose. This is similar to a classroom setting in some ways which is why group questions and observations are so important. Students can still work independently but should come together every once in a while to share out for student feedback. This process gets students more practice with sharing or presenting to classmates, listening thoughtfully, and giving/receiving constructive feedback.
B. Healthy Use Of Social Media
I, like many of us, grapple with my use of social media. Over the past few years, I've slowly unfollowed my friends and family on Facebook and increased the number of science, history, math (yes math) and culture pages that I follow. It's an amazing way to get a wide variety of news and information when used correctly. I would never have found the "Green Islands" blog post if I hadn't followed In Defense of Plants. As teachers, you're in a unique position to teach students how to judge articles and websites that they incorporate in their learning. Now, more than ever this needed. This is sometimes hard to do because schools are increasingly blocking Facebook and other social media websites. Students can always follow pages on their own time and show you the digital proof or the articles. Podcasts are also an excellent source of scientific information.
C. Contacting Specialists
As a teacher, you are really busy. You often don't have the time to teach a lesson, manage a classroom, grade and monitor students, and on top of that bring in classroom visitors or specialists in the field. The good news is that you don't have to! Students are more than capable of reaching out to professionals themselves and professionals, more often than not, are happy to help. Students may need a brief introduction to professional emails or phone call etiquette but this lesson in itself is a skill that will take them miles beyond the classroom. As students reach out to professionals you can build a network for your classroom, another huge benefit.
If you need help incorporating inquiry or project-based learning experiences into your science classroom there are some really great tools here in Maine. Here at Rural Aspirations, we are always excited to talk with teachers. Please reach out to us to get more information. Project Learning Tree provides teachers with nature-based based learning experiences and they even provide teacher training in the summer months. Project WILD is provided by Maine Inland Fisheries and Wildlife, with teacher trainings also available. If you know of any other curriculum supplements or materials please leave them in the comments. We'd love to hear from you!