On Tuesday, October 12th, the second half of the seventh grade took a field trip to the Hammond Woods. This trip was originally scheduled for two days after the first trip, but heavy rains and scheduling conflicts postponed it by almost two weeks. The extended time between trips will allow the two groups of students to compare their experiences.
The weather for and leading up to each trip was markedly different. The conditions during the first trip were hot and damp, with temperatures near 80F and high humidity–more like mid-summer than late September. The second trip occurred on cooler day. The temperature was around 60F, and the start of autumn was evident in the woods. It had rained for several days before this trip, so the water level in the pond was higher and parts of the woods were flooded. The contrast in precipitation and temperature between the trips could provide interesting opportunities for the students to explore ecosystem change and feedbacks.
If asked to identify overarching themes for each trip, the first would be decomposition, due to humid weather and the abundance of fungus (and mold on the fugus!) observed in the woods. The second trip had a much greater focus on animal life, with many more animal sighting at each stop on the trip.
As it was later in the fall season, poison ivy was a lesser threat to the second group. Though beginning to turn, the vines and groundcover were still out in full force. I am still astounded at the size of some of the leaves. One tree in the parking lot was completely encased with poison ivy vines. Sue used this as an example of plant growing to maximize the amount of sunlight it receives.
Yellow poison ivy leaves
1. The Pond
The trees bordering the pond had begun to change color. The purple loosestrife that had been easily identified by its bright color during the last trip was now brown and dry. One student noticed a dead rodent when the group stopped to examine a willow tree. The great blue heron observed on the first trip was also still hunting in the pond, providing another good example of a vertebrate.
The Great Blue Heron
2. The Rock Wall
Near the rock wall, the students found a salamander under a rock.
Due to heavy rain during the few days leading up to the trip, the meadow was flooded. This allowed us to spend more time on the path to the meadow and to the valley. When Sue stopped near a Sassafras bush to have students ID the species and observe the three different leaf shapes on one plant, the observant also spotted an interesting organism feasting on the bush. “It’s a frog!” I heard one student exclaim. “No, it’s a snake!” said another. Looking where they were pointing, I realized it was a caterpillar (a spicebush swallowtail to be specific) with excellent mimicry that allowed it to resemble a snake head. This was probably the coolest thing we saw all day. The visual appearance of the caterpillar was truly astounding and it really captivated the students. I am sure when they cover defense mechanisms and mimicry, even if it isn’t until high school or college, this group will recall the caterpillar from Hammond Woods.
The spicebush swallowtail caterpillar feasting on Sassafras
As with the first trip, there were many interesting mushrooms that caught my eye. I am interested to see if the change in temperature and precipitation causes any differences in species observed between the two field trip dates.
Though the students knew what “moss” was, they had difficulty identifying differences between species (and they needed to find two different species to complete their individual data sheets!). Since we didn’t have time to ID moss species in the field, the students were told to use descriptive names that would help them identify the moss later in pictures. Many settled on things like “soft moss” for the carpet-like, low-to-the-ground types, or “spiky moss” for the taller, pointier species. I also captured some images of the moss’s reproductive structures that we can show the students when they discuss bryophytes in more detail.
Some carpet moss
Reproductive structures for spiky moss
We also looked at some interesting rocks. One area of the woods has rocks etched with a wave-like pattern. Further down the path, Sue pointed out a place where the puddingstone the students observed at the rock wall is overlaying a smooth type of rock. The students also noticed a cracked rock that reminded them of the puzzle rocks Jen Lamp studies in Antarctica. We took a picture to send to Dave and the team for more input.
Rock with wave-like pattern
Puddingstone on top of smooth rock
Puzzle rocks in Hammond Woods?
3. The Meadow
The meadow was too wet for the students to venture in as far as the previous group, and sitting down to sketch was out of the question. Sue had the students do a very quick drawing standing at the edge of the meadow, and I kept assuring the students I would take lots of pictures so we could identify species later on. A few of the students and I also had an interesting run-in with burrs that initiated a discussion about seed dispersal. Several species in the meadow had seeds with hooks on the ends that stuck to any fabric that brushed near, allowing the seeds to attach to animals (or people) and travel away from their parent plant .
4. The Valley
Despite the shift in seasons, the ecosystem in the valley, which is mainly comprised of conifers, did not change much between the trips. After a quick lunch, the students spent some time doing scale drawings on lichens. At this point in the previous trip, we were running out of time, so this activity was skipped. The students also had more time to work on their transect observations.
On the way out of the woods, several students stopped at the Sassafras bush again to see if the caterpillar was still there. It was, and they quickly realized that it had completely devoured the leaf it had been on not more than an hour before and was halfway through a neighboring leaf. A real life very hungry caterpillar!