campus ecology – Montessori Muddle

Dendrochronology with Bradford Pears

A slice out of the trunk of a Bradford Pear tree.

With the help of Scott Woodbury from the Shaw Nature Reserve, Dr. Sansone lead the effort to remove the six mature Bradford Pear trees from the front of the school over the last interim. We collected slices of each of the trees so students could do a little dendrological work with the tree rings.

The trees were planted as part of the original landscaping of the school campus. They’re pretty in the spring and fall, but are an aggressive invasive species.

The fast growth, however, make for wide growth rings. In fact, in addition to the annual rings, there are several millimeter wide sub rings that are probably related to specific weather events within the year. I’d like to see if we can co-relate some of the sub-ring data to the longer term instrumental record of the area.

The tree cutting was quite fun as well, despite being done on a cold day near the end of November. Students helped stack logs and organize branches along the road for the woodchipper. I learned how to use a chainsaw.

Six Bradford Pear tree slices, cut on November 25th, 2013.

Fall on Campus

Transit

This spring I was nominated by my head of school for a small, Teacher of Distinction award offered by the Independent Schools of St. Louis (ISSL). I proposed to get a survey transit that our students could use to map ecological change on campus. My outdoor group has been slowly cutting down the invasive Bradford pear saplings on the slope and I’ve been curious to see if mapping their locations would help us better understand where they’re coming from.

Measuring the distance down to the creek.

The transit would also be a great tool for math. Geometry, algebra, and pre-calculus classes could all benefit because surveying can require quite a bit of geometry and trigonometry.

View through the transit. The middle mark on the reticule allows you to measure elevation change, while the upper and lower marks are used to measure distance. There’s a 100:1 conversion from the distance between the upper and lower marks and the distance from the transit to the measuring rod.

So, I’ve started training a few of my outdoor group in making the measurements. They’ve spent a few weeks learning how to use the transit; we only meet once a week so it goes slowly. However, we’ll start trying to put marks on paper at our next class.

Life on the Hill

One of two turtles found on the slope above the school.

Last week, on one of our daily hiking trips up the slope for P.E., we came across two turtles. It was odd enough to find the first one on the way up the hill since they’re so well camouflaged against the brown leaves littering the floor of the forest.

The students wanted to take it with them, but since we’ve had a turtle in the lab this semester already I told them they should leave it there.

They left it on the ground and we continued on. It was only about 15 meters off the top of the ridge, so they wanted to stop by and see it again on our way back down. I bet them they couldn’t find it again, even though it had only been five minutes and turtles are known to be slow. They still couldn’t find it, but less than a minute later they found the second turtle on a different place.

It was quite a bit of fun looking for turtles in the forest. It occurred to me that it would be nice to have another objective on our hikes. So now, every time we go up the hill, we’re bringing a bunch of sample jars. Since I’ve been thinking about arthropoda lately our first few outings will be to collect insects and spiders on different parts of the slope to see if there’s an ecological difference due to the microclimatic differences.

Searching for bugs in an old, rotten log.

Bobcat?

Ms. Mertz believes she found some feline tracks in the soft sediment next to the puddles in the creek that may belong to a bobcat. Or maybe a large housecat. Unlike canine tracks — like dogs and coyotes — felines don’t leave claw marks in their tracks.

The Michigan DNR has a nice comparison of bobcat to other tracks, while the Missouri Dept. of Conservation has a nice reference of common animal tracks for the state.

Rotifers

Two students working on their campus ecology project were using the compound microscope to look at microbes associated with the leaf matter from the creek, and they found these two rotifers.

The one on the left was trying to suck in the two green protists, which generated a current that sent the protists into a circular loop.

Searching for Life in a Drying Creek

The puddles along the creek’s bed are getting smaller and smaller. Last week, Ms. Mertz’s class was out doing their ecological survey of the creek life lead by Ms. Currier. They still found lots of arthropods, frogs and some fish concentrated around the remaining puddles.

Wild Plums

I asked Scott Woodbury to give my Biology students another tour of their campus. The last time was for the Environmental Science class, with a focus on invasive species. This time we spent a little more time identifying species for students’ ecology projects; they each had to identify and research a species found on the campus.

One of the more interesting finds was a wild plum (Prunus americana) that we found on the slope at the boundary between the grassy/shrubby slope and the taller trees of the forest above.

The diverse ecosystems on the TFS campus -- from the creek to the grassy school grounds to the reforesting slope to the forested ridge -- are well shown in this diagram. — The plums tree was located up on the slope at the edge of the forest’s tree line.

The plums are edible. They’re supposed to be good for pies and sauces. The Shaw Nature Center finds that these tall shrubs/small trees are a good sellers at their plant sales.

Propagation from seed is apparently a little tricky. The best way is to process them through the digestive system of a coyote. Alternatively, you have to let them ferment for a while to break down the outer coating of the seeds.

They would be a nice, native addition to our orchard.