Wednesday, October 18, 2017

An autumn walk at Forest Hill Nature Area

The weather yesterday was absolutely beautiful.  After arriving home from work, we decided to head out to Forest Hill Nature Area for a walk.  Here are a few of the sights.

Tuesday, October 17, 2017

Fall Forest Ecology at Audubon Woods Preserve

Whenever I can, I like to get students out of the classroom and into local woods or wetlands.  Last Friday, I had the opportunity to meet Third, Fourth, and Fifth Grade students from Winn Elementary at the Chippewa Watershed Conservancy's Audubon Woods Preserve.

Winn Elementary students are no strangers to Audubon Woods.  Located only a few miles from the school, Audubon Woods is a great place for them to put science concepts into action.  For the the Third Graders, this was their first trip to Audubon Woods as a class; Fourth and Fifth Graders have made multiple trips the preserve, beginning in Third Grade.

It was homecoming for Shepherd Public Schools - that explains all the blue and yellow (including the hair)

Before the trip to Audubon Woods, I had visited each grade in the classroom at least once.  Third Grade began the year learning about trees - their parts and adaptations, how to age a tree and measure diameter, and learning to classify leaves.  My Fourth Grade presentation focused on plant adaptations and how plants use adaptations to overcome challenges.  The Fifth Grade program repeated much of the information from Third Grade, but with a deeper emphasis on adaptations and using growth ring patterns to analyze past growing conditions.

In the woods, the focus shift a little.  Here I ask all three groups of students to measure diameter of trees.  While in the classroom this was easy - students simply measured the distance across prepared slices of tree trunk (AKA "tree cookies").  In the woods this is not an option.  Instead students must measure the circumference (distance around) of the tree and divide that by pi (approx. 3.14) to find diameter.

Measuring circumference with a tape measure

For Third Grade students this can be quite a challenge.  They have to be able to measure the circumference with a tape measure, convert that that circumference from feet and inches to all inches, and finally use a calculator to divide by pi to find the diameter.  We do one tree as a whole group before the students measure two more trees on their own.

Calculating diameter

Fourth Graders should be able to do all of these things on their own.  Just as a refresher, we go over one tree as a group and then they measure three trees on their own.

Fifth Graders have already done this activity as Third and Fourth Graders.  They measure three trees on their own without a demonstration.  This might seem like overkill, but in the Spring when the students return, the Fifth Grade students will learn a shortcut to estimating diameter - the Biltmore Stick.  I just want them to have a firm understanding of how to calculate diameter before they learn the tricks to make it easier.

During this Fall visit, the classrooms have a very limited amount of time in the woods (about 1 hour to 1.25 hours for each class).  This means that they have a limited amount of work to accomplish.  For Third Graders, tree measurement and diameter calculation may take all of the available time.  If they finish this activity, they are also given the assignment of finding, drawing, identifying, and classifying leaves.  Most students do one or two leaves in the time allowed.  If time is short (as it was this time), Fourth Grade students are assigned the same work, but are expected to accomplish more.

Student drawing of an American Beech leaf

Fifth Grade students are given two additional activities to complete.  First they are asked to determine the total number of leaves to be found on the forest floor.  Audubon Woods is forty acres!  This seems impossible, but it is a much less daunting task if broken into parts.

Counting every leaf in one square foot section of forest

Instead of counting every leaf on the forest floor, students are asked to count the number of leaves in a single square foot of the forest.  This number is then multiplied by the number of square feet in an acre.  An acre measures 43,560 square feet.  Then that number is multiplied by the number of acres in the forest.

Using this method, six groups of students came up with estimates ranging from 179 million to 390 million leaves on the floor of Audubon Woods.  The average of the six groups was approximately 254 million leaves!

Once students have found an estimate of the number of leaves, they are then tasked with finding the weight of all the leaves on the forest floor.  This is accomplished by determining the average weight of a single leaf and multiplying by the number of leaves in the forest.

To find the weight of a single leaf, students count out 100 random leaves from the forest floor.  The leaves are placed in a plastic bag and weighed (in grams).  Next the weight of the bag (already known) is subtracted.  This number is then divided by 100 to find the average weight of an individual leaf.

Estimates for the weight of the leaves on the floor of Audubon Woods ranged from 100 thousand kilograms to 241 thousand kilograms with an average of approximately 138 thousand kilograms of leaves!  Converted to pounds this more than 304 thousand pounds.  (If you had the equivalent weight in $1 bills, you would have approximately $138 million dollars!)

Why are all of  these leaves important?  They provide the organic matter (humus) that is providing food and homes for billions of bacteria, fungi, and invertebrates such as insects.  These organisms break down the organic matter into forms that can be taken up by plants (including trees).  Essentially by releasing their leaves, the trees are providing food for themselves.

Here are a few more photographs from the day.

Monday, October 16, 2017

Upcoming Event - 2017 Mid-Michigan Rock Club Annual Show (04 - 05 NOV 2017)

On Saturday November 4th and Sunday November 5th, the Mid-Michigan Rock Club will be hosting its 24th Annual Rock Show at the Chippewa Nature Center at 400 S. Badour Rd, Midland MI.

The show is open 10:00AM to 5:00PM on Saturday (04 NOV) and 10:00AM to 4:00PM on Sunday (05 NOV).  Admission to the 2017 show is FREE!

While the show is being held at a new location this year, it actually represents a return to the past.  The first several Mid-Michigan Rock Club shows that I attended were held at the Chippewa Nature Center.  Over the past few years, the show has moved to a couple different locations, before returning back to the CNC for this 2017.

If you are a rock hound or an aspiring rock hound be sure to attend.  This is a great way to add to your collection.  In addition to the regular vendors, the Mid-Michigan Rock Club always has a selection of low-priced rock and mineral samples that can be used to build a beginner's rock collection.  Over the past several years we have constructed beginner rock kits for several nieces and nephews from rocks purchased at this sale.

Thursday, October 12, 2017

Earth Science Week 2017 - Thursday

Happy Earth Science Week 2017!

The Mississippi River is known as "The Father of Waters".  The name comes from the Algonquin language group and translates roughly as "large flowing water", "beyond age", or  "ancient father of waters" depending on the translation.  The Mississippi River and its tributaries form the fourth largest watershed in the world.  It drains an area of land from just north of the US-Canada border to the Gulf of Mexico and stretches from the Rocky Mountains in the west to the Appalachians in the east.

This summer we crossed the Mississippi River in two places.  The Great River Bridge connects Gulf Port, IL to Davenport, IA.  The bridge measures 1,245 feet at that point.  I don't have any photos of the bridge, but I did photograph the river from a nearby bluff.

The second place that we crossed the river was at Lake Itasca State Park, MN.  The lake is considered the headwaters of the Mississippi.  The experience of cross the river here is very different.

Here the river is shallow (and narrow) enough that it can be waded across in only a few steps.
From there the river winds through or past 10 states and drains parts of 31 states.

Wednesday, October 11, 2017

Earth Science Week 2017 - Wednesday (National Fossil Day™)

Happy Earth Science Week 2017!

Wednesday of Earth Science Week is celebrated as National Fossil Day™.  This summer, during our Out West vacation, we visited two large fossil sites the Mammoth Site of Hot Springs, SD and the Vore Buffalo Jump near Sundance, WY.

The Mammoth Site formed approximately 26,00 years ago when a sinkhole formed.  As the sinkhole filled with groundwater, it began to attract local wildlife (including mammoths).  Unfortunately for the mammoths, the sides of the sinkhole were steep and many mammoths fell into the shallow water where they were unable to escape.  Over time the sinkhole filled with sediment (and the remains of dead mammoths).  Overtime, the sediments surrounding the sinkhole eroded away and the former sinkhole was left behind as a hill!  This amazing site was discovered by accident in 1974 during excavation of a proposed housing development.  The importance of the discovery was recognized immediately.  Today the mammoth site remains an active paleontological dig with 61 separate mammoths being identified to date (along with other Ice Age fauna).

People in this photo give an idea of the scale of the site.
The arrows point out mammoth tracks in the sediment.
The goal at the Mammoth Site is to leave as many of the bones in place as possible.  On occasion some bones must be moved due to instability or the possibility of other more complete skeletons lying underneath them.  The site has a large overhead lift system to facilitate removal of bones when needed.

A mammoth skull wrapped in plaster for removal.

The fossils found at the Vore Buffalo Jump are much more recent than those of the Mammoth Site.  This site is also a sinkhole, but rather than accidental the deaths of the animals found here were intentional.  Over the course of 300 years (from about 1500AD - 1800AD) Native American tribes used the site to kill migrating bison by driving them over the edge of the sinkhole.  At least five different tribes used the location over time, as evidenced by stone projectile points found at the site.  While other buffalo jump sites have been located at cliffs, this is the only known use of a sinkhole for the purpose.  Less than 10% of the site has been excavated.

A building has been constructed over the active dig site at the bottom of the sinkhole.

The bones in the sinkhole are so jumbled that it is impossible to tell exactly how many buffalo died here.

What's with the ™ after National Fossil Day?  The National Park Service holds a trademark on the phrase National Fossil Day - while they allow use of the phrase, they do require that the trademark appear after the first use of the phrase in a document.

Tuesday, October 10, 2017

Earth Science Week 2017 - Tuesday

Happy Earth Science Week 2017!

Of the four disciplines included in earth science, geology is my favorite.  Mid-Michigan does not have many interesting geological features so whenever we go on vacation we try to see any unique features that are near our destination.  This summer our vacation took us west to North and South Dakota (and places in between).  I have already shared pictures of Custer State Park, Badlands National Park, and Devil's Tower National Monument.  Now I want to share a few pics from two other destinations.

First up is a feature known as "The Castles".  This limestone feature is found in the Custer National Forest  near Reva, SD.  It is listed as a National Natural Landmark by the National Park Service.

My favorite feature of these rocks is the tilted beds of limestone seen in the next image.  It's pretty amazing to think that these beds would have originally been deposited horizontally, then tilted, partially eroded, and then overlain with more horizontal layers of rock.


The next set of images comes from our visit to the South Unit of Theodore Roosevelt National Park near Medora, SD.  This unit of the park centers on an area known as the North Dakota Badlands.  While not as monumental as the Badlands of South Dakota, the scenery is still spectacular.