Vernal: A Spring Photo Project (Day 61 through Day 70)

To this point I've shared two months worth of spring photographs.  As of today (June 21st) spring has reached its end, but I have a months worth of photographs still to share.  Here are the photos from day 61 through day 70.  To see the previous set of images follow this link.

Day 61 (19 May 2019) - Plum flowers

We have a plum tree right outside our back door.  It rarely produces much fruit, but every spring it is absolutely covered with blossoms.  I photographed these flowers after a light rain covered everything with water and softened the light.

Day 62 (20 May 2019) - Audubon Woods Creek

Another rainy day.  This image was taken in a light drizzle at the Chippewa Watershed Conservancy's Audubon Woods Preserve.  The CWC owns 23 separate properties, but Audubon Woods is my favorite because of the mature trees.  The center of the preserve can often feel ten degrees cooler than the edge.  The water trickling over these rocks helps add moisture to the air cooling it even further.  Even the color of the woods feels cool as the mist in the air diffuses the light making everything glow green as the sunlight penetrates the forest canopy.

Day 63 (21 May 2019) - Dandelions 

Spring wouldn't be spring without dandelions.  Homeowners may not love them, but the bees and other pollinators do.  Some people are taking notice - the Ziibiwing Center of Anishinabe Culture has adopted the policy of not mowing until the dandelions have gone to seed.  I photographed this dandelion bloom in the lawn at the Isabella Conservation District office.

Day 64 (22 May 2019) - Forest Ecology Studies 

Most of the programs that I do are in the classroom out of necessity, but every year I take students from Winn Elementary out to Audubon Woods to explore forestry and forest ecology.  In this photograph the students are measuring the distance from a stake (representing the center a 0.1 acre plot) to a tree in their study plot.  If the tree is within 37 feet of the stake (the radius of a 0.1 acre plot), they will then get an azimuth to the tree, measure the diameter of the tree, and record all of this date on a map of their plot.  I keep copies of all this date in the hope that it can be used to record changes in the forest over time.

Day 65 (23 May 2019) - Look up...

May 23rd was another day of forest ecology studies at Audubon Woods.  I think actually took more photographs of students on this day than I did on the 22nd, but my favorite photo of the day was taken when the students had gone back to school for lunch.  Looking up, I spotted this combination of blue sky, white clouds, dark branches, and yellow-green leaves.  With the sun lighting up the edge of a cloud formation I couldn't resist this photograph.

Day 66 (24 May 2019) - Honey Locust Thorn 

This photograph was taken right outside my back door.  We have a large honey locust (Gleditsia triacanthos) growing only a few feet from the house.  This tree provides lots of shade in the summer and a home for many species of birds and insects (not to mention squirrels).  The most interesting thing about the tree is the large thorns that grow from a few branches.  The honey locust originally developed these thorns as defense against ice age mammals - now they are just a reminder of a time when elephants walked the tundra and forests of North America.

Day 67 (25 May 2019) - Fern Frond 

Another photograph from home.  This fern covered with a layer of fine spider webs was photographed in the garden on the side of the house.  This image has been cropped to a square from its original format.

Day 68 (26 May 2019) - Home, Sweet Home

On May 26th we drove about forty-five minutes from home to visit my parents near Laingsburg, MI.  At one point I took a few minutes to walk around their property looking for something to photograph.  As I walked past this nesting box in a wooded area, a wren popped its head out of the box.  It's not grand architecture, but it's good enough for a wren.  If you look close you can see the wren's toes gripping the entrance hole.  The bird looked at me for a few seconds and then flew off into the underbrush.

Day 69 (27 May 2019) - Iris

When we moved into our house eight years ago there was already a patch of irises planted on the south side of the house.  I think these are Siberian iris, but am not certain.  I love the nectar guides on each large landing pad of a petal directing pollinators toward the nectar (and pollen).  The large serrated leaves in the background belong to cut-leaved coneflower (Rudbeckia laciniata).

Day 70 (28 May 2019) - Wild Columbine 

My final image from this set of photos was taken at the Chippewa Watershed Conservancy's Williams-Blackburn Preserve.  Wild Columbine (Aquilegia Canadensis) is one of my favorite late-spring wildflowers.  It's very photogenic when the flowers are fully mature (like this one), but I often miss out on finding them so it's always exciting to find a perfect bloom.  One really interesting thing to me about these flowers is how hairy they are.  Look close and you can see that the petals, stem, and leaves are all covered with minute hairs.  I like being able to peer in and see that level of detail.

A Tree Might Forgive, But It Never Forgets

I recently started doing a program on plant adaptations for 4th grade classrooms.  One of the things that we discuss in this program is the idea that plants can defend themselves.  They do this either through chemical means (such as being toxic or tasting bad) or physical means (such as prickly leaves, thick bark, prickers, etc.).

I have a tree in my backyard that has taken physical defense to an extreme level.

Honey Locust thorns

Those long three-pronged thorns belong to a Honey Locust  (Gleditsia triacanthos).  The Honey Locust is a deciduous tree that native to the central United States from the west slope of the Appalachians westward to a line running from central Texas north to central Kansas and eastern Nebraska.  It ranges south to the Gulf Coast and north as far as Minnesota and Wisconsin.  In Michigan it is native only to the southern tier of counties.  The Honey Locust can grow to heights of 80 feet and commonly lives 120 to 150 years.  It has compound leaves and as a member of the Bean Family (Fabaceae) it produces long seed pods with large seeds.

Honey Locust seed pod and leaves

The Honey Locust developed its impressive thorns to deter herbivores from browsing its leaves and branches.  This seems like a sensible approach, many other species have developed similar defenses (roses, raspberries, prickly ash, etc.).  Let's take a closer look at those thorns to see if they would be a good defense.

Honey Locust branch with leaves removed to show thorns

The thorns are certainly impressive and would seem to be enough to deter the average herbivore, but lets add a ruler for scale.

Honey Locust branch with 12-inch rule for scale

Those thorns seem to rather far apart to deter an herbivore like a White-tailed Deer (Odocoileus virginianus).  The thorns spiral around the branch and are all at least three inches apart.  The distance between any two thorns on the same side of branch may be greater than eight inches.  It would not be too difficult  for a deer to avoid.  Also the length of the thorns seems a little more than is needed to deter a deer.  Many of the thorns are over 4 inches long! 

This Honey Locust thorn measures more than four inches long!

Just for fun here is picture of one of the thorns with my hand for scale.  I have repeatedly stepped on fallen limbs in my yard and stuck those small thorns in the soles of my shoes.  I definitely do not want to close my hand around them.

A Honey Locust thorn in hand

So these thorns are a little big to be defense against herbivores like White-tailed Deer.  Just what is the Honey Locust trying to protect itself against?

The Honey Locust, like most plants, has a long memory.  A very long memory.  While each individual tree might only reach an age of 150 years, the memory of the species goes back much further.  When the tree species was developing those thorns there were much larger herbivores walking around North America.  

How much larger?