Identifying Trees by Their Bark: A Challenge

On a recent walk in Eliza Howell Park, I focused attention on the bark of a number of mature trees. From a distance, the variations in color and texture may not be especially noticeable, but viewing close-up photos helps one understand how tree species can sonetimes be identified by the bark alone.

The trees in the first collage, clockwise starting from the top left, are: American Sycamore, Sugar Maple, Eastern Cottenwood, Yellow-bud Hickory (aka Bitternut Hickory).

Here is a second group of four. From top left, clockwise, they are: Pin Oak, Black Locust, Wild Black Cherry, and American Beech.

I took pictures of trees that I have gotten to know in the past, my identification being made on the basis of a variety of considerations — leaves, seeds/fruit/nuts, shape, size, and bark — not on the bark of the trunk alone. Even in winter, when there are no leaves on trees, the size and shape can be used to help identify the species, along with the bark.

It is very difficult for most of us, myself included, to identify trees by the bark alone. If the reader wants a challenge, try identifying the trees below. They are the same 8 as above, but in a different sequence. The real challenge is to identify them before looking back to the top.

The bark of each species has its own characteristics, but I find it much easier to recognize tree species when I have a little more complete picture.

March 1: First Day of the New Year

A naturalist once said to me that, in our climate, the new year begins in March, not January. I definitely agree. March is the month of new beginnings, new beginnings that I do not observe in Eliza Howell Park in January or February.

March is the month that the first of the birds returning from winter to the south arrive back in Detroit. Red-winged Blackbirds (the males come back earlier than the females) are often the very first.

Photo courtesy of Margaret Weber.

Another welcome return to the park each March is the Killdeer.

Photo courtesy of Margaret Weber .

March is the month when hibernating animals begin to emerge. On a sunny day in the middle of March I often see the first Garter Snakes of the year, warming in the sun’s rays on the brown grass.

And usually a little later in March, depending on the weather, Eastern Chipmonks can be spotted, venturing outside for the first time since they sought refuge for the winter.

It is nothing new to think of the new year beginning in March. Calendars have varied with cultures and have changed over the centuries.The Roman calendar which we use is a revision of an earlier Roman one that started the year in March. The month names “September, October, November, December” come from the Latin numbers seven, eight, nine, ten — an annual reminder that March once was the first month of the calendar year.

March in Eliza Howell is also the time when perennial flowers, long dormant, begin to green and grow.Two of the earliest are Blue Flag Iris and Violet.

While I have long recognized that nature’s new year begins in March, this is the first year that I am noting the beginning of a new year in my records.

If you happen to see me during my visit to Eliza Howell Park on March 1, perhaps we can exchange “Happy New Year” greetings.

The Cardinal Sings: Spring Is Nigh

The Northern Cardinal doesn’t sing in winter, at least this far north. It communicates with a softer chirping call until the days grow longer, when its loud whistling songs can again be heard.

I always expect to hear the Cardinal’s first “spring” singing in February in Eliza Howell Park. In 2020 I heard it on February 12. This year, it was on February 17, the coldest morning of tbe winter, when the snow cover was the deepest.

The snow was undisturbed in most areas of the park about 24 hours after the snowfall ended. The combination of a zero degree night and deep snow had apparently led most mammals to declare “a snow day” and stay in their shelters. About the only tracks visible, apart from a few scattered squirrel ones, were those of deer. Deer had been out browsing — and creating a number of crossing routes over the river.

The winter birds were active, however, foraging in the trees. I saw or heard 13 species, a high number for the middle of February.

Though I have been expecting to hear rhe Cardinal sing one of these days, it still caught me somewhat by surprise. Cardinals are one of the minority of song bird species in which both males and females sing. (The Cardinal photos here were taken at other times and locations.)

Photo courtesy of Margaret Weber.

Photo courtesy of Margaret Weber.

The Cardinal is traditionally a more southern bird, spreading north gradually in the 20th century. It is now one of the most best-known yard and park birds in southern Michigan. It does not migrate.

I was reminded of the attractiveness of this common bird a couple of years ago while doing some bird watching in Washington state. In a brief conversation with a local birder, I was asked if we had cardinals in our area. He envied those who did.

(Range map is from the Cornell Lab of Ornithology.)

When the Cardinal starts singing in February, the message is clear: winter is moving toward its end and it will soon be time to begin the cycle of life again.

When I heard the Cardinal sing this week, I began to think of Cardinals nesting in the park. Perhaps the singer and its mate did as well.

The Case of the Little Freeze-resistant Pond

On a sunny day near the end of January, I was walking in a pathless area of the floodplain in Eliza Howell Park when I came across a small pond in a dip in the ground, a little body of water that was unfamiliar to me.

What was most remarkable about the pond or pool was that it was not ice-covered. Other standing bodies of water that are not part of the flowing river had already been frozen over for weeks at this point. Before February it had not been a very cold winter, but cold enough to freeze non-running water.

I checked to see if the water was moving at all; it did not appear to be. There were some deer tracks near the water, but not many and it did not look as though the pond was a watering hole, at least at this tine of the year. I was curious and decided to come back for another look on a different day.

In the next visit, I realized that the pond, which I had stumbled upon the first time, was not easy to relocate. I needed to walk through thick understory growth.

Fortunately, I was able to follow my own tracks in the snow from a couple days before.

The pond was that day roughly 15 feet long and 5 feet wide. I could see nothing like bubbles or rising water suggesting that it was spring-fed (which could account for its remaining open).

Though the water looked clear, I was beginning to wonder whether it might be contaminated and a potential risk to the environment. When I got home, I emailed contacts in several different organizations seeking information about the possibility of getting the water tested.

On the next visit, the pond looked basically unchangedI, though we had now had several consecutive days of sub-freezing temperatures. I filled a small glass jar that I had brought with the clear water.

I left the jar on the floor of our unheated detached garage and the next day the water in the jar was frozen almost completely solid. Apparently there is not something in the water that acts as an “antifreeze.”

By this point I was getting responses to my inquiries. From the Michigan Nature Association came the suggestion that ground water might be seeping to the surface, despite the fact that no spring activity was visible to me.

Now that I know that the water removed from the site did definitely freeze, this explanation makes good sense to me. Ground water in this region is reportedly over 40 degrees F when it emerges from the ground. A regular supply of “warmer” water would keep much of the pond unfrozen, though I would expect freezing to occur at the pond edges, especially when the air temperatures in consistently below freezing.

In my most recent visit, such edge icing is noticeable.

So the puzzle is probably solved and I likely do not need to be concerned about contamination entering the river the next time it floods.

And I now know where to find a small, hidden, sunken pool of water to observe and to see what it attracts in the different seasons.

The Seasons: Quarterly Images

I walk more miles in my visits to Eliza Howell Park in the coldest days of winter than I usually do in other seasons. There are fewer day-to-day changes to catch my attention and stop me for closer looks; some of the life here is dormant now.

Recently, after I took a picture of the river from the footbridge, I reviewed seasonal images of the past year from that spot.

February 7, 2021

November 9, 2020

August 10, 2020

May 3, 2020

These times — early in February, May, August, and November– are good times to experience the heart of each season. The following pictures are examples of other photos taken in the park at approximately the same times of the river pictures above.

Staghorn Sumac seed cluster, February 7, 2021

Mushrooms/fungi on tree, November 10, 2020

Clouded Sulphur butterfly on coneflower, August 9, 2020

Gray Catbird nest, May 8, 2020

One of the great things about living in this geograpical region is that there are four distinct seasons to observe and enjoy. Whatever time of the year that I walk in Eliza Howell Park, I am well aware that seasonal change is coming soon.

Tree Burls: Prized Abnormalities

Near the path along the river in Eliza Howell Park is a tree with a large, rounded, bark-covered growth (about 2 feet across) near the ground. A growth like this on a tree, called a burl, might be compared to a benign tumor, an abnormal mass that is not likely to do harm to the organism as a whole.

Most burls in the park are not this large and it is easy to walk by a tree burl without really noticing it. One day earlier this winter I took a “burl walk,” searching both for quantity and variety. Though I found several that I was not aware of previously, I realized that they are not all that common and I confirmed that they are not restricted to a few tree species and that they take a variety of shapes.

I noted above that it is easy to walk by without noticing burls. But that doesn’t happen when walking with a woodworker, someone who knows that the grain patterns in burl wood are very different from normal wood and can result in fascinating art. A woodworker is quick to spot and point out a burl.

Readers interested in seeing why burls are prized by woodworkers might google “burl bowls” or something similar.

Since the day of my burl walk, I have gone bsck to take another look at a couple trees I found. One is a young tree, with a burl larger than the trunk.

Another tree that I have returned to is a larger one with many different burls covering much of the trunk.

Burls are thought to be the result of abnormal bud growth, but apparently no one has been able to stimulate such growth delibetately. This prized wood needs to be found in natural settings.

i am not a woodworker, but I have come to prize burls also. They are another of the many natural wonders in this local park.

Ice Watch: Will the River Freeze Over This Winter?

It has been a mild winter so far in Detroit, with the temperature not yet falling below 15 degrees F in January, even at night. The daytime high has often been in the 30s. Not surprisingly, the Rouge River, being moving water, has not frozen over.

The last few days have been more typical late January weather, mostly in the 20s, with no afternoon thaws. So I have been watching for ice, conscious of the fact that the river never did freeze over last year. (On February 10, 2020, I posted “The River This Winter: I Miss the Ice.”)

On January 24 this year, I saw the first indications of ice on the river.

Ice typically forms along the banks first, where the water is flowing more slowly.

These next 3 photos were taken from the same location on the following three days, January 25. January 26, and January 27.

The ice covering appears to be increasing, but very, very slowly. Since the open water is constantly flowing, it appears doubtful that there will be a full covering if the temperature does not drop further.

Since different locations on the river freeze at different rates, I made a record of another spot during the same days (starting upper left, clockwise: January 24, 25, 26, 27).

It is quite unusual, in my 17 years of visiting Eliza Howell Park regularly, for the river not to freeze over at least once during the winter. Two consecutive years is definitely noteworthy.

My most recent photo of the river covered with ice and snow is from February 1, 2019.

Winter is not over. The ice watch continues.

Log Pathway of Nocturnal Mammals

I don’t walk through the woods of Eliza Howell Park at night (and wouldn’t see much if I did) and I have not placed trail cameras there to try to record some of what happens nocturally. So my only information comes from evidence or signs that I might find in the daylight.

On a morning walk earlier this week, following a dusting of snow the evening before, I noted — and began to follow — a mammal pathway from the river into the heart of the woodland.

Mammals often follow the same route repeatedly and different species sometimes use the same path, so I was interested both in where the pathway led and in finding clear tracks that would help me identify what had passed this way since the snow fell.

The snow was so minimal that no tracks were discernible on the leaves, but the path led to and then on a log. As I looked ahead, it became evident that much of the parhway was on logs.

While the tracks were clearly visible on the logs, more than one mammal had recently walked here and the individual tracks were not distinct. Nocturally active mammals in the park include, at least, raccoon, oppossum, mink, skunk, mice. Squirrels are diurnal, but could have been present in the early morning before I arrived.

Coyotes are present in the park but their pathways are different enough that I was quite sure that this was not a path they traveled.

The tracks on the logs were multiple, making identification more difficult, but they definitely suggested raccoon in shape and size.

I was now following the path to see how far I could follow it and to see how extensively logs were used. They were clearly favored, with the animals descending to the forest floor only to reach the next log.

Several of the logs were traveled for 30 feet or more. The abundance of fallen trees in the heart of the woodland meant very little need to walk on the ground.

It is a well-traveled pathway, which one would not know when there is no snow. I only occasionally got a look at distinct tracks, but it was enough to confirm that one or more raccoons had recently been walking the logs.

I followed the path for a couple hundred yards. Along the way, there were indications of side paths, also mostly on logs. There was no single destination.

What became abundantly clear, however — and this was the most important observation of the day — is that raccoons, and possibly other nocturnal mammals as well, prefer to walk on logs rather than on the ground. Sitting at home at night, I can envision a raccoon, maybe several, walking the logs in Eliza Howell.

Logs without a coverong of snow show nothing about who has passed over. But when it snows again, I will take another look.

Carolina Wren: Loud, Often Hidden, No Longer Rare in Michigan

Bird watchers sometimes refer to a time and location with few noticeable birds as “quiet.” In Eliza Howell Park, January and February are the quiet times of the year. Many species have migrated south and the food supply is limited (and no one has placed bird feeders here). In the first two weeks of January, I have seen only 15 species.

Few species does not mean, however, that they are of little interest. One that I am encountering quite often this month is the Carolina Wren.

Photo courtesy of Kevin Murphy.

Carolina Wren is more easily heard than seen. Its loud song can be heard throughout the year, even in January. I see it most often in the forest understory or at forest edges, as it forages among logs and in brushy thickets. Usually it does not come out in the open even to sing.

It does not “pose” for photos very often. I am not aware of any photos of it taken in the park; the two in this report were taken elsewhere.

I caught a glimpse of one in this thicket today, saw just enough to identify it:

This is the only wren found in Michigan that does not migrate. It has historically been a bird of the southeast and has been gradually expanding north in the last century. (This current range map is from the Cornell Lab of Ornithology.)

Carolina Wrens eat insects and spiders primarily. Their spread north has been related to more mild winters, as well, perhaps, to more backyard feeders. They seem attracted to residential neighborhoods where there are trees and brushy shrubs.

They are now a fairly common breeding bird of southeast Michigan, something that was not the reality a few decades ago.

The Michigan Breeding Bird Atlas I was completed in the 1980s and MBBA II was completed two decades later. A comparison demonstrates a significant change. (Yellow means possibly breeding in the specified location; orange means probably breeding there; red means definitely breeding there.)

Those of is who have not grown up aware of this bird are finding that it is definitely worth getting to know. It is richly colored, with a bold white stripe. Females and males look very much alike and they are normally found in pairs all year round, long-time mates. They nest near the ground, usually in some sort of cavity. The common form of their loud song is distinctive and memorable.

Photo courtesy of Kevin Murphy.

It will be weeks yet before the first migratong birds return in March. Meanwhile, the birds of winter include some fascinating species that invite return visits.

Bladdernut Seeds: Ready to Float Downstream

Not often, but sonetimes, winter is the best time of the year to find a particular tree species. This week I found a clump of Bladdernut trees (or shrubs) in Eliza Howell Park. The seed capsules still clinging to the stems, noticeable now that the leaves have fallen, were what caught my attention from a distance — and drew me close for a better look.

This clump, made up of trees about 12 to 15 feet tall, is very close to the Rouge River. The trees can easily be passed by without being noticed (I have done it many tines) as they are similar to other small trees that make up the understory of the forest.

The seed capsules are distinctive, one to two inches long, lightweight, and feeling like dried paper. They have been described as “bladder shaped,” the source of the name given to the tree. Each segment of the capsules contains one or more small seeds that, at this time of the year, are dried and loose. The capsule is a rattle when shaken. The seeds are almost the same color as the capsule that holds them.

Bladdernut is native to eastern North America, often found along rivers and streams. (The range map is from the USDA.)

As I examined the seed capsules on the trees, pulling the branches down for a better look, a few capsules fell. On the ground, unopened and lightweight, they are ready to be carried into the river the next time the water rises after a heavy rain (or after melting snow). At least some of these seeds will likely end up a long way from the parent teee.

One capsule fell into the river and immediately began to float downstream.

Plant seed dispersal occurs in a variety of ways in addition to simply falling (dispersal by gravity). Wind dispersal is common; cottonwood and milkweed are two examples. Dispersal by animals is probably even more common; nuts are carried away and buried and the seeds of fruit that is eaten by birds often pass through their intestines and dropped quite far from the fruit source.

Bladdernut is a good example of seed dispersal by water. It would be fascinating to know how far the bladdernut seeds I was observing this week will travel before spring.