A Sunny Morning in Late October

The early morning sun was shining and there was a combination of dew and frost on the ground when I arrived at Detroit’s Eliza Howell Park on October 28, 2019. Here are a few images from the next three hours.

Bittersweet on Oak Tree

Bittersweet vines grow high on some trees in the park, most noticeable when the leaves of the vine turn yellow.

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Dew Drop on Sumac

In the blow up, one can clearly see the reflections.

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Three Hundred Year Old Bur Oak Tree

I stopped by a massive Bur Oak that has been estimated to be over 300 years old.

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Rouge River from Footbridge

I often take a picture from this spot, looking upstream. The look of the river changes with the season, the sunlight/clouds, and the water level.

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A Walk in the Woods

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Sugar Maple

Several Sugar Maple trees, seen from the park road, have inspired park visitors to pull out their cameras.

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A Favorite Cottonwood

There are some trees, friends, that I stop by to visit to see how they are doing. This Cottonwood tree is one.

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In my records, this is Walk # 1351. Another good one.

 

Poison Ivy on Cottonwood: Taking A Good Look

In early to mid-October in Eliza Howell Park, before most other plants had reached their Fall color peak, Poison Ivy gets my attention. It adds color to the trunks of trees and the fruit attracts birds.

The vine climbs many of the Cottonwood trees inside the road loop, where it is easy to get a good look.

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Poison Ivy is a native species that usually gets talked about for only one reason: stem, leaves, and roots all contain urushiol, which causes a rash reaction in most people who come into contact with it. So the message is to avoid it. But it is safe to look and I have enjoyed getting to know some of its characteristics. I have recently been observing how it grows on Cottonwood trees and each picture here is of Poison ivy on a Cottonwood.

Poison Ivy often grows 20 feet or more up the trunk of a large tree.

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The leaves in fall are red or yellow or orange.

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The fruit is abundant this year. Humans (and other primates, I think) are the only animals that have the rash reaction to the urushiol in Poison Ivy. Birds eat the fruit and deer and insects eat the leaves.

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The craggy bark of Cottonwood trees provides a good surface for the Poison Ivy vines to climb. The vines tend to be hairy, a fact that helps to identify the species during the months of the year when there are no leaves.

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Poison Ivy is not the only colorful vine that climbs trees (the leaves of Virginia Creeper, for example, also turn reddish), but most of the red vines on large trees that a visitor is likely to see within the road loop in the park at this time of the year are Poison Ivy.

This is an ideal time to take a good look and to get a better understanding of its role among the flora and fauna of North America.

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The classic advice of “Look, but Don’t Touch” applies here. Maybe take several good looks.

 

Cottonwood Trees: The Fan Club

As I was thinking about the cottonwood trees in Eliza Howell Park recently, I recalled the old song, “Don’t Fence me In,” sung by “cowboys” like Gene Autry and Roy Rogers. It includes these lyrics:

     “Let me be by myself in the evenin’ breeze; Listen to the murmur of the cottonwood trees”

I don’t know if the cottonwood leaves actually murmur, but they definitely get my attention at this time of the year.

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There are dozens of large Eastern Cottonwoods in the park, many of them quite close to the park road. One that stands alone next to the road is a favorite.

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The Baltimore Orioles that spend three months of the year in the park are also fans of the cottonwoods. Of the 44 Baltimore Oriole nests that I have found in the park in the last 8 years, 24 have been in cottonwoods. The others have been scattered among 5 other tree species, with no other species having more than 7.

In 2019 the preference for cottonwoods is even more evident: 8 nests found; 7 in cottonwoods.

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Photo by Kevin Murphy

Cottonwoods are dioecious, separate female and male trees. This is the first year I have made note of the sex of the cottonwoods selected by the Baltimore Orioles for nests. 5 of the 7 are female trees. Without additional records, of course, I don’t know if this is typical.

The sex difference is easiest to notice in the spring, when the male trees have reddish flowers (catkins), which appear earlier than female catkins.

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The catkins on the female trees are green and the seed capsules are, at the beginning of June, getting ready to split open to release the seeds attached to the “cotton.” The cotton will soon be flying.

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The orioles are fans of the hanging branches in which to build and hide their hanging nests. I have become a cottonwood fan partly because of the orioles, but I also simply admire the trees:

– the shaking leaves with the sky as background

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– standing tall and leafless in January.

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I am proud to be a member of the Eliza Howell Cottonwoods fan club.

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Estimating the Age of Trees: November 11

Having learned recently about the effort to determine the approximate age of a large Bur Oak tree in the Rosedale neighborhood of Detroit, I decided to use the same method to arrive at an estimate of several large trees in Eliza Howell Park.

Anyone interested in assisting in this project is welcome: Sunday, November 11, at 1 p.m.

Please email if you are intending to come (so I can let you know if there is a late need to reschedule because of weather): leonard.weber9@gmail.com

This Pin Oak is one to be measured.

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The following steps are followed to get a non-invasive estimate of a living tree’s age:

  1. Measure the circumference at 4 and 1/2 feet from the ground (54 inches).
  2. Divide the circumference number by pi (3.14) to get the diameter.
  3. Multiple the diameter (in inches) by the growth factor which has been identified for the specific species. (Several organizations have estimated and published the growth factor for various species, based on how fast a species usually grows.)
  4. The resulting number is the approximate age of the tree, in years.

Another of the trees I plan to measure is this American Sycamore.

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I am hoping to measure about 8 large trees, different species, ones that are often noticed by park visitors and participants in nature walks. At present, when I am asked “How old do you think that tree is?” I can only give a general response.

This Eastern Cottonwood, the location of a Baltimore Oriole nest every year, is also on my list of trees to be measured.

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I have been asked specifically about the approximate age of the Bur Oak (next picture) at the edge of the path leading down to the floodplain.

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In my initial use of this formula for estimating tree age, I have found that not all online sites of growth factor information have the same number for a particular species. It will be necessary for me to do more research before November 11 in order to determine the most appropriate numbers to use.

As I noted in a February post (“Beech Trees and Beechnuts”), Passenger Pigeons used to eat many beechnuts. I am wondering whether this American Beech is old enough to have been visited by those legendary birds.

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As I get to know more about the flora and fauna of Eliza Howell Park, I realize how much more there is to know. And I look forward to this learning project.