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): firstname.lastname@example.org
This Pin Oak is one to be measured.
The following steps are followed to get a non-invasive estimate of a living tree’s age:
- Measure the circumference at 4 and 1/2 feet from the ground (54 inches).
- Divide the circumference number by pi (3.14) to get the diameter.
- 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.)
- The resulting number is the approximate age of the tree, in years.
Another of the trees I plan to measure is this American Sycamore.
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.
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.
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.
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.