<p>From my correspondence with Dr. Hamilton, who is one of the leading researchers on forest rings (emphasis mine):</p>
<blockquote>
<p>They can be irregular (see figure below) but it is not very common. You
are right, the circularity is why we notice them and there are
probably lots that we don’t notice because they are not round.
However, the mechanism of formation that we have postulated ought to
produce circular shapes. All point-source force fields in an isotropic
medium will produce a circle if the area of influence is large enough.
We argue that the source of energy is the electrochemical potential
(redox) difference between the inside and outside of the ring; and the
force is an electrical field. The groundwater and glacial overburden
have fairly isotropic electrical conductivity (the inverse of
resistance) and therefore <strong>circularity is a requirement if the current
density is sufficient</strong>.</p>
<p><a href="https://i.sstatic.net/V43hP.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/V43hP.jpg" alt="various forest rings of various sizes and shapes" /></a>
This photo was taken near from northeastern Ontario north of Kapuskasing. The circular ring is  ~150m across.</p>
</blockquote>

CC BY-SA 3.0
2017-10-30T21:56:02.233Z
2017-10-30T21:56:02.233Z
2020-06-18T08:25:19.090Z
Seanny123
<p>In the <a href="https://earthscience.stackexchange.com/a/8245/11353">answer to "Why is ground water rising on these forest rings?"</a> it is written: </p>

<blockquote>
  <p>these rings are too numerous and too regular in shape to be related to either kimberlites or (even more bizarrely) Oklo-type natural nuclear reactors</p>
</blockquote>

<p>How is the regularity of forest rings assessed? How many near-rings and other shapes have been found?</p>

<geophysics><forest>
Forest rings shape regularity
Seanny123
# Forest rings shape regularity

(Asked by: username_0 on 2017-10-28)

In the [answer to "Why is ground water rising on these forest rings?"](https://earthscience.stackexchange.com/a/8245/11353) it is written:

> these rings are too numerous and too regular in shape to be related to either kimberlites or (even more bizarrely) Oklo-type natural nuclear reactors

How is the regularity of forest rings assessed? How many near-rings and other shapes have been found?

**Tags:** geophysics, forest


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## 1 answers

### Answer by username_0 on 2017-10-30. Score: 1 | Accepted answer

From my correspondence with Dr. Hamilton, who is one of the leading researchers on forest rings (emphasis mine):

> They can be irregular (see figure below) but it is not very common. You
> are right, the circularity is why we notice them and there are
> probably lots that we don’t notice because they are not round.
> However, the mechanism of formation that we have postulated ought to
> produce circular shapes. All point-source force fields in an isotropic
> medium will produce a circle if the area of influence is large enough.
> We argue that the source of energy is the electrochemical potential
> (redox) difference between the inside and outside of the ring; and the
> force is an electrical field. The groundwater and glacial overburden
> have fairly isotropic electrical conductivity (the inverse of
> resistance) and therefore **circularity is a requirement if the current
> density is sufficient**.
>
> [![various forest rings of various sizes and shapes](https://i.sstatic.net/V43hP.jpg)](https://i.sstatic.net/V43hP.jpg)
> This photo was taken near from northeastern Ontario north of Kapuskasing. The circular ring is ~150m across.


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