
Could a tree help find a decaying corpse nearby? - Cyphase
https://www.wired.com/story/could-a-tree-signal-if-a-corpse-is-decaying/
======
derefr
> So Stewart and his colleagues set out in June to do exactly that. “Right
> now, for the Body Farm study,” says Stewart, “we're basically just taking
> the trees and shrubs that are growing naturally within our plots, then
> placing donors—as they refer to them—and then looking at leaf responses,
> plant responses, at various distances.”

Given that they’ve been putting bodies in these woods for decades now to study
other things — and given that they presumably have records of where they put
them — can’t they just do an analytical study of the effects of previous
decomposition on current trees that grew near the placed corpses, rather than
having to do an experiment on the scale of tree growth (= presumably years)?

Or is this all supposed to happen over a much shorter term than I’m imagining,
such that you’d _need_ to do an experiment to see the effects right away; and
that a tree would be expected to revert to the mean in appearance after it
runs out of human-type nutrients? (That’d kind of suck, since it would mean
you wouldn’t be able to solve a missing-persons case that's been cold for
decades this way — which is precisely the kind of case where you’d want to
pull out this sort of technique. There are already good methods to find a body
in the woods if they've only been missing for months/years, e.g. corpse-
sniffing dogs.)

~~~
ElFitz
I guess the advantage over a dog is that, should it indeed have a detectable
effect, and a sufficiently noticeable one, one could fly a drone (even,
perhaps, a Global Hawk; I don't know how precise the pictures it takes are),
and just scan huge swaths of forest at once, much faster than one could with
even a hundred dogs.

But that's a lot of ifs.

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freetime2
I suspect the answer is no. Things are always dying and decaying in forests,
and it seems like it would be hard to differentiate the affect of a decaying
human corpse from any number of other things that affect soil composition. But
it would sure be interesting if this works.

~~~
jmnicolas
They acknowledge it :

> “there would be a need to differentiate effects from human decomposition
> with those from other animals' decomposition.”

But then :

> However, there could be subtle differences in how plants respond to the
> decomposition of different kinds of mammals.

I really think it's a long shot and the number of false positive would make
the technique impractical, unless you know there's a human body in this forest
and you want to exhaust all possibilities to find it.

~~~
leoc
OTOH, in the circumstances where someone _is_ looking for the body of a
fairly-recently-deceased human in a forest they're probably motivated enough
to search through quite a large number of false positives to find it. And if
the search finds, or can be made to find, only largish mammal corpses then
you'd tune out the many dead crows and squirrels and the like. Relatedly, I
wonder if the technique might be more effective in the earthwormless parts of
North America
[https://en.wikipedia.org/wiki/Invasive_earthworms_of_North_A...](https://en.wikipedia.org/wiki/Invasive_earthworms_of_North_America)
?

~~~
martyvis
TIL done temperate parts of the world don't have earthworms

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bch
CBC story[0] (The Nature of Things “The Salmon Forest” c. 2001) about the work
of Dr. Tom Reimchen[1] documenting[2] salmon (unwittingly) supplying a rare
nitrogen isotope to hemlock trees.

[0] [https://curio.ca/en/video/the-salmon-
forest-844/](https://curio.ca/en/video/the-salmon-forest-844/)

[1]
[https://www.uvic.ca/science/biology/people/profiles/reimchen...](https://www.uvic.ca/science/biology/people/profiles/reimchen-
thomas.php)

[2]
[http://web.uvic.ca/~reimlab/salmonforest.html](http://web.uvic.ca/~reimlab/salmonforest.html)

------
bb123
It seems that this would only work once the bodies are pretty thoroughly
decomposed, and the trees have had time to absorb the nutrients this creates.
I imagine this takes quite a while. A useful technique perhaps, but I can't
imagine it solving any hot cases because of that delay.

~~~
pvaldes
The problem is that they are underestimating how hard can be the botany. For
many people trees are just geometric figures in an architect plan.

1-Is well known that trees have symbiotic fungus. Sometimes the fungus is not
present locally, sometimes there are more than one fungus species. Same tree,
three types of grow.

2-The same tree can grow different in different soils also

3-The same tree can be perennial or semi-decicuous in dry spells or different
years (Totally different color in satellite photos)

4-Some trees (Liriodendron for example) behave very differently just by
genetic variation. Each seedling grows at their own pace. Therefore, you can't
compare two trees.

5-Some trees are hybrid, their grow can be stunted or increased by hybrid
vigor. Is difficult even for trained botanists armed with microscopes to
distinguish hybrid oaks or willows (and they hybridize all the time).

6-Is known that sometimes a bigger tree nurtures a smaller tree by mean of a
root bridge. Sometimes is the same tree, other a genetically different
specimen. So if a sapling suddenly starts to growing faster and greener than
the other, maybe it just has connected to rooternet.

7-Or one of its roots managed to enter in a water pipe or reached a very low
phreatic level

8-Or is genetically resistant to a common plague that affects 90% of the other
trees.

9-Or it has a raptor nest, so it has a lot of nitrogen and zero resident
squirrels.

10-Or an alellopathic neighbour has being struck by a lightning and died,
stopping to poison the soil.

In brief, they just didn't meditate enough before to jump to this pool. Should
have asked a botanist about the project. I'm sad to inform them that the task
that they are trying is a titanic effort.

------
082349872349872
YIL corpse disposal via feeding to pigs is now illegal in many jurisdictions,
due to the biosecurity threat:
[https://news.ycombinator.com/item?id=24397612](https://news.ycombinator.com/item?id=24397612)

~~~
pvaldes
What means YIL in this context?

~~~
24gttghh
Yesterday I Learned? Or it's just a T(oday)IL typo.

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anonAndOn
Salmon carcasses are a vital nutrient source for coastal forests[0], so it
seems like there might be something to this.

[0][http://depts.washington.edu/pnwcesu/reports/J9W88040015_Fina...](http://depts.washington.edu/pnwcesu/reports/J9W88040015_Final_Report.pdf)

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sampo
Something like this is a small plot device in the novel The Naturalist by
Andrew Mayne.

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tenbino
I heard about a body found in the woods because some unusual plant was
growing, germinated from a seed inside their stomach.

Probably apocryphal but hey.

~~~
nkrisc
I believe it was a man killed in a cave in Cyprus during conflict there. He
had eaten a fig, I believe and the tree grew in the opening of the cave.

I believe it is true and that should help you find a reference.

~~~
jaclaz
Here:

[https://cyprus-mail.com/2018/09/23/did-a-fig-tree-grow-
out-o...](https://cyprus-mail.com/2018/09/23/did-a-fig-tree-grow-out-of-the-
remains-of-a-turkish-cypriot-man-missing-since-1974/)

"The remains of the three Turkish Cypriots, the sources said, were found
several metres away from the tree roots during the excavations, suggesting it
did not grow from a seed inside the deceased man."

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pvaldes
There are easier ways to attack the problem.

~~~
JoeAltmaier
But it would be low-hanging fruit.

~~~
regimeld
It's kind of a dead-end if you ask me.

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dang
Url changed from [https://arstechnica.com/science/2020/09/could-a-tree-help-
fi...](https://arstechnica.com/science/2020/09/could-a-tree-help-find-a-
decaying-corpse-nearby/), which points to this.

