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Comment by freetime2 | Hacker News Reader

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.

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There's this article that I just read this morning. It suggests there are some valid ways to distinguish growth changes in plants caused by dead bodies and those caused by dead animals. Regarding your point, decaying dead bodies in the case of murder will typically be buried, whereas dead animals will die above ground and be scavenged, resulting in far fewer nutrients being absorbed by nearby plants. Of course that would limit its application to murder in comparison to missing people in general.

https://www.economist.com/science-and-technology/2020/09/03/...

Animals that die in burrows would be 'buried', but those animals are probably generally smaller than humans. Perhaps you'd find a few bear skeletons.

As others have pointed out the article mentions this.

I'm a bit skeptical, but I've also read a number of articles talking about how "unnatural" humans biology is due to our diet.

AKA, maybe we have a higher mercury level concentration (artificial sweetener, or whatever) than local species and maybe that can be reflected and sensed in the trees.

My skepticism is more about remote sensing. It wouldn't surprise me if these kinds of things can be detected when a tree's bark/leaves are chemically analyzed. OTOH, being able to sense that optically seems much harder.

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.

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... ?

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

The article kind of ends up not giving a conclusive answer to the question posed in the headline though, just a pet peeve of mine. It's really more about the possibility of a new technology helping and even that, as you've said, is a murky option.

The best way to use something like this is probably to find the remains if the murderer confesses and says they're buried "somewhere" in a certain forest. But that's such a niche use case.

False positives are exactly why certain elements of society love this sort of thing.

Maybe a good way to find deer bones or antlers.

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