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Comment by kadoban | Hacker News Reader

Is 1:5000 an actually good assessment? I'd suspect it's very much not, especially if you avoid obviously dead trees and maybe move if a storm comes.

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If the story is based on Jared Diamond’s story, the tree was dead, and the estimate was 1:1000. https://www.openculture.com/2015/08/jared-diamond-underscore...

1:5000 would suggest an average lifetime of 13.7 years for a grown tree (i.e. not counting the years where it's too young to sleep under), and that's before the ability to avoid trees that look more likely to fallover.

I don't know anything about trees around there, maybe they're really short-lived? For forests around here, it's a gross overestimate.

Even if you multiple by ten this still means you'll end up with one dead hunter every few decades (depending on how often they hunt and how many hunters there are exactly). That seems like quite a high risk for a small self-sustained community.

Also, I bet it's not just the tree you're sleeping under that poses a risk, but also other trees in the vicinity that might fall on you. In a forest there are probably a bunch of trees "in range".

All of that said, I've often camped and slept in forests, as have many of my friends, and I've never heard of anyone being killed or injured by a falling tree, or ever heard or seen any "don't sleep under a tree, it might kill you"-advice, so I don't know...

Remember that the relevant set isn't the set of all trees, but the set of trees old enough to be large enough to sleep under. That means the average lifetime would be: (number of years it takes for a tree to become big enough to sleep under) + 13.7.

I would still guess that the number is wrong, I suspect that trees have a longer life on average from becoming what we would consider "big" until they fall over. But it's still an important detail.

I mean “big enough to sleep under” is around 50+ years for most hardwoods IIRC. Also, you have to consider groups of trees that can fall on you in the surrounding area. So it’s really the probability that a tree falls within any given 50m radius, towards the center. I think the stated probability is pretty accurate. Also as humans, we tend to pick trees that provide the best shelter, thus older. From experience, if one of those big older branches decide to fall, you don’t want to be underneath. As a kid, a huge oak tree lost a huge branch right in front of me. It scared the crap out of my 8yr old self, so much that I still remember it quite vividly, it would have killed my brother and I if we hadn’t just moved out of the area. The limb looked perfectly healthy btw, green and all. There was no indicating factors, according to the adults at the time.

Don't know about Papa New Guinea, but where I live we have had lots of healthy trees fall over from a bit of wind when the ground is soaked.

Somehow I suspect trees in Papa New Guinea are different than the trees where you are

or perhaps the main difference between Papua New Guinea and the GP's location is that people feel entitled to make up weird questionable stories about PNG and not about their place.

PNG has a lot of eucalyptus trees, and some species drop their branches with zero warning, which originated as a mechanism for surviving droughts. I don't know enough to tell whether that's what's going on in the estimate.

You could calculate it by taking the average lifetime of a tree and dividing by the length of time slept and the number of trees in squashing distance.

Only if tree death is uniformly distributed over a tree's lifetime for some bizarre reason. And it isn't.

The logic in the story is BS. First, you would never, ever get into a car with that logic. Second, trees just aren't that ephemeral. People who live in a forest would be very aware of when they do or don't fall (or more problematically, drop large branches.) It's not as straightforward as just avoiding storms or dead-looking trees. Sustained wet weather, especially after a period of dry weather, is a common cause. As is the opposite for some trees (eg oak trees drop limbs in sustained hot dry weather.) As for disease or other causes, an experienced hunter in a familiar area could tell at a glance.

The message I got from the story is that they probably did have a very good reason. They either thought it would be too hard to communicate, or they were themselves cargo-culting the falling tree excuse when the reality was more likely to be... I dunno, snakes or nasty bugs or annoying sticky sap or whatever.

I think your explanation is pretty plausible, I wonder why people are downvoting it.

Like these guys probably have homes, with bedding of some sort, maybe they'd rather sleep next to their wives than some caterpillars. If I was giving somebody from a far-off place a tour of my workplace and, on the bus ride home, they suggested it was getting dark and we should camp on the sidewalk I'd probably not go for it. If they were really insistent I'd probably amplify the danger of sleeping on the sidewalk to shut them up.

> First, you would never, ever get into a car with that logic.

The logic isn't applicable to any set of risks. As deadly as cars are, the risk of car crash death is much, much lower than 1/5000 per trip. It's probably closer to applicable to being a drunk driver, and "you would never operate a car drunk" is pretty accurate for many people.

I think most trees fall when there is stormy weather. A wind free day, I think much less than one in 5000 trees fall.

Not an expert on this, but I suspect you wouldn't want to move camp during the night if you can avoid. Especially in the rain.

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