Compound interest? Exponential decay? Both apply here.
Probability of surviving a night under a tree is (1-1/5000).
15 years of hunting is roughly 5000 nights. The chances of never getting hit by a tree over that period are (1-1/5000) for each night, which compounds to
(1-1/5000)^5000 ≈ 1/e ≈ 1/2.7 < 0.4
That's to say, the odds are 3:2 (at least!) that you'd get killed by a tree in 15 years.
Make it at least 5:1 for 30 years.
That's to say, at least 5 out of 6 hunters who sleep under a tree every day wouldn't survive doing it for 30 years.
And that, children, is why credit cards are a scary thing.
Ergodicity?
E.g. A single player playing Russian roulette for a 100 times v/s 100 players playing it once are very different risks for the single player :)
There’s a term for this which I’m unable to recall and it’s not easy to Google. Would greatly appreciate if someone could help me out here!!