Salem

How long does it take for a stump to turn hollow
I cut a tree down and it instantly (no normal stump) turned into a hollow stump

I believe it happens randomly with decay ticks.

Having it happen instantly seems highly unlikely.

it happens though (I've had it happen in a couple of seconds as well). Of course, it's very rare and you should cherish such moments of RNG awesomeness.

I destroyed it a minute later because I was terraforming