Trigger affecting respawn

[solide]

We all know certain items in the long dark respawn. For instance wood and coal. However I wonders if anybody can explain what triggers the respawn. For instance, say a cave contains 5 coal. What triggers this coal to respawn? I would assume that when I never visit the cave the coal does not respawn. When I visit the cave but do not gather the coal it does not respawn. When I gather all coal does it respawn one at a time untill again 5 pieces? Or all 5 at once? Or can the cave contain (randomly) either more or less than 5 pieces? And say I do not gather all 5 pieces but just 3 ( leave 2 behind in the cave). How does this affect the respawning of the coal? 

And am I right in assumming the mechanism for respawning is equal for all resources or are there differences? 

Any clarifications from the experienced players would be appriciated.

[Serenity]

Seems to be time based. And modified by the length of the game and difficulty settings. As in resources becomes rarer as time goes on.

[Jimmy]

Coal respawns after 10 days on Interloper difficulty IIRC. Not sure on the lower difficulties as I don't usually bother tracking resources that closely when they're so abundant. If you don't pick it up, you won't get new respawns, so make sure to grab any resources you see! Each piece you pick up will prompt the game to respawn one piece, so if you see five coal and only grab four of them, only four will respawn after sufficient time passes.

I believe the same applies to beachcombing, where respawns occur on a 10 day cycle from when you pick up the item.

Branches and sticks respawn faster, but vary depending on weather. A good blizzard will usually mean a generous amount of new fuel nearby. Big tree limbs that can be cut with a hacksaw or hatchet respawn, but the massive ones that can only be cut with a hatchet don't respawn from memory.

[solide]

So let me see if i understand. Difficulty determines how much of a certain resource, say coal, is present. Is this a number for a region or for a seperate location in a region (cave)? say if a regions total coal is 20, and i gather 10, then 10 more will spawn after 10 days. But do they spawn in fixed numbers in a locatio? Or does each location has a change to spawn the resource until the total for the region is reached?

I have also noticed coal can be found outside a location. For instance along rail tracks. Does picking these up then affact respawning?

Edited September 14, 2019 by solide

[Serenity]

Only cave coal respawns. The pieces just lying around like the train cars in FM or the river in CH don't.

[Jimmy]

Resources which respawn will reappear in the same number as you'd collected close to if not perfectly on top of the same location you'd previously looted them from. Sticks, branches and tree limbs will commonly be found in similar quantities as previously looted after a respawn trigger, and coal will be found in the same location after the required number of days have passed. Note that the placement and number of these items can vary between save files, as even within the same difficulty, a different game seed will affect the layout of items within the world. Coal naturally respawns within caves and mines, but not other locations such as near train cars or forges.