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[Panando]

So I built a magma pump stack on a heavily forested swamp type map, coincidently this exercise confirmed that things like piercing aquifers and pump stacks work just as before, no surprises or new behaviour at all. Having built the stack the next logical thing to do was to set the forest on fire for the sake of !!SCIENCE!! ala seeing what happens.

First of all, it's about as cool as you'd imagine, the fire sweeps up into the branches then spreads through the canopy and stuff. It does not appear to jump gaps, but only spreads from one burnable tile to another (in 3-diminisons)

But then things start getting a bit weirder.

The fire isn't very destructive and when a tree is burned out the parts all show as 'dead XYZ' (i.e. dead trunk, dead branches, dead twigs), oddly enough the bottom z-level of trunk does not burn and does not become dead. If you cut down a dead tree you still get logs. After a while the dead trunk and dead branches spontaneously come back to life, this appears to rely on a percentage chance per tick that the tree will return to life, as it can both happen nearly instantly after burning, and take basically forever. A regrown tree is immediately flammable again.

Tree regrowth is fast, within one season a fully burned out forest will look pretty normal again. It's fast enough that trees come back to life before the fire has finished sweeping the map, also there are hotspots which keep burning for a long time then re-ignite the regrowth meaning you could conceivably have a permanent forest fire. But as noted above, fires don't appear to jump gaps nor burn dead trees, since it takes a while for twigs and leaves to regrow, the regrowth fires have more trouble spreading.

As before, trees are generally unperturbed by being flooded with magma. They don't even catch on fire if there is nothing flammable below (like a forest fire has already swept through recently), it probably requires grass->leaves to start a canopy fire. I have not built the stack high enough to dump magma on a tree from above, but that is the next logical step.

There is one serious disappointment though, as trees burn the game will announce "Something on the surface has collapsed!" and pause . This means you have to hit resume about a bazillion times a second. Unless you turn CAVEINS off, this makes forest fires totally unplayable until toady fixes this or DFhack is back in business - with autoresume it would be pretty cool. It seems the 'collapsed' bits are branches or perhaps twigs, as a fire seems to outright destroy a percentage of the canopy tiles leaving other bits unsupported. This results in big bombs of dust which in the rare times when it's not pausing it's ass off looks pretty cool to watch unfolding. It would be awesome to set a forest on fire when the elves come and have them burnt alive and bombed by their beloved trees! Right now though, the caving in thing just makes it uncool.

Here's a picture of the forest fire:

Spoiler (click to show/hide)

Note:
Core of dead trees where fire started, fire still spreading outwards.
Tree bombs going off! Especially around the top-right firefront.
Regrowth in the middle, some trees turning green or yellow.

[RealFear]

You could've done this is arena, btw, it's got trees in it, you can spawn new trees in it, and spawn magma.
You'd also not have had constant pausing.

[ImagoDeo]

You could've done this is arena, btw, it's got trees in it, you can spawn new trees in it, and spawn magma.
You'd also not have had constant pausing.

He took the dwarfier route.

I applaud you, sir!

[Panando]

You see there is science for the sake of science and then there is science for the sake of setting things on fire (or is that setting things on fire for the sake of science). It should be noted that arena tests are unlikely to capture real life phenomena like 'permanent forest fires', whether such things happen depends on the density of trees under natural growing conditions, meaning the only scientific test is to set an actual natural forest on fire and see what happens.

The test of pouring magma onto a tree has been performed. It appears that magma (and presumably by extension, the heat of fire) eventually incinerates both twigs and branches. However the trunk appears completely immune to magma. It will be interesting to see how trees recover from being cauterized by magma.

Another surprising little factette, is that being dead is no hindrance to growing fruit. Fruit grows just fine on dead branches.

I believe in the long run it will be possible to weaponize !!TREES!!, as all you need to do is set one on fire and in no time the ground is being saturation bombed by burning debris. This would tend to rather ease the construction of a FTW device, one merely needs enough magma to set one tree on fire, and the fire then spreads through the canopy wrecking havoc. Within a season or two the "ammunition" has regrown and the weapon can be fired again. Most of the heat of the fire wouldn't reach the ground, but this could be somewhat remedied by building walkways through the tree canopies so when elves attempt to infiltrate your fortress through the delightfully elvish canopy walkways, they suddenly find themselves !!burning!!.

[CRM114]

I was carrying out a similar experiment, except I dug straight into a volcano.

So apparently dorfs will climb trees to try to escape fires (and potentially other dangers). Also, announcement spam seems to have a 'x' multiplier next to it, which is nice. E.x "Something on the surface has collapsed x 173"

[Cobbler89]

Announcements that pause the game or pause it and zoom to a location are actually configurable in a file -- announcements.txt in the init folder. (Actually, you can configure *a lot* in there. It's pretty interesting. I wonder if the wiki shows what each of the listed announcements is, and how many are new for 0.40?) The one thing I don't know is whether turning off pausing for aboveground collapses would turn it off for other things like caveins -- but I would guess that each message is separate, so probably not. The bigger issue, I suppose, is whether turning off aboveground collapse message pausing would cause you to miss real collapses, whatever they are...

[vjek]

It's interesting that the forest will grow back after being burned, but it won't after being cut down and the logs remove.

I wonder... does ash count as a covering, in the same way cut/fallen logs and stockpiles do, permitting the sapling to reach maturity?

[Loud Whispers]

You could've done this is arena, btw, it's got trees in it, you can spawn new trees in it, and spawn magma.
You'd also not have had constant pausing.

The arena is relatively clean, controlled and sterile. Fortress mode is chaotic, filthy and full of the RNG God's creations. Testing in Fortress mode is highly valuable. Setting trees on fire also has more meaning there.

[MarcAFK]

My current embark is covered in trees, I like the idea of weaponising them.

[stool]

hello, since this is the only 0.40.x science thread i've found,
i might post my results of a large scale double soil layer drop/cave in here with Multi-Tile-Trees [ MTT ].
includes 10 pictures, sorry for broken english.

setup: version 0.40.02, phoebus tileset
3*3 embark forest with an aquifer
the first 2 soil layers (loam) will be dropped, about 60 by 60 Urist
including Multi-Tile-Trees [ MTT ], 8 of which with a diameter of 2 Urist, and some ponds
leading questions:
how will MTT, and their roots, react on cave-ins?
do attached dug-out stairs resist cave-ins?
bonus: some human volunteers, a sow strapped to a rope, 1 wild bear and its 3 cubs in seperate constructed cages, a group of animals in a pasture.

Spoiler (click to show/hide)

****DF computes 5mins~****
as to be expected all buildings deconstruct, except for the bridge with the human wagons on, attached to the wrong side.

Spoiler (click to show/hide)

dust shooting up to the highest z-level +16
pastured animals crash into each other on the way down.
masterworks are lost.

Spoiler (click to show/hide)

some animals and the human test subject show spontaneous combustion on impact, unknown behavior for these species.

Spoiler (click to show/hide)

the impact site, z-level -8
no MTT to be found, no logs to be seen (those in the middle are the ruins of a 2 story wooden house).
at the uppest level,the attached stairs turned to loam, a YES to my 2nd question.
as to be expected the duck and the cat survived the 8 story drop of all the animals(of the pasture).

Spoiler (click to show/hide)

the impact site, z-level -9
the ponds were transfered with some water loss, possible relation to volume, depth and original size of the pools.
MTT-roots vanished, leaving holes in the ground.

Spoiler (click to show/hide)

ground level
most of the MTT have vanished.
remaining MTT, downward ramps, bumblebee colonies and a hamster refuse to obey to gravity. which is still the law.
ramps have shown similar behaviour in past expirements.

Spoiler (click to show/hide)

above ground, z-level +1
MTT exist(?) as before on all z-levels.

Spoiler (click to show/hide)

building floor to reach the trunk seem to trigger the cave-in check.
parts of the tree collapse into thin air.
no logs are found.

Spoiler (click to show/hide)

after weeks more trees shift back into the dwarven realm of existence.

Spoiler (click to show/hide)

same behavior as the remaining first, MTT without a floor beneath them, seem to be trapped in a paradox state of being there or not, or both, and will vanish out of existence, by building a floor in its/their proximity.
the caged bears were assigned to a pasture, and may have been unharmed(from the fall), but i watched the trees reappear in the meantime, results unclear.
the sow had no chance, its piglet survived with a broken nose and a missing rear leg.
the human was fine overall, just some broken bones.

conclusion:
multi tile trees attached to a falling soil layer will not accept gravity or the common frame of reference , but will go into a metaphysical state of existence instead.
dugout stairs (attached to solid ground/rock) will resist a cave-in.
freefalling may result in spontaneous combustion on impact. results indecisive.

[MarcAFK]

not sure what to make of this.....

[stool]

me neither, these are just results of science.

they behave like a http://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat in some ways ....

[Edmus]

Jolly good sciencing Sir!

[Solon64]

A couple of notes to help make sense of your findings:

The humans and so on are not spontaneously combusting, the combat reports you read about bursts of boiling magma are just the games way of saying a cave-in happened.  It isn't magma, nothing catches on fire, and so on.  Test: cave-in any stone tile near a creature and read the combat reports.

Trees also currently do not check for cave-ins.  What happens is when a tree's soil layer is removed, an invisible fake unsupported tile is created.  Whenever you cause anything next to it or even nearby to cause a cave-in check, such as building a construction like a floor, the game will realize that the fake tile is in fact unsupported and will cave-in.  This cave-in will destroy the tree in its entirety, leaving no logs, much like if you chop out all of a trees roots.  Poof, gone.  This fake floor tile is why you get a lot of random cave-in warnings on the surface right now, particularly when channeling near where trees used to be.

(side note: the game not checking for cave-ins with the invisible fake floor tile amuses me.  I always picture Wile E. Coyote chasing the roadrunner and then looking down and realizing he's over a canyon.)

The water loss from your pools is interesting, really.  Possibly mid-air evaporation?  Some being crushed under falling debris?  Possibly needs more looking into.


All in all, great work.  My computer would probably melt trying to calculate all that.

[stool]

(side note: the game not checking for cave-ins with the invisible fake floor tile amuses me.  I always picture Wile E. Coyote chasing the roadrunner and then looking down and realizing he's over a canyon.)

that was also on of my first thoughts, and i would also accept the roadrunner/coyote frame of reference as the possible explanation.