In the noble pursuit of SCIENCE!, I've attempted mad botany; making an evil tree that emits clouds of poison gas that, while not being immediately lethal, drive dwarves insane over the course of months and years.
Unfortunately, my initial test was... disappointing. Namely, the tree doesn't seem to be poisoning people, or, if it is, I haven't been able to detect it's effects.
The raw file, for your pursual:
[PLANT:SPINE_SHADOW]
[NAME:shadow spine][NAME_PLURAL:shadow spines][ADJ:shadow spine]
[USE_MATERIAL_TEMPLATE:STRUCTURAL:STRUCTURAL_PLANT_TEMPLATE]
[BASIC_MAT:LOCAL_PLANT_MAT:STRUCTURAL]
[USE_MATERIAL_TEMPLATE:WOOD:WOOD_TEMPLATE]
[STATE_NAME:ALL_SOLID:shadow wood]
[STATE_ADJ:ALL_SOLID:shadow wood]
[STATE_COLOR:ALL_SOLID:DARK_INDIGO]
[PREFIX:NONE]
[DISPLAY_COLOR:1:0:0]
[MAT_FIXED_TEMP:10000]
[USE_MATERIAL_TEMPLATE:POISON:CREATURE_EXTRACT_TEMPLATE]
[STATE_NAME:ALL_SOLID:frozen haze]
[STATE_ADJ:ALL_SOLID:frozen haze]
[STATE_NAME:LIQUID:liquid haze]
[STATE_ADJ:LIQUID:liquid haze]
[STATE_NAME:GAS:haze]
[STATE_ADJ:GAS:haze]
[MAT_FIXED_TEMP:10060]
[BOILING_POINT:9900]
[PREFIX:NONE]
[SYNDROME]
[SYN_NAME:delirium]
[SYN_AFFECTED_CLASS:GENERAL_POISON]
[SYN_INHALED]
[CE_DIZZINESS:SEV:50:PROB:100:RESISTABLE:SIZE_DILUTES:START:5:PEAK:1000:END:1500]
[CE_DROWSINESS:SEV:50:PROB:100:RESISTABLE:SIZE_DILUTES:START:5:PEAK:1000:END:1500]
[CE_FEVER:SEV:50:PROB:100:RESISTABLE:SIZE_DILUTES:START:5:PEAK:1000:END:1500]
[MATERIAL_BREATH_ATTACK:LOCAL_CREATURE_MAT:HAZE:UNDIRECTED_GAS]
[TREE:LOCAL_PLANT_MAT:WOOD][TREE_TILE:181]
[TREE_COLOR:1:0:0]
[DEAD_TREE_COLOR:0:0:1]
[PREFSTRING:unearthly chill]
[PREFSTRING:gaunt appearance]
[WET][DRY][EVIL]
[BIOME:NOT_FREEZING]
[SOLID_DENSITY:150]
[SAPLING]
[SAPLING_COLOR:1:0:0]
[DEAD_SAPLING_COLOR:0:0:1]
I theorize that it's not working either because plants are incompatible with breath weapons, or the symptoms were either too weak to be noticed, or were being universally resisted by my dwarves.
However, a second opinion would be much appreciated.