We in wildfire country commonly refer to "limbing" (or "limb up a tree") as removing growth in the lower part of the trees to protect against the spread of wildfires/decrease likelihood of crown fires.
I use "limbing" to differentiate my meaning from "pruning," which I would describe as trimming branches for the health of the tree and/or for training it to grow in a certain way.
I think your regional location could determine the context for this one, which may make it ambiguous.
I can report that, although I am close to an active wildfire, we are not under evacuation orders yet, and the wind(at this time) seems to be pushing the fire away from us.
We do have a friend who runs a permaculture CSA farm, and, due to the evacuations, has not been able to care for his crops.
I don't know if this is biologically accurate, but it seems to make sense to me:
Avoid growing leaf-centric produce in favor of fruiting or root crops - any gaseous or sooty emissions that would enter through the leaf systems would have to travel through the entire plant(and hence be partially filtered/remediated) before getting to the part of the plant you would eat?
I feel like usually they just don't want our "alternative" systems to be the ONLY system we have, so that if we change our minds, sell the house, or have issues, etc. we can go back to the "conventional system" with little hassle.
If you put in a conventional system AND a grey water diversion system, and they might be happy.