Is it me, or does that picture look like poison ivy halfway down the page where he says:
"and possibly two smaller ones (unconfirmed, since they didn't look like they could spare any leaf) peeking out from under a pile of downed trees. Why still so small? My theory is that the top growth was crushed in the general wreckage and the rootstocks had to start over with fresh shoots."
Other than having leaves of three it looks nothing like poison ivy to me. My bonafides are I have poison ivy growing on my property and clear it out frequently.
Poison ivy usually has a red stem and typically the leaves have a prominent "thumb" sticking out near the base on one side.
I had the same gut response to that photo, but (at least in the case of the first) if you look closely there appears to be a single-leaf sprout further down one of the stems, which is not poison ivy's pattern.
In the latter two photos with the smaller sprouts I could see the argument, but the leaves look to have very straight edges relative to poison ivy (and I would assume someone like this would be aware of poison ivy growing in an area of his property, especially if he has a blog about growing a plant that looks a bit like poison ivy).
"and possibly two smaller ones (unconfirmed, since they didn't look like they could spare any leaf) peeking out from under a pile of downed trees. Why still so small? My theory is that the top growth was crushed in the general wreckage and the rootstocks had to start over with fresh shoots."