I noticed early on that the items we expanded to.....troll pit, tablet, roost, etc. were not storable. I'm glad we can at least move those, and the barons tent. But I wish they could be stored!
As for the outpost......I wish they would stop the sparrow animation so we could move the thing. And they really need to shrink its footprint. Lots of prime real estate going to waste!
I suppose not storing the cellar makes sense, because we had to build it to start our inventory, but what I've never been able to understand is why clicking on it doesn't bring us to the inventory, since it is our 'storage' after all.
Ps. I agree about trees. I really think they should be storable. It makes me sad to think of how many full grown trees I had to chop down to clear space when I first started expanding.
My guess is the developers don't want us to be able to grow and store trees in advance for use in timed events.