
Jonathon O. answered 04/17/23
MS in Botanical Systematics (currently pursuing)
Well, this does depend a bit on which tree species you're dealing with. The term "deciduous" just means that the plant tends to drop its leaves when conditions are less favourable or when it is energetically beneficial. There are many different degrees to which a plant can be deciduous or even different processes by which their leaves senesce.
Generally, I believe that if you're relocating a native, southeastern (US) tree to a greenhouse, it most likely won't drop its leaves as it won't be stressed by changing temperatures as it normally might. (assuming that moving it, changing water regimes, changing light regimes, differing fertilization regimes, etc. won't also be a potential issue). Hope this helps a bit!