Unfortunately, it's not mechanically possible. The trees used as exterior customizations don't actually exist. Once you put them on your home, they become a part of the home and cease to exist as their own item. That's why when you want to remove a customization, you have to REMOVE {HOME} rather than REMOVE TREE/FOUNTAIN/whatever.
It's a nice idea, just not something we can do with the current setup.
ASGM Zadraes
Premium Liaison
ALAE GM (Platinum)
Logistics Lead