I’ve printed a few and they don’t need supports. One thing I would recommend to add variation is to heat and bend them to add new shapes.
It might be a bit difficult to bend the main tree trunks but the platforms, walkways and tree branches can all be bent by applying some heat (from a heat gun or even a lighter) and twisting them into new shapes.
This would give you some variety and make each one unique.
The Alien Jungle Clusters would also be great for Kashyyk as ground cover and you could print the single plants to add to the trees and other scenery pieces.
Hope thats given you some ideas to work with 🙂