Quoted from Gogdog:
Looks great! What did you use for the clear washers at the bottom of the trees?
Yeah used these clear plastic/ rubber washers I got off Amazon, drilled a 1/8" hole in the center, I liked the idea of clear not to block what little art work on the plastics. Oddly enough I first tried super glue, no luck would not adhere, I could glue my fingers together but not plastic and rubber LOL. Then tried model glue, same result. Then went to Lowes and got some DAP Rapid Fuse with primer for $5, which was made for plastic and rubber and worked like a charm. Then used two sided tape under the rubber disc cut out the access and pealed and stuck on where I wanted. I used two sided tape I got off Amazon, the kind you can remove if needed, just in case to avoid damage.
Anyways below is some links off Amazon of washers and two sided tape and a pick of the glue I got from Lowes
If you need trees let me know I will sell you mine dirt cheap, shipping plus maybe $10,I could only find a 30 pack LOL and have a bunch left over.