They look nice in the coroplast. How are you going to secure them to the ground? My immediate concern would be that you have a lot of surface area for wind to hit.
I basically made to triangles and slip jointed them to form the tree. I also kerf cut along the edge for a place to slip the wires into so they won't sag.
For the "trunk" I took a piece of 1" PVC and slit it at 90 degrees and slid the 4 fins of the tree into it. Sort of like the fletches on a dart.
My plan was to drive rebar into the ground and slide the PVC over them and maybe run a screw or two through the trunk to put enough friction on it so it would stay put.
I too am concerned about the amount of surface area making flying projectiles out of them...
Time being of the essence right now, I might scour the area for tomato cages. Surely I can find an avid gardener that isn't using theirs.
-Aaron