The final steps were to paint over each base with the same cheap craft paint I use for all of my bases. I’ve had this paint for about 10 years and I think I bought it new for about $2.50 from Michael’s. Once dry I painted a third coat and dipped each base in the flock wet. The results were pretty nice. The bases did warp slightly but not enough to make it noticeable. The only thing left to do is put a couple of coats of matte varnish on the bases to hold the flock in place.

The (nearly) finished product. An inexpensive solution to getting some trees on the table. The white stuff on the tree in the foreground is probably some plaster dust. It was easily removed.
Over the course of 3 days, it took me a total of 3 hours to produce the bases and mount the trees. Doing the initial spray down of the trees with matte varnish took maybe 15 minutes. The trees themselves cost about $30. All other products costs were negligible and came from supplies I had on hand.