When I made these trees they were to go with my 6mm Napoleonics , but they ended up looking too huge, but they work well with 10 & 15 milimetre scales and they can work as small trees in 20mm.
These trees are scratch built. The majority of the trees in this picture (above) are made out of 1.5" Styrofoam balls, some are uncut balls others are cut in half and glued back together but as two half circles, then they are painted green and brown are covered with bits of green foam (from scenic effects) which are then glued onto brown painted wooden dowels which are then attached to 3/4" metal washers, which are then flocked.
The narrow tree im n the front row, sceond from the left is two 1" styrofoam ball cut in half painted a mottled green and brown colour then all four round end up are threaded and glued one at a time onto a piece of brown painted paper-coated floral wire, the balls are then covered by pieces of the green foam foliage from scenic effects.
