Diorama recipe asks for "flock" and "architect paper"

If you are trying to make paper mache', just buy a brick of celluclay and throw that recipe away...

architect paper is often called foam-core or gatorboard in the US. Flock is used a lot for model car interiors, it's finely dispersed fibre particles.

 

the "BOARD" can be found in places like Staples, used for making presentations and also fabricating buildings etc.

Flock can be material used in model airplane {radio control} as a gap filler  sulka floc or sulka flock, like micro ballons only slightly larger particals. Micro ballons are fine enough that it could be used for snow. not sure if it is available, I always snagged some from work. {used in making artificial limbs}

sulka floc has strength properties that micro ballons does not.

I also will be using plaster bandage for my dioramas {expensive to buy but cheap if you already have it}

Just glancing at the article you could use styrofoam to build up terain just be careful of using enamels on it (covering it the celuclay would do, I think)

Grizz

 

What I've been reading is the techniques used to build dioramas are as varied as the themes we can use. If I can carve a block of wood to make it look like a swamp then that works for me. May not work for others though. Like the artist who uses pen and ink in their drawings may not be able to paint a wall one color. Go with what you know.

I use stryofoam and carve/cut/melt away (using a styrofoam cutter--available in the train/diorama section of your LHS) the contours of the terrain that I need.  I then cover it all with plaster cloth (available in the train/diorama section of your LHS).  If any adjustments are needed or extra smoothing/build-up of the terrain, I use drywall joint compound. Be sure to test fit your model(s) during this build up process. Next I press-in sand, pebbles and rocks (the stuff found in the gutter or next to the curb in the street works GREAT!) followed by a liberal brush coating of white glue to lock everything down.

Once that's all dry, I coat with a plaster sealant (available in the Craft Paint section of Wal-Mart or K-Mart or similar store), then paint the basic ground color. Followed by any grass (static grass) and trees (dried roots). 

Using styrofoam as your base is nice because when you add the trees, you just punch a small hole through the thin plaster layer, fill the hole with white glue and position your "tree." The foam and plaster help hold the tree in place until the glue dries.

I then glue the styrofoam groundwork to the finished and sealed wooden plaque to complete the base.

This whole process takes a few hours and I usually have complete dio base done within a day (usually, 4-8 hours).