I have followed the techniques described below in making my trees.  Lynn Gobin was a member of the now-disbanded West Side Lumber Co. Model Railroad Club of Rochester, MN.  Their web site is still on line.  Click their logo to visit it.  The article below is copied from their site because I do not know how much longer their site will remain active.  Many thanks to Lynn Gobin for giving me permission to publish his article here.  You can visit Lynn's current model railroad work at his personal web site, the Zumbro Valley and Western.

    

I have added a few comments on my experience with Lynn's techniques at the end of this page

Tree Construction
Lynn Gobin

Materials

A tree trunk armature Use anything that looks like a miniature tree of the scale, height, and species you want to model. I prefer sage brush twigs for larger deciduous trees like mature oaks and cottonwoods. For birches and smaller deciduous trees, I use pieces from a decorative broom I bought at a Ben Franklin craft store. You can, of course, use anything that looks like a tree, from yarrow and goldenrod weeds; to herb and tree roots; to manufactured cast metal and plastic armatures.

Ground foam Ground foam represents the leaves of the tree. You can certainly use Woodland Scenics ground foam, but I prefer AMSI. (Your favorite hobby store can order AMSI ground foam from Walthers.) I think AMSI ground foam is lighter and fluffier than Woodland Scenics. And, in my opinion, AMSI ground foam colors are more muted and more realistic than Woodland Scenics. For any tree, mix different colors and textures of ground foam. Remember, not all the leaves on a tree (or the sides of an individual leaf) are all exactly the same size and color. I’ve included a chart of the colors and texture mixes I use.

Woodland Scenics Polyfiber Used to build up the volume of the tree’s foliage.

Here's an interesting and cost-saving tip from Paul R. Rivers, Webmaster of the NMRA: You can use plain old white poly pillow stuffing to make trees if you paint it black beforehand. The application of black paint also adds an illusion of depth to the tree.

Fast drying clear spray enamel or lacquer Stiffens the Polyfiber foliage, readying it to accept the ground foam leaves.

Hair spray This is the world’s cheapest spray adhesive, and is used to glue the ground foam to the Polyfiber. I suppose you could use some other brand, but I prefer Aqua Net Unscented Super Extra Hold in the pretty lavender can. (Can anyone explain why an “unscented” hair spray includes fragrance in its list of ingredients?)

Another fine tip from Paul R. Rivers: The cheaper the hairspray the better. The cheapest brands are usually diluted clear varnish in a spray can.

Ground Foam Color and Texture Mixtures

The following table of foam color and texture mixtures is used courtesy of Sweetwater Scenery Products. For realistic scale model scenery and supplies, contact Sweetwater Scenery Products, PO Box 4242, Casper, WY 82604, (307) 237-8474.

Species Parts AMSI Ground foam color/texture AMSI
catalog
number
Oak 1
1
1/4		 Olive Medium
Grass Green Medium
Olive Fine		 432
442
431
Silver Maple 1
1/4
1/16		 Grass Green Medium
Grass Green Fine
Spruce Fine		 442
441
551
Elm 1
1/4		 Medium Tree Texture
Grass Green Fine		 207
441
Ash 1
1/4
1/8		 Grass Green Medium
Grass Green Fine
Yellow Green Fine		 442
441
411
Cottonwood 1
1/2
1/4		 Olive Medium
Eucalyptus Medium
Olive Fine		 432
562
431
Sycamore 1
1/2
1/4		 Gray Green Medium
Olive Medium
Olive Fine		 472
432
431
Poplar 1
1		 Spruce Fine
Grass Green Fine		 551
441
Aspen 3
1
1		 Grass Green Fine
Spruce Fine
Timber Products Meadow Green Course, #102-12		 441
551
-
Birch 1
1
1/2		 Medium Tree Texture
Grass Green Fine
Olive Fine		 207
441
431

Assembly Instructions

  1. Prepare the tree trunk armature by trimming it to size. Optionally (but preferably for larger trunks), "peg" the bottom of the trunk with a small wooden dowel or a nail so you have something to stick and glue your tree into your layout.
  2. Prepare your ground foam mixture, and put a cupful in a shaker container with 1/4" holes.
  3. With your fingers, tease out a golfball-sized chunk of Polyfiber into a thin sheet.
  4. Cut out a postage stamp-sized (or smaller) piece of the Polyfiber sheet. With two tweezers, tease out this piece of Polyfiber until it is as thin, as wispy, and as lacy as you can possibly make it.
  5. Using the tweezers, pull the Polyfiber piece onto an individual branch of the tree. If you are using an armature of a natural material like sage brush, you won’t need to glue the Polyfiber to the armature. Natural materials have enough surface texture to grab and hold the Polyfiber in place. Manufactured armatures, however, like those made from cast metal or plastic, might be too slippery, and sometimes need just a touch of some sort of adhesive to hold the Polyfiber.
  6. Repeat steps 4 and 5 until all of your branches are covered with the Polyfiber. Remember that when you look up through the branches of a real tree you see mostly blue sky. So on your model tree, leave plenty of empty space, and maybe a "dead" branch or two.
  7. Fast path alternative: Instead of cutting, teasing, and pulling small pieces of Polyfiber onto your tree armature, take the sheet of Polyfiber from step 3 and drape it over the entire tree. Tease the Polyfiber around the branches.
  8. Please use a spray booth or an appropriately rated mask or respirator during this step! (I use both.) Spray the Polyfiber foliage base with clear enamel or lacquer. Set aside and let dry for at least 15 minutes. This will ensure that the Polyfiber sticks to the armature. The enamel or lacquer also stiffens the Polyfiber, thus preparing the fiber to receive the ground foam.
  9. Liberally spray the Polyfiber foliage base with hair spray, avoiding, if possible, those parts of the trunk and branches you don’t want covered with ground foam. Immediately go to the next step!
  10. Turn your tree upside down and sprinkle the ground foam mixture onto the still-wet-with-hair-spray Polyfiber. Cover the bottom side of the foliage base on each branch. Then, turn your tree right-side up and finish sprinkling the foam mixture onto the tree. Stop sprinkling the ground foam just as the Polyfiber starts to "disappear."
  11. Suggestion: Sprinkle the ground foam over a grocery bag or some newspaper. The "over sprinkle" can be reused on other trees.
  12. Tap off the extra ground foam and lightly spray with hair spray. Let dry for at least 15 minutes.
  13. Using your scissors, trim off any stray Polyfiber strands.
  14. Lightly spray one last time with hair spray.
  15. Plant, and stand back and marvel at your creation!

Tips

bulletUse a darker green ground foam on the underside of the foliage and a light sprinkling of yellow or yellow-green on the top of the foliage. These add shadow and highlight to the foliage and provide a greater sense of depth.
bulletI can’t stress enough how important it is to tease out the Polyfiber as much as you possibly can. Your goal should be to build a tree that you can see through.
bulletVary the color and texture of your ground foam mixtures, certainly from species to species, but also from tree to tree.
bulletExpect to spend a lot of time with each tree. Although relatively simple to do, this technique can require up to an hour per tree. Putting the Polyfiber on the armature is time consuming and, frankly, boring. But sprinkling on the ground foam is quick, fun, and rewarding! That’s when your tree really takes on life!
bulletIf you’re making a bunch of trees all at once, try building them all one step at a time. For example, prepare all the trunks, then fiber all the armatures, and so on.
bulletAnd one last reminder: please use a spray booth or a respirator when using spray enamel or lacquer!

John Hubbard's Comments

I have built two sets of trees.  I had some white polyfibre when I built the first set, and used some Hunter Green spray paint to color it.  The polyfibre for the the second set came from the Woodland Scenics Moonshine Still kit and was already black.  The black polyfibre definitely gives a better appearance, because it seems to disappear as the "leaves" are added and does not give such a dense green appearance.   Also, I found that a gentle touch with the application of the leaves is important.  Too many leaves gives a fuzz ball appearance, whereas a lighter covering, where the black polyfibre just begins to fade into the background, is more authentic looking (at least to my eye).

This page last updated 01/15/2007