Now that's a question that has plagued me for years... There are lots of ways to make trees--almost as many ways as there are modellers out there making them. Some methods are only appropriate for certain kinds of trees, and results vary depending on the technique.
I got fortunate this past January when I happened on a patch of
iron weed in a vacant lot. The weeds were dried out, and the ends of the stems were covered in "exploded" seed pods. With a little paint and some ground foam (for leaves) they made really nice trees. I've been on the lookout for more of these plants, but so far have not found any...
I do have a technique for making pine trees that look somewhat like the loblolly, short leaf and long leaf pines that we have here in East Texas. Here are the steps:
1. Taper a dowel stick to a point.
2. Rough up the surface with a sawblade or file to give it a "bark" texture.
3. Paint the dowel a bark color and highlight it with India ink diluted with rubbing alcohol.
4. Drill holes in clusters down the length of the dowel.
5. Glue branches of preserved caspia (not the dried stuff, it's too brittle) into the holes.
Click here for a picture of some caspia. You can find this stuff in craft stores and flower shops.
6. Cover the branches on Woodland Scenics foliage (the colored polyfiber covered in ground foam).
I do these in assembly-line fashion. It seems to speed up the process, and the results are pretty good. I use a mini drill bit that I mount in a hobby knife handle to drill the holes. There are miniature screwdriver-type drills that would be easier to use, though. I think those can be purchased from
Micro-Mark (assuming they don't charge an arm and a leg to ship to Portugal).
One word of warning: preserved caspia STINKS!! I keep it wrapped in newspaper and tucked away in the closet. When I need some, I break off a few bits at a time. The amount that I use on the trees isn't enough to create any noticeable smells...
Attached is a picture of a couple of my pine trees. My layout is N-scale, BTW...