Mostly because I haven't found a group consistent and committed enough in my immediate area for any form of regular play. And so I build a lot of terrain for that specifically, that can be used modularly to help generate a better idea of the imaginative world in which I am playing the game. Of all the terrain I make, trees are by far my favorite. I never feel as if I can have too many.
Sometimes a small encounter is perfect though, and for that, a bit of extra foliage and even just a small scene-scape can be ideal. Not only can it add to a greater forest diversity when used in with larger terrain, but on it's own it stands as a unique scene. For this use I created a small scene with only two small aspen trees, a small base, and a few natural stone accents with surrounding foliage.
I started with two strands of small wires, and banded these together with simple electrical tape. From the tops of that I added actual wood strands in smalls tick like branches, gluing each individual stick onto another to get just the right natural look.
Once I had the sticks 'bound' together and the basic tree form assembled, I added more masking tape, winding it up and around the trunks before adding a cream-white colored paint (rather thick) to the masking tape itself, allowing the lines of the masking tape to show through just a bit to give the look of bark and natural wood grain.
This was followed with a charcoal colored paint dabbed in varying sizes to give the aspen-like illusion of knots and divers in the natural wood-the 'spots' look. A very light dry-brushing of a softer tan over putter edges of the branches mirrored well the changing look of the flocking added to the tree tops too.
Instead of going with completely green as I have done in the past, I added in flecks of lighter almost, burnt, coloring to give the look of changing leaves, or maybe a bit of natural tree fungus, disease, parasite, etc.
The base was made with my go-to material: thick foam-core in black with paper-backed edging (called Gator board in the Design/Advertising world), and carved first with a simple hobby knife for texture and stone, then flocked with a mixture of green foliage made from a combination of pencil shavings, standard pva glue, green paint, and light bits of green food coloring.
Applied over a thin layer of painted-on pva glue and allowed to dry before drilling the tree holes allows the flocking to run right up to the base of each tree trunk.
Finally, I added a few small natural stone accents (to give the base weight0 and surrounded the tree trunks with standard hobby-shop floral lichen.
Finally, once completed, the stone edging of the foam board was painted in three layers of alternating gray:
1: A darker, deep gray in vertical strokes only.
2: A lighter stone gray in sideways lightly applied strokes, allowing both the black of the foam core and the gray of the previous layer to show through ever-so-slightly.
3: a dry brushed layer of light, almost white-gray over the top giving highlights of natural granite.
The result is a small little grove, single forested encounter piece, or modular tree stand for use alone or in conjunction with additional tree pieces.
As Cavalier Elrik once said, "There are more trees in Flannessia than tears. Pray it will always be so."