Here are a few illustrations from my early years of modeling, lighting, texturing, and rendering in 3D software, from 2001.
The forest was generated from the technique of instancing using hair as the guide. So, for each strand of hair in the scene, it was replaced with an instance, or copy, of a tree. The tree was generated using an old Lightwave tool called Treecage. The instancing software was called Shave and a Haircut. Shave is now an integrated part of all major off-the-shelf software, such as Maya, SI, Max, and C4D.