Placing trees through script

Hello, I have a question about placing trees. Right now, I'm trying to create a Terrain generator based on Perlin Noise. I've been able to generate a heightmap then apply that to a terrain and generate a splatmap for terrain textures. However, I can't seem to find any sort of forum post/answered question/documentation regarding placing trees on terrain using script. I know I could be using a tree prefab, but I would like it to be integrated in the terrain, if possible. I heard Terrain trees are treated much the same way as textures - using maps... I'm not sure if this is true. If it is, how can I apply a "treemap"? help pl0x :S