Including vegetation/forestry in a terrain
 

I am new to ANSYS and am currently self-teaching myself on how to model terrain features, which I find very difficult!

My task is to model airflow over a specific terrain that contains vegetation (trees, shrubs, etc) and potentially other obstacles to determine wind speeds at selected areas and subsequently determine if this would be a suitable site for wind turbines.

So far I have successfully uploaded my terrain as STL file and was able to create a volume mesh in ICEM, however it is just the terrain. I have been reading a lot of literature and it seems that most of these problems are dealt with using ANSYS Windmodeller. Unfortunately I do not have access to this and have to figure out how to do it in ICEM and/or CFX.

In Windmodeller there is a "canopy input" option which allows roughness to be uploaded from a file, which is exactly what I'm looking for in ICEM/CFX. Is there any way to do this? What file type do I need to have my vegetation/roughness in?

Any tutorials/documentation/etc would be much appreciated!