I'm pretty sure I can replace my cogo point marker with a 3d tree that I can see in the object viewer using the realistic style and print out. Problem is where is that 3d block of the trees?
Not sure if this helps but the default symbols can be found here:
Your path may be slightly different. But -
C:\autodesk\AutoCAD_Civil3D_2012_English_Win_64bit OOPS. That's the instalation directory. Try: