First let me mention, that when working with Forest objects, you can easily select any used Custom Object via 3ds max's quad menu (right click) - Select Forest Custom Object.
If you need to access any of distributed object(s), besides of the way mentioned above, you can find all these under "forest_templates" layer. By default all objects inside of this layer are hidden and frozen. The object name will be _forest_library_*******. Any of these objects can be manipulated like any other 3ds max's object - moved to other layer, copied etc.
Hope that helps.