Please take into account, that scenProc is completely dependant on the quality and quantity of OSM data: No buildings, no trees - nothing in aerofly.
What can be done?
You can use a GIS system as I did before we had scenProc. Place semiautomatically objects there and export them to TOC file format. But GIS is a topic which requires a lot of knowledge.
For single trees go to Google Maps, click to the desired point, copy the coordinate and paste it to another set of lines in the TOC. It sounds arduous, but in fact, single trees with a customized size don't look bad.