Hi Scorpion,
First - the trees. The first thing that comes to mind is your autogen density setting in Settings. The higher it is, the more trees you get as well as buildings. Maybe it's on a different setting than before?
As to the display problems, they bear all the hallmarks of a graphics driver problem. Was it just FS2002 you re-installed or had you re-installed your operating system beforehand?
System specs would also be a help here.
