Blender is amazingly powerful, but might be hard to use for beginners. Maybe you'd be better off with
OpenFX or
Wings 3D (I believe it's just a modeler, but you can
export your models to
POV-Ray or even render using POV-Ray from within Wings 3D) or perhaps
Anim8tor if you just want to learn the basics.
hamaPatch and
sPatch are two nice free spline modelers so you could give them a look as well.
For landscapes you could use
Terragen which is free for personal non-commercial use and
Arbaro seems like a neat tree generator.
There are plenty of tutorials on all those sites, good luck!