I went from Paris to Cologne (Koln), which is only a little further north, and some of the journey was actually quite picturesque, as you get close to the border, through the forests of the Alsace area.

I actually remember remarking to myself how pretty the area was (little chimney-smoking timber shacks in the middle of forests, that kind of thing) but I'm not sure whether it's enough to drastically alter your journey.

Trees take nearly forever to grow. Most likely you'll never get the chance to enjoy the benefits of growing the tree yourself. However, it WILL eventually provide benefit to society (eg. bearing fruits, providing shade, beautifying the scenery, helping slow down global warming). So the reason anyone would usually plant a tree is to benefit society.