I don't think you understand what I'm suggesting. My numbers of 20 cm are purely arbitrary. However, the 1 meter lengths you suggest make it even easier. Measure 1 meter up from where your ground level cut would be. Make your felling cut there. Not so much stooping and much easier to level your notch and line up the back cut. After dropping the tree, cut the pre-measured 1 meter stump at ground level. I'd never suggest someone leave a high stump in the woods. Make sense?
Everyone has there methods. I think most people DO make there felling cuts at ground level. I'm just saying that if you're going to cut the tree into short lengths, and your not trying to preserve board length for lumber, it's not necessary.