Lol welcome to Valheim.

Here's a few tips when felling trees.

1: A tree on relatively flat land, when felled will generally fall in the direction you (Your character, NOT THE CAMERA) are facing.

2: Survey the tree, note everything around it. Is the ground flat or angled (this can cause the tree to tumble in an undesired direction); Is the tree touching another tree. Think of the tree as you would a Domino-piece, will it fall into another tree and cause a cascading effect?

3: Bring wood. Build a crafting table and then build Vertical Wooden Poles (two high) on the sides of the trees in the direction you DO NOT want the tree to fall towards. Ex: On a slanted hill slanting North, you want the tree to fall Northwards, so you then build Vertical Poles on the South to catch the Timbers and prevent them from rolling. The poles do not need to be exactly next to the tree being felled, they may be placed 4-8m away from the tree in staggered rows.

4: A Timber that is falling can have its direction manipulated if you Jump-Punch the tree (Punching from the ground can work too but has less manipulating effects). As long as you're character hits the top portion of the timber (The top being towards the sky) then falling damage from the timber is negated because you are not underneath the tree.

Good luck!