2/6
Once in position, you can perform the spellswap glitch (double frame perfect inputs) to cast Homeward using the cast animation of Force. If you are standing in the correct location, you will drop off the roots and cancel the ending animation of Force.
Explanation (1/6):
This is a sequence of precise movement and queued actions, needing to be done almost entirely on keyboard inputs, to place the character in a consistent location on the roots of this tree in Firelink. (Setup found by androv)
3/6
Once your animation is cancelled, you can move around before the Homeward warp occurs. If you rest at a bonfire before this warp goes off, you will get wrong warped to the default location of the area your *previous* bonfire was in.
4/6
For Any% runs, which this setup will be useful for, my previous bonfire would be the Lordvessel in Firelink Altar, and the "default" location for that map is in the Kiln of the First Flame.
5/6
This setup is being used because getting on the correct spot on that tree is EXTREMELY annoying through conventional analog stick movement. However if you do this sequence correctly, you will end up in the right spot 100% of the time!