The question is: May a player stand on the roots of a tree as a supporting point, even if the roots are suspended above a dry creek bed? In other words, several places have trees lining the bank of creeks. some of those trees have roots that protrude out from the bank and resemble a twisted web. If a disc lands touching the bank, yet supported by the roots, may the player stand on the roots for his next shot? The roots are technically above playing surface (as in the dry creek bed example)by several feet. Or would the player have to stand down in the creek bed and place a hand (or foot possibly) on the bank to make his throw?

I would say the answer is no if all supporting points have to be on roots with no ground directly under them. The player would have to play from the creek bed unless the TD gave special instructions.

However, if the player can place at least part of one supporting point behind the mini that's still on the bank or a root that has playing surface under it, then the player could stay up on the bank.

On Hole #16, New Quarter Park, York County, VA, there is a drainage way at the end of the fairway near the pin where tree roots stretch across the drainage way and cover part of it like lattice. We take the position that if your disc lands on the roots and stays there, that's where you shoot from. If it falls through the roots and down into the drainage way, then you take your shot from below the roots in the drainage way.

I have yet to see a shot stay on the roots. Anyone who has landed there has gone into the drainage way. Someone asked if the verticality rule allowed them to shoot from directly above the disc while standing on the tree roots. I said "no" since the verticality rule is an OB thing, not a stance thing.

There is a Q&A that is close to this, see Rule Question: Bridge Over OB (Multiple Playing Surfaces)

The question is whether it can be considered a playable surface and I would say that if you can stand on it AND DO NO DAMAGE TO THE TREE ROOTS, then it is a playable surface. Though, I am sure this will generate some discussion. I doubt the TD intended the roots for use, but I have seen some hills that require you to stand on and use some roots for support to throw.

The game of disc golf tries to be as environmentally friendly as possible and does not allow breaking branches from live trees or bushes, even if they are behind the lie. This is a type of course distruction and not allowed, but if the roots are solid and thick, I think it is an allowed. However, if you accidentally break the root then there may be some discussion about course destruction. Breaking small branches can occur by accident, just be careful of intent.

It is up to the TD to define whether the roots are a playing surface. The answer to your question depends on that. The player has to play from the playing surface behind where the disc came to rest, or take relief under one of the relief rules.

In this case the roots are solid and thick with not much danger of breaking. No OB below (except during and after a rain shower). I think it would be similar to landing on a root not suspended over the dry creek bed (not all tree root systems are underground). The player may stand on tree roots if they are on the LOP behind the lie. Many times players must take a stance that involves standing on root or a rock that is not actually flush with the ground.