Ground Under Repair/3 - Fallen Tree or Tree Stump Is Not Always Ground Under Repair
A fallen tree or tree stump that the Committee intends to remove, but is not in the process of being removed, is not automatically ground under repair. However, if the tree and the tree stump are in the process of being unearthed or cut up for later removal, they are "material piled for later removal" and therefore ground under repair.
First, the tree is not necessarily automatically ground under repair. This quoted case is, in my opinion, borderline. It depends on whether we view a single cut through the trunk and then abandoned as being 'in the process of being cut up for later removal'.
When the tree fell or when that single cut was made by the staff, the tree should have been marked as GUR in order to remove all doubt about the status of the tree.
Assuming the fallen tree was GUR, it sounds like you have not proceeded incorrectly. You do not take a club length from the ball. First you need to find the nearest point of complete relief not nearer the hole where the tree is not interfering with your ball, stance, or area of intended swing. From your very crude diagram it looks like this point would be 'behind' the tree. Then you drop the ball within one club length of that point. You are not entitled to line of play relief but the thoughtful Committee, as well as marking the area as GUR, should also establish a dropping zone (as an additional relief option) off to the side somewhere to alleviate the potential line of play issues.
If the fallen tree was NOT deemed GUR then you need to play the ball as it lies or take an unplayable. As the tree is fully detached from the stump, it is a loose impediment so you are entitled to move it, or to break off any interfering branches to the extent that this is physically possible. Be careful not to move your ball during this process.
