First, set up the gymnastics rings around the tree. Next, grab the rings and walk away from the trunk. The rings should be waist-height or slightly higher, and you should keep tension with them the entire time. Keeping the core engaged, walk the feet slightly forward as you lean the upper body back. Ideally, you want to position the body at a 45-degree angle to the ground. As you lean back and get into position, keep the arms long. Make sure the body stays like a plank throughout this movement. On an exhalation, pull yourself towards the tree using the back muscles and biceps. Keep the elbows close to the body, as opposed to allowing them to flare out. On an inhalation, slowly return back to the starting position. Practice for a couple of breaths dynamically. You can also hold this pose statically for breaths at the top to greatly strengthen the back.