We actually had a class on this on Saturday. A local gentleman called Madi came to teach us how to climb the tree using a traditional method, a loop around one's shoulders and a small loop around the feet. I really wish I could post a video here of his dexterous ascent but it doesn't work right now.
Here are a couple of photos of Madi and then our valiant efforts. And yes I tried it too, and while I did quite brilliantly no photos are available....
Madi going for it.

The feet push out into a loop, which is in tension and catches on the tree.
Here goes Amir!
Here is Dante's style.
Amos comfortable with the resting position.