In case anyone is interested, here are the original photos that were combined to create my first Pep Ventosa image posted in my main album on 13 November. I walked around the tree, the same distance away all the way round. I took a photo every two steps keeping my focus point in the same position on the trunk for every shot. The photos were then combined as layers in Photoshop.
@ludwigsdiana I think it can be done with less images - maybe 10-15-ish. Amazed me how the background buildings and the white container disappeared when I put the layers all together.
@maggiemae Each photo is laid one on top of the other, then the opacity is reduced by differing amounts so that they become slightly see-through. One part of each photo is overlaid in the same spot as a focal point, and in my instance it was the trunk of the cabbage tree.