Revision history [back]

What you should do is trying to align the pictures based on feature points. What I would do is

1. Use a manual step to select a bounding box of the tree in all images
2. Calculate feature points in each bounding box (SURF, SIFT, ORB, ...)
3. Align the picture by finding matching feature points
4. Combine images based on this points --> merging them with an opacity of 50% or so.

However, I think that in order to get a great result, you will need to find more robust implementations. But this would give you a start.