Strange Result

A number of years ago, I was on a photo outing to our Missouri Botanical Garden here in St. Louis Missouri. During that outing, I took two photos of the tree pictured below. These photos were taken 17 seconds apart . My shooting position was in the shade of the trees and the tree was backlit.

The camera I was using was a Canon 1D-III... 1.3x crop sensor. The lens used was a Canon 100mm Macro f/2.8

First photo: ISO 200, f/14, 0.5 sec

Second photo: ISO 200, f/2.8, 1/5 sec - taken a bit closer to the tree 17 seconds later

Any thoughts on what may have caused the phenomenon experienced in the first photo?