Explain This

I was walking down a wide trail in Eagle Creek Park yesterday. I had been birding for about three hours at the time and wasn't moving very fast. The usual hikers, runners and bicyclists were enjoying the warm spring day along with me.

There was very little ground cover and the leaves were still small on the trees, allowing for excellent visibility. I was approaching a point where the trail I was on intersected with another equally large one. I looked to the right down the trail that crossed and saw a rather tall Caucasian hiker wearing a gray t-shirt, blue shorts and tennis shoes walking toward where the two trails intersected. His hair was light brown.

The man continued walking when he went behind a tree that was rather big in circumference. He never came out the other side. At the pace he was walking, he should have only been blocked from view behind that tree for a couple of seconds at the most. I kept watching for him to come out from behind the tree, either in the direction he had been walking or the opposite.

Then I thought the man had stopped behind the tree, perhaps to rest or relieve himself. I continued to wait for him to appear from behind the tree. After a couple of minutes, curiosity got the better of me and I went to the tree. There was no one behind it.

The man was not an illusion. When I saw him, he appeared to be a normal living human being. He was not translucent nor did he resemble, in any way, something I would call a ghost. Yet, he had disappeared as surely as if illusionist/magician David Copperfield had conjured him out of the picture.

I offer this small event to the reader and ask you, what do you think I saw? How did this man, walking so normal down a wooded trail in a city park come to disappear behind a tree?