Tree Generation Glitch

I created a world, with the seed "jeb_", and I found a Jungle Biome, so I went and checked it out. I also found a river going across this Jungle, so I followed it. I was looking around at the trees, when I stumbled upon a tree that had some logs chopped off. I was like "WTF? Weird." So, I moved on, and found another tree with it's logs chopped off. I thought this world was edited by Jeb himself, or something like that. I was astonished by this world, and I have not seen anything like this before. The screenshot below shows what I mean. Put in the seed "jeb_", and see it's features for yourself. The coordinates to the beginning of this river are -212, 79, -127. Facing the Jungle, go to the left, and discover what I see through my eyes.