What happened to my trees?

What's the deal with trees in minecraft? Ever since the update they've been.. er... three-toned. alt text

Is this intentional behavior?


I'm fairly sure this is a bug upon the save moving to the newer version of Minecraft. alt text

I made a new world, and all the trees were generated with the same colour of leaves. Because of this, I'm almost certain the multicoloured trees were unintentional.