The idea that the thermodynamic arrow of time arose from a gigantic fluctuation leads to an amusing form of solipsism. From the standpoint of entropy, I, sitting at my keyboard typing these lines, am a pretty big fluctuation. A tree that I remember seeing is also a big fluctuation. It would be a smaller fluctuation, entropy-wise (recalling that entropy is extensive), not to have the tree, but to change my brain slightly and create the memory of that tree. Therefore, in terms of likely or unlikely fluctuations (and that's what entropy measures) it would be far more likely that the tree doesn't exist. You, reading this, should similarly doubt the existence of the writer.