I think both have there advantages. I guess the question really is whether the players need to know the extent of the tree's canopy? I can think of no situation where this is necessary. Therefore the tree canopy is just pretty, not useful. What is useful is knowing where the stream is, or a rock that can be used for cover, or difficult terrain. From that point of view I like the first of the two you posted. I can see that the tree canopy is there, but I can also see what the terrain is doing. I don't see a need for outlining the canopy.

The tree on the left has a 20' wide trunk and the tree on the right has a 10' wide trunk, if these are 5' squares. That seems spectacularly large for any tree I've ever seen. Not sure if this was intentional.