I have this issue since update 1.5 for minecraft. When I move around after starting a map in survival mode, the game freezes and stops responding. I have to force it to close with the task manager. Because of this I don't have a crash report.

I noticed this mostly happens when aboveground so I have few issues in a cave, but when I tried to cut a tree underground the game also freezes. In general it freezes when walking on the leaves of a tree, cutting a tree, walking on grass, or walking in the Nether.

I did some tests in creative mode too, and the same things happen. I can't even walk a few seconds in a Jungle Biome without freezing, but I have no problems at all when walking in a superflat world made of sandstone.

The freeze happen both in singleplayer and multiplayer.