As I, and other, have been experienceing crashes related to the plugin MCMMO, due to such when mining or chopping down trees we get dissconnected. I believe it has been an effect of the plugin being corrupt, from my own personal experience an update to it or a simple clean install would work out the kinks. I would recommend in the meantime that the plugin be disabled or simply removed. I appreciate your help in this matter and I hope it may be resolved.
P.S. In realtime
P.S.S. Here is the crash screen backing up the theory of it being a caused by a plugin.