The Log-splitting scrimshaw is an item that can be made with the Fletching skill at level 85 once all four scroll fragments of Log Splitting have been retrieved from the Player-owned port.
The scrimshaw requires level 70 Woodcutting to use. When active it gives a 15% chance of destroying a log as it is cut, granting additional Woodcutting experience equivalent to a proportion of the experience gained when Woodcutting a log normally. Depending on your Woodcutting level, you could expect about a 5-10K xp/hr increase if cutting Arctic Pines.
The inferno adze also has a chance to destroy a log but grants full woodcutting and firemaking experience instead.