Abstract: A method and apparatus for use in breaking wood, such as wood splitting and tree felling, for causing the wood to break under the influence of a force acting on the cutting surfaces of a notch in the wood, such as a saw notch. The wood breaking force is produced by means of an inflatable cushion which is inserted in a flattened state into the saw notch and connected to the combustion chamber of the cylinder of the power saw motor to be inflated with compressed gas from the combustion chamber. Also disclosed is a special spark plug for the power saw motor for use in supplying the compressed gas from a combustion chamber to the inflatable cushion.

Abstract: A method and apparatus for use in tree felling for causing a tree to tip under the influence of a force acting on the cutting surfaces of a saw notch in the tree trunk. The tipping force is produced by means of an inflatable cushion which is inserted in a flattened state into the saw notch and connected to the combustion chamber of the cylinder of the power saw motor to be inflated with compressed gas from said combustion chamber.