The chainsaw is a powerful time saver if used correctly, but a dangerous tool if wielded with little regard for safety. Pinching of the saw blade is one of the many dangers of using a chainsaw. When cutting a large log that has lots of weight, the two ends of the log being cut may squeeze together, pinching the blade of the chainsaw. This can cause the blade to kick back, causing serious injury. There are several ways to avoid pinching.
Lift the log up onto supports if possible to expose the underside of the wood.
Cut 1/4 of the way through the log, from the top. Stop the chainsaw blade and lift it out.
Make a second cut going from the underside of the log up through the first cut. Reverse this procedure, cutting first from the bottom then through the top, if the log is only supported from one side.
Insert a wedge into the log if it is too big to be lifted or rolled over to keep the cut open while you are cutting. This prevents the log from closing on to the saw blade.