This is from the ILBA standards for log construction,
2.J. Kerfing
2.J.1. The kerf is usually, though not always, a cut made with a chainsaw.
Logs are known to check, or crack, in those places where wood has
been removed closest to the pith, (or the center) of the log. Kerfing is therefore an effective way to control the location of checks as green logs dry.
Because dry logs already have seasoning checks, kerfing usually will not change the location of checks, and therefore kerfing is not required for dry logs.
2.J.2. The kerf must be deep enough to promote checking. Note that even those long groove profiles that do not require kerfing (like the double-cut) are nevertheless required to be the depth of at least onequarter of the diameter of the log at every point along the top of the log. (See also Section 2.D.5.)
After a log has both the kerf and the long groove cut, there must still be at least one-half of the diameter of the log remaining un-cut. Removing more than half the diameter of the log for kerf and groove combined would weaken the log, and so should be avoided.
