Spalting best explained is a rot process. It is caused by a fungus, as it goes through it's 3 stages it creates the different basic 3 stages of rot,
In the first 2 stages it doesn't do much harm to the strength but creates beautiful markings and stains throughout the wood.
From my understanding, as the first stage is finishing up the second stage starts to move in and the 2 fight which in turn
creates the bold black streaks. The wood doesn't lose much strength until the 3rd stage as this is when the damaging reaction starts.
We allow ours to spalt in a natural state in log form. Most of the time the logs will "lay" around our log yard for 2 or more yrs
prior to sawing, this also allows the logs to relax more and actually have a aged look and feel when sawn. Oaks
in my opinion have a more prominent aging when this process is used. Some types of wood will spalt quickly while others
resist the fungus with their natural abilities as sassafras and walnut.