If the wood splinters with longer fragments, it is likely sound.

Some researchers or engineers use the pick test to determine if the wood is sound.

For example, mixtures of borate and glycols are used to treat sound wood left in place during repair of decay problems.

Wood can appear stained and yet be sound, or can appear normal yet have already suffered significant strength loss due to decay.

The removal of adjacent wood is because the fungus may have extended deep into the wood beyond the area of decay and may be ready to cause more damage in adjacent sound wood.