The first consideration is the way the wood is cut. When the wide face of the board is parallel to the annual growth rings the cut is called flat sawn. When the rings are perpendicular to the wide face, it is called quarter sawn. When the board is somewhere in between, it is called mix grain or bastard cut. The cut is important because the natural tendency of wood is for the annual growth rings to flatten out plus the shrinkage of the wood is greater across the grain (flat sawn) than through the grain(quarter sawn). For these reasons, builders should normally choose quarter sawn wood for greater stability.
Along with the type of cut the builder should look carefully for straight grain on both the face and the edge of the wood. This is easier on quartered pieces because the straight lines in the grain are obvious but with practice it can be done with flat grain.
After determining the cut and straightness of the board, look carefully at the quartered face of the piece or at the end gain. Are the lines or growth rings more or less uniform or are there big differences in the size of the rings? More uniform is more desirable.
Next, examine the piece for defects that would compromise the strength of the piece or its attractiveness. Obviously, cracks, checks, knots or other structural defects are not acceptable but fungus or mineral stains or spots are only an aesthetic consideration. Tension wood or fuzzy grain usually caused by a leaning tree is an unacceptable flaw.
I will always remember my instructor at the hardwood inspector trade school, Mr. Otis Goolsby, telling the class: “Boys, when you are grading wood, don’t look for flaws, look for clear wood that will make the grade”. This advice, given to me nearly 50 years ago is timeless and applies to much more than grading wood.