2003,Brent Hull,Historic Millwork, ISBN 0471416223:
In rift sawn wood cuts, the end grain is oriented 30-60 degrees to the face of the board.
2003,. B.C. Punmia, Ashok Kumar Jain, & Arun Kr. Jain,Basic Civil Engineering, ISBN 8170084032, page 79:
Rift sawn planks shrink about one half of those cut tangentially, due to the restraining action of medullary rays. Also, rift sawn timber gives a harder wearing surface than the other and hence these may be used in flooring and other locations subjected to abrasive actions.