I have a variety of responses that I give to this question, but the short answer is, "No."
This article will cover many other questions regarding this such as, "Why not?"
*NOTE* Do not try to break boards! It's a silly thing to do!
Why don't we break boards? It's not that we can't. We have the strength and technique to break boards, but like the picture shows, there really isn't much point in it. Most board breaking that you see involves a martial artist winding up for sometimes over a minute before letting out one powerful strike. Against a living opponent, winding up for a minute is not an option. An effective Shorin Ryu martial artist should be able to completely finish a fight in far less than a minute.
Also, blocks of wood and concrete will never try to attack you. So learning how to fight them is pointless. The only time that I have heard of a student utilizing their karate against an inanimate object has been from firefighters and military personnel that I have trained. They have used our techniques to knock doors down with great effectiveness, but they always trained against people and punching bags.
From the research I have done there are only two lessons to be learned from board breaking (and these lessons are learned just as easily in the normal way). The first lesson is to aim through your target. You want your strike to penetrate 3-6 inches into your opponent in order to push them backwards. The other is that you want to align your bone structure correctly when striking.
Board breaking also carries a high probability for injuries that can significantly shorten your martial arts life. The Grandmaster would not be training into his late 80s if he spent his youth pounding slabs of concrete. In karate, we take care of our bodies so we can be effective and train for a lifetime.
*Repeat* DO NOT TRY TO BREAK BOARDS! THE LIKELIHOOD OF INJURY IS SIMPLY TO HIGH TO EVEN GIVE IT A TRY!