People don't like the thought of tillering the power fibers, but yes, you can. It is straight grained, and holds together with or without a violation so long as you don't have rot. I wouldn't do it on a high poundage bow, but don't worry about it unless you are going past 50#. Some bamboo bows have the power fibers on the belly and the back is literally the inside of the stalk and is tillered on the back, not the belly. Point is, it is straight grained and will hold together unless you overdo it. If you want to get rid of the nodes, go for it. There are many examples of this online, but yes, it is not as sound. If you want a perfect bow with maximum performance and high poundage, of course don't dig into the power fibers. The power fibers give the bow stiffness and seem to enhance the performance for the oftentimes unusable belly wood it is working for.