Question about birch bark backing

[takefive]

Been thinking about making a hickory selfbow and backing it with as thin a layer of birch bark as I can make it.  Just for looks, because I think it might look kinda neat.  Every thread I've read says that you have to run the bark vertically on the bow, the opposite of how it grows on the tree.  I'm probably missing the obvious, but does anyone know why you shouldn't run it horizontally?

[razorback]

Greg, I'm not sure on why it HAS to be vertical on the bow but I do know that that is the natural way for the fibers to run and that is usually preferable  when building a bow. I did one of these a few years ago and lengthwise just seemed the right way to do it. I found a large yellow birch and took a couple of strips of bark from around the tree. Since the fibers of this bark goes around the tree, turning lengthwise seemed the right way to do it. All backings run the fibers lengthwise down the bow to take advantage of the natural strength this imparts.
Again I don't know if going across the bow will do anything detrimental but i wasn't willing to take chances. Of course my birch baked bow was my first shooter.

 

 

 

[takefive]

Very neat looking bow!  Thanks for the explanation.  We had a storm here last month that took some of my neighbor's white birch branches down.  They're only a few inches in diameter so I guess I'll just strip the bark off and lay it out to see if it will work vertically.