Love this idea - where I live (near the beach), there are always odd planks of seadrifting wood, sometimes natural sometimes not.

My question is: how did they get afixed to the wall? Is this a permanent display or a panel that is removable?

This idea reminds me of a repurposed ski fence I photographed during a trip to Mt. Rainier: http://craftscafe.wordpress.com/2010/02/04/artful-re-purposing/

This is a great way to bring in color! Love the reclaimed...think I have half of what I need already to do this!
Sandcitygal - think you could do it either way. You could easily screw or nail the pieces directly to a wall. If you wanted a panel, you could use either attach all to sheets of plywood or use 2x4s (or any long strip of wood) every so often on the back. This way you would only need to attach in a few places, rather than having nail holes all over the place. If you can't attach anything to the wall, maybe lean the completed piece?