my thought was they look like pretzels to me
you could also use 'twiglets' or 'mint sticks' found inthe british section of the grocery store or world market type stores. sometimes even Ross has them.
I did a cake simular to that one I used craft sticks I purchased at Michael's and used Sugar in the Raw for the sand. I just glued the sticks just like a fence. laid out 7 or 8 and then glued a 2 cross sticks to hold them. Worked out great.. you could even white wash them or color any color you want.. I just left mine natural.
If you want them to be edible you can make them out of chocolate or make them out of chocolate rolled fondant an let them dry.
I did something close to this & just rolled up some chocolate fondant very thin & let it dry on some wax paper.
bcake that is a sweet cake!
i would use chocolate covered mini pretzels. they come in different colors here.