I couldn't say for sure if the string material is stronger than B50 but I would tend to think not.
I think long arrows are common world wide and not just in tropical areas
Pat; All the arrows are 2 fletched. I don't know what the blade is on the Bamboo arrow but the edge is fairly sharp. I've never seen a Palm frond so couldn't say if that is what it is.
I took a few more picture with a different background