River cane or bamboo, "nature's carbon".
I only recently took up archery and began by building bows and arrows. The river cane is easy to work with, can be straightened easily by heating on a stove top for a few seconds. I self nock and treat the nock with super glue for durability and hardness. For practice arrows, 9MM shell casings make a durable blunt point. I have not yet learned to fletch with feathers, using duct tape shaped with scissors.
The cane is tapered naturally, and the joints can be smoothed out somewhat. I don't fully understand why they work so well, they just do.
I also made a couple of arrows from 5/16" oak dowells that work very well also. I had to sort through a bin of 30-40 to find 5 straight ones.