if it is like river cane then just let it season for about a month or more and then heat the center between the node adn straighten out the bends there first. then set aside do another once you get all of them done that way then start over with the first one and heat the nodes and straighten them out. let cool once all of those are done you can take the heatgun again and heat up the nodes and roll them on a good hard surface and a press down with a smooth flat item and compress the nodes down to wokable straightness. or you can just scrape them down and sand smooth but doing that you have to seal the nodes to prevent fungus and rot
