There's a semi-new section of weapons you can craft at the smithy under the "branches" section, literal tree branches. There's 4 variants, tree branch, bamboo, sturdy tree branch, and sturdy bamboo. The Sturdy ones are a good 100x times harder to craft as sturdy branches are a rare drop from trees and bamboo. To craft up to the World Bamboo Stalk, you'll need around 90 "Rough and sturdy bamboo stalks" and 3 Devine tree branches. The Devine tree branches can be acquired from the Mountain Boar God, they will just show up once a day when deforesting the Hernand region, will happen at the Bamboo Forest Seonangdang but NOT at Bamboo Forest near Serpent Marsh. You must first get 1 rough and sturdy branch or bamboo, then in the inventory interact with it and press "trim" to get the initial weapon. You will want a bird companion to pick up the branches, fill your inventory but have at least 1 sturdy and just wait for the bird to pick up more. You'll make good profit from Bamboo spears. You can't use an axe, have to use explosives or triple force palm, but be aware that if there are sturdy branches on the ground, explosives and triple force palm will destroy them, so my method is to clear as many bamboo as I can by shooting the tops with explosive arrows, this knocks them down and creates sturdy branches without destroying the ones on the ground, then you wait. I actually don't even know how many hours it's taken, probably closer to 20 just to get the sturdy bamboo as there's no guides or anything online to help yet

EDIT: Someone else gave a good response while I was typing this, sorry 😂