Hello, great site. I've lurked about a year or so, back into archery after a 20 yr hiatus; here is my humble observation.
I harvested some shoots of willow from the Pinalenos of AZ, and let them sit a year. Made target points of nails, and went to bareshaft tune with 570 grain arrows.
Result....each arrow broke, three of them. Took about 5-10 shots, but the shafts split down the middle. One went through the target and struck the ground, rock and all.
Conclusion....I need to harvest at a different time of year. I keep at it, learning. Constructed three ramin(?) Home Depot arrows to keep learning alive, and they work great, with actual points and self nocks. I kinda wonder if the long nail points helped the willow break.