Unlike some basket materials that require travelling high into the mountains, we collect our willow along waterways like the Klamath River - and more recently a small patch we are "maintaining" closer to home. Like hazel, we want the long, straight, thin sticks as these are the best to use as the warp of our baskets. Sometimes, in larger open weave baskets (baby baskets and burden baskets), the thinner pieces can also be use as weavers.
Some of our basket materials are best to gather after fire has gone through the area. That isn't so with willow. But still, the most usable sticks come from new, fresh growth. To that end, many basket weavers will maintain a personal willow area by cutting back the plants every year.
When a weaver first decides on an area to maintain, often it has years-old willow plants that have grown quite full and wild. Some weavers will cut them to the ground, but we like cutting them to about waist height. New growth of long, straight sticks will grow from the cut off places, making future gathering easier than bending to cut them from the ground.