The amount of ribbon you need for your Christmas tree will depend on a few factors, such as the size of your tree and how densely you want to decorate it. As a general rule of thumb, you should aim to use at least 100 yards of ribbon for a 6-foot tall tree, but you may need more or less depending on your personal preferences. If you're looking to cover the entire tree in ribbon, you may want to consider using a longer length, such as 150-200 yards or more.