I made a few of these some years back and planned on making a bunch more to cover the top of our entertainment center. Here's how.
Wooden log, ~1 inch smaller in diameter than the base of your cone
Green craft paint
Glue gun with plenty of sticks
Green spray glitter in a can
1. First you're going to break out that green paint and cover the base and tip of your styrofoam cone. This is because you are more likely to have some bare spots that show through at these two parts of the tree and we don't want them to be white and stick out.
2. Now we are going to start glueing your feathers on. I'm totally crazy and ordered my feathers online because I knew I was going to do alot of trees and therefore needed alot of green feathers. You don't have to do green of course. White, red or gold would look fantastic too. Just pick up your feathers at the craft store or you can even take apart an old feather boa.
Start by glueing a round of feathers to the very base of your cone overlapping them all the way around. Notice that these feathers are flush with the styrofoam and not curving away from it.
3. Next you're going to go back over your first layer of feathers with another but these will curve away from the base.
4. Continue to glue feathers on moving your way up to the top of the cone. Make sure to offset the feathers as you adhere them so your "branches" are staggered like below.
5. Take your tree outside and spray it all over with as much glitter as you want for a sparkling finish. I used green glitter but you can use white or other colors for a more dramatic effect.
6. Now you're going to want to cut a piece of your log to use as the base/trunk of your tree. Luckily I got this from our backyard but if you're short on tree limbs check your local park or even a friend's firewood pile. I suggest about a 2 inch chunk but you can try out different heights under your feather tree. Adhere this to your cone's base to form the trunk of your tree.
A quick note on where you get your wood base: I like to take the bark off and for a couple reasons. One being its easier to keep clean and two is that I like the smooth look. My log came with a couple extra details too.
7. Last but not least take your star and insert the wire end into the top of your foam cone through the feathers. I found these in the wreath/fake flower section of my local Joanne and you can see that they have a few different colors.
Tada! You're done. Here's some shots of the finished product featuring two of my best models.