My keyring is 6 cm x 8 cm.
Materials:
- Green yarn, leftovers of various colours’ yarn (acrylic or cotton) of your choice. The consumption is minimal. I used acrylic yarn, 450 m / 100 g
- A crochet hook, I used 1,25 mm crochet hook
- Hollow fiber for stuffing 
- A piece of wire approx. 1,5-2,0 mm thick and 40 cm long
- A sewing needle, matching sewing threads
- Trinket

Abbreviations:
ch – chain
sc – single crochet
inc – increase (2 sc in 1 st)
dec – decrease (single crochet two stitches together)
(...) x N times – repeat instructions in brackets N times

Make a 40cm long tube 
Rnd 1: 6 sc in Magic Ring
2-120 Rnds: 6 sc
Cut the thread.

Prepare a piece of wire, it should equal the length of the tube. Insert the wire into the tube. Pull off the loops, hide the end.

Bend the wire to form a ‘snake’. Use the pliers if the wire is stiff or if not then simply bend it with fingers. Start from the top. See the photo for guidance. 

Insert the Christmas baubles in the hollows and sew them on. Alternatively you may use ready made large beads. 
Small Christmas bauble
Rnd 1. 6 sc in Magic Ring
Rnd 2. 6 inc (12)
Rnd 3-4. 12 sc
Rnd 5. 6 dec (6)
Add hollow fiber. Pull off the loops. Cut the thread, hide the end.

Big Christmas bauble
Rnd 1. 6 sc in a Magic Ring
Rnd 2. 6 inc (12)
Rnd 3. (1 sc, inc)× 6 times  (18)
4-6. 18 sc
Rnd 7. (1 sc, dec)× 6 times (12)
Rnd 8. 6 dec (6)
Add hollow fiber. Pull off the loops. Cut the thread, hide the end.

Attach the key ring, chain, carabiner or a loop. 

Christmas tree keychain is completed! My other crochet patterns are in my store https://www.crazypatterns.net/en/items/56167/christmas-fawn-crochet-pattern