UPDATED 3/17 to show when to change needle size.
Finlandia is a fitted, worsted-weight beanie that is knitted in the round from the brim to the crown. The repeated tree motif is made from basic lace stitches (K2tog, YO, and SSK).
The yarn used in the example is Malabrigo Merino Worsted in Fresco y seco. I recommend using a solid or slightly variegated colorway to bring out the lace stitches.
This pattern is made to fit an adult head appx. 21”/22”, but it can stretch up to 24”.