How to Get The 5 Centimeters Per Second Achievement
To get the new 5 Centimetres Per Second Achievement simply collect the pink/white cherry blossom flowers you will find scattered across the world floor.
Once you have ten of either the white or pink cherry blossom you can craft the Pink or White Cherry Tree by having the flowers in your hotbar and right-clicking whilst selected to craft either tree. Once you have a total of 10 trees just plant them all.
I planted mine in a single row and the achievement unlocked.