The text on the bottom of the GUI reads and operates as is: "Trees take a while to grow when a server first starts. This typically takes around three minutes. Sorry for the wait!". When the numbers all count down to zero, the GUI and its text will disappear and will now show the welcoming GUI.
It is meant for the growth of trees (which grows at an accelerated rate, starting from a sapling and growing into adult stage in a matter of seconds), to prepare features ready for interaction (for example, the Boulders that fill up the entrance that blocks the passage to the Taiga), and prevent glitches.
A glitch that occurs when a player loads in their Land right after the initialization leaves players stuck on the waiting process when loading their base. A solution added by an anonymous player is to walk to the Bridge and back to the spawning area, and will now the problem.