Wood Treasure Chests will randomly spawn on the surface as soon as night falls (ca. 10:34 PM) and then some more during the night, always in range of view of player-characters (no direct line of sight needed though). Wood Treasure Chests will not spawn during daytime any more like they did in earlier versions on Creativerse. Wood Treasure Chests can also appear on surface-blocks in deeper layers of the world, for example if you purify corrupted blocks/wood/leaves or place surface blocks underground. Wood Treasure Chests can - randomly - contain (as of R26 in December 2015):