Minecraft wiki entry for Before_Beta_1.8, associated text: There were 13 biome types: 10 in the Overworld, 1 in the Nether, and 2 unused ones that are in the code but aren't encountered in normal play. These biomes were added in Java Edition Alpha 1.2.0, and relatively few changes were undergone to these biomes other than the introduction of birch and spruce trees in Beta 1.2 (which allowed for new chunks to have birch trees generate in forests and spruce to generate in taiga in place of oak trees), desert biome borders being rotated due to then not lining up in Beta 1.4, and the introduction of tall grass and ferns in Beta 1.6.