Biome



Biomes are regions in a Minecraft world with varying geographical features, flora, heights, temperatures, humidity ratings, sky colours and foliage colours. Introduced in the Halloween Update, biomes separate every generated world into different environments, paralleling the real world; examples of biomes include the forest, jungle, desert and tundra. Prior to the Halloween Update, every world had only a single theme, either grassy or snowy.

In the Anvil file format, biomes are stored directly in the world data. This differs from the previous Region file format format, where biomes were dynamically calculated from the seed.

The term biome is analogous to its scientific usage: on Earth, a biome is climatically and geographically defined by distinctive communities of plants, animals and soil organisms supported by similar climatic conditions. They are often referred to as ecosystems.

Biome types
As of 1.4.2 there are 12 main biome types and a number of technical biomes. Main biomes can be distinguished by the grass and leaf colors in the biome, along with the types of blocks present (e.g. types of trees or other plants like cacti, sand coverage in deserts). Biomes are pseudo-randomly generated using the map seed. Technical biomes provide smoother transitions between main biome types, or introduce extra custom features within a main biome, such as rivers, beaches, hills and border areas.

Technical biomes
Technical biomes are found alongside or within their larger counterparts. They are not considered true biomes but they are referred to as biomes in the code and the debug menu. However, these technical biomes serve an important role in the Minecraft world in creating more realistic terrain.

There are seven known technical biomes.

Biome numbers
Each type of biome, including technical biomes, has its own biome number, shown in the following table. These biome numbers are used when creating a customized superflat world.

Anvil file format
The Anvil file format allows for biomes to be stored in the world data. In contrast, the Region file format relies on the seed to dynamically calculate biome placement. This would cause biome placement in older worlds to change when the biome generation code was changed. With the current Anvil format, the biome data is stored along with the rest of the world data, meaning it will not change after the world is generated and can be edited by third-party map-editing tools. Furthermore, "edge" biomes allow for biomes to continue extend beyond the edge chunks of an old world. This allows for smooth transitions in world generation after the generation code changes in an update.

Effect on gameplay
It can be difficult to play and gather sufficient resources if the player starts in the middle of a biome with no trees, such as deserts, tundras, and especially oceans.

There have been several reports of players spawning on tiny islands in the middle of a vast ocean with no trees for several Minecraft days in any direction. It appears that these desert islands generate in the Ocean biome, where animals cannot spawn (on the water); sometimes, the island spawns with no trees, forcing players to delete the world and start again, swim great distances to a landmass, or search for nearby underwater openings into abandoned mineshafts to acquire wood. Of course, this is not a problem if the player uses Creative Mode.

In contrast, spawning near a Mushroom Island biome grants the player a very large sanctuary from monsters, where they can build and mine with little fear. Of course, they will need to travel to other biomes for wood and other supplies, but once they have a bowl, their food supply is assured.

Bugs

 * Sometimes, an "ocean" biome may generate with absolutely no connection to the real ocean.
 * Example: (It doesn't just occur with this seed; there's also one in the seed "C99", coordinates unknown. Just keep going north and you might find it.)
 * Seed "Cylays99", X=-507, Z=-120