Minecraft wiki entry for Fire, associated text: In the following table, the higher the encouragement, the more quickly a block catches fire if the fire is available to spread there. The higher the flammability, the more quickly a block on fire burns away. These are relative values; actual flammability and burn time depends not only on these values, but on difficulty, rain, the age of the fire, and a certain amount of randomness due to block ticks, among other things.[more information needed] Fire spread is also reduced significantly if the flammable blocks are located in a rather humid biome. Humid biomes are swamp, mushroom fields and jungle (excluding sparse jungle).