Savanna
Roofed Forest (Dark Forest). The roofed forest biome was added as of 1.7.2. It features dark oak trees and huge mushrooms. The roofed forest biome is a very dangerous biome to spawn in as there are many dark places in the forest where hostile mobs are likely to spawn. Forest. Subtype: Birch Forest This biome only includes Birch Trees, with some Oak Trees possible. It also looks much like a forest biome although none of the birch trees can be large like their oak variants. But if its a hilly version of this biome, the birch trees can be extra tall. The Savanna Biome. The Savanna biome is characterized by an extensive cover of grasses with scattered trees. It is a transitional biome between those dominated by forests and those dominated by grasses. The Savanna biome is associated with climates having seasonal precipitation accompanied with a seasonal drought. Scattered, individual trees or small groves of trees are common. The umbrella shaped Acacia tree is a notable species of the Savanna biome. The acacia tree uses its long tap roots draw water from deep below the surface during the dry season of the savanna. Acacia trees are found in the Lush Desert and Outback biomes. In vanilla Minecraft 1.7.2, Mojang added their own acacia trees. : Acacia wood. : Acacia planks. : slab, stairs. 1  Acacia Leaves. 2  Acacia Wood. 3  Acacia Sapling.  A relatively flat and dry biome with a dry grass color and scattered acacia trees. Villages can generate in this biome, and it is one of only two biomes (the other being plains) where horses spawn naturally. Rain never falls in this biome, similar to the desert. Biome types. There are 61 distinct biomes. 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. Biomes are separated into 5 categories Biomes are regions or the terrains in a Minecraft world with varying geographical features, flora, heights, temperatures, sky colours and foliage colours. Forest. Subtype: Birch Forest This biome only includes Birch Trees, with some Oak Trees possible. It also looks much like a forest biome although none of the birch trees can be large like their oak variants. But if its a hilly version of this biome, the birch trees can be extra tall. Trees are naturally generated structures that can be found naturally or grown from saplings. They can be found in grassland, swamp, jungle, taiga, plains, and savanna biomes. One of the styles of a pine tree. There are 6 forms of trees to date: oak, birch, pine, jungle, dark oak, and acacia. Oak and birch trees come in a variety of sizes, and jungle and pine trees do even more so. Thick jungle trees are often naturally found, being made by 4 saplings in a square shape. Oaks can grow tall, but not as tall as jungle trees They are found in most biomes, and are abundant in forest-related biomes. There are six base species of trees – oak trees, birch trees, spruce trees, jungle trees, acacia trees, and dark oak trees. All the trees can grow in many shapes and sizes. Acacia trees are only found in the savanna biome (their wood is also found in bonus chests). Acacia trees feature unique diagonal trunks, and may occasionally have multiple canopies. The way the tree forms is unique. Tropical Savannah: Plants Grasses are the dominant plant life in the savanna. A wide variety of grasses grow in savannas, but different varieties are found in different savannas. Some grasses grow 6 to 9 feet tall. Trees growing alone or in small clusters are also part of the savanna biome. In fact, without the trees, the savanna biome would be considered a prairie. The variety of trees in a particular savanna is dependent upon the geographic location of the savanna. The acacia and baobab trees are common in African savannas. 
http://minecraft.wikia.com/wiki/Biomes http://www.earthonlinemedia.com/ebooks/tpe_3e/biomes/biomes_savanna_page_1.html http://biomesoplenty.wikia.com/wiki/Acacia_Tree http://minecraft.gamepedia.com/Biome http://minecraft.wikia.com/wiki/Biomes http://minecraft.wikia.com/wiki/Tree http://minecraft.gamepedia.com/Tree http://www.cotf.edu/ETE/modules/msese/earthsysflr/savannahP.html
what biome does an acacia come from