Log

Wood, or log (from the name ID), is a naturally occurring block found in trees, primarily used to create wood planks. It comes in six species: oak, birch, spruce, jungle, dark oak, and acacia.

Obtaining
Wood can be broken by hand, but using an axe will speed up the process.

Natural generation
Oak wood blocks generate as part of houses in plains villages, acacia wood blocks in case of a savana village and spruce wood blocks in case of a taiga village. Spruce wood blocks generate as supporting beams of witch huts.

Trees
Wood blocks of all six types generate naturally as part of trees. Trees can also be grown using saplings.

Further crafting
The following table presents the amount of wood needed to produce an even multiple of a given item with no waste left over, and the quantity produced:

Fuel
Wood logs can be used as a fuel in furnaces, smelting 1.5 items per block. However, it is far more efficient to craft one of the wood blocks into wood planks: each of the 4 planks will burn as long as the log would have, for a total of 6 items.

Data values
The wood blocks are defined by block IDs and block data. They also have block states which may replace block data in the future.

Note that when a wood block is placed, it changes its facing parameters, placing in the direction relative to the block it is placed on.

Block data
The block data for wood blocks consists of two facing bits (high-order) and two wood type bits (low-order).

Block 17 

Block 162 

Block state
Block 17 

Block 162 

Trivia

 * Dark oak and acacia logs share a new block ID separate from the old logs, called log2, because all the other data values on the previous log block were occupied by rotated variants (red sandstone slabs suffered a similar fate). There are still 2 remaining data values on the block that cannot be obtained. The next two trees, if more are added, will likely use these values.

Gallery
Holz Tronco Bois Nyersfa Legno 原木 나무 (블록) Hout Drewno pt-br:Madeira Древесина 木头