Leaves

Leaves are a type of block. They are abundant in normally generated maps, appearing on every tree. Leaves have multiple textures, each varying slightly in color, however only one texture is on all six sides of the leaf at one time.

Leaves are available for use in Creative mode. They are often used in making plants, foliage, and tree houses. Leaf blocks are very weak, are readily destroyed by hitting them with any tool, are extremely vulnerable to explosions and are highly flammable. As of Beta 1.2, leaves in snowy areas have a different texture. It is possible, but extremely unlikely for a leaf block to stay on fire after catching on fire.

In Survival mode, Indev, Infdev, Alpha, and Beta, leaves cannot be obtained. Destroying leaves occasionally yields saplings which can be planted by the player in order to grow new trees.

Leaves can be destroyed faster by using a sword, though swords lose double normal durability when used on leaves. As no other tool yields any increase in removal speed, leaves are best removed with bare hands, or a block or object unaffected by durability, so as not to damage your tools unnecessarily.

There is also a new texture found after 1.2, It looks like leaf but appears to have flowers.

Alpha
In Alpha, leaves would decay using an algorithm that checks whether it has a solid or leaf block underneath it or is adjacent to a solid block. If it doesn't, it must be connected to a leaf block that is also supported as long as it is no further than five blocks away from said support.

Beta
In Beta, leaves decay according to a simple formula: leaf blocks decay unless they are within 4 blocks of a log, and connected to the log by other leaf blocks.

Trivia

 * In "Fancy" graphics mode, leaf textures are partially transparent, but in "Fast" graphics they are opaque.
 * Leaves were used as windows before Glass was implemented.
 * In Beta, while hitting leaves, clouds and Snow cannot be seen behind the block you are hitting.
 * Allowing leaves to decay off trees instead of destroying them yourself yields more chance of Saplings coming off the leaves.
 * Occasionally, leaves will grow through other blocks, acting as though they are still connected to the tree. They may also completely replace blocks they try to grow into.
 * Leaves do not prevent a sapling from growing. As long as the five blocks above a sapling are either leaves or air, it will grow provided it has enough light. Similarly, leaves will not suffocate the player if they just grew from a sapling, nor will they prevent chests from opening.

Blätter