Tree

Trees are the structures created both by the automatic generation of the map, and by players. They are built of trunk blocks and leaves. When generated by the map, they are frequently found in groups, in the style of a forest. Tree generation was added in version 0.0.14a.

Trees come in 3 different heights and do not all grow exactly the same.

They can be generated in a third way as well. If a shrub is placed in sunlight on a grass block with enough space, a tree will likely grow within several seconds.

This feature was added to Creative Mode in version 0.28_01. But since this was removed due to its griefer-friendly applications ("treespam"), it was added to server.properties of the server files.

Indev Trees
Currently, in Indev mode, trees wither and die if the leaves no-longer have a connection to a piece of soil below them and lost their connection to a tree trunk on the same height. The tree trunk can be cut from under the leaves to have a floating tree top. Low-lying trees will sometimes leave pillars of leaves that touch the ground and will not wither.

When planting trees in Indev mode they do not require grass to grow and must be planted at least 3 blocks away from other obstacles, they take around 1-2 minecraftian days in order to reach maturity. They can also be grown anywhere that sufficient light and space exist, including underground with torchlight.

After some research it was shown that when shrubs are planted near each trees other they usually grow bigger.

Infdev Trees
Infdev now has some changes with respect to the code used in indev. Leaves wither when not in contact with a trunk or the ground and will occasionally drop saplings.

A Sapling should be able to grow into a Tree as long as it has:
 * Sunlight -or- an adjacent Torch
 * 5 empty spaces directly above the sapling block itself

Some factors that were tested and still allowed saplings to grow into trees:
 * Sapling being surrounded by blocks or torches
 * Sapling having only one adjacent torch in an otherwise enclosed, dark room
 * Sapling being planted next to another sapling
 * Sapling being planted next to a fully-grown tree (assuming that any leaves above are cleared)

Saplings will sometimes fail to grow for no reason, or take an exceptionally long time to do so. The above factors have been tested, but your mileage may vary due to the random aspects involved. It's possible that the above factors may have an impact on growth failure rates, but it's difficult to tell. At the very least, trees can grow with just light and 1x1x5 headroom.

Helpful hint: Looking straight up and mining/digging until you can no longer reach will clear just enough space to plant a sapling at your feet and give it enough space to grow.