Trees

Usually made of wood, there are some trees in the mod that aren't. Usually they have a trunk made of some block, and have leaves, which usually drops saplings.

Appearance
Usually trees have wood and leaves, the glass tree doesn't really. It's made of glass, but the block are named glass logs and glass leaves. You don't use an axe to cut this tree down, and the leaves don't decay.

Bone trees are only made of bone logs, no leaves generate. There isn't even a sapling for you to grow a bone tree. It is just a skinny poll that only generates on bone blocks.

Glass
Glass trees only generate in the Glassland biome, and only on glass. The leaves do drop a glass sapling, which can only be placed and grown on glass. The leaves also have a chance in dropping glass shards.

The glass tree generation shape is similar to the spruce lollipop design.

Aside from being made of glass, it acts like a normal tree.

Bone
Bone trees only generate in the Bone biome, and only on bone blocks. There are no saplings for you to grow bone trees. There aren't even leaves for this tree. When the logs are broken, they give 0-3 bones.

History
later.