In total, there are 17 types of trees in the game, all with individual textures, breaking difficulty, burn length, burn temperature, and growth speed. The leaf-blocks on the trees are non-solid, meaning players and mobs can pass right through them (no more climbing on top of trees). Hitting these leaves will sometimes produce sticks, and rarely a new sappling (most trees will yield a dozen sticks and 0-3 saplings). Chopping a tree block will make the whole tree above pop out, yielding logs but no sticks or saplings. The tree types grow in their appropriate biomes, and will yield different amounts of logs.
Apart from log producing trees, there are also fruit trees. These do not yield logs, however, they produce harvestable fruit in their leaves.
Note: Sequoia leaves do not produce saplings, but their forests regenerate saplings automatically. Kapok and acacia saplings are only available from creative mode. This is due to balancing, but also to force awareness of the deforestation of forests and jungles.