No
You place Saplings into dirt. Saplings can be found by breaking leaf blocks from trees - you can remove all the wood blocks and the leaves will decay naturally, dropping apples and saplings. You can place bones in your crafting slot to create Bone Meal, and use Bone Meal on the planted sapling to make it grow instantly.
If you have worldedit select the area you want trees in and do //forest
Wallabies will only eat the new, young shoots of eucalyptus saplings. They will not eat the tough, stringy leaves of mature trees.
Saplings attempting to grow amongst mature trees, may not get enough water through their roots, nor sunlight on their leaves. This is due to the mature trees taking up most of the ground water, and casting a shadow over the saplings below.
There are no apple trees in any Minecraft versions, but in the latest update of Minecraft for Xbox apples drop from tree leaves.
Saplings
the definition of saplings is that they are young trees about to grow into a tree called bonsai
you left click on them with any block or your fist and wait for it to break. -_-
with an update, they are the only way to get wool now. you can also collect leaves off trees with them
it can be shrubs,ferns, and tree saplings
The answer is in the question. Fire must be harmful to them. Pine trees, and other conifers have high levels of substances called turpines in their leaves. This serves two maior purposes, to make them taste foul (few animals graze on pine leaves) and to act as a kind of anti-freeze, so the leaves work all year round, even in subarctic conditions. However, turpines are highly flammable, so pine saplings will rarely survive a grassland fire. The saplings don't survive on the grassland and the trees don't encroach.
Apples are only found in dungeons.. You must be lucky to find one or use a mapper The 1.1 Update allows a 1/200 chance of apples dropping from leaves. If you have 1.1 = Apples can be found in dungeons and grown from trees (U break the leaves to get apples)