Prior to previous updates, when destroyed, leaves would drop as "woven leaves", however, since the update before 1.8, 1.7, you will now actually pick up the leaf block itself, and must instead craft the woven leaves yourself.
Under normal circumstances, the leaves disappear when the entire tree is cut down, but a current bug prevents this.
- Tenative Data from the DEF, provided verbatim from a forum thread:
Structure: 4 high column of wood. Top level is surrounded by 8 blocks of leaves. Above that is a 3x3 square of leaves. Above that, in line with the trunk, is a single block of leaves. Total mass- Wood: 4 Leaves: 18
Growth: Any suitable space with a sapling placed on a square of dirt will give rise to a tree. Trees will not grow within 1 space of each other. It takes a minimum of 60 seconds for a tree to grow and it would appear that trees will only grow on "counts" of 60. Thus as 60 seconds, 120 seconds, ect. No tree in the study grew in more than 300 seconds or less than 60. The tree growth process destroys the dirt block it was placed on, with wood replacing it. Note that while grass requires sunlight, trees do not.
Saplings: Trees in the study produced between 1 and 4 saplings that fell from the trees in a random patern. Maximum drop distance is still uncertain but estimated at 7. If the random square for drop that is selected is not dirt or clay, the sapling will not fall. Saplings cannot manualy be placed in clay, and if they fall into it, they will not grow.
Leaf Death: Leaves will "die" and fall as collectable blocks if they are unsupported by nearby wood blocks. Each wood block, weather artificialy placed or part of a tree, generates a "life aura" with a radious of 7 squares within which leaves will not die. Unsupported leaves will die in an estimated 10 to 60 seconds and in virtualy every case one leaf block lingered significantly longer (perhaps a few minutes) than the rest before it died. In one test the researcher got non-typical results where more than 7 squares had to be cleared away, however, leaf death did eventually trigger.
Costs and Burn Times: Wood: 30sec | 100gold Plank: 20sec | 30gold Stick: 10sec | 20gold