Lumberjacking

Info
Lumberjacking is a gathering skill that increases as you cut down different trees. The higher your level is, the more wood you can get from each tree, the less you will fail while woodcutting, and the risk of breaking a Lumberjacking Axe goes down.

Lumberjack Fiddle tells you the basics about lumberjacking and gives you some supplies to get started.

Possible Outcomes
There are 4 possible outcomes of a single woodcutting attempt:
 * 1) Success: You get up to 5 pieces of wood and lumberjacking experience depending on your lumberjacking level and what tree you managed to cut. Check formula and trees to see what you can expect from cutting different trees.
 * 2) Axe breaks: One of your axes breaks. You do not receive any experience or wood, but you can make another woodcutting attempt on the same tree. Following message appears: "Your axe has broken".
 * 3) You hurt yourself: You receive 25% of lumberjacking experience you would normally get from successful attempt. You get hit for a small fraction of your max health points and you can try again to cut the tree. Following message appears: "You hurt yourself trying to cut it".
 * 4) Failure: You chop down the tree receiving inconsiderable ammount of experience and you don't get any wood. One of the following messages appears:
 * 5) * "The chopped off pieces are of poor quality. You refuse to take them." - 1 xp
 * 6) * "None of it was suitable for taking." - 0.5 xp
 * 7) * "You mutilated it to the point of uselessness" - 0.3(3) or 0.5 xp

Formula
You can find a brief explanation of lumberjacking mechanics posted here by Necronia Developers. According to given information player with 50+ lumberjacking should have: This means player should expect to get an average of 2.02 pieces of wood from a successful woodcutting attempt.
 * 27% chance to get exactly 1 piece of wood,
 * 50% chance to get exactly 2 pieces of wood,
 * 18% chance to get exactly 3 pieces of wood,
 * 4% chance to get exactly 4 pieces of wood,
 * 1% chance to get exactly 5 pieces of wood.

As of 22nd July 2016 given formula seems to be wrong. Receiving 4 or 5 pieces of wood occurs a lot more frequently then it should in theory. I will add accurate values later this week