All you need to know about how rubber tree resin extraction works.

This was a question posed in a thread that is now closed. How often can you tap a resin hole using a timer (RP2 stuff) without breaking the hole.

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The meta data of the block is as follows:
1 = Not a resin block, just a normal rubberwood
2-5 = resin in hole (The different numbers are for the different faces, East, West, North, South)
8-11 = no resin in hole (The different numbers are for the different faces, East, West, North, South)

If there is resin in the hole, you can use the tree tap on it and gain between 1 and 3 resin. The number 6 is now added to the meta data of the block. (turning it into one of the empty faces for E,W,N,S respectively)
The block is scheduled to update in 100 ticks (5 secs).

If there is no resin in the hole, the block is updated after 100 ticks (5 seconds).
Here, there is a 1 in 200 (0.5%) chance that the blocks meta data will be set to metadata % 6. Effectively adding resin in the hole again. Thus, statistically it should take ~1,000 seconds (16 minutes and 40 seconds) for a resin hole to refill.
If the resin hole isn't filled, the block is scheduled for another update. Until the hole gets filled. (All based on chance)

IF you use a tree tap on an empty hole there is a 1 in 5 (20%) chance that the hole will be destroyed. Leaving you with just a rubbertree block.
However, there is an additional 1 in 5 (20%) chance that you extract 1 resin out of an empty hole. Destroyed after the fact or not, doesn't matter.
So before you cut down a rubber tree that has empty holes in it. It is a good idea to tap all empty holes until the disappear (unless you are in love with that particular tree tap)
Doing so will give you one extra resin per 5 holes you tap on average.

Now you know all you need to know about resin extraction.

EDIT: Updated a miss i made, meta 8-11 is no resin in hole. Had it wrong at 7-11.

Quote from mahkra

With my totally non-scientific method of observation I also noted that tapping empty holes kills your taps pretty quick. (twice as fast?) I didn't test it much just stoped doing it. Have not tried it in 1.337b

Good thing then that it was totally non-scientific or otherwise i would have your licence revoked.

setMaxDamage(16);
...
itemstack.damageItem(1, entityplayer);

Those two are the ONLY codes that deals with tree tap damage. You get 16 uses per tree tap, empty hole or not.

When using a (RP2) deployer the "entityplayer" is "world" or "null" (IIRC, cannot remember which of the two it was though) but they should still work. I shall test this later and return with my findings.
When a sap hole emits resin it doesn't care about blocks in front of it. the resin will fall into (and out of if no block is surrounding) the deployer. If you can't catch the resin with something (flowing water) then use an obsidian pipe. (BC's obsidian pipes suck items THROUGH blocks)