Roll up your sleeve, stretch out your arm palm-up and imagine your arm is a tree. Now take a look at the veins on your forearm.... that's kinda how resin spreads.
You can have small 'pockets' of resin in different shapes, sizes and angles due to insect and inoculation holes at random spots, but
generally resin runs along like veins on your arm and matures in a circular pattern.
In reality, you've got veins within veins, which is why, to me, the resin development actually mimics the annual growth rings of a tree itself and the simile works well when thinking of different degrees of resin.
You've got the bark on the outside, then the inner bark (phloem), the cambium which acts sort of like a bridge between the inner bark and the sapwood. Then you've got the heartwood and the inner core. You'll see how this comes into play as we go along
To keep things simple, the three main veins, or strains of resination, that distillers identify in practice are:
1.
Seah: “Incense-grade”, super hard resin, also called “the crust”.
2.
Kyen: High resin content heartwood.
3.
Lue: The area of infection immediately surrounding the trigger of the infection. For example, the ant holes.
We can add a Nr. 4 to the list which we simply call ‘white wood’ or ‘bunk wood’. This is the uninfected area that basically contains no resin, no oud oil…. but it still gets distilled, believe it or not!