When the wood becomes infected with a particular type of mold, the tree reacts by producing a dark, scented resin, which is often called “liquid gold.” “oud” is used to refer to both the resin-saturated wood (the agarwood) as well as the oil distilled from it. One reason oud is so expensive is its rarity; by some estimates, fewer than 2% of wild agar trees produce it.
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