Why Do Some Trees Produce Oud and Not Others?

If you walked in a forest in which oud trees grow, you would find hundreds of them adjacent, and yet only a small few among them carries oud of value. So why does one tree produce abundant oud while its neighbor — of the same type — remains almost free of it? This article does not explain how oud forms; that is a mechanism we detailed in how oud forms. Rather it answers a different and more precise question: why does this formation not occur except in some trees and not others? And it is a question that leads us to a deeper understanding of the scarcity of oud, and it is a part of the complete guide to oud.

1. Why is not every tree oud?

The answer begins from a simple paradox: the oud trees of the two genera Aquilaria and Gyrinops are ordinary trees in their origin, their wood light in color, light in weight, almost devoid of scent. For the tree in its natural, healthy state does not make oud, and may live its whole life and die without a resin to mention forming in its trunk. Oud is not a fruit that the tree produces the moment it ripens, but an exceptional response to an exceptional circumstance.

And we clarified in what is oud that oud is a resinous aromatic material absorbed into the wood, not the wood itself; and we detailed in how oud forms the mechanism of that: how the injury transforms into a defensive response that secretes the resin gradually. So if the mechanism is known in general, the question remains: as long as all these trees are capable — in principle — of producing the resin, why does that not actually happen except in the fewest of them?

The concise answer, as the accumulated observations of the oud extractors and the researchers indicate, is that the resination is contingent on the gathering of conditions that are not available equally among the trees. For it does not suffice that the tree be of the correct type; rather a circumstance that provokes the resin must pass through it, and it must respond a strong response, and it must be granted of the time and the conditions what allows the accumulation of the resin. The disruption of any of these conditions means — mostly — a light wood with no aromatic value to mention.

And what is well-known and circulated among the people of this industry, and among what several studies indicate even if their estimates varied, is that only a small proportion of the wild oud trees develops an oud of considerable commercial value. And we deliberately avoid here mentioning a particular numerical proportion, because the estimates differ with the difference of the region, the type, and the method of calculation; but the general trend, in which there is hardly a difference, is that the well-resinated trees are the exception, not the rule. And this is the point around which this whole article revolves.

And to understand this exception we must look into the factors that make a tree cross this threshold while another stands short of it. And they are — as is believed — concurrent factors, not a single factor: the injury first, then the strength of the tree's response, then the surrounding environment, then the time. And we present them in the following axes one by one, with the constant reminder that these are matters deemed likely, not decisive laws, and that in the formation of oud there is an amount of variance difficult to trace back to a single cause.

2. The first condition: the injury or the wound

The first of the conditions and the clearest of them is that the tree does not begin to secrete the resin unless it is exposed to an injury or a wound or an infection that penetrates its internal tissue. For the resin — as the studies indicate — is a defensive response: the tree secretes it to isolate the site of the damage and resist what entered into it. And where there is no damage, there is no need for defense, and hence no resin. And this alone explains why many of the trees remain free of oud: simply because they were never injured.

And the injuries that may provoke this response are varied, as is known among the people of the specialty: a break in the trunk by the action of the winds or the fall of a neighboring tree, or a lightning strike, or the activity of insects that bore in the wood, or the entry of fungi and microbes through an open wound. And not all these influences are available to every tree; for a tree that arose in a protected spot that was not exposed to a break nor to an infection may pass its whole life without the first trigger of the resination.

And it is important that we realize that the mere presence of a wound does not guarantee the formation of abundant oud. For it appears — according to what is observed — that the type of the injury and its depth and its accompaniment with a microbial or fungal infection all affect the extent of the response. For a superficial wound that healed quickly may not leave a trace to mention, whereas a deeper injury accompanied by a continuous infection may provoke a wider resination. And we avoid here being decisive that a particular type of infection is the crucial "cause," for the matter is more complex than to be reduced to a single factor, and the research into it is still ongoing.

And this first condition is the entrance to understanding the idea of induced cultivation that appeared in the recent decades: for when people realized that the injury is a condition for the resination, they came to make deliberate wounds in the cultivated trees to provoke the resin instead of waiting for the rare natural injury. And it is a large transformation in the industry that we traced in from wild oud to the farms; but what concerns us here is to establish the principle: no injury, then no resin mostly, and from here the variance of the trees begins.

3. The difference of the response between the trees

Let us suppose two trees exposed to the same injury at the same time; do they produce the same amount of oud? What is observed in practice is that the answer is mostly: no. For the trees vary — as is believed — in the strength of their defensive response, exactly as the living creatures vary in their immunity. A tree may secrete abundant resin around the wound, and another contents itself with a weak response that hardly produces oud of significance, and the injury is one in the two cases.

And it is deemed likely that a set of individual characteristics enters into this variance: the age of the tree, and its general vitality and its health, and the amount of resources it stores that allow it to build the resin. For the young or weak tree may not possess of energy what suffices for a strong, long response, while the mature, healthy tree may be more capable of that. And these are likelihoods supported by practical observation, not steady laws that apply to every case.

And it is of honesty that we pause here a pause: it tempts some to trace this variance back to "genetic differences" between the trees and make them the crucial cause. And the truth is that the relationship between the genes and the resination is still a subject of research and has not been settled in a decisive manner, and the individual differences may be the outcome of a complex interaction between the heredity and the environment and the history of the injury together. So we content ourselves with saying that the trees vary in their response a real, noticeable variance, without our claiming a certain knowledge of all its causes.

And the practical conclusion of this axis is that the resination is not an inevitable result that follows the injury automatically by a fixed amount, but rather passes through a "filter" which is the response of the tree itself. And this filter narrows the circle of the producing trees further: for even among the injured trees, only the ones that respond strongly reach an abundant resination. And thus two conditions gather — the injury, then the strength of the response — to keep oud in the domain of the few.

4. The role of the environment and the conditions

The tree does not live in a vacuum, but in an environment that affects — as is believed — its ability to become resinated and the character of the resulting resin. For the climate and the heat and the humidity, and the type of the soil, and the nature of the surrounding forest, are all factors that are deemed likely to enter into the equation. A humid, warm environment may be more active in enhancing the activity of the fungi and the microbes that accompany the injury, and another environment may be less suitable. And honesty requires saying that these are complex relationships deemed likely, not a simple equation that can be controlled.

And added to the environmental factors is the nature of the injury itself in terms of the intensity and the continuity: for it appears that a light, passing injury differs in its effect from a deep, extended injury accompanied by an infection that settled for a long period. The gathering of a favorable environment with an appropriate injury with a tree capable of the response is — as is observed — what makes the formation of abundant oud likely; and the absence of any of these elements diminishes the probability. And this interlacing is exactly what makes the resination an unguaranteed matter.

And these environmental factors have an effect that does not stop at the presence of oud or its absence, but extends to its character. For it is observed that the oud of one region may incline toward sweetness and warmth, and the oud of another region toward depth and earthiness, and it is a diversity connected partially to the difference of the environments and the origins. And because we bring the oud from its sources in Indonesia, we clarify the transparency of the origin on the oud sources page, and you can touch this diversity in the Indonesian collection.

5. The temporal factor

Even if the injury and the strong response and the favorable environment gather, a final factor no less important remains: the time. For the resin does not accumulate all at once, but deposits slowly in the tissue of the wood over the course of long years after the injury. And hence a tree that was injured a few months ago differs a clear difference from a tree that remained affected by its injury for extended years; the first may carry only a slight trace, and the second may have developed a dense resination.

And this explains another aspect of the variance of the trees: for two trees identical in everything may differ in the amount of oud merely because one of them is "older in injury" than the other. The time here is not a mere waiting, but it is the period during which the resin works on accumulating and maturing. And for this reason the oud extractors used to estimate a special value for the aged trees whose period of being affected lengthened, because the time was in favor of their resination.

And because the time is a crucial factor, the question "how long does the formation of oud take?" we devoted to it a special axis in this guide in which we address the temporal range and its variance and the impossibility of fixing it in a uniform number. And it suffices us here to establish the principle: oud is the yield of time as it is the yield of injury, and the tree that was not granted enough time will not produce abundant oud however the other conditions are available to it.

6. Why this explains the scarcity of oud

If we gather what preceded, the secret of the scarcity of oud becomes clear to us from its biological roots, not from the angle of the market only. For oud passes through a chain of successive "filters": first the tree must be injured (and many of them are not injured), then it must respond a strong response (and not every tree does), then the environment must favor it, then it must be granted enough time. Every time we add a condition, the circle narrows, until at its end only a few of the trees carrying considerable oud remain.

And this conditional succession is the biological explanation of oud being among the rarest of the natural materials and the most expensive of them. For the scarcity is not manufactured, nor is it a mere result of market policies, but it is in its origin a biological scarcity: nature itself produces oud with scantness. And when this natural scantness meets a rising demand across the centuries, the high value by which oud is known arises. And we detailed this intersection between the scarcity and the demand in from wild oud to the farms.

And this natural scarcity had a regulatory effect too: for when the pressure intensified on the wild trees, scant in production to begin with, the trade of oud became subject to international restrictions aiming to protect its species from depletion, which we addressed in why is oud subject to the CITES convention. For the chain begins from a tree that may not become resinated, and ends at conventions that govern the trade of a material whose natural existence has become threatened.

And here induced cultivation appears as a direct response to this biological scarcity: for instead of relying on the wild trees of which the fewest become resinated, people resorted to planting the trees and making the injury in them deliberately to raise the probability of the resination. But this solution does not cancel the other filters; for even the cultivated, induced tree remains subject to the variance of the response and the environment and the time, and the variance of quality remains standing between one piece and another. The scarcity lightens with cultivation, but it does not vanish, because its root is in the nature of the resination itself.

7. What does this mean for the buyer?

All this may seem a theoretical research far from the concerns of whoever wants to buy oud, and the truth is the exact opposite of that. For the variance of the trees in the resination is the very variance of the oud that you see in the market: as long as the trees differ in the amount of the resin and its density and its character, it is natural for the pieces to differ a great difference in the color, the weight, the scent, and the price. There is no single homogeneous "oud," but a wide range governed by these biological factors.

And from here comes the importance of the classification and the transparency of the origin. For when the serious seller mentions to you from where the oud came and which grade it is, he in reality translates for you the effect of these factors: the density of the resin, the nature of the resination, and the origin. And because oud did not historically know a unified global system of grading — as we detailed in the history of oud grading — the clarity of the seller in describing what he sells becomes more important than any shiny appellation. And we clarify how we examine oud and classify it on the quality-control page.

And the most important practical lesson is that you expect the variance and deal with it with awareness instead of it surprising you. For because a single piece is the product of a particular tree that passed through a history of injury, an environment, and a time particular to it, it may differ from its sister even if they carry the same name. And for this reason the truest judgment upon oud remains what your senses touch — the weight of the piece and the depth of its scent upon heating — not the marketing phrases. And the best thing to begin with is a small sample by which you test the scent and the grade yourself, which we make possible on the samples page.

For when you understand that oud is a material made by the concurrence of rare conditions in a particular tree, your view of it changes: you no longer search for "the cheapest oud," but for an oud honest in description that suits your taste and your need. And this awareness is the best that the buyer comes out with from understanding the reason for the scarcity of oud, since it makes him value the piece in his hands by the amount of real resin in it, not by the amount of name upon it.

Read also

For a wider deepening, begin from the complete guide to oud which gathers all the axes of the subject in one place, and from how oud forms inside the tree to understand the mechanism of formation upon which this article was built. And we are working on devoting independent articles to interconnected axes such as: "what is oud resin?", and "how long does the formation of oud take?", and where does oud grow? — and we add the links of the rest successively whenever they are completed.