How Does the Oud Tree Species Affect the Scent?

Having learned the compounds, we move to what changes their proportions. The first factor is the tree species; oud does not come from a single tree but from several species, each differing in the nature of the resin it forms. In this article — the first of the factors group — we show how the species leaves its mark on the scent, and why the species alone is not enough to explain it.

Why does the species matter?

Oud belongs to botanical genera, the most prominent of which are Aquilaria and Gyrinops, and under them many species. Each species carries a different genetic disposition in how the resin forms and in the proportions of its compounds. Just as the fruit of two trees of one family differ, the fingerprint of the resin differs between one species and another, and this is reflected in the general character of the scent.

Some species have a resin that leans toward a sweeter or softer character, and some toward a sharper, woodier, or earthier one. These leanings are general, not strict rules, but they explain part of why the "personality" of oud differs between origins in which certain species predominate.

This goes back to the fact that each species has a genetic makeup that determines the chemical pathways it takes when the resin forms. The species does not "make" a ready-made scent, but sets up a disposition to produce certain proportions of sesquiterpenes, chromones, and others. From this disposition emerges the "aromatic family" the species leans toward, before the conditions of growth and processing modify it.

The main species and their general leanings

We mention here general leanings circulated among oud lovers, with the reminder that they are approximate impressions, not conclusive rules, and overlap greatly with region and age:

• Aquilaria malaccensis: often described as having a deep, balanced woody character, and among the most famous and widespread species.
• Aquilaria crassna: often described with warm, sweet touches favored by some regions of Southeast Asia.
• Aquilaria sinensis: mentioned as sometimes leaning toward a sharp or distinctive character in some pieces.
• Gyrinops species: common in the regions of eastern Indonesia and Papua, and described as having a wide variety of character from one piece to another.

Notice that these descriptions deliberately use "often described as" and "mentioned"; because the aromatic description is partly subjective, and because two pieces of the same species may differ according to their habitat and age. So consider them approximate maps to start from, not guarantee cards for the scent.

What makes matters more complex is that identifying the species itself is not always easy; the commercial names in the market often mix species or attribute a piece to a species famous for its quality. So relying on the species name alone is exposed to inaccuracy twice: once because the species is a tendency not a certainty, and once because the declared name may not match the true species. The solution in both cases is one: prioritize the scent and the documented source over the bare name.

The species is a tendency, not an inevitability

It is important not to exaggerate attributing the scent to the species alone. The species gives a general tendency, but the final scent is shaped by many other factors we will detail in this group:

• Region and climate: the same species may differ in scent according to its home.
• Resin age: maturity changes the character regardless of species.
• Drying and processing: they affect what reaches you of the scent.

And so you may find two pieces of the same species with different scents, and two pieces of two different species sharing close notes. The species is a starting point for understanding the scent, not a final verdict on it.

What does this mean for you?

When you hear that an oud is of a certain species, consider that an indicator of a possible "tendency" in the scent, not a conclusive promise. And most importantly, do not buy by the species name alone, but by the scent you test yourself through a sample. The species name is useful for understanding the background, but your nose is what judges whether this piece pleases you.

For those who want to go deeper into the tree species themselves and their classification, we have a separate guide about them. Here we continue the journey of the factors, and in the following article we move to the effect of region and climate on the scent.