What is agarwood?

The international English name for “trầm hương” is agarwood. It is the part of the Aquilaria tree (also known as “cây dó bầu”) that becomes infused with aromatic resin.

The natural formation of agarwood in the Aquilaria tree is a process in which the wood fibers transform due to pathological effects such as cracks or injuries, combined with the invasion of fungi and bacteria. This transformation occurs naturally over many years.

When a part of the tree becomes infected, it secretes resin around the affected area to heal the wound. This is a defense mechanism, as the tree produces resistant substances (agarwood oil) to fight the infection — resulting in the formation of agarwood.

Agarwood has a distinct, pleasant fragrance, and its aroma intensity varies depending on the region where it forms. When burned, agarwood releases a rich, spreading scent into the air.

The quality of agarwood depends on several factors: the species of Aquilaria tree, the location of resin formation, the soil composition and climate of the growing area, as well as the techniques and duration of the formation process.

Distribution of Agarwood
Agarwood trees are distributed across various Asian countries, typically growing in tropical rainforest regions such as Vietnam, Thailand, Cambodia, Laos, Malaysia, Indonesia, northern India, the Philippines, Borneo, and New Guinea, among others.

Due to the high value of agarwood and loose management, it has been heavily exploited, making it increasingly rare.

In recent years, Philippine agarwood has become well-known and widely harvested, which is why you may now see many products originating from this country on the market.

In Vietnam, agarwood trees are found widely across tropical evergreen rainforests in provinces such as Tuyên Quang, Thanh Hóa, Nghệ An, Hà Tĩnh, and especially from Quảng Bình, Quảng Trị, Thừa Thiên Huế, Quảng Nam, Đà Nẵng, Quảng Ngãi, Bình Định, Ninh Thuận, Bình Thuận, extending to the Central Highlands, An Giang, Kiên Giang, and Phú Quốc Island.

However, these forests have also been rapidly overexploited, and high-quality agarwood has become increasingly scarce, leading to a sharp rise in the price of sinking-grade agarwood (the densest, most resin-rich type).

Characteristics of the Agarwood Tree

The agarwood tree—also known by other names such as “cây dó bầu,” “cây trầm dó,” or “dó núi”—belongs to the Thymelaeaceae family. It is a hardy species, capable of thriving in hot climates and adapting to a variety of environmental conditions.

Its scientific name is Aquilaria, which includes 21 species. It is a woody plant, and a mature tree can reach over 40 meters in height with a trunk diameter of more than 60 centimeters.

Agarwood Timber

The wood of the agarwood tree, before resin formation, is ivory-white in color. When resin begins to develop, the wood gradually darkens as it absorbs the aromatic oil, changing in tone from yellowish to gray, then to brown, reddish-brown, dark brown, and finally black.

The core wood of agarwood has no visible growth rings, since the annual circular grain layers are absent. Therefore, it is difficult to determine the tree’s age based on its wood.

The patterns often seen on agarwood that many people mistake for wood grain are in fact resin (oil) veins formed by the accumulation of aromatic resin within the wood.

The grain of the Aquilaria tree is sparse, with wide spaces between the fibers. This structure allows the agarwood resin to penetrate and spread easily throughout the wood.

However, this also means that the wood itself is soft and porous, and without the resin formation, it remains an ordinary, low-value type of wood.

Bark of the Agarwood Tree

The bark of the agarwood tree is thin, with long vertical wrinkles running along the trunk. Its color ranges from gray to brown or moss green, interspersed with lighter grayish-white spots. The inner bark is white, containing dense, silky fibers that can be easily peeled and drawn into long strands running along the tree’s trunk, separating from the wood underneath.

Agarwood Leaves

The leaves of the Aquilaria (agarwood) tree are green, growing alternately and evenly spaced on both sides of the branch. They are thin and elongated, with a lanceolate shape—broad in the middle and tapering to a pointed tip. Mature leaves typically measure 5–12 cm in length and 3–5 cm in width.

The leaf stalk (petiole) is 2–4 cm long and covered with fine hairs.

The leaf veins are feather-shaped and prominent on the underside. The leaf margin contains firm veins that extend toward the tip. The upper surface of the leaf is smooth and glossy, while the underside is hairy.

Agarwood Flowers

The flowers of the Aquilaria tree grow in clusters, forming small bunches along the leaf axils of the branches.

The flower buds of the agarwood tree are green, and when they bloom, the calyx (outer floral part) remains predominantly green, forming most of the flower’s structure. The petals are small, thin, and ash-white, while the stamens are pale greenish-white with brown anthers.

The tree typically blooms in July each year.

Fruits and Seeds of Agarwood

The fruit is a capsule-shaped pod, inversely egg-shaped (obovate), measuring 3–5 cm in length and 2–3 cm in width, and is covered with fine hairs. The fruit usually ripens in October.

The seed shell of agarwood is hard but porous. When the fruit ripens and dries, it splits open into two halves, revealing and releasing one or two Aquilaria seeds into the wild.

Each agarwood seed is about 1 cm long, dark brown to black in color, pointed at both ends, and slightly thicker near the head.

Fragrance of Agarwood

Agarwood has a unique and distinctive scent. Depending on the growing region, soil conditions, and species of Aquilaria, the aroma may vary slightly.

In general, agarwood gives off a sweet, warm, rich fragrance that lingers long in the air, with white smoke rising straight upward when burned.

When burned, the scent of agarwood resembles that of cinnamon bark, but it is not sharp or spicy—instead, it is sweet, smooth, soothing, and deeply warm, leaving a subtle, refined aroma that resonates across the senses.

The higher the resin content, the richer and more luxurious the scent becomes.

Vietnamese sinking agarwood (Trầm Rục Chìm) is often regarded as the “king of fragrances”, highly prized among Taiwanese incense connoisseurs.

Conversely, agarwood with less resin tends to produce a harsher, smoky odor and less pleasant aroma when burned.

Color of Agarwood

The wood of the Aquilaria tree is initially ivory-white, but as resin accumulates over time, the affected areas gradually darken, deepening from yellowish to brown, reddish-brown, and eventually dark brown or black, depending on the amount of resin formed.

The color of agarwood can be seen in the image above, with quality increasing from left to right, and from top to bottom.
Agarwood’s color mainly includes shades of yellow, brown, gold-brown, reddish-brown, and blackish tones. The longer the formation period, the darker and richer the color becomes in the resin-producing areas.

Formation Process of Agarwood

Whether naturally or artificially, the Aquilaria tree must go through stress, wounds, and hardship before it can produce resin (agarwood).

Natural Formation of Agarwood

Naturally formed agarwood mainly comes from wild mountain Aquilaria trees (Dó núi).

These trees develop agarwood after suffering injuries caused by:

  • Broken branches due to weather or animals.

  • Drilling or boring by insects, birds, ants, or termites.

  • Lightning strikes that cause trunk fractures.

  • Fragments from bombs or bullets during wartime.

These open wounds allow fungi and bacteria from the environment to infect the tree, triggering a defense mechanism that produces resin (agarwood oil) to protect itself.

Depending on factors such as the wound’s location, the cause of infection, the tree species, and the duration of resin formation, the resulting type and quality of agarwood differ.

However, not every Aquilaria tree that is injured or infected produces agarwood—it depends on many biological and environmental factors, making natural formation extremely rare.

In the wild, only about 1 in 1,000 Aquilaria trees contains agarwood.
In the past, wild mountain forests had many Aquilaria trees, but today they are nearly gone due to overharvesting—as harvesters cut down every tree they find in hopes of discovering resin within the wood.

Cultivated and Artificially Induced Agarwood

Today, most agarwood in Vietnam is produced from cultivated Aquilaria trees through artificial resin induction.

There are three main methods used to stimulate agarwood formation:

  1. Physical methods: creating wounds by nailing, hammering, or drilling holes into the trunk.

  2. Chemical methods: injecting chemical substances into the tree’s vascular system to cause stress and resin formation.

  3. Biological methods: using fungi or bacteria to infect the tree naturally, prompting it to secrete resin.

Each method has its advantages and disadvantages, and tree death due to overstimulation is often unavoidable.

Time Required for Agarwood Formation

On average, resin begins to form within 1–2 years after induction at the wound site.
The speed and quality of formation depend on the tree’s condition, soil, and environment.
The longer the formation process, the better the quality, the higher the resin yield, and the greater the chance of producing “sinking-grade agarwood” (Trầm chìm nước loại 1)—the most valuable type.

Classification of Agarwood

In truth, agarwood is classified in many different ways, depending on human perception rather than any official standard.

However, MNVN Agarwood experts commonly distinguish three main types, with the highest grade being Kỳ Nam (also called Kynam).

This is the highest-grade form of natural agarwood, known for its exceptional quality. The wood contains a very high concentration of aromatic resin, making it soft, pliable, and smooth in texture.

When tasted, it reveals all four basic flavors — sour, spicy, bitter, and sweet. Holding a small piece in the mouth causes a tingling sensation on the tongue that can last up to 30 minutes. This rare type is called Kỳ Nam (Kynam).

The fragrance of Kỳ Nam is extremely strong and rich due to its dense resin content. The resin oil has a honey-like consistency, visibly coating the wood.

When burned, Kỳ Nam releases a distinct, exquisite aroma, with bluish-white smoke that rises straight and steadily into the air.

Kỳ Nam is traditionally divided into four ranks based on its color and properties:

  1. Bạch Kỳ (White Kynam)

  2. Thanh Kỳ (Blue-Green Kynam)

  3. Huỳnh Kỳ (Yellow Kynam)

  4. Hắc Kỳ (Black Kynam)

Second Grade: Trầm (Regular Agarwood)

This is the second-highest grade of agarwood, characterized by its dense, heavy wood. The high resin concentration often makes the wood sink in water—hence the term “sinking agarwood”.

When tasted, it has a bitter flavor, and when burned, it emits a sweet, pleasant aroma with white smoke that swirls gently before dispersing into the air.

Sinking agarwood is classified into six grades, each with different color tones and values. Among them, the white waxy hue (sáp trắng) is considered the most valuable, believed to bring good fortune and positive energy to its owner.

Ancient texts divide agarwood into five traditional categories:

  1. Hoàng Lạp Trầm (Golden Wax Agarwood)

  2. Hoàng Trầm (Golden Agarwood)

  3. Giác Trầm (Horn Agarwood)

  4. Tiến Hương (Offering Incense)

  5. Kê Cốt Hương (Chicken-Bone Incense)

Among these, Hoàng Lạp Trầm is considered to have the finest quality.

Third Grade: Tốc (Low-Resin Agarwood)

This is the lowest grade of agarwood, containing less resin than Kỳ Nam or Trầm. Because of the low oil concentration, it is regarded as the least valuable type within the agarwood family.

Tốc is identified by thin black resin lines running through the wood like fine hair strands, with sparse and uneven resin distribution.

There are many subtypes of “Tốc” agarwood, each differing in resin distribution and scent. The most common varieties include Tốc Đỉa, Tốc Dây, Tốc Hương, Tốc Pi, and Tốc Banh. Among them, Tốc Hương is considered the most fragrant.

Types of Tốc Agarwood

  • Tốc Đỉa
    Belongs to the group with a moderate resin concentration within the wood fibers.
    The pieces are small, about the size of a finger or chopstick tip, and resemble leeches in shape — hence the name “Đỉa” (leech).

  • Tốc Dây
    Has alternating resin layers that follow the natural growth rings of the tree.
    The resin forms circular patterns between the wood fibers, producing round or root-like elongated shapes.

  • Tốc Hương
    Contains thin resin veins running along the wood grain.
    It stands out for its exceptionally pleasant and distinct aroma, making it the most fragrant type among all Tốc grades.

  • Tốc Pi
    Characterized by thin layers of resin coating the outer surface of the wood fibers, forming cone- or tube-shaped pieces.
    The resin content is relatively light compared to other types.

  • Tốc Banh
    Contains large resin patches spreading deep inside the tree trunk.
    The resin gradually expands and seeps through the surrounding wood fibers.
    The oil is sticky and aromatic, producing a rich, noticeable scent when burned.

  • …And there are many other names coined by local agarwood harvesters in different regions.

    6. Uses of agarwood

    Agarwood has long been recorded in traditional East Asian medicine (Đông y) as a remedy to treat illness and improve health, with many formulas documented in classical texts.

    Its fragrance is distinctive, pleasant, and relaxing, helping to relieve stress, so it is extracted into essential oil for perfumes and made into incense for burning.

    In feng shui, agarwood is considered to have a yang nature and strong energetic effects, so more and more people use it in various feng-shui items such as agarwood bracelets, miniature displays, and statues.

    7. Why is agarwood so valuable?

    In nature, it is extremely difficult for agarwood to form on an Aquilaria tree, and not every tree can produce it.

    Unsustainable, exhaustive harvesting has driven wild agarwood into scarcity.

    Because of its many uses in daily life and the dwindling supply of natural agarwood, prices have continued to rise.

    8. Products made from agarwood

    Agarwood is widely used for feng-shui and craft purposes; medicinal use is relatively limited because of its high value.

    Main product categories include:

    • Agarwood jewelry: bracelets, necklaces, 108-bead malas.

    • Burning/incense products: agarwood incense sticks, cones, powder, essential oil, and chips.

    • Agarwood crafts: landscape pieces, statues, pendants, pens.

    There are also agarwood-infused liquors and many other products—medicines, teas, and tobacco—made in combination with agarwood.

    9. Finding a reputable agarwood store

    Agarwood has no universal grading standard, making it difficult to accurately determine its value. Pricing largely depends on the buyer’s perception and the seller’s reputation.

    Distinguishing genuine agarwood from counterfeits is also challenging, and the lack of transparency in some stores has made customers even more cautious.

    With the trusted reputation of MNVN Agarwood, we are confident in our ability to satisfy you with genuine, high-quality products.