How to Identify Agarwood Tree Species: A Grower's Step-by-Step Field Guide

Here is how to identify agarwood tree stock in one line: check the leaf, the bark, the flowers and fruit, then the source papers. When four clues agree, you are almost certainly looking at Aquilaria, the genus behind nearly all traded agarwood.

Scarcity starts in the forest. According to a 2013 study in Molecules (Liu 2013), agarwood forms naturally in only about 10% of Aquilaria trees, which is why plantations now induce resin on purpose.^[6]

We suggest the same order to every buyer. First the agarwood leaf, because it is there all year. Then the bark and its tough inner fibre. Then flowers and fruit, if the season allows. Finally, we check what the grower or nursery says about species and origin.

None of this tells you whether a tree holds oud. Resin forms only after a wound and an infection, so a perfectly identified tree can still be worth only its timber. Step 5 covers that second question.

Before You Start

You need very little: a hand lens, a phone camera and permission from the owner. Take photos of the whole tree, the trunk, both sides of a leaf and anything on the ground below.

Please do not peel bark or cut wood on a tree that is not yours. Every wound lets microbes in, and on a plantation we make such wounds on purpose. On someone else's tree, it is simply damage.

The agarwood leaf is the best first clue. It is simple, smooth-edged, leathery and glossy, and it sits alternately along the twig rather than in pairs.

Agarwood Tree Leaves: Shape, Size and Veins

On our own species, Aquilaria sinensis, the leaves run from obovate to elliptic. They are typically 5 to 11 cm long and 2 to 4 cm wide.^[1] The tip comes to a short point, and the upper side shines in sunlight.

Now turn the leaf over and hold it to the sky. You should see 15 to 20 pairs of fine side veins leaving the midrib almost in parallel.^[1] They are faint, so a hand lens helps. In our experience, this vein pattern is the single most useful leaf clue.

Agarwood tree leaves also tell you little about value. A tree with a full, glossy crown may hold no resin at all, while a tree with thin foliage may be reacting to a deep wound.

Leaves That Fool Beginners

Many tropical trees have a glossy, pointed, smooth-edged leaf. Therefore leaf shape alone is never enough, especially in a mixed hedge or garden.

If the side veins are few and widely spaced, or the leaves sit in opposite pairs, look again. In that case, move on to the bark and fruit before you decide.

Aquilaria bark is smooth and pale, grey to light brown, on young and middle-aged trunks. Its inner bark is the real giveaway: tough, stringy fibre that peels in long strips.

That fibre is a family trait. Aquilaria belongs to the Thymelaeaceae, a family known for strong bast fibre. So when a fallen twig refuses to snap cleanly and leaves long threads instead, it supports your identification.

Colour, however, is a weak clue on its own. Older trees in damp sites carry moss and lichen, and the same trunk can look quite different after a wet season. Use bark to confirm the leaf, not to replace it.

The wood under the bark is pale yellowish-white, light and almost scentless. On a healthy tree, it stays that way right through the trunk. That plain wood makes up most of any trunk, even one that has formed resin.

Agarwood leaves and fruits together give the strongest field identification. The flowers are small, fragrant and yellowish-green, in clusters at the tips of shoots or in the leaf axils.^[1] They are easy to miss outside the season.

The fruit lasts longer as a clue. In A. sinensis it is a woody, egg-shaped capsule about 2.5 to 3 cm long, covered in short grey hairs. When ripe, it splits into two flat valves. Usually one seed, sometimes two, hangs from a silky thread inside.^[1]

So check the ground under the crown. A split two-valved capsule there can confirm a tree long after the flowers have gone. Collect seed promptly if you need it, because Aquilaria seed loses viability quickly.

That short viability is also why most plantations, ours included, raise nursery seedlings instead of sowing seed straight into the field. Our agarwood seed guide explains germination in detail.

Species is where field identification gets honestly hard. Leaf shape, bark and habit overlap, so botanists separate species mainly by flowers and fruit.

A 2022 study in North Aceh, Indonesia, shows how hard. Researchers sorted 66 trees by leaf and bark into A. beccariana, A. malaccensis and A. microcarpa. Yet one DNA marker placed all of them in A. malaccensis.^[2] If trained researchers disagree with their own DNA results, a buyer with a phone camera should be careful.

For trade, therefore, species comes from the source and its documents. We name A. sinensis on every invoice and CITES permit. Chemical work on A. malaccensis and Gyrinops also shows that the wood from different genera is not identical, which is one more reason to know what you are buying.^[3] Our guide to Aquilaria species compares the main ones in more depth.

Plantations exist because natural resin is so unreliable. Growers wound trees on purpose, by drilling, by inserting an inoculant or by infusing the whole tree, so the defence response starts on a known schedule.^[4] Even so, resin builds slowly and unevenly around each wound.

Dieback deserves a warning. A branch dying back near a wound can mean a strong defence response. However, drought, root rot and poor soil look exactly the same, with no oud inside. We treat dieback as a reason to inspect, never as proof.

Most mistakes we see come from mixing up two questions: "is this Aquilaria?" and "does it hold oud?". Here are the ones that cost buyers money.

• Trusting one clue. A glossy leaf or pale bark proves nothing alone. Use at least three clues from the checklist above.
• Grading a tree by its outside. Healthy Aquilaria bark and leaves have little scent. Resin inside a living trunk does not perfume the air in any reliable way.
• Buying standing trees on promises. Nobody can guarantee the resin in an uncut trunk. Treat any promised yield or return with great caution.
• Ignoring paperwork. All Aquilaria species sit in CITES Appendix II, which covers wood, oil and live plants in international trade.^[5] Seedlings also need a phytosanitary certificate.
• Accepting vague species names. "Agarwood tree" is not a species. Ask the seller to name it, and to say where and how the tree was raised.

How We Use This on Our Plantation

On our 100+ mu plantation in Guan Zhu Town, identification is mostly record-keeping. Every tree is A. sinensis, and we know which ones we inoculated and when. We also buy from more than 100 contracted plantation farmers, under the same rules: documented species, documented inoculation, inspection at harvest.

The resin decision always happens on the grading table, not in the field. Founder Wang Jianyu grades harvested wood by look, aroma, resin content and the sink test, into our own D, C, B, A and AAA scale, with Kynam on allocation only. That scale is ours, not an ISO or CITES standard; our agarwood grades guide explains it.

The grade then sets the product. Solid sections become resinated agarwood logs from $88 per piece. Smaller pieces become D–AAA oud wood chips from $0.24/g with a 100 g MOQ. If you want to grow your own, our Aquilaria sinensis seedlings cost $15 per plant, MOQ 10, with a phytosanitary certificate.

When a Field Check Is Not Enough

A field check narrows the answer; it rarely proves it. For species-level certainty, botanists compare a pressed specimen with leaves, flowers and fruit against herbarium references, and research groups increasingly add DNA barcodes, such as the matK gene region.

Resin needs its own proof. A lab test such as GC-MS shows whether the dark wood contains agarwood compounds. Before you buy a plantation or a large lot of trees, we suggest asking a forestry office or botanist to confirm the species in writing.