Tree species · ARR

Agarwood / Gaharu (Aquilaria malaccensis): Growth, Allometry and Carbon Potential

Updated 2026-11-02 · 4 min read · By the akar.earth specialist team

Agarwood (gaharu) carbon sequestration in Indonesia: range, inoculation and harvest, light wood density, allometry, CITES, agroforestry role and risks.

Agarwood trees store a moderate amount of carbon in light wood while they grow, but they are usually felled once resin forms, so their carbon value depends on harvest timing and mixing them with permanent trees. In Indonesia, gaharu is high-value agroforestry that can fund restoration, but it is not a long-term carbon store on its own.

Identity and range

Aquilaria malaccensis is in the family Thymelaeaceae. In Indonesia the resinous wood is called gaharu, and the tree is known as karas or gaharu, among other names. Agarwood (also aloeswood or oud) is the dark, fragrant resin-impregnated wood formed after wounding or fungal infection. Other Indonesian agarwood producers include Aquilaria microcarpa, A. beccariana, A. filaria in eastern Indonesia, and Gyrinops versteegii in Nusa Tenggara.

A. malaccensis is native to South and Southeast Asia, including Sumatra and Kalimantan. Wild trees grow in lowland and hill rainforest. Plantations and smallholder gardens are found in Sumatra, Kalimantan, Java, Nusa Tenggara (for Gyrinops) and elsewhere, including Jambi, Riau and West Nusa Tenggara.

Growth habit and rotation

Aquilaria is a medium to large evergreen tree that can reach 20 m or more in forest. It tolerates shade when young and grows well under partial cover, which makes it suitable for agroforestry and enrichment planting.

Healthy trees do not contain agarwood. Resin forms in response to injury and infection. Plantation growers induce it by artificial inoculation, typically once trees reach a usable size after roughly 5 to 10 years. Resin then develops over months to years before trees are felled and the dark wood is carved out. Reported growth and resin yields vary widely.

Wood density and biomass estimation

Healthy Aquilaria wood is light and soft. Reported basic density is roughly 0.30 to 0.45 g/cm³, varying with site and age. Resin-impregnated wood is far denser but makes up a small share of the stem. Use the density of uninfected wood for biomass. See wood density.

Use the Chave et al. 2014 model:

AGB (kg) = 0.0673 × (ρ × D² × H)^0.976

with ρ in g/cm³, D (DBH) in cm and H in m. We are not aware of a widely used agarwood-specific equation. Inoculation holes and wounds do not change the allometry meaningfully, but dead or dying inoculated trees should be flagged in monitoring. See our allometric equations guide.

Convert to carbon with the IPCC default 0.47 and to CO2 with 44/12.

Carbon role in ARR and agroforestry

High-value agroforestry. Agarwood under shade of rubber, fruit trees or native forest can give farmers a large future payoff. See the agroforestry hub.
Enrichment planting. Planting Aquilaria in degraded forest adds a native species with economic value to ARR and restoration designs.
Harvest accounting. Because trees are felled for resin, VM0047 crediting for harvested systems is capped at the long-term average carbon stock. Plan staggered inoculation and harvest, and include long-lived companion trees.

Co-benefits and livelihoods

Agarwood is among the most valuable non-timber forest products in the world, used for incense, perfume (oud oil) and medicine. A small number of well-resinated trees can provide large household income. Cultivation also reduces pressure on wild trees.

Risks and cautions

Felling and permanence. Harvesting removes the tree. Model it in the permanence and reversal assessment.
CITES and legality. All Aquilaria and Gyrinops are in CITES Appendix II. Trade needs permits, and plantation origin must be documented. Check current national quota and registration rules.
Wild poaching. High prices drive illegal cutting of wild trees, including in protected areas.
Uncertain resin yields. Inoculation results vary, and farmers may fell many trees with little resin.
Pests. Leaf-eating caterpillars can defoliate young plantations.

Planning notes for project developers

Stagger inoculation. Inoculating and felling trees in batches across years keeps the farm’s standing stock steadier than a single harvest.
Record tree status. Tag each tree as healthy, inoculated or harvested in your monitoring data so plot estimates reflect removals.
Pair with permanent shade. Rubber, durian, petai or native timber trees carry the durable carbon while agarwood carries the income.
Document origin. Keep planting records, maps and farmer registration, because CITES permits for cultivated agarwood depend on proving plantation origin. The same plot data support carbon monitoring.

Worked example

An Aquilaria tree before inoculation with DBH 20 cm, height 12 m and density 0.38 g/cm³:

ρ × D² × H = 0.38 × 400 × 12 = 1,824
AGB = 0.0673 × 1,824^0.976 ≈ 103 kg
Carbon = 103 × 0.47 ≈ 48 kg C
CO2e = 48 × 44/12 ≈ 177 kg CO2e (above-ground only, before harvest)

Test other sizes in the tree CO2 calculator, and see species selection for ARR for permanent companions.

Frequently asked questions

Does agarwood store much carbon?

Moderately. Agarwood trees have light wood, so carbon per tree is lower than for dense species of the same size, and trees are usually felled to extract the resin, which limits long-term stock.

What wood density should I use for Aquilaria malaccensis?

Healthy, unresinated wood is light, roughly 0.30 to 0.45 g/cm³. Resin-infused heartwood is much denser but is a small, removed fraction.

Is agarwood protected?

Aquilaria species are listed in CITES Appendix II, so international trade needs permits and quotas. Wild Aquilaria malaccensis is also assessed as threatened on the IUCN Red List.

Can agarwood plantations earn carbon credits?

They can contribute to ARR or agroforestry projects, but because trees are usually felled after inoculation, crediting is limited to the long-term average carbon stock under VM0047.