Nutmeg (Myristica fragrans): Growth, Allometry and Carbon Potential

Updated 2026-11-02 · 3 min read · By the akar.earth specialist team

Nutmeg carbon sequestration in Indonesia: Banda origin, long productive life, wood density, allometry, spice agroforestry role and key risks.

Nutmeg trees store carbon steadily for decades because farmers harvest only the fruit, leaving the tree standing. Traditional nutmeg gardens in Maluku grow under tall canarium and other shade trees, forming multi-strata agroforests with high carbon and biodiversity value.

Identity and range

Nutmeg (Myristica fragrans) is in the family Myristicaceae. In Indonesia it is called pala. One fruit yields two spices: the seed (nutmeg) and the red aril around it (mace, fuli). The fruit flesh is made into sweets and drinks.

Nutmeg is native to the Banda Islands in Maluku, once the world’s only source and the reason for violent colonial competition. Today it is grown in Maluku, North Maluku, North Sulawesi (notably the Sangihe and Siau islands), Aceh (South Aceh), West Java and Papua. In Fakfak, West Papua, the related Papuan nutmeg (Myristica argentea) is grown. Indonesia is among the largest producers.

Growth habit and rotation

Nutmeg is an evergreen tree, usually 10 to 20 m tall, with a dense crown. It prefers humid lowlands, deep well-drained soils and partial shade when young. In Banda, nutmeg is traditionally grown under tall kenari (Canarium indicum) trees.

Trees are usually dioecious: male and female flowers grow on separate trees, and sex is only known when a seedling first flowers, often after 5 to 8 years. Farmers then thin out excess male trees or graft them. Female trees can produce fruit for many decades. Harvest is by picking ripe fruit, so trees are not felled. Reported growth rates vary by site and management.

Wood density and biomass estimation

Wood density data for M. fragrans are limited. Values roughly in the 0.45 to 0.6 g/cm³ range are a reasonable starting point for Myristica, but this is uncertain. Measure locally or use a cited database value, and state the range. Wood density varies with site and age.

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 nutmeg-specific equation. Measure height, since nutmeg under shade can be taller and slimmer than open-grown trees. See the allometric equations guide.

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

Carbon role in ARR and agroforestry

• Spice agroforests. Traditional nutmeg gardens with kenari, clove, coconut and fruit trees hold high carbon stocks. Restoring or expanding them on eligible degraded land fits agroforestry projects.
• Permanence. Fruit harvest leaves trees standing for decades, supporting durable stock under VM0047.
• Native species. In Maluku, nutmeg and kenari are native, which strengthens biodiversity claims.

Co-benefits and livelihoods

Nutmeg and mace are high-value export spices. Nutmeg oil, fruit sweets and syrup add value locally. Spice gardens anchor cultural heritage in Banda and other islands and support birds and other wildlife that live in the canopy.

Risks and cautions

• Sex uncertainty. Seedlings may turn out male, delaying income. Grafted female material reduces this, but farmers still need some male trees.
• Disease and pests. Stem borers, fruit rots and dieback affect gardens, especially old ones.
• Aflatoxin and quality. Poor drying can cause aflatoxin contamination, which threatens export access and income.
• Price swings. Nutmeg prices are volatile.
• Shade removal. Removing kenari or other shade trees to boost yields lowers carbon and biodiversity.

Planning notes for project developers

• Keep the kenari. Shade trees carry much of the carbon; protect them in farmer agreements.
• Graft for females. Grafted female plants and a planned ratio of male trees reduce the waiting time for income.
• Island logistics. Many nutmeg areas are on small islands; budget for transport and remote monitoring.
• Customary land. In Maluku, many gardens sit on customary (adat) land with collective rules on harvest and planting. Agree carbon rights and benefit sharing with customary institutions before enrolling plots.

Worked example

A female nutmeg tree with DBH 25 cm, height 14 m and an assumed density of 0.50 g/cm³:

1. ρ × D² × H = 0.50 × 625 × 14 = 4,375
2. AGB = 0.0673 × 4,375^0.976 ≈ 241 kg
3. Carbon = 241 × 0.47 ≈ 113 kg C
4. CO2e = 113 × 44/12 ≈ 415 kg CO2e (above-ground only)

Try the range of density values in the tree CO2 calculator, and see the ARR hub for how tree-level numbers scale to a project.