Petai (Parkia speciosa): Growth, Allometry and Carbon Potential

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

Petai carbon sequestration in Indonesian agroforestry: native range, growth, wood density, allometry, nitrogen fixation, livelihoods and risks.

Petai stores a good amount of carbon because it grows into a tall, long-lived native tree whose pods are harvested without cutting it down. In Sumatra and Kalimantan, petai is a common upper-canopy tree in mixed gardens and jungle rubber, which makes it a natural fit for agroforestry carbon projects.

Identity and range

Petai (Parkia speciosa) is a legume in the family Fabaceae, subfamily Caesalpinioideae (formerly Mimosoideae). In Indonesia it is called petai or pete; in English, stink bean, bitter bean or twisted cluster bean. Related species include kedawung (Parkia timoriana), also found in Indonesia.

Petai is native to western Malesia, including Sumatra, Kalimantan and Java, as well as the Malay Peninsula and southern Thailand. It grows naturally in lowland forest and is widely planted in home gardens and agroforests across Sumatra, Java and Kalimantan, including West Sumatra, Jambi and Bengkulu.

Growth habit and rotation

Petai is a tall tree, often 15 to 30 m or more, with a spreading crown and fine bipinnate leaves. Its ball-shaped flower heads hang on long stalks and are pollinated mainly by bats. Long, flat pods contain the edible seeds.

Trees from seed usually start bearing after several years; grafted trees can bear earlier. Productive life runs for decades. Because pods are harvested by climbing or using poles, trees are rarely felled while productive. Reported growth rates vary widely with site and management.

Wood density and biomass estimation

Wood density data for Parkia speciosa are limited. Moderate values roughly in the 0.4 to 0.55 g/cm³ range are a reasonable starting point, but this is uncertain. Where possible, take wood cores locally or use a cited database entry at species or genus level, and state the range. Wood density varies with site and age.

Use the Chave et al. 2014 pantropical 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 petai-specific equation. Because petai trees are tall, measuring height properly (with a clinometer, laser or canopy height model) matters more than for short garden 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

• Upper canopy in agroforests. Petai forms the top layer in multi-strata gardens with durian, rubber, coffee and spices, raising stand carbon. See rubber agroforestry.
• Native species. Many standards and buyers prefer native species for biodiversity. Petai helps meet that preference while giving farmers food income.
• Permanence. Pod harvest leaves trees standing, supporting long-term stock under VM0047 and similar ARR methods.

Co-benefits and livelihoods

Petai seeds are popular in Indonesian, Malaysian and Thai cooking and fetch good prices in local markets. As a legume, petai is often reported to associate with nitrogen-fixing bacteria, which may benefit soil, though this varies within Parkia. Its flowers feed bats, which also pollinate durian, so petai supports pollination of neighbouring crops.

Risks and cautions

• Data gaps. Limited wood density and growth data make ex-ante estimates uncertain. Use conservative assumptions and update with plot data.
• Late fruiting from seed. Farmers may lose interest before seedling trees bear. Grafted material helps.
• Height and safety. Harvesting tall trees is dangerous, which can push farmers to cut tall trees or replace them with shorter crops.
• Price swings. Petai prices are seasonal and volatile.
• Monoculture. Petai is rarely grown as a monoculture, but if it is, pest and price risk rise.

Planning notes for project developers

• Core sampling. A few increment cores per site can replace an uncertain database density with local data.
• Graft where possible. Grafted petai bears earlier and is shorter, which helps farmer retention.
• Group farmers. Petai is usually scattered across many small gardens, so aggregate them; see smallholder ARR aggregation.

Worked example

A mature petai with DBH 30 cm, height 18 m and an assumed wood density of 0.50 g/cm³:

1. ρ × D² × H = 0.50 × 900 × 18 = 8,100
2. AGB = 0.0673 × 8,100^0.976 ≈ 439 kg
3. Carbon = 439 × 0.47 ≈ 206 kg C
4. CO2e = 206 × 44/12 ≈ 757 kg CO2e (above-ground only)

Because the density is uncertain, rerun the example at 0.40 and 0.55 g/cm³ in the tree CO2 calculator to see the range. For smallholder schemes, see smallholder ARR aggregation.