Sengon (Falcataria falcataria): Growth, Allometry and Carbon Potential

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

Sengon carbon sequestration explained: growth, rotation, wood density, allometry, ARR and agroforestry role, and harvest risks in Indonesia.

Sengon sequesters carbon fast in its first years because it is one of the quickest-growing timber trees in Indonesia, but its light wood and short harvest cycle limit how much carbon a project can credit. For carbon accounting, treat sengon as a short-rotation crop: estimate biomass with the Chave et al. 2014 model using a low wood density, then credit only the long-term average stock if trees are harvested.

Identity and range

Sengon is a nitrogen-fixing legume in the family Fabaceae. Its current accepted name is Falcataria falcataria; older literature uses Falcataria moluccana, Paraserianthes falcataria and Albizia falcataria, so search under all four when looking for growth or allometry data. Local names include sengon, sengon laut, jeungjing (Sundanese) and albasia.

The species is native to Maluku and Papua in eastern Indonesia, and to Papua New Guinea and the Solomon Islands. It has been planted across the archipelago for decades. The largest planted area is in Java, where smallholders grow it in hutan rakyat (community and private woodlots) in West Java, Central Java and East Java. It feeds a large plywood, light timber, pallet and packaging industry.

Growth habit and rotation

Sengon is a light-demanding pioneer with a wide, open crown. On good, well-drained soils it puts on height and diameter very quickly in the first five years. Reported growth rates vary widely with site, spacing and seed source, so we do not quote a single mean annual increment figure. Smallholders typically harvest at around 5 to 8 years, sometimes earlier when cash is needed. Longer rotations are less common because trees become prone to breakage and stem defects.

Because it fixes nitrogen and casts light shade, sengon is often planted with coffee, cacao, cassava or other crops, or as a nurse tree for slower species.

Wood density and biomass estimation

Sengon has low wood density. Reported basic density values fall roughly between 0.25 and 0.40 g/cm³. The value varies with site, age, growth rate and position in the stem, so state the range and the source you used. See our wood density entry for why this single parameter moves the result so much.

For above-ground biomass, the default is the Chave et al. 2014 pantropical model:

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

where ρ is wood density (g/cm³), D is diameter at breast height (cm) and H is total height (m). Species-specific equations for sengon have been published from plantations in Java, typically in the form of a power function of DBH, sometimes with height. If you use one, check that the source plantation’s age and diameter range covers yours. Do not extrapolate beyond the data range. Our guide to allometric equations covers how to choose and validate an equation.

Convert biomass to carbon with a carbon fraction (IPCC default 0.47), then to CO2 by multiplying by 44/12. Add below-ground biomass with a root-to-shoot ratio appropriate to the methodology.

Carbon role in ARR and agroforestry

Sengon fits two kinds of project design:

• Smallholder woodlots and agroforestry. Farmers already plant it, so it is easy to establish and survival is high. In grouped ARR projects, it can deliver early biomass while slower species establish.
• Nurse or mixed plantings. Planted with longer-lived natives such as meranti or fruit trees, sengon provides shade and nitrogen, then is thinned or harvested.

What it does not provide is long-term standing stock. Under VM0047, harvested systems can only be credited up to the long-term average carbon stock of the planting cycle. A rotation that peaks at a high stock and drops to near zero at harvest averages out to a much lower creditable number. Check the current VM0047 version for the exact rule before building a model.

Co-benefits and livelihoods

Sengon is valuable to smallholders because it turns into cash quickly, with an established buyer network of sawmills and plywood factories in Java. Its nitrogen fixation can improve soil for intercrops. Its leaves are used as fodder in some areas.

Risks and cautions

• Harvest and permanence. Short rotations mean frequent stock drops. Model the cycle explicitly and assume farmers will harvest when prices are good.
• Gall rust. Gall rust (karat tumor, caused by Uromycladium fungi) has caused heavy losses in Java. Stem borers also attack plantations.
• Wind damage. The light, brittle wood breaks in storms.
• Monoculture. Large single-species blocks concentrate disease and price risk. Mixing species reduces both.
• Invasiveness. Sengon has naturalised outside its native range in some Pacific islands. Within Indonesia it is native in the east and long established elsewhere, but avoid planting it next to intact natural habitat.

Our species selection guide compares sengon with other fast-growing options.

Worked example

Take a single sengon tree at harvest age with a DBH of 25 cm, a height of 18 m and a wood density of 0.33 g/cm³:

1. ρ × D² × H = 0.33 × 625 × 18 = 3,712.5
2. AGB = 0.0673 × 3,712.5^0.976 ≈ 205 kg
3. Carbon = 205 × 0.47 ≈ 96 kg C
4. CO2e = 96 × 44/12 ≈ 354 kg CO2e (above-ground only)

At 0.25 g/cm³ the same tree would hold roughly a quarter less, which shows why the density source matters. Run your own numbers in the tree CO2 calculator. For a whole-project forecast including rotations and harvest, see ex-ante carbon estimation or ask our carbon modelling team.