General · EdgepediaOctober 21, 20267 min read

Pterocarpus macrocarpus

Pterocarpus macrocarpus Kurz is a deciduous timber tree of the legume family (Fabaceae) native to Indochina, best known under its trade name Burma padauk, whose reddish, termite-resistant heartwood ranks among the valuable rosewood-type hardwoods of Southeast Asia. The species was validly described by Wilhelm Sulpiz Kurz in 1874 in the Journal of the Asiatic Society of Bengal (volume 43, page 187)¹^•². It belongs to the subfamily Faboideae and the tribe Dalbergieae², within a genus that Kew's Plants of the World Online accepts as containing 37 species across the tropics and subtropics³.

Key fact	Detail
Scientific name	Pterocarpus macrocarpus Kurz, first published 1874 in J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 43: 187¹
Family and tribe	Fabaceae, subfamily Faboideae, tribe Dalbergieae²
Native range	Cambodia, Laos, Myanmar, Thailand, and Vietnam; introduced into Assam, Cuba, and Puerto Rico⁴
Wood density	0.78–0.86 g/cm³, medium-weight to heavy and hard, with interlocked grain⁵
Common names	Burma padauk, padauk, pradoo (Thai), thnong (Khmer), mai du (Lao)⁵^•¹
Chromosome number	2n = 22⁶

Description

It is deciduous, shedding its leaves during the dry season⁷. Young trees carry pale brown, slightly fissured bark, while mature trees have dark brown to gray, scaly bark; the fibrous inner bark is reddish brown and exudes drops of red sap when cut⁷.

The compound leaves are odd-pinnate, 15–25 cm long with 7–13 alternate elliptic leaflets 4–7.5 cm long and 2–3.5 cm wide⁷; a separate account gives pinnate leaves of 200–350 mm with 9–11 leaflets. The yellow, pea-like flowers, 1.4–1.7 cm wide with four or five wavy-margined petals, are borne in axillary panicles or racemes, and in the tropics flowering occurs from February to April⁷.

Distribution and habitat

Kew records the native range as Indochina, specifically Cambodia, Laos, Myanmar, Thailand, and Vietnam, with introductions into Assam, Cuba, and Puerto Rico⁴. An Indian floristic database additionally lists the species as native to India and Myanmar and recorded in Goa and Kerala⁸.

The tree grows in dry, open Dipterocarp forests that are deciduous or semi-deciduous, at altitudes up to 700 m and where annual rainfall is 1,000–2,000 mm⁷. In Vietnamese forest studies it occurs in semi-deciduous or deciduous forests, is light-demanding, and shows lower potential for natural regeneration than associated timber species⁹. In northern Thailand it was recorded as the dominant species in old-growth forest sites and the second most dominant in 10-, 30-, and 40-year-old teak plantation sites¹⁰.

Timber and uses

Wood anatomically it shows distinct or indistinct growth rings, brown to red to purple heartwood that darkens to reddish brown, sapwood distinct in color, and interlocked grain; the wood is of medium weight to heavy and hard, at 0.78–0.86 g/cm³⁵. Although not a true rosewood of the genus Dalbergia, the timber is sometimes traded as if it were rosewood, and it appears in the Chinese national standard for hongmu (rosewood) furniture woods¹¹.

Demand has shifted toward the species in recent years: a CITES information paper reports an increasing shift from Dalbergia cochinchinensis to Dalbergia oliveri and P. macrocarpus in the Southeast Asian rosewood trade¹². Beyond timber, the species is listed as used for medicine and fodder in regional consultations¹³, and its heartwood has a history of use in Chinese medicine¹⁴.

The tree also carries cultural weight.

Conservation and trade status

Sources disagree on the species' formal protection status, and the disagreement is documented here rather than resolved. The USDA-ARS GRIN database records the conservation status as CITES Appendix II, described as vulnerable to extinction². The CITESwoodID reference states the species is not protected under CITES(EU)⁵, and a CITES timber identification guide shows that only African populations of Pterocarpus are included in Appendix II, with P. macrocarpus instead carried in the EU's Annex D from 19 January 2022, covering live specimens and all parts and derivatives except seeds, pollen, and finished products packaged and ready for retail trade¹⁵.

Threat assessments likewise diverge. The 2024 Angiosperm Extinction Risk Predictions compiled at Kew predict the species is not threatened, with confident assessment¹, and ILDIS likewise lists it as not threatened¹. The IUCN Red List status reported through iNaturalist, however, is Endangered (EN)¹⁶. On the ground, populations have dwindled due to overexploitation for timber and conversion of forest to farmland⁷, and a Vietnamese report describes the species, listed in Vietnam's Red Book, as having been exploited excessively¹⁷.

Population genetics and research

An isozyme survey of 11 natural populations across different forest habitats in Thailand, using 18 loci coding for 11 enzymes, found a high level of genetic variation: the percentage of polymorphic loci per population ranged from 66.67 to 100 percent with a mean of 82.32 percent, and alleles per locus averaged 2.67. Observed heterozygosity (0.222) was lower than expected (0.246), with an F_IS of 0.099 suggesting some inbreeding, and among-population differentiation was high, with an F_ST of 0.12. Cluster analysis revealed an east-west pattern of population grouping consistent with correlations between allele frequencies and longitude, and a genetic-geographic distance correlation of 0.515 (P < 0.0001) points to isolation by distance as a partial cause¹⁸.

Genomic resources have expanded recently. The species (2n = 22) is one of five hongmu heartwood species for which chromosome-level genomes have been assembled using short-read, long-read nanopore, and Hi-C data⁶, and its chloroplast genome has been sequenced alongside four congeners, showing the typical four-part structure with 110 unique genes and abundant SSR loci¹⁹. Because P. macrocarpus and P. indicus are morphologically close and hard to separate by anatomy, a real-time PCR method targeting a partial calcium-dependent protein kinase (CPK) gene region was developed in 2023 for wood identification, with a reported detection limit near 1.8 × 10^-2 ng/µL²⁰. Macroscopic wood identification remains difficult within the genus: in one deep-learning study, P. angolensis, P. erinaceus, P. macrocarpus, and P. indicus were misjudged between each other because of large anatomical similarities²¹.

The species is also used in plantation forestry. In 15-year-old plantations in the Katha District of Myanmar, P. macrocarpus stands held 77.2 tons per hectare of tree biomass and a total carbon content of 130.8 tons per hectare including undergrowth, litter, and soil, with a mean annual carbon increment of about 2.5 tons per hectare; biomass allocation was 2.8 percent in leaves, 24.4 percent in branches, 61.3 percent in stems, and 11.5 percent in roots²². Provenance trials of five Thai seed sources in western Guangdong, China, have screened young trees for growth and wood traits to select material for local planting²³.

References

Topic: Encyclopedia › Life and health › Plants and algae › Seed plants › Other flowering plants › Rosids › Fabaceae: legumes and the pea family › Titles M to W

Initially written Oct 21, 2026 · Edited: Oct 25, 2026

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