Albizia niopoides
(silk tree)

Preferred Common Name

• silk tree

Other Scientific Names

• Acacia guacamayo (Britton & Killip) Standl.
• Albizia caribaea (Urb.) Britton & Rose
• Albizia caribaea (Urb.) Britton & Rose
• Albizia colombiana Britton
• Albizia guacamayo (Britton & Killip) L. Cárdenas
• Albizia hassleri
• Albizia hassleri (Chodat) Burkart
• Albizia richardiana King & Prain
• Feuilleea niopoides (Benth.) Kuntze
• Pithecellobium caribaeum Urb.
• Pithecellobium hassleri Chodat
• Pithecellobium niopoides Benth.
• Senegalia guacamayo Britton & Killip
• Senegalia liebmannii Britton & Rose

International Common Names

• English: guanacaste; monkey's earring
• Spanish: gallinazo; gavilana; guanacaste blanco

Local Common Names

• Bolivia: jebió
• Brazil: angico branco; gurujuba
• Colombia: guacamayo
• Grenada: wild tamarindo
• Paraguay: yvirá-yú; yvyrá-ju
• Peru: llambo paspaco; paspaco bianco
• Venezuela: camburi chiquito; carabeli; caro; hueso de pescado

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Fabales
•                         Family: Fabaceae
•                             Subfamily: Mimosoideae
•                                 Genus: Albizia
•                                     Species: Albizia niopoides

The genus Albizia comprises about 150 species of small to large trees widely spread in the tropical and subtropical zones of Asia, Africa, Australia, and the Americas. The highest diversity of species is found in mainland Africa, Madagascar, and Central and South America (Nielsen 1981; Arce et al., 2008). This genus is placed within the subfamily Mimosoideae. The Mimosoideae comprises 82 genera and about 3,335 species of shrubs, trees and, rarely, herbs distributed mainly across tropical and warm temperate regions of the world (Stevens, 2019).

The following description is from Vozzo (2002):

A medium to tall tree, 10 m to 30 m in height and 35 cm to 100 cm in dbh. The tree has straight bole and glabrous young twigs, greenish or yellowish with scarce lenticels. The bark is light gray or yellowish with exfoliating, thick scales in a concentric pattern; the scales leave crateriform scars that seem excavated with a chisel. Leaves are alternate, bipinnate, paripinnate; with 5 to 10 pairs of opposite pinnae, each with 30 to 55 pairs of pinnules. The leaf pinnules are (5-) 7-9 (-11) by 1 (-2) mm, linear, apex obtuse or acute, and glabrous. The petiole has a short pubescence and is pulvinate. The pulvinus is adaxial, basal, concave, and longitudinally oblong. The rachis is adaxially channeled, bearing an extrafloral nectary toward the distal end. The petiolules bear basal and adaxial pulvinuli. Stipules are 6 to 7 mm long, setiform, and deciduous. The fragrant, white flowers are grouped in pedunculate heads and are pentamerous, synsepalous and synpetalous. The calyx is tubular, distally toothed, and 1 mm long. The corolla is funnelform, valvate, and 2 to 3 mm long. The numerous stamens are basally united forming a tube. The anthers are small. The pod is laterally compressed (6 to 14 by 1 to 2.5 cm), straight, glabrous, thin, chartaceous, and longitudinally dehiscent. The seeds are ovate or oblong, laterally compressed, and without aril; the testa is thick, glossy, creamy or light brown, monochrome, hard, and osseous, with pleurogram, linea fissura open at the hilar end, and fracture lines.

Soil drainage

• free
• seasonally waterlogged

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• light
• medium

Albizia niopoides spreads by seeds. Pods are dehiscent and when dry they burst open, releasing the seeds (Vozzo, 2002).

Albizia niopoides is a pioneer species that grows faster than many native species. Consequently, it displaces and outcompetes native plants, reducing native species diversity and negatively impacting natural successional processes. It is also a nitrogen-fixing species with the potential to change soil nutrient balance in invaded areas (Vozzo, 2002; Oviedo and Gonzalez-Oliva, 2015).

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Benefits from human association (i.e. it is a human commensal)
• Long lived
• Fast growing
• Has propagules that can remain viable for more than one year

• Ecosystem change/ habitat alteration
• Modification of nutrient regime
• Modification of successional patterns
• Reduced native biodiversity
• Threat to/ loss of native species

• Competition - monopolizing resources
• Rapid growth

• Highly likely to be transported internationally deliberately

Social Benefit

Albizia niopoides is often planted as an ornamental and shade tree and to be used as forage. Its wood is used for light constructions, floors, furniture and boxes and as firewood. In South American natives used the saponin-rich roots to heal contusions and angina, and the boiled bark is used to heal scorpion bites. This species has been planted in grasslands and areas undergoing early natural regeneration because its nitrogen-fixing capacity improves the soil conditions. The tree is grown in coffee plantations in order to provide shade and organic matter for enriching the soil. The flowers provide good forage for bees (Vozzo, 2002; USDA-ARS, 2019; Useful Tropical Plants, 2019).