Common Name: Algarrobillo

General Information

Prosopis affinis is a small to medium sized deciduous tree with a flat-topped canopy, growing 2 - 8 metres tall[]. The tree is much and irregularly branched with a short bole 50 - 60cm in diameter[].
The tree is harvested from the wild for its timber, and has been recommended for reforestation projects. It is in semi-cultivation as a fodder plant; for the production of durable fence posts in South America; and it is planted in Hawaii for the production of honey[].
The species' range is large but declining as a result of increasing agriculture and cattle ranching, as well as other activities. The plant is classified as 'Data Deficient' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

Range

S. America - Argentina, Paraguay, Uruguay, Brazil, Bolivia, Peru.

Habitat

An important campos-tree, forming light forests with a herbaceous understorey rich in grasses[]. An important tree in open forests covering a grass swath; found on stony soils, flat meadows, riverside forests, prefers humid/flooded places[].

Properties

Conservation Status	Data Deficient
Other Uses Rating
Habit	Deciduous Tree
Height	6.00 m
Pollinators	Bees, Insects
Cultivation Status	Cultivated, Wild

Cultivation Details

Prosopis affinis is a plant of low elevations in the tropics and subtropics, being found as far south as about 30°s in northeastern Argentina, where it can experience occasional light frost. It grows better where the mean annual rainfall is in the range 600 - 1,200mm[].
Prefers a sunny position[]. Established trees are drought tolerant[].
The growth rate of this species is not as slow as many people believe where the species is cultivated from Chaco
seed[]. Specimens were full-grown and produced mature fruits for the first time at the age of 7½ years when they were 3.5 metres tall with a trunk 75mm in diameter[].
The flowers are a valuable bee fodder[].
There are conflicting reports on whether or not this tree has a symbiotic relationship with certain soil bacteria, so it is unclear as to whether this tree fixes atmospheric nitrogen[].

Edible Uses

The seedpods of many Prosopis species contain a fleshy pulp that is edible, usually with a sweet flavour[]. We have no specific information for this species other than the seedpod is 7 - 17cm long, 9 - 16mm wide and 6 - 8mm thick, containing a thin layer of acidic pulp[, ].

Medicinal

None known

Agroforestry Uses:

This species is to be recommended for reforestation[].
A potential shade tree, protecting undergrowing vegetation from winter frosts and providing shade in the summer[].
The flowers are an excellent source of nectar and pollen for bees[].

Other Uses

The heartwood is greyish-red; it is demarcated from the thin band of white sapwood. The wood is compact, very hard, heavy, little elastic and very durable. It is highly valued when used for posts and is also used for furniture, construction work[, , , , ].
The wood is a valuable firewood and makes an excellent charcoal[, , ].

Propagation

Like many species within the family Fabaceae, once they have ripened and dried the seeds of this species may benefit from scarification before sowing in order to speed up and improve germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing[].