Acacia nilotica (L.) Willd. ex Del. (Egyptian thorn, Red-heat, Barbar)

A. nilotica is a leguminous, nitrogen-fixing tree.  It is an extremely valuable source of fuel, gum, small timber, fodder, tanin (12-20%), and honey in tropical Africa and the Indian subcontinent.  It is very drought tolerant, withstands extreme temperatures, and grows fast under favorable soil irrigation.  Furthermore, it grows on a variety of (poor) soils, but prefers alluvial soils.  A. nilotica rarely grows over 10 meters tall and is incredibly thorny, which sometimes becomes a problem, and therefore should only be introduced in arid areas where firewood necessity is crucial.  Being resistant to termites and impervious to water, the wood is also used for railroad ties, tool handles, carts, and oars. It is also good for carving and boat building.

 

Acacia senegal (Gum acacia, Gum arabic)

This leguminous tree has been planted widely for its gum production. Its rainfall requirements are 300-1200 mm and it grows at altitudes of 100-1700 m. It can survive temperatures of 48 ˚C but will generally not withstand frost.  A. Senegal is also used for restoring soil fertility by nutrient cycling after leaf fall, and providing fuel and fodder (the nitrogen-fixing ability of this species is questionable).  It has also been used for desertification control, re-establishment of a vegetative cover in degraded areas and sand dune stabilization.  Its wood is used locally for fuelwood and charcoal, though its biomass yield is not high enough to plant it exclusively for these purposes. It is susceptible to some insect attacks.

Acacia tortilis (Umbrella thorn, Israeli babool, Seyal)

A. tortillis is a leguminous nitrogen-fixing tree.  This species has been known for supplying fuel to much of arid and semiarid Africa and the Middle East.  In addition, it favors alkaline soils and grows well in shallow places. Maximum temperatures may reach 50˚C and rainfall up to 1,000 mm, or as low as 100mm.  Its calorific value is very high (4,400 kcal per kg), therefore making superior firewood and charcoal.  A. tortilis is also used for wood for fence posts, fodder (19% protein content), and for sand stabilization.  In fact, its only limitations are the abundance of thorns, the fact that insects often reduce seed production and that trees can be susceptible to attack by caterpillars and beetles.

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Albizia lebbeck (East Indian walnut, Kokko, Woman's tongue)

Leguminous and nitrogen-fixing tree as well, this is a very adaptable species that produces small timber and fuel, and is good for reforesting dry, alkaline soils.  It is one of the best known trees in India, and has spread through much of the southern hemisphere.  The wood is dense, coppices well, and carries a high calorific value at 5,200 kcal.  Also, it can grow in a varied rainfall range of 500 - 2,000mm, anywhere up to 1,600 meters in elevation.  A. lebbek thrives on many different soils, though it prefers moist conditions such as well-drained loam.  Due to its extreme tolerance of salt spray, it grows well near the seashore.  Furniture, beautification, fodder (20% protein), and erosion control make up its other main uses.  Be weary of browsing animals, shallow roots, and fungal diseases that attack the leaves and pods.
 

Cajanus cajan (Pigeon pea, Gandul)
 

Another leguminous, nitrogen-fixing tree species, C. cajan is very tolerant of extremities in temperature and drought and will grow in a wide range of soils.  However, this tree will not tolerate frost, high soil salinity or extended water logging.  Nonetheless, it is highly adaptive and easy to establish at elevations from sea level to 3000 meters.  The pigeon pea's most notable use is as food for both human and animal consumption.  Its drought tolerance makes it possible to harvest fodder from the tree well into the dry season. Though it is not as good a fuelwood as the others, its rapid growth does make it an excellent supplement fuelwood.  In addition to this, it is beneficial as green manure and is an excellent choice for alley-cropping systems.

 

Cassia siamea (Bombay blackwood, Yellow cassia)

This species is cultivated for firewood in the tropics, in as little time as 3 years (7 years for a complete harvest).  It needs full sunlight for fastest growth and can resist termites fairly well.  Unable to withstand cold, it instead thrives in tropical heat, humid or dry,at a low altitude.  Rainfall varies from 500-1000mm.  However, at the lower levels, the roots need access to deep soil moisture to produce the fastest results.  Wood for cabinet making and re-vegetation for denuded hills serve as the primary other uses.  Again, browsers must be kept away, as well as scale insects.  This species does not fix nitrogen.
 

Dalbergia sissoo (Sisu, Nelkar, Shewa, Yette)

This nitrogen-fixing tree is a moderately fast growing tree that adapts well to semiarid conditions and produces first-class firewood (roughly 5,000 kcal per kg).  Its temperature range is from just below freezing (making it frost hardy) to nearly 50˚C.  Rainfall can be anywhere from 500 - 2,000 mm. D. sissoo is most typically found on alluvial ground (along streams and river beds) and does not do well on stiff clay.  Primarily it is sought for furniture, shipbuilding, and fuel, but it is also used for other kinds of woodworking, fodder, ornamentals, and as a living barrier against soil movement. Insects have been noted to damage root systems and irrigated plantations may be severely destroyed by root fungus.  It is susceptible to browsers and the pinhole borer.

 

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Gliricidia sepium (Madre de cacao)
Though the fast-growing, nitrogen-fixing Gliricidia sepium prefers altitudes less than 500 meters, the species can grow at elevations of up to 1600 meters.  Annual rainfall requirements fall between 1500mm and 2300mm, while the temperature should range from 22°-30°C.  G. sepium, highly resistant to termites and decay, produces good fuelwood and timber suitable for furniture and tools. The leaves are a nutritious fodder for cattle, an excellent provider of shade, and a recommended means of pest control.

 

Gleditsia triacanthos inermis (honey locust)
 

This valuable legume tree is well suited for cooler climates, it is very tolerant to lower temperatures ranging from 15 to 24˚C.  The honey locust has deep tap roots and can survive on all but the driest soil, good growth occurs with 500mm-1500mm of rainfall. This species can be a good for the highlands of Thailand, Africa, Nepal and Latin America.  It germinates easily and grows best in soils with at pH of 6-8.  It can be successfully grown to elevations of 1,500 meters in temperate areas and has survived at 2,500 meters in subtropical highlands.  In addition to fuelwood, this species produces pods with a sweet tasting pulp that are edible by people. The pods can also be used to make high quality feed for animals.  This tree is leguminous but does not fix nitrogen.


Grevillea robusta (Encino Plateado)

G. robusta is a nitrogen-fixing, very versatile tree that has gained popularity in temperate and subtropical regions of the world.  It grows rapidly in climates that have a temperature range of 15 to 20˚C and a precipitation rate of 700 to 2,000 mm per year.  Traditionally it has been used to shade coffee trees, but it is currently used as fuelwood, lumber, posts and its leaves are used to make fertilizer.  This species spreads easily and does not have many natural enemies.  The branches like the roots are very hearty and grow in soils with few natural nutrients.

Leucaena leucocephala (Ipil-ipil, Leadtree)
 

Note: due to the invasiveness potential of this species the World Seed Program has restricted its shipments to Mexico and Central America.

 L. leucocephala is a leguminous nitrogen-fixing species that flourishes in tropical lowland areas with elevations below 1000m. Annual rainfall between 500mm and 2000mm is optimal, however, this species is able to withstand long periods of drought.  Preferred soil pH is between 5 and 8, making L. leucocephala unsuitable for waterlogged or highly acidic soils.  Fuelwood, livestock forage, poles, and pulpwood are among the species' most useful byproducts.  In addition, the tree's rapid growth makes it an excellent choice for live fences and erosion control.
 

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Moringa oleifera (Moringa tree)

Practically every part of this forest species has nutritional value.  The leaves are an outstanding source of vitamins, minerals and protein.  The seeds can be consumed as nuts and the roots can be used as condiments.  This plant can also be used to produce clear, sweet and odorless oil that is used in perfume and other cosmetic products.  The seeds can be used to purify water and its green leaves and branches are added to livestock feed.  This species grows in a variety of environments from tropical to subtropical and from dry to humid.  Hospitable climates include those with precipitation rates of up to 4800 mm annually, mean annual temperatures from 13 to 40˚C, and soils that are acidic or alkaline (pH 4.5 – 8).  However, it grows best in sandy, dry soil.  Flowers and fruit are produced year-round.  This tree does not fix nitrogen.

Prosopis juliflora (Mesquite)
 

P. juliflora is also from the Leguminosae family and fixes nitrogen.  It is best known for its tolerance to drought and marginal soils and is best suited for very warm, dry climates.  Its annual rainfall requirements of 150mm to 750mm are considerably lower than those of the Leucaena and Robinia species. It flourishes on sandy and rocky soils, and has the ability to withstand periods of frost. The fast-growing P. juliflora makes excellent fuelwood and charcoal. Additional useful byproducts include timber, forage, and honey.
 

Note: P. juliflora can become an invasive species and must be managed with much care. It is only recommended for very arid regions where deforestation is a serious problem and where there is no previous evidence of it becoming invasive.  Cattle should be kept away to reduce chances of dispersing the seeds to unwanted areas.

Robinia pseudoacacia (black locust)
 

R. pseudoacacia, also a leguminous tree species, is better suited for temperate climates and higher elevations where the ability to withstand frost and persistent cold is necessary. It grows best in well drained, calcareous soils, but can also thrive on poor soils with a pH as low as 4.8. Annual rainfall should be close to 1000mm, but the species is able to survive dry periods. Though not as fast-growing as the Leucaena, R. pseudoacacia has nitrogen-fixing capabilities that make it extremely useful for alley cropping and soil rehabilitation.  Due to its wood hardness and resistance to rot, it is widely used for furniture, posts, and other building purposes.  An added benefit of the black locust is its highly prized honey.

 

Sesbania sesban (Sesban, Suriminta)

S. sesban grows well in the subtropics and is significant in extending the nitrogen-fixing forage trees into cooler, higher elevation regions of the tropics.  It grows widely in subtropical regions of Africa, Asia, and Australia.  Rainfall requirements are 500-2000 mm and mean annual temperature requirements are 18-24˚C, though it can tolerate lower and higher extremes.  It can grow at altitudes of 100 to 2300 meters.  It is recommended for use in pasture as well as for agro-silvo-pastoril production and for soil improvement.  The tree produces a very soft wood that can be used as fuelwood but not as timber. 

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